Merge pull request #650 from fxamacker/fxamacker/update-stream-mode-with-v2.8

Sync feature/stream-mode branch with v2.8.0

.github/workflows/ci-go-cover.yml

@@ -14,7 +14,7 @@
 # 1. Change workflow name from "cover 100%" to "cover ≥92.5%". Script will automatically use 92.5%.  
 # 2. Update README.md to use the new path to badge.svg because the path includes the workflow name.
 
-name: cover ≥96%
+name: cover ≥97%
 
 # Remove default permissions.
 permissions: {}
@@ -25,6 +25,10 @@ on:
   push:
     branches: [main, master]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
 
   # Verify minimum coverage is reached using `go test -short -cover` on latest-ubuntu with default version of Go.
@@ -36,11 +40,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
     - name: Install Go
-      uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+      uses: actions/setup-go@0aaccfd150d50ccaeb58ebd88d36e91967a5f35b # v5.4.0
       with:
-        go-version: 1.21
+        go-version: 1.24
         check-latest: true
     - name: Install x448/float16
       run: go get github.com/x448/float16@v0.8.4

.github/workflows/ci.yml

@@ -11,11 +11,16 @@ on:
   pull_request:
   push:
     branches:
+      - 'main'
       - 'master'
-      - 'release*'
-      - 'feature/stream-mode'
-    tags:
-      - 'v*'  
+      - 'release**'   # Match both 'release-v2.3.4' and 'release/*'.
+      - 'feature/**'
+      - 'v**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   # Test on various OS with default Go version. 
   tests:
@@ -26,16 +31,16 @@ jobs:
     strategy:
       matrix:
         os: [macos-latest, ubuntu-latest, windows-latest]
-        go-version: [1.17, 1.18, 1.19, '1.20', 1.21, 1.22, 1.23]
+        go-version: ['1.20', 1.21, 1.22, 1.23, 1.24]
     steps:
     - name: Install Go
-      uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+      uses: actions/setup-go@0aaccfd150d50ccaeb58ebd88d36e91967a5f35b # v5.4.0
       with:
         go-version: ${{ matrix.go-version }}
         check-latest: true
         
     - name: Checkout code
-      uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       with:
         fetch-depth: 1
 

.github/workflows/codeql-analysis.yml

@@ -5,12 +5,15 @@ permissions: {}
 
 on:
   push:
-    branches: [ master ]
+    # Run on push for all branches.
   pull_request:
-    # The branches below must be a subset of the branches above
-    branches: [ master ]
+    # Run on pull request for all branches.
   schedule:
-    - cron: '30 5 * * 4'
+    - cron: '30 12 * * *' # Run daily at 12:30 UTC / 7:30 AM Central.
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
 
 jobs:
   analyze:
@@ -28,18 +31,20 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@4dd16135b69a43b6c8efb853346f8437d92d3c93 # v3.26.6
+      uses: github/codeql-action/init@1b549b9259bda1cb5ddde3b41741a82a2d15a841 # v3.28.13
       with:
         languages: ${{ matrix.language }}
 
+    # Don't need setup-go because default version of Go is updated regularly in ubuntu-latest.
+
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@4dd16135b69a43b6c8efb853346f8437d92d3c93 # v3.26.6
+      uses: github/codeql-action/autobuild@1b549b9259bda1cb5ddde3b41741a82a2d15a841 # v3.28.13
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@4dd16135b69a43b6c8efb853346f8437d92d3c93 # v3.26.6
+      uses: github/codeql-action/analyze@1b549b9259bda1cb5ddde3b41741a82a2d15a841 # v3.28.13

.github/workflows/govulncheck.yml

@@ -10,20 +10,15 @@ permissions: {}
 on:
   workflow_dispatch:
   pull_request:
-    paths:
-      - '**'
-      - '!**.md'
+    # Run govulncheck on PR for all branches and paths.
   push:
-    paths:
-      - '**'
-      - '!**.md'
-    branches:
-      - 'main'
-      - 'master'
-      - 'release*'
-      - 'feature/stream-mode'
-    tags:
-      - 'v*'
+    # Run govulncheck on push for all branches and paths.
+  schedule:
+    - cron: '45 12 * * *' # Daily at 12:45 UTC / 7:45 AM Central
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
 
 jobs:
   Check:
@@ -33,15 +28,18 @@ jobs:
       contents: read
     steps:
     - name: Checkout source
-      uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       with:
         fetch-depth: 1
-    - name: Set up Go
-      uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+
+    - name: Install Go and setup env
+      uses: actions/setup-go@0aaccfd150d50ccaeb58ebd88d36e91967a5f35b # v5.4.0
       with:
-        go-version: 1.21.x
+        go-version: 1.23
         check-latest: true
-    - name: Install latest from golang.org
-      run: go install golang.org/x/vuln/cmd/govulncheck@4ea4418106cea3bb2c9aa098527c924e9e1fbbb4 # v1.1.3
-    - name: Run govulncheck      
+ 
+    - name: Install latest govulncheck
+      run: go install golang.org/x/vuln/cmd/govulncheck@d1f380186385b4f64e00313f31743df8e4b89a77 # v1.1.4
+
+    - name: Run govulncheck
       run: govulncheck -show=traces ./...

.github/workflows/safer-golangci-lint.yml

@@ -17,13 +17,17 @@ on:
 
 env:
   GO_VERSION: '1.22'
-  GOLINTERS_VERSION: 1.56.2
+  GOLINTERS_VERSION: 1.59.1
   GOLINTERS_ARCH: linux-amd64
-  GOLINTERS_TGZ_DGST: e1c313fb5fc85a33890fdee5dbb1777d1f5829c84d655a47a55688f3aad5e501
+  GOLINTERS_TGZ_DGST: c30696f1292cff8778a495400745f0f9c0406a3f38d8bb12cef48d599f6c7791
   GOLINTERS_TIMEOUT: 15m
   OPENSSL_DGST_CMD: openssl dgst -sha256 -r
   CURL_CMD: curl --proto =https --tlsv1.2 --location --silent --show-error --fail
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   main:
     name: Lint
@@ -32,12 +36,12 @@ jobs:
       contents: read
     steps:
       - name: Checkout source
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           fetch-depth: 1
 
       - name: Setup Go
-        uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+        uses: actions/setup-go@0aaccfd150d50ccaeb58ebd88d36e91967a5f35b # v5.4.0
         with:
           go-version: ${{ env.GO_VERSION }}
           check-latest: true

README.md

@@ -1,6 +1,4 @@
-# CBOR Codec in Go
-
-<!-- [![](https://github.com/fxamacker/images/raw/master/cbor/v2.5.0/fxamacker_cbor_banner.png)](#cbor-library-in-go) -->
+<h1>CBOR Codec <a href="https://pkg.go.dev/github.com/fxamacker/cbor/v2"><img src="https://raw.githubusercontent.com/fxamacker/images/refs/heads/master/cbor/go-logo-blue.svg" alt="Go logo" style="height: 1em;" align="right"></a></h1>
 
 [fxamacker/cbor](https://github.com/fxamacker/cbor) is a library for encoding and decoding [CBOR](https://www.rfc-editor.org/info/std94) and [CBOR Sequences](https://www.rfc-editor.org/rfc/rfc8742.html).
 
@@ -8,23 +6,26 @@ CBOR is a [trusted alternative](https://www.rfc-editor.org/rfc/rfc8949.html#name
 
 `fxamacker/cbor` is used in projects by Arm Ltd., Cisco, EdgeX&nbsp;Foundry, Flow Foundation, Fraunhofer&#8209;AISEC, Kubernetes, Let's&nbsp;Encrypt (ISRG), Linux&nbsp;Foundation, Microsoft, Mozilla, Oasis&nbsp;Protocol, Tailscale, Teleport, [etc](https://github.com/fxamacker/cbor#who-uses-fxamackercbor).
 
-See [Quick&nbsp;Start](#quick-start) and [Releases](https://github.com/fxamacker/cbor/releases/).  🆕 `UnmarshalFirst` and `DiagnoseFirst` can decode CBOR Sequences.  `cbor.MarshalToBuffer()` and `UserBufferEncMode` accepts user-specified buffer.
+See [Quick&nbsp;Start](#quick-start) and [Releases](https://github.com/fxamacker/cbor/releases/).  🆕 `UnmarshalFirst` and `DiagnoseFirst` can decode CBOR Sequences.  `MarshalToBuffer` and `UserBufferEncMode` accepts user-specified buffer.
 
 ## fxamacker/cbor
 
 [![](https://github.com/fxamacker/cbor/workflows/ci/badge.svg)](https://github.com/fxamacker/cbor/actions?query=workflow%3Aci)
-[![](https://github.com/fxamacker/cbor/workflows/cover%20%E2%89%A596%25/badge.svg)](https://github.com/fxamacker/cbor/actions?query=workflow%3A%22cover+%E2%89%A596%25%22)
+[![](https://github.com/fxamacker/cbor/workflows/cover%20%E2%89%A597%25/badge.svg)](https://github.com/fxamacker/cbor/actions?query=workflow%3A%22cover+%E2%89%A597%25%22)
 [![CodeQL](https://github.com/fxamacker/cbor/actions/workflows/codeql-analysis.yml/badge.svg)](https://github.com/fxamacker/cbor/actions/workflows/codeql-analysis.yml)
 [![](https://img.shields.io/badge/fuzzing-passing-44c010)](#fuzzing-and-code-coverage)
 [![Go Report Card](https://goreportcard.com/badge/github.com/fxamacker/cbor)](https://goreportcard.com/report/github.com/fxamacker/cbor)
+[![](https://img.shields.io/ossf-scorecard/github.com/fxamacker/cbor?label=openssf%20scorecard)](https://github.com/fxamacker/cbor#fuzzing-and-code-coverage)
 
 `fxamacker/cbor` is a CBOR codec in full conformance with [IETF STD&nbsp;94 (RFC&nbsp;8949)](https://www.rfc-editor.org/info/std94). It also supports CBOR Sequences ([RFC&nbsp;8742](https://www.rfc-editor.org/rfc/rfc8742.html)) and Extended Diagnostic Notation ([Appendix G of RFC&nbsp;8610](https://www.rfc-editor.org/rfc/rfc8610.html#appendix-G)).
 
 Features include full support for CBOR tags, [Core Deterministic Encoding](https://www.rfc-editor.org/rfc/rfc8949.html#name-core-deterministic-encoding), duplicate map key detection, etc.
 
+API is mostly same as `encoding/json`, plus interfaces that simplify concurrency and CBOR options.
+
 Design balances trade-offs between security, speed, concurrency, encoded data size, usability, etc.
 
-<details><summary>Highlights</summary><p/>
+<details><summary> 🔎&nbsp; Highlights</summary><p/>
 
 __🚀&nbsp; Speed__
 
@@ -38,7 +39,7 @@ Codec passed multiple confidential security assessments in 2022.  No vulnerabili
 
 __🗜️&nbsp; Data Size__
 
-Struct tags (`toarray`, `keyasint`, `omitempty`) automatically reduce size of encoded structs. Encoding optionally shrinks float64→32→16 when values fit.
+Struct tag options (`toarray`, `keyasint`, `omitempty`, `omitzero`) automatically reduce size of encoded structs. Encoding optionally shrinks float64→32→16 when values fit.
 
 __:jigsaw:&nbsp; Usability__
 
@@ -58,164 +59,201 @@ Features include CBOR [extension points](https://www.rfc-editor.org/rfc/rfc8949.
 
 `fxamacker/cbor` has configurable limits, etc. that defend against malicious CBOR data.
 
-By contrast, `encoding/gob` is [not designed to be hardened against adversarial inputs](https://pkg.go.dev/encoding/gob#hdr-Security).
+Notably, `fxamacker/cbor` is fast at rejecting malformed CBOR data.
 
-<details><summary>Example decoding with encoding/gob 💥 fatal error (out of memory)</summary><p/>
+> [!NOTE]  
+> Benchmarks rejecting 10 bytes of malicious CBOR data decoding to `[]byte`:
+> 
+> | Codec | Speed (ns/op) | Memory | Allocs |
+> | :---- | ------------: | -----: | -----: |
+> | fxamacker/cbor 2.7.0 | 47 ± 7% | 32 B/op | 2 allocs/op |
+> | ugorji/go 1.2.12 | 5878187 ± 3% | 67111556 B/op |  13 allocs/op |
+>
+> Faster hardware (overclocked DDR4 or DDR5) can reduce speed difference.
+> 
+> <details><summary> 🔎&nbsp; Benchmark details </summary><p/>
+> 
+> Latest comparison for decoding CBOR data to Go `[]byte`:
+> - Input: `[]byte{0x9B, 0x00, 0x00, 0x42, 0xFA, 0x42, 0xFA, 0x42, 0xFA, 0x42}`
+> - go1.22.7, linux/amd64, i5-13600K (DDR4-2933, disabled e-cores)
+> - go test -bench=. -benchmem -count=20
+> 
+> #### Prior comparisons
+> 
+> | Codec | Speed (ns/op) | Memory | Allocs |
+> | :---- | ------------: | -----: | -----: |
+> | fxamacker/cbor 2.5.0-beta2 | 44.33 ± 2% | 32 B/op | 2 allocs/op |
+> | fxamacker/cbor 0.1.0 - 2.4.0 | ~44.68 ± 6% | 32 B/op |  2 allocs/op |
+> | ugorji/go 1.2.10 | 5524792.50 ± 3% | 67110491 B/op |  12 allocs/op |
+> | ugorji/go 1.1.0 - 1.2.6 | 💥 runtime: | out of memory: | cannot allocate |
+> 
+> - Input: `[]byte{0x9B, 0x00, 0x00, 0x42, 0xFA, 0x42, 0xFA, 0x42, 0xFA, 0x42}`
+> - go1.19.6, linux/amd64, i5-13600K (DDR4)
+> - go test -bench=. -benchmem -count=20
+> 
+> </details>
 
-```Go
-// Example of encoding/gob having "fatal error: runtime: out of memory"
-// while decoding 181 bytes.
-package main
-import (
-	"bytes"
-	"encoding/gob"
-	"encoding/hex"
-	"fmt"
-)
+In contrast, some codecs can crash or use excessive resources while decoding bad data.
 
-// Example data is from https://github.com/golang/go/issues/24446
-// (shortened to 181 bytes).
-const data = "4dffb503010102303001ff30000109010130010800010130010800010130" +
-	"01ffb80001014a01ffb60001014b01ff860001013001ff860001013001ff" +
-	"860001013001ff860001013001ffb80000001eff850401010e3030303030" +
-	"30303030303030303001ff3000010c0104000016ffb70201010830303030" +
-	"3030303001ff3000010c000030ffb6040405fcff00303030303030303030" +
-	"303030303030303030303030303030303030303030303030303030303030" +
-	"30"
+> [!WARNING]  
+> Go's `encoding/gob` is [not designed to be hardened against adversarial inputs](https://pkg.go.dev/encoding/gob#hdr-Security).
+> 
+> <details><summary> 🔎&nbsp; gob fatal error (out of memory) 💥 decoding 181 bytes</summary><p/>
+>
+> ```Go
+> // Example of encoding/gob having "fatal error: runtime: out of memory"
+> // while decoding 181 bytes (all Go versions as of Dec. 8, 2024).
+> package main
+> import (
+> 	"bytes"
+> 	"encoding/gob"
+> 	"encoding/hex"
+> 	"fmt"
+> )
+> 
+> // Example data is from https://github.com/golang/go/issues/24446
+> // (shortened to 181 bytes).
+> const data = "4dffb503010102303001ff30000109010130010800010130010800010130" +
+> 	"01ffb80001014a01ffb60001014b01ff860001013001ff860001013001ff" +
+> 	"860001013001ff860001013001ffb80000001eff850401010e3030303030" +
+> 	"30303030303030303001ff3000010c0104000016ffb70201010830303030" +
+> 	"3030303001ff3000010c000030ffb6040405fcff00303030303030303030" +
+> 	"303030303030303030303030303030303030303030303030303030303030" +
+> 	"30"
+> 
+> type X struct {
+> 	J *X
+> 	K map[string]int
+> }
+> 
+> func main() {
+> 	raw, _ := hex.DecodeString(data)
+> 	decoder := gob.NewDecoder(bytes.NewReader(raw))
+> 
+> 	var x X
+> 	decoder.Decode(&x) // fatal error: runtime: out of memory
+> 	fmt.Println("Decoding finished.")
+> }
+> ```
+>
+>
+> </details>
 
-type X struct {
-	J *X
-	K map[string]int
-}
+### Smaller Encodings with Struct Tag Options
 
-func main() {
-	raw, _ := hex.DecodeString(data)
-	decoder := gob.NewDecoder(bytes.NewReader(raw))
+Struct tags automatically reduce encoded size of structs and improve speed.
 
-	var x X
-	decoder.Decode(&x) // fatal error: runtime: out of memory
-	fmt.Println("Decoding finished.")
-}
-```
-
-<hr/>
-
-</details>
-
-`fxamacker/cbor` is fast at rejecting malformed CBOR data.  E.g. attempts to  
-decode 10 bytes of malicious CBOR data to `[]byte` (with default settings):
-
-| Codec | Speed (ns/op) | Memory | Allocs |
-| :---- | ------------: | -----: | -----: |
-| fxamacker/cbor 2.5.0 | 44 ± 5% | 32 B/op | 2 allocs/op |
-| ugorji/go 1.2.11 | 5353261 ± 4% | 67111321 B/op |  13 allocs/op |
-
-<details><summary>Benchmark details</summary><p/>
-
-Latest comparison used:
-- Input: `[]byte{0x9B, 0x00, 0x00, 0x42, 0xFA, 0x42, 0xFA, 0x42, 0xFA, 0x42}`
-- go1.19.10, linux/amd64, i5-13600K (disabled all e-cores, DDR4 @2933)
-- go test -bench=. -benchmem -count=20
-
-#### Prior comparisons
-
-| Codec | Speed (ns/op) | Memory | Allocs |
-| :---- | ------------: | -----: | -----: |
-| fxamacker/cbor 2.5.0-beta2 | 44.33 ± 2% | 32 B/op | 2 allocs/op |
-| fxamacker/cbor 0.1.0 - 2.4.0 | ~44.68 ± 6% | 32 B/op |  2 allocs/op |
-| ugorji/go 1.2.10 | 5524792.50 ± 3% | 67110491 B/op |  12 allocs/op |
-| ugorji/go 1.1.0 - 1.2.6 | 💥 runtime: | out of memory: | cannot allocate |
-
-- Input: `[]byte{0x9B, 0x00, 0x00, 0x42, 0xFA, 0x42, 0xFA, 0x42, 0xFA, 0x42}`
-- go1.19.6, linux/amd64, i5-13600K (DDR4)
-- go test -bench=. -benchmem -count=20
-
-<hr/>
-
-</details>
-
-### Smaller Encodings with Struct Tags
-
-Struct tags (`toarray`, `keyasint`, `omitempty`) reduce encoded size of structs.
-
-<details><summary>Example encoding 3-level nested Go struct to 1 byte CBOR</summary><p/>
-
-https://go.dev/play/p/YxwvfPdFQG2
-
-```Go
-// Example encoding nested struct (with omitempty tag)
-// - encoding/json:  18 byte JSON
-// - fxamacker/cbor:  1 byte CBOR
-package main
-
-import (
-	"encoding/hex"
-	"encoding/json"
-	"fmt"
-
-	"github.com/fxamacker/cbor/v2"
-)
-
-type GrandChild struct {
-	Quux int `json:",omitempty"`
-}
-
-type Child struct {
-	Baz int        `json:",omitempty"`
-	Qux GrandChild `json:",omitempty"`
-}
-
-type Parent struct {
-	Foo Child `json:",omitempty"`
-	Bar int   `json:",omitempty"`
-}
-
-func cb() {
-	results, _ := cbor.Marshal(Parent{})
-	fmt.Println("hex(CBOR): " + hex.EncodeToString(results))
-
-	text, _ := cbor.Diagnose(results) // Diagnostic Notation
-	fmt.Println("DN: " + text)
-}
-
-func js() {
-	results, _ := json.Marshal(Parent{})
-	fmt.Println("hex(JSON): " + hex.EncodeToString(results))
-
-	text := string(results) // JSON
-	fmt.Println("JSON: " + text)
-}
-
-func main() {
-	cb()
-	fmt.Println("-------------")
-	js()
-}
-```
-
-Output (DN is Diagnostic Notation):
-```
-hex(CBOR): a0
-DN: {}
--------------
-hex(JSON): 7b22466f6f223a7b22517578223a7b7d7d7d
-JSON: {"Foo":{"Qux":{}}}
-```
-
-<hr/>
-
-</details>
-
-Example using different struct tags together:
+We can write less code by using struct tag options:
+- `toarray`: encode without field names (decode back to original struct)
+- `keyasint`: encode field names as integers (decode back to original struct)
+- `omitempty`: omit empty fields when encoding
+- `omitzero`: omit zero-value fields when encoding
 
 ![alt text](https://github.com/fxamacker/images/raw/master/cbor/v2.3.0/cbor_struct_tags_api.svg?sanitize=1 "CBOR API and Go Struct Tags")
 
-API is mostly same as `encoding/json`, plus interfaces that simplify concurrency for CBOR options.
+> [!NOTE]  
+>  `fxamacker/cbor` can encode a 3-level nested Go struct to 1 byte!
+> - `encoding/json`:  18 bytes of JSON
+> - `fxamacker/cbor`:  1 byte of CBOR  
+>
+> <details><summary> 🔎&nbsp; Encoding 3-level nested Go struct with omitempty</summary><p/>
+>
+> https://go.dev/play/p/YxwvfPdFQG2
+> 
+> ```Go
+> // Example encoding nested struct (with omitempty tag)
+> // - encoding/json:  18 byte JSON
+> // - fxamacker/cbor:  1 byte CBOR
+> 
+> package main
+> 
+> import (
+> 	"encoding/hex"
+> 	"encoding/json"
+> 	"fmt"
+> 
+> 	"github.com/fxamacker/cbor/v2"
+> )
+> 
+> type GrandChild struct {
+> 	Quux int `json:",omitempty"`
+> }
+> 
+> type Child struct {
+> 	Baz int        `json:",omitempty"`
+> 	Qux GrandChild `json:",omitempty"`
+> }
+> 
+> type Parent struct {
+> 	Foo Child `json:",omitempty"`
+> 	Bar int   `json:",omitempty"`
+> }
+> 
+> func cb() {
+> 	results, _ := cbor.Marshal(Parent{})
+> 	fmt.Println("hex(CBOR): " + hex.EncodeToString(results))
+> 
+> 	text, _ := cbor.Diagnose(results) // Diagnostic Notation
+> 	fmt.Println("DN: " + text)
+> }
+> 
+> func js() {
+> 	results, _ := json.Marshal(Parent{})
+> 	fmt.Println("hex(JSON): " + hex.EncodeToString(results))
+> 
+> 	text := string(results) // JSON
+> 	fmt.Println("JSON: " + text)
+> }
+> 
+> func main() {
+> 	cb()
+> 	fmt.Println("-------------")
+> 	js()
+> }
+> ```
+> 
+> Output (DN is Diagnostic Notation):
+> ```
+> hex(CBOR): a0
+> DN: {}
+> -------------
+> hex(JSON): 7b22466f6f223a7b22517578223a7b7d7d7d
+> JSON: {"Foo":{"Qux":{}}}
+> ```
+> 
+> </details>
+
 
 ## Quick Start
 
 __Install__: `go get github.com/fxamacker/cbor/v2` and `import "github.com/fxamacker/cbor/v2"`.
 
+> [!TIP]  
+>
+> Tinygo users can try beta/experimental branch [feature/cbor-tinygo-beta](https://github.com/fxamacker/cbor/tree/feature/cbor-tinygo-beta).
+>
+> <details><summary> 🔎&nbsp; More about tinygo feature branch</summary>
+>
+> ### Tinygo
+>
+> Branch [feature/cbor-tinygo-beta](https://github.com/fxamacker/cbor/tree/feature/cbor-tinygo-beta) is based on fxamacker/cbor v2.7.0 and it can be compiled using tinygo v0.33 (also compiles with golang/go).
+>
+> It passes unit tests (with both go1.22 and tinygo v0.33) and is considered beta/experimental for tinygo.
+>
+> :warning: The `feature/cbor-tinygo-beta` branch does not get fuzz tested yet.
+>
+> Changes in this feature branch only affect tinygo compiled software.  Summary of changes:
+> - default `DecOptions.MaxNestedLevels` is reduced to 16 (was 32).  User can specify higher limit but 24+ crashes tests when compiled with tinygo v0.33.
+> - disabled decoding CBOR tag data to Go interface because tinygo v0.33 is missing needed feature.
+> - encoding error message can be different when encoding function type.
+>
+> Related tinygo issues:
+> - https://github.com/tinygo-org/tinygo/issues/4277
+> - https://github.com/tinygo-org/tinygo/issues/4458
+>
+> </details>
+
+
 ### Key Points
 
 This library can encode and decode CBOR (RFC 8949) and CBOR Sequences (RFC 8742).
@@ -252,16 +290,17 @@ rest, err = cbor.UnmarshalFirst(b, &v)   // decode []byte b to v
 // DiagnoseFirst translates first CBOR data item to text and returns remaining bytes.
 text, rest, err = cbor.DiagnoseFirst(b)  // decode []byte b to Diagnostic Notation text
 
-// NOTE: Unmarshal returns ExtraneousDataError if there are remaining bytes,
-// but new funcs UnmarshalFirst and DiagnoseFirst do not.
+// NOTE: Unmarshal() returns ExtraneousDataError if there are remaining bytes, but
+// UnmarshalFirst() and DiagnoseFirst() allow trailing bytes.
 ```
 
-__IMPORTANT__: 👉  CBOR settings allow trade-offs between speed, security, encoding size, etc.
-
-- Different CBOR libraries may use different default settings.
-- CBOR-based formats or protocols usually require specific settings.
-
-For example, WebAuthn uses "CTAP2 Canonical CBOR" which is available as a preset.
+> [!IMPORTANT]  
+> CBOR settings allow trade-offs between speed, security, encoding size, etc.
+>
+> - Different CBOR libraries may use different default settings.
+> - CBOR-based formats or protocols usually require specific settings.
+>
+> For example, WebAuthn uses "CTAP2 Canonical CBOR" which is available as a preset.
 
 ### Presets
 
@@ -312,9 +351,9 @@ err = em.MarshalToBuffer(v, &buf) // encode v to provided buf
 
 ### Struct Tags
 
-Struct tags (`toarray`, `keyasint`, `omitempty`) reduce encoded size of structs.
+Struct tag options (`toarray`, `keyasint`, `omitempty`, `omitzero`) reduce encoded size of structs.
 
-<details><summary>Example encoding 3-level nested Go struct to 1 byte CBOR</summary><p/>
+<details><summary> 🔎&nbsp; Example encoding 3-level nested Go struct to 1 byte CBOR</summary><p/>
 
 https://go.dev/play/p/YxwvfPdFQG2
 
@@ -382,13 +421,13 @@ JSON: {"Foo":{"Qux":{}}}
 
 </details>
 
-<details><summary>Example using several struct tags</summary><p/>
+<details><summary> 🔎&nbsp; Example using struct tag options</summary><p/>
 	
 ![alt text](https://github.com/fxamacker/images/raw/master/cbor/v2.3.0/cbor_struct_tags_api.svg?sanitize=1 "CBOR API and Go Struct Tags")
 
 </details>
 
-Struct tags simplify use of CBOR-based protocols that require CBOR arrays or maps with integer keys.
+Struct tag options simplify use of CBOR-based protocols that require CBOR arrays or maps with integer keys.
 
 ### CBOR Tags
 
@@ -404,7 +443,7 @@ em, err := opts.EncModeWithSharedTags(ts)  // mutable shared CBOR tags
 
 `TagSet` and modes using it are safe for concurrent use.  Equivalent API is available for `DecMode`.
 
-<details><summary>Example using TagSet and TagOptions</summary><p/>
+<details><summary> 🔎&nbsp; Example using TagSet and TagOptions</summary><p/>
 
 ```go
 // Use signedCWT struct defined in "Decoding CWT" example.
@@ -430,7 +469,7 @@ if err := dm.Unmarshal(data, &v); err != nil {
 em, _ := cbor.EncOptions{}.EncModeWithTags(tags)
 
 // Marshal signedCWT with tag number.
-if data, err := cbor.Marshal(v); err != nil {
+if data, err := em.Marshal(v); err != nil {
 	return err
 }
 ```
@@ -439,7 +478,7 @@ if data, err := cbor.Marshal(v); err != nil {
 
 ### Functions and Interfaces
 
-<details><summary>Functions and interfaces at a glance</summary><p/>
+<details><summary> 🔎&nbsp; Functions and interfaces at a glance</summary><p/>
 
 Common functions with same API as `encoding/json`:  
 - `Marshal`, `Unmarshal`
@@ -472,11 +511,24 @@ Default limits may need to be increased for systems handling very large data (e.
 
 ## Status
 
-v2.7.0 (June 23, 2024) adds features and improvements that help large projects (e.g. Kubernetes) use CBOR as an alternative to JSON and Protocol Buffers. Other improvements include speedups, improved memory use, bug fixes, new serialization options, etc.   It passed fuzz tests (5+ billion executions) and is production quality.
+v2.8.0 (March 30, 2025) is a small release primarily to add `omitzero` option to struct field tags and fix bugs.   It passed fuzz tests (billions of executions) and is production quality.
+
+v2.8.0 and v2.7.1 fixes these 3 functions (when called directly by user apps) to use same error handling on bad inputs as `cbor.Unmarshal()`:
+- `ByteString.UnmarshalCBOR()`
+- `RawTag.UnmarshalCBOR()`
+- `SimpleValue.UnmarshalCBOR()`
+
+The above 3 `UnmarshalCBOR()` functions were initially created for internal use and are deprecated now, so please use `Unmarshal()` or `UnmarshalFirst()` instead.  To preserve backward compatibility, these deprecated functions were added to fuzz tests and will not be removed in v2.
+
+The minimum version of Go required to build:
+- v2.8.0 requires go 1.20.
+- v2.7.1 and older releases require go 1.17.
 
 For more details, see [release notes](https://github.com/fxamacker/cbor/releases).
 
-### Prior Release
+### Prior Releases
+
+v2.7.0 (June 23, 2024) adds features and improvements that help large projects (e.g. Kubernetes) use CBOR as an alternative to JSON and Protocol Buffers. Other improvements include speedups, improved memory use, bug fixes, new serialization options, etc.   It passed fuzz tests (5+ billion executions) and is production quality.
 
 [v2.6.0](https://github.com/fxamacker/cbor/releases/tag/v2.6.0) (February 2024) adds important new features, optimizations, and bug fixes. It is especially useful to systems that need to convert data between CBOR and JSON.  New options and optimizations improve handling of bignum, integers, maps, and strings.
 
@@ -489,7 +541,7 @@ See [v2.5.0 release notes](https://github.com/fxamacker/cbor/releases/tag/v2.5.0
 See ["Version and API Changes"](https://github.com/fxamacker/cbor#versions-and-api-changes) section for more info about version numbering, etc.
 
 <!--
-<details><summary>👉 Benchmark Comparison: v2.4.0 vs v2.5.0</summary><p/>
+<details><summary> 🔎&nbsp; Benchmark Comparison: v2.4.0 vs v2.5.0</summary><p/>
 
 TODO: Update to v2.4.0 vs 2.5.0 (not beta2).
 
@@ -549,7 +601,7 @@ geomean                                                      2.782
 
 ## Who uses fxamacker/cbor
 
-`fxamacker/cbor` is used in projects by Arm Ltd., Berlin Institute of Health at Charité, Chainlink, Cisco, Confidential Computing Consortium, ConsenSys, Dapper&nbsp;Labs, EdgeX&nbsp;Foundry, F5, FIDO Alliance, Fraunhofer&#8209;AISEC, Kubernetes, Let's Encrypt (ISRG), Linux&nbsp;Foundation, Matrix.org, Microsoft, Mozilla, National&nbsp;Cybersecurity&nbsp;Agency&nbsp;of&nbsp;France (govt), Netherlands (govt), Oasis Protocol, Smallstep, Tailscale, Taurus SA, Teleport, TIBCO, and others.
+`fxamacker/cbor` is used in projects by Arm Ltd., Berlin Institute of Health at Charité, Chainlink, Cisco, Confidential&nbsp;Computing&nbsp;Consortium, ConsenSys, EdgeX&nbsp;Foundry, F5, Flow&nbsp;Foundation, Fraunhofer&#8209;AISEC, IBM, Kubernetes, Let's&nbsp;Encrypt&nbsp;(ISRG), Linux&nbsp;Foundation, Matrix.org, Microsoft, Mozilla, National&nbsp;Cybersecurity&nbsp;Agency&nbsp;of&nbsp;France&nbsp;(govt), Netherlands&nbsp;(govt), Oasis&nbsp;Protocol, Smallstep, Tailscale, Taurus SA, Teleport, TIBCO, and others.
 
 `fxamacker/cbor` passed multiple confidential security assessments.  A [nonconfidential security assessment](https://github.com/veraison/go-cose/blob/v1.0.0-rc.1/reports/NCC_Microsoft-go-cose-Report_2022-05-26_v1.0.pdf) (prepared by NCC Group for Microsoft Corporation) includes a subset of fxamacker/cbor v2.4.0 in its scope.
 
@@ -588,7 +640,7 @@ By default, decoder treats time values of floating-point NaN and Infinity as if
 __Click to expand topic:__
 
 <details>
- <summary>Duplicate Map Keys</summary><p>
+ <summary> 🔎&nbsp; Duplicate Map Keys</summary><p>
 
 This library provides options for fast detection and rejection of duplicate map keys based on applying a Go-specific data model to CBOR's extended generic data model in order to determine duplicate vs distinct map keys. Detection relies on whether the CBOR map key would be a duplicate "key" when decoded and applied to the user-provided Go map or struct. 
 
@@ -601,7 +653,7 @@ APF suffix means "Allow Partial Fill" so the destination map or struct can conta
 </details>
 
 <details>
- <summary>Tag Validity</summary><p>
+ <summary> 🔎&nbsp; Tag Validity</summary><p>
 
 This library checks tag validity for built-in tags (currently tag numbers 0, 1, 2, 3, and 55799):
 

bench_test.go

@@ -188,16 +188,16 @@ var decodeBenchmarks = []struct {
 var encodeBenchmarks = []struct {
 	name   string
 	data   []byte
-	values []interface{}
+	values []any
 }{
-	{"bool", hexDecode("f5"), []interface{}{true}},
-	{"positive int", hexDecode("1bffffffffffffffff"), []interface{}{uint64(18446744073709551615)}},
-	{"negative int", hexDecode("3903e7"), []interface{}{int64(-1000)}},
-	{"float", hexDecode("fbc010666666666666"), []interface{}{float64(-4.1)}},
-	{"bytes", hexDecode("581a0102030405060708090a0b0c0d0e0f101112131415161718191a"), []interface{}{[]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26}}},
-	{"text", hexDecode("782b54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f67"), []interface{}{"The quick brown fox jumps over the lazy dog"}},
-	{"array", hexDecode("981a0102030405060708090a0b0c0d0e0f101112131415161718181819181a"), []interface{}{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26}}},
-	{"map", hexDecode("ad616161416162614261636143616461446165614561666146616761476168614861696149616a614a616c614c616d614d616e614e"), []interface{}{map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"}}},
+	{"bool", hexDecode("f5"), []any{true}},
+	{"positive int", hexDecode("1bffffffffffffffff"), []any{uint64(18446744073709551615)}},
+	{"negative int", hexDecode("3903e7"), []any{int64(-1000)}},
+	{"float", hexDecode("fbc010666666666666"), []any{float64(-4.1)}},
+	{"bytes", hexDecode("581a0102030405060708090a0b0c0d0e0f101112131415161718191a"), []any{[]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26}}},
+	{"text", hexDecode("782b54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f67"), []any{"The quick brown fox jumps over the lazy dog"}},
+	{"array", hexDecode("981a0102030405060708090a0b0c0d0e0f101112131415161718181819181a"), []any{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26}}},
+	{"map", hexDecode("ad616161416162614261636143616461446165614561666146616761476168614861696149616a614a616c614c616d614d616e614e"), []any{map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"}}},
 }
 
 func BenchmarkUnmarshal(b *testing.B) {
@@ -226,7 +226,7 @@ func BenchmarkUnmarshal(b *testing.B) {
 		{
 			"CBOR map to Go map[string]interface{}",
 			hexDecode("a86154f56255691bffffffffffffffff61493903e76146fbc0106666666666666142581a0102030405060708090a0b0c0d0e0f101112131415161718191a6153782b54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f6764536c6369981a0102030405060708090a0b0c0d0e0f101112131415161718181819181a634d7373ad6163614361656145616661466167614761686148616e614e616d614d61616141616261426164614461696149616a614a616c614c"),
-			reflect.TypeOf(map[string]interface{}{}),
+			reflect.TypeOf(map[string]any{}),
 		},
 		// Unmarshal CBOR map with string key to struct.
 		{
@@ -238,7 +238,7 @@ func BenchmarkUnmarshal(b *testing.B) {
 		{
 			"CBOR map to Go map[int]interface{}",
 			hexDecode("a801f5021bffffffffffffffff033903e704fbc01066666666666605581a0102030405060708090a0b0c0d0e0f101112131415161718191a06782b54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f6707981a0102030405060708090a0b0c0d0e0f101112131415161718181819181a08ad61646144616661466167614761686148616d614d616e614e6161614161626142616361436165614561696149616a614a616c614c"),
-			reflect.TypeOf(map[int]interface{}{}),
+			reflect.TypeOf(map[int]any{}),
 		},
 		// Unmarshal CBOR map with integer key, such as COSE Key and SenML, to struct.
 		{
@@ -250,7 +250,7 @@ func BenchmarkUnmarshal(b *testing.B) {
 		{
 			"CBOR array to Go []interface{}",
 			hexDecode("88f51bffffffffffffffff3903e7fbc010666666666666581a0102030405060708090a0b0c0d0e0f101112131415161718191a782b54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f67981a0102030405060708090a0b0c0d0e0f101112131415161718181819181aad616261426163614361646144616561456166614661696149616e614e616161416167614761686148616a614a616c614c616d614d"),
-			reflect.TypeOf([]interface{}{}),
+			reflect.TypeOf([]any{}),
 		},
 		// Unmarshal CBOR array of known sequence of data types, such as signed/maced/encrypted CWT, to struct.
 		{
@@ -384,7 +384,7 @@ func BenchmarkMarshal(b *testing.B) {
 		}
 	}
 	// Marshal map[string]interface{} to CBOR map
-	m1 := map[string]interface{}{ //nolint:dupl
+	m1 := map[string]any{
 		"T":    true,
 		"UI":   uint(18446744073709551615),
 		"I":    -1000,
@@ -406,7 +406,7 @@ func BenchmarkMarshal(b *testing.B) {
 		Mss:  map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"},
 	}
 	// Marshal map[int]interface{} to CBOR map
-	m2 := map[int]interface{}{ //nolint:dupl
+	m2 := map[int]any{
 		1: true,
 		2: uint(18446744073709551615),
 		3: -1000,
@@ -428,7 +428,7 @@ func BenchmarkMarshal(b *testing.B) {
 		Mss:  map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"},
 	}
 	// Marshal []interface to CBOR array.
-	slc := []interface{}{
+	slc := []any{
 		true,
 		uint(18446744073709551615),
 		-1000,
@@ -451,7 +451,7 @@ func BenchmarkMarshal(b *testing.B) {
 	}
 	var moreBenchmarks = []struct {
 		name  string
-		value interface{}
+		value any
 	}{
 		{"Go map[string]interface{} to CBOR map", m1},
 		{"Go struct to CBOR map", v1},
@@ -501,9 +501,9 @@ func BenchmarkMarshalCanonical(b *testing.B) {
 	for _, bm := range []struct {
 		name   string
 		data   []byte
-		values []interface{}
+		values []any
 	}{
-		{"map", hexDecode("ad616161416162614261636143616461446165614561666146616761476168614861696149616a614a616c614c616d614d616e614e"), []interface{}{map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"}, strc{A: "A", B: "B", C: "C", D: "D", E: "E", F: "F", G: "G", H: "H", I: "I", J: "J", L: "L", M: "M", N: "N"}, map[int]int{0: 0} /* single-entry map */}},
+		{"map", hexDecode("ad616161416162614261636143616461446165614561666146616761476168614861696149616a614a616c614c616d614d616e614e"), []any{map[string]string{"a": "A", "b": "B", "c": "C", "d": "D", "e": "E", "f": "F", "g": "G", "h": "H", "i": "I", "j": "J", "l": "L", "m": "M", "n": "N"}, strc{A: "A", B: "B", C: "C", D: "D", E: "E", F: "F", G: "G", H: "H", I: "I", J: "J", L: "L", M: "M", N: "N"}, map[int]int{0: 0} /* single-entry map */}},
 	} {
 		for _, v := range bm.values {
 			name := "Go " + reflect.TypeOf(v).String() + " to CBOR " + bm.name
@@ -860,7 +860,7 @@ func BenchmarkUnmarshalMapToStruct(b *testing.B) {
 	type input struct {
 		name   string
 		data   []byte
-		into   interface{}
+		into   any
 		reject bool
 	}
 

bytestring.go

@@ -38,11 +38,38 @@ func (bs ByteString) MarshalCBOR() ([]byte, error) {
 
 // UnmarshalCBOR decodes CBOR byte string (major type 2) to ByteString.
 // Decoding CBOR null and CBOR undefined sets ByteString to be empty.
+//
+// Deprecated: No longer used by this codec; kept for compatibility
+// with user apps that directly call this function.
 func (bs *ByteString) UnmarshalCBOR(data []byte) error {
 	if bs == nil {
 		return errors.New("cbor.ByteString: UnmarshalCBOR on nil pointer")
 	}
 
+	d := decoder{data: data, dm: defaultDecMode}
+
+	// Check well-formedness of CBOR data item.
+	// ByteString.UnmarshalCBOR() is exported, so
+	// the codec needs to support same behavior for:
+	// - Unmarshal(data, *ByteString)
+	// - ByteString.UnmarshalCBOR(data)
+	err := d.wellformed(false, false)
+	if err != nil {
+		return err
+	}
+
+	return bs.unmarshalCBOR(data)
+}
+
+// unmarshalCBOR decodes CBOR byte string (major type 2) to ByteString.
+// Decoding CBOR null and CBOR undefined sets ByteString to be empty.
+// This function assumes data is well-formed, and does not perform bounds checking.
+// This function is called by Unmarshal().
+func (bs *ByteString) unmarshalCBOR(data []byte) error {
+	if bs == nil {
+		return errors.New("cbor.ByteString: UnmarshalCBOR on nil pointer")
+	}
+
 	// Decoding CBOR null and CBOR undefined to ByteString resets data.
 	// This behavior is similar to decoding CBOR null and CBOR undefined to []byte.
 	if len(data) == 1 && (data[0] == 0xf6 || data[0] == 0xf7) {

bytestring_test.go

@@ -3,7 +3,11 @@
 
 package cbor
 
-import "testing"
+import (
+	"io"
+	"strings"
+	"testing"
+)
 
 func TestByteString(t *testing.T) {
 	type s1 struct {
@@ -99,3 +103,110 @@ func TestByteString(t *testing.T) {
 	dm, _ := DecOptions{}.DecMode()
 	testRoundTrip(t, testCases, em, dm)
 }
+
+func TestUnmarshalByteStringOnBadData(t *testing.T) {
+	testCases := []struct {
+		name   string
+		data   []byte
+		errMsg string
+	}{
+		// Empty data
+		{
+			name:   "nil data",
+			data:   nil,
+			errMsg: io.EOF.Error(),
+		},
+		{
+			name:   "empty data",
+			data:   []byte{},
+			errMsg: io.EOF.Error(),
+		},
+
+		// Wrong CBOR types
+		{
+			name:   "uint type",
+			data:   hexDecode("01"),
+			errMsg: "cbor: cannot unmarshal positive integer into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "int type",
+			data:   hexDecode("20"),
+			errMsg: "cbor: cannot unmarshal negative integer into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "string type",
+			data:   hexDecode("60"),
+			errMsg: "cbor: cannot unmarshal UTF-8 text string into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "array type",
+			data:   hexDecode("80"),
+			errMsg: "cbor: cannot unmarshal array into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "map type",
+			data:   hexDecode("a0"),
+			errMsg: "cbor: cannot unmarshal map into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "tag type",
+			data:   hexDecode("c074323031332d30332d32315432303a30343a30305a"),
+			errMsg: "cbor: cannot unmarshal tag into Go value of type cbor.ByteString",
+		},
+		{
+			name:   "float type",
+			data:   hexDecode("f90000"),
+			errMsg: "cbor: cannot unmarshal primitives into Go value of type cbor.ByteString",
+		},
+
+		// Truncated CBOR data
+		{
+			name:   "truncated head",
+			data:   hexDecode("18"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Truncated CBOR byte string
+		{
+			name:   "truncated byte string",
+			data:   hexDecode("44010203"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Extraneous CBOR data
+		{
+			name:   "extraneous data",
+			data:   hexDecode("c074323031332d30332d32315432303a30343a30305a00"),
+			errMsg: "cbor: 1 bytes of extraneous data starting at index 22",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Test ByteString.UnmarshalCBOR(data)
+			{
+				var v ByteString
+
+				err := v.UnmarshalCBOR(tc.data)
+				if err == nil {
+					t.Errorf("UnmarshalCBOR(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("UnmarshalCBOR(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+			// Test Unmarshal(data, *ByteString), which calls ByteString.unmarshalCBOR() under the hood
+			{
+				var v ByteString
+
+				err := Unmarshal(tc.data, &v)
+				if err == nil {
+					t.Errorf("Unmarshal(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("Unmarshal(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+		})
+	}
+}

cache.go

@@ -17,6 +17,7 @@ import (
 type encodeFuncs struct {
 	ef  encodeFunc
 	ief isEmptyFunc
+	izf isZeroFunc
 }
 
 var (
@@ -31,6 +32,7 @@ type specialType int
 const (
 	specialTypeNone specialType = iota
 	specialTypeUnmarshalerIface
+	specialTypeUnexportedUnmarshalerIface
 	specialTypeEmptyIface
 	specialTypeIface
 	specialTypeTag
@@ -50,7 +52,7 @@ type typeInfo struct {
 func newTypeInfo(t reflect.Type) *typeInfo {
 	tInfo := typeInfo{typ: t, kind: t.Kind()}
 
-	for t.Kind() == reflect.Ptr {
+	for t.Kind() == reflect.Pointer {
 		t = t.Elem()
 	}
 
@@ -69,7 +71,9 @@ func newTypeInfo(t reflect.Type) *typeInfo {
 		tInfo.spclType = specialTypeTag
 	} else if t == typeTime {
 		tInfo.spclType = specialTypeTime
-	} else if reflect.PtrTo(t).Implements(typeUnmarshaler) {
+	} else if reflect.PointerTo(t).Implements(typeUnexportedUnmarshaler) {
+		tInfo.spclType = specialTypeUnexportedUnmarshalerIface
+	} else if reflect.PointerTo(t).Implements(typeUnmarshaler) {
 		tInfo.spclType = specialTypeUnmarshalerIface
 	}
 
@@ -237,7 +241,7 @@ func getEncodingStructType(t reflect.Type) (*encodingStructType, error) {
 	e := getEncodeBuffer()
 	for i := 0; i < len(flds); i++ {
 		// Get field's encodeFunc
-		flds[i].ef, flds[i].ief = getEncodeFunc(flds[i].typ)
+		flds[i].ef, flds[i].ief, flds[i].izf = getEncodeFunc(flds[i].typ)
 		if flds[i].ef == nil {
 			err = &UnsupportedTypeError{t}
 			break
@@ -321,7 +325,7 @@ func getEncodingStructType(t reflect.Type) (*encodingStructType, error) {
 func getEncodingStructToArrayType(t reflect.Type, flds fields) (*encodingStructType, error) {
 	for i := 0; i < len(flds); i++ {
 		// Get field's encodeFunc
-		flds[i].ef, flds[i].ief = getEncodeFunc(flds[i].typ)
+		flds[i].ef, flds[i].ief, flds[i].izf = getEncodeFunc(flds[i].typ)
 		if flds[i].ef == nil {
 			structType := &encodingStructType{err: &UnsupportedTypeError{t}}
 			encodingStructTypeCache.Store(t, structType)
@@ -337,14 +341,14 @@ func getEncodingStructToArrayType(t reflect.Type, flds fields) (*encodingStructT
 	return structType, structType.err
 }
 
-func getEncodeFunc(t reflect.Type) (encodeFunc, isEmptyFunc) {
+func getEncodeFunc(t reflect.Type) (encodeFunc, isEmptyFunc, isZeroFunc) {
 	if v, _ := encodeFuncCache.Load(t); v != nil {
 		fs := v.(encodeFuncs)
-		return fs.ef, fs.ief
+		return fs.ef, fs.ief, fs.izf
 	}
-	ef, ief := getEncodeFuncInternal(t)
-	encodeFuncCache.Store(t, encodeFuncs{ef, ief})
-	return ef, ief
+	ef, ief, izf := getEncodeFuncInternal(t)
+	encodeFuncCache.Store(t, encodeFuncs{ef, ief, izf})
+	return ef, ief, izf
 }
 
 func getTypeInfo(t reflect.Type) *typeInfo {

decode.go

@@ -13,6 +13,7 @@ import (
 	"io"
 	"math"
 	"math/big"
+	"math/bits"
 	"reflect"
 	"strconv"
 	"strings"
@@ -104,7 +105,7 @@ import (
 // if there are any remaining bytes following the first valid CBOR data item.
 // See UnmarshalFirst, if you want to unmarshal only the first
 // CBOR data item without ExtraneousDataError caused by remaining bytes.
-func Unmarshal(data []byte, v interface{}) error {
+func Unmarshal(data []byte, v any) error {
 	return defaultDecMode.Unmarshal(data, v)
 }
 
@@ -114,7 +115,7 @@ func Unmarshal(data []byte, v interface{}) error {
 // If v is nil, not a pointer, or a nil pointer, UnmarshalFirst returns an error.
 //
 // See the documentation for Unmarshal for details.
-func UnmarshalFirst(data []byte, v interface{}) (rest []byte, err error) {
+func UnmarshalFirst(data []byte, v any) (rest []byte, err error) {
 	return defaultDecMode.UnmarshalFirst(data, v)
 }
 
@@ -151,6 +152,10 @@ type Unmarshaler interface {
 	UnmarshalCBOR([]byte) error
 }
 
+type unmarshaler interface {
+	unmarshalCBOR([]byte) error
+}
+
 // InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
 type InvalidUnmarshalError struct {
 	s string
@@ -193,7 +198,7 @@ func (e *InvalidMapKeyTypeError) Error() string {
 
 // DupMapKeyError describes detected duplicate map key in CBOR map.
 type DupMapKeyError struct {
-	Key   interface{}
+	Key   any
 	Index int
 }
 
@@ -780,11 +785,13 @@ type DecOptions struct {
 	MaxNestedLevels int
 
 	// MaxArrayElements specifies the max number of elements for CBOR arrays.
-	// Default is 128*1024=131072 and it can be set to [16, 2147483647]
+	// Default is 128*1024=131072 and it can be set to [16, 2147483647] on 32-bit arch
+	// or [16, 9223372036854775807] on 64-bit arch.
 	MaxArrayElements int
 
 	// MaxMapPairs specifies the max number of key-value pairs for CBOR maps.
-	// Default is 128*1024=131072 and it can be set to [16, 2147483647]
+	// Default is 128*1024=131072 and it can be set to [16, 2147483647] on 32-bit arch
+	// or [16, 9223372036854775807] on 64-bit arch.
 	MaxMapPairs int
 
 	// IndefLength specifies whether to allow indefinite length CBOR items.
@@ -953,13 +960,19 @@ func (opts DecOptions) DecModeWithSharedTags(tags TagSet) (DecMode, error) { //n
 }
 
 const (
+	maxInt = 1<<(bits.UintSize-1) - 1
+
 	defaultMaxArrayElements = 131072
 	minMaxArrayElements     = 16
-	maxMaxArrayElements     = 2147483647
+	maxMaxArrayElements     = maxInt
 
 	defaultMaxMapPairs = 131072
 	minMaxMapPairs     = 16
-	maxMaxMapPairs     = 2147483647
+	maxMaxMapPairs     = maxInt
+
+	defaultMaxNestedLevels = 32
+	minMaxNestedLevels     = 4
+	maxMaxNestedLevels     = 65535
 )
 
 var defaultSimpleValues = func() *SimpleValueRegistry {
@@ -1126,7 +1139,7 @@ type DecMode interface {
 	// Unmarshal returns an error.
 	//
 	// See the documentation for Unmarshal for details.
-	Unmarshal(data []byte, v interface{}) error
+	Unmarshal(data []byte, v any) error
 
 	// UnmarshalFirst parses the first CBOR data item into the value pointed to by v
 	// using the decoding mode.  Any remaining bytes are returned in rest.
@@ -1134,7 +1147,7 @@ type DecMode interface {
 	// If v is nil, not a pointer, or a nil pointer, UnmarshalFirst returns an error.
 	//
 	// See the documentation for Unmarshal for details.
-	UnmarshalFirst(data []byte, v interface{}) (rest []byte, err error)
+	UnmarshalFirst(data []byte, v any) (rest []byte, err error)
 
 	// Valid checks whether data is a well-formed encoded CBOR data item and
 	// that it complies with configurable restrictions such as MaxNestedLevels,
@@ -1161,6 +1174,12 @@ type DecMode interface {
 	// NewDecoder returns a new decoder that reads from r using dm DecMode.
 	NewDecoder(r io.Reader) *Decoder
 
+	// NewStreamDecoder returns a new StreamDecoder that reads from r using dm DecMode.
+	NewStreamDecoder(r io.Reader) *StreamDecoder
+
+	// NewByteStreamDecoder returns a new StreamDecoder that reads from data using dm DecMode.
+	NewByteStreamDecoder(data []byte) *StreamDecoder
+
 	// DecOptions returns user specified options used to create this DecMode.
 	DecOptions() DecOptions
 }
@@ -1241,7 +1260,7 @@ func (dm *decMode) DecOptions() DecOptions {
 // Unmarshal returns an error.
 //
 // See the documentation for Unmarshal for details.
-func (dm *decMode) Unmarshal(data []byte, v interface{}) error {
+func (dm *decMode) Unmarshal(data []byte, v any) error {
 	d := decoder{data: data, dm: dm}
 
 	// Check well-formedness.
@@ -1261,7 +1280,7 @@ func (dm *decMode) Unmarshal(data []byte, v interface{}) error {
 // If v is nil, not a pointer, or a nil pointer, UnmarshalFirst returns an error.
 //
 // See the documentation for Unmarshal for details.
-func (dm *decMode) UnmarshalFirst(data []byte, v interface{}) (rest []byte, err error) {
+func (dm *decMode) UnmarshalFirst(data []byte, v any) (rest []byte, err error) {
 	d := decoder{data: data, dm: dm}
 
 	// check well-formedness.
@@ -1313,7 +1332,25 @@ func (dm *decMode) Wellformed(data []byte) error {
 
 // NewDecoder returns a new decoder that reads from r using dm DecMode.
 func (dm *decMode) NewDecoder(r io.Reader) *Decoder {
-	return &Decoder{r: r, d: decoder{dm: dm}}
+	return &Decoder{r: r, d: &decoder{dm: dm}}
+}
+
+// NewStreamDecoder returns a new StreamDecoder that reads from r using dm DecMode.
+func (dm *decMode) NewStreamDecoder(r io.Reader) *StreamDecoder {
+	return &StreamDecoder{
+		dec: &Decoder{r: r, d: &decoder{dm: dm}},
+	}
+}
+
+// NewByteStreamDecoder returns a new StreamDecoder that reads from data using dm DecMode.
+func (dm *decMode) NewByteStreamDecoder(data []byte) *StreamDecoder {
+	return &StreamDecoder{
+		dec: &Decoder{
+			r:   nil,
+			d:   &decoder{dm: dm},
+			buf: data,
+		},
+	}
 }
 
 type decoder struct {
@@ -1337,13 +1374,13 @@ type decoder struct {
 // If CBOR data item fails to be decoded into v,
 // error is returned and offset is moved to the next CBOR data item.
 // Precondition: d.data contains at least one well-formed CBOR data item.
-func (d *decoder) value(v interface{}) error {
+func (d *decoder) value(v any) error {
 	// v can't be nil, non-pointer, or nil pointer value.
 	if v == nil {
 		return &InvalidUnmarshalError{"cbor: Unmarshal(nil)"}
 	}
 	rv := reflect.ValueOf(v)
-	if rv.Kind() != reflect.Ptr {
+	if rv.Kind() != reflect.Pointer {
 		return &InvalidUnmarshalError{"cbor: Unmarshal(non-pointer " + rv.Type().String() + ")"}
 	} else if rv.IsNil() {
 		return &InvalidUnmarshalError{"cbor: Unmarshal(nil " + rv.Type().String() + ")"}
@@ -1357,7 +1394,7 @@ func (d *decoder) value(v interface{}) error {
 func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolint:gocyclo
 
 	// Decode CBOR nil or CBOR undefined to pointer value by setting pointer value to nil.
-	if d.nextCBORNil() && v.Kind() == reflect.Ptr {
+	if d.nextCBORNil() && v.Kind() == reflect.Pointer {
 		d.skip()
 		v.Set(reflect.Zero(v.Type()))
 		return nil
@@ -1382,7 +1419,8 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 
 				registeredType := d.dm.tags.getTypeFromTagNum(tagNums)
 				if registeredType != nil {
-					if implements(registeredType, tInfo.nonPtrType) {
+					if registeredType.Implements(tInfo.nonPtrType) ||
+						reflect.PointerTo(registeredType).Implements(tInfo.nonPtrType) {
 						v.Set(reflect.New(registeredType))
 						v = v.Elem()
 						tInfo = getTypeInfo(registeredType)
@@ -1394,7 +1432,7 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 
 	// Create new value for the pointer v to point to.
 	// At this point, CBOR value is not nil/undefined if v is a pointer.
-	for v.Kind() == reflect.Ptr {
+	for v.Kind() == reflect.Pointer {
 		if v.IsNil() {
 			if !v.CanSet() {
 				d.skip()
@@ -1455,6 +1493,9 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 
 		case specialTypeUnmarshalerIface:
 			return d.parseToUnmarshaler(v)
+
+		case specialTypeUnexportedUnmarshalerIface:
+			return d.parseToUnexportedUnmarshaler(v)
 		}
 	}
 
@@ -1783,12 +1824,12 @@ func (d *decoder) parseToTime() (time.Time, bool, error) {
 // parseToUnmarshaler parses CBOR data to value implementing Unmarshaler interface.
 // It assumes data is well-formed, and does not perform bounds checking.
 func (d *decoder) parseToUnmarshaler(v reflect.Value) error {
-	if d.nextCBORNil() && v.Kind() == reflect.Ptr && v.IsNil() {
+	if d.nextCBORNil() && v.Kind() == reflect.Pointer && v.IsNil() {
 		d.skip()
 		return nil
 	}
 
-	if v.Kind() != reflect.Ptr && v.CanAddr() {
+	if v.Kind() != reflect.Pointer && v.CanAddr() {
 		v = v.Addr()
 	}
 	if u, ok := v.Interface().(Unmarshaler); ok {
@@ -1800,9 +1841,29 @@ func (d *decoder) parseToUnmarshaler(v reflect.Value) error {
 	return errors.New("cbor: failed to assert " + v.Type().String() + " as cbor.Unmarshaler")
 }
 
+// parseToUnexportedUnmarshaler parses CBOR data to value implementing unmarshaler interface.
+// It assumes data is well-formed, and does not perform bounds checking.
+func (d *decoder) parseToUnexportedUnmarshaler(v reflect.Value) error {
+	if d.nextCBORNil() && v.Kind() == reflect.Pointer && v.IsNil() {
+		d.skip()
+		return nil
+	}
+
+	if v.Kind() != reflect.Pointer && v.CanAddr() {
+		v = v.Addr()
+	}
+	if u, ok := v.Interface().(unmarshaler); ok {
+		start := d.off
+		d.skip()
+		return u.unmarshalCBOR(d.data[start:d.off])
+	}
+	d.skip()
+	return errors.New("cbor: failed to assert " + v.Type().String() + " as cbor.unmarshaler")
+}
+
 // parse parses CBOR data and returns value in default Go type.
 // It assumes data is well-formed, and does not perform bounds checking.
-func (d *decoder) parse(skipSelfDescribedTag bool) (interface{}, error) { //nolint:gocyclo
+func (d *decoder) parse(skipSelfDescribedTag bool) (any, error) { //nolint:gocyclo
 	// Strip self-described CBOR tag number.
 	if skipSelfDescribedTag {
 		for d.nextCBORType() == cborTypeTag {
@@ -2219,15 +2280,15 @@ func (d *decoder) parseTextString() ([]byte, error) {
 	return b, nil
 }
 
-func (d *decoder) parseArray() ([]interface{}, error) {
+func (d *decoder) parseArray() ([]any, error) {
 	_, _, val, indefiniteLength := d.getHeadWithIndefiniteLengthFlag()
 	hasSize := !indefiniteLength
 	count := int(val)
 	if !hasSize {
 		count = d.numOfItemsUntilBreak() // peek ahead to get array size to preallocate slice for better performance
 	}
-	v := make([]interface{}, count)
-	var e interface{}
+	v := make([]any, count)
+	var e any
 	var err, lastErr error
 	for i := 0; (hasSize && i < count) || (!hasSize && !d.foundBreak()); i++ {
 		if e, lastErr = d.parse(true); lastErr != nil {
@@ -2293,12 +2354,12 @@ func (d *decoder) parseArrayToArray(v reflect.Value, tInfo *typeInfo) error {
 	return err
 }
 
-func (d *decoder) parseMap() (interface{}, error) {
+func (d *decoder) parseMap() (any, error) {
 	_, _, val, indefiniteLength := d.getHeadWithIndefiniteLengthFlag()
 	hasSize := !indefiniteLength
 	count := int(val)
-	m := make(map[interface{}]interface{})
-	var k, e interface{}
+	m := make(map[any]any)
+	var k, e any
 	var err, lastErr error
 	keyCount := 0
 	for i := 0; (hasSize && i < count) || (!hasSize && !d.foundBreak()); i++ {
@@ -2363,11 +2424,7 @@ func (d *decoder) parseMapToMap(v reflect.Value, tInfo *typeInfo) error { //noli
 	hasSize := !indefiniteLength
 	count := int(val)
 	if v.IsNil() {
-		mapsize := count
-		if !hasSize {
-			mapsize = 0
-		}
-		v.Set(reflect.MakeMapWithSize(tInfo.nonPtrType, mapsize))
+		v.Set(reflect.MakeMap(tInfo.nonPtrType))
 	}
 	keyType, eleType := tInfo.keyTypeInfo.typ, tInfo.elemTypeInfo.typ
 	reuseKey, reuseEle := isImmutableKind(tInfo.keyTypeInfo.kind), isImmutableKind(tInfo.elemTypeInfo.kind)
@@ -2375,9 +2432,9 @@ func (d *decoder) parseMapToMap(v reflect.Value, tInfo *typeInfo) error { //noli
 	keyIsInterfaceType := keyType == typeIntf // If key type is interface{}, need to check if key value is hashable.
 	var err, lastErr error
 	keyCount := v.Len()
-	var existingKeys map[interface{}]bool // Store existing map keys, used for detecting duplicate map key.
+	var existingKeys map[any]bool // Store existing map keys, used for detecting duplicate map key.
 	if d.dm.dupMapKey == DupMapKeyEnforcedAPF {
-		existingKeys = make(map[interface{}]bool, keyCount)
+		existingKeys = make(map[any]bool, keyCount)
 		if keyCount > 0 {
 			vKeys := v.MapKeys()
 			for i := 0; i < len(vKeys); i++ {
@@ -2408,7 +2465,7 @@ func (d *decoder) parseMapToMap(v reflect.Value, tInfo *typeInfo) error { //noli
 			if !isHashableValue(keyValue.Elem()) {
 				var converted bool
 				if d.dm.mapKeyByteString == MapKeyByteStringAllowed {
-					var k interface{}
+					var k any
 					k, converted = convertByteSliceToByteString(keyValue.Elem().Interface())
 					if converted {
 						keyValue.Set(reflect.ValueOf(k))
@@ -2579,7 +2636,7 @@ func (d *decoder) parseMapToStruct(v reflect.Value, tInfo *typeInfo) error { //n
 
 	// Keeps track of CBOR map keys to detect duplicate map key
 	keyCount := 0
-	var mapKeys map[interface{}]struct{}
+	var mapKeys map[any]struct{}
 
 	errOnUnknownField := (d.dm.extraReturnErrors & ExtraDecErrorUnknownField) > 0
 
@@ -2589,7 +2646,7 @@ MapEntryLoop:
 
 		// If duplicate field detection is enabled and the key at index j did not match any
 		// field, k will hold the map key.
-		var k interface{}
+		var k any
 
 		t := d.nextCBORType()
 		if t == cborTypeTextString || (t == cborTypeByteString && d.dm.fieldNameByteString == FieldNameByteStringAllowed) {
@@ -2759,7 +2816,7 @@ MapEntryLoop:
 			// check is never reached.
 			if d.dm.dupMapKey == DupMapKeyEnforcedAPF {
 				if mapKeys == nil {
-					mapKeys = make(map[interface{}]struct{}, 1)
+					mapKeys = make(map[any]struct{}, 1)
 				}
 				mapKeys[k] = struct{}{}
 				newKeyCount := len(mapKeys)
@@ -2964,18 +3021,19 @@ func (d *decoder) nextCBORNil() bool {
 }
 
 var (
-	typeIntf              = reflect.TypeOf([]interface{}(nil)).Elem()
-	typeTime              = reflect.TypeOf(time.Time{})
-	typeBigInt            = reflect.TypeOf(big.Int{})
-	typeUnmarshaler       = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
-	typeBinaryUnmarshaler = reflect.TypeOf((*encoding.BinaryUnmarshaler)(nil)).Elem()
-	typeString            = reflect.TypeOf("")
-	typeByteSlice         = reflect.TypeOf([]byte(nil))
+	typeIntf                  = reflect.TypeOf([]any(nil)).Elem()
+	typeTime                  = reflect.TypeOf(time.Time{})
+	typeBigInt                = reflect.TypeOf(big.Int{})
+	typeUnmarshaler           = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
+	typeUnexportedUnmarshaler = reflect.TypeOf((*unmarshaler)(nil)).Elem()
+	typeBinaryUnmarshaler     = reflect.TypeOf((*encoding.BinaryUnmarshaler)(nil)).Elem()
+	typeString                = reflect.TypeOf("")
+	typeByteSlice             = reflect.TypeOf([]byte(nil))
 )
 
 func fillNil(_ cborType, v reflect.Value) error {
 	switch v.Kind() {
-	case reflect.Slice, reflect.Map, reflect.Interface, reflect.Ptr:
+	case reflect.Slice, reflect.Map, reflect.Interface, reflect.Pointer:
 		v.Set(reflect.Zero(v.Type()))
 		return nil
 	}
@@ -3078,7 +3136,7 @@ func fillFloat(t cborType, val float64, v reflect.Value) error {
 }
 
 func fillByteString(t cborType, val []byte, shared bool, v reflect.Value, bsts ByteStringToStringMode, bum BinaryUnmarshalerMode) error {
-	if bum == BinaryUnmarshalerByteString && reflect.PtrTo(v.Type()).Implements(typeBinaryUnmarshaler) {
+	if bum == BinaryUnmarshalerByteString && reflect.PointerTo(v.Type()).Implements(typeBinaryUnmarshaler) {
 		if v.CanAddr() {
 			v = v.Addr()
 			if u, ok := v.Interface().(encoding.BinaryUnmarshaler); ok {
@@ -3167,7 +3225,7 @@ func isHashableValue(rv reflect.Value) bool {
 // This function also handles nested tags.
 // CBOR data is already verified to be well-formed before this function is used,
 // so the recursion won't exceed max nested levels.
-func convertByteSliceToByteString(v interface{}) (interface{}, bool) {
+func convertByteSliceToByteString(v any) (any, bool) {
 	switch v := v.(type) {
 	case []byte:
 		return ByteString(v), true

decode_not_tinygo.go

@@ -1,19 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build !tinygo
-
-package cbor
-
-import "reflect"
-
-const (
-	defaultMaxNestedLevels = 32
-	minMaxNestedLevels     = 4
-	maxMaxNestedLevels     = 65535
-)
-
-func implements(concreteType reflect.Type, interfaceType reflect.Type) bool {
-	return concreteType.Implements(interfaceType) ||
-		reflect.PtrTo(concreteType).Implements(interfaceType)
-}

decode_not_tinygo_test.go

@@ -1,109 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build !tinygo
-
-package cbor
-
-import (
-	"reflect"
-	"testing"
-)
-
-func TestUnmarshalDeepNesting(t *testing.T) {
-	// Construct this object rather than embed such a large constant in the code
-	type TestNode struct {
-		Value int
-		Child *TestNode
-	}
-	n := &TestNode{Value: 0}
-	root := n
-	for i := 0; i < 65534; i++ {
-		child := &TestNode{Value: i}
-		n.Child = child
-		n = child
-	}
-	em, err := EncOptions{}.EncMode()
-	if err != nil {
-		t.Errorf("EncMode() returned error %v", err)
-	}
-	data, err := em.Marshal(root)
-	if err != nil {
-		t.Errorf("Marshal() deeply nested object returned error %v", err)
-	}
-
-	// Try unmarshal it
-	dm, err := DecOptions{MaxNestedLevels: 65535}.DecMode()
-	if err != nil {
-		t.Errorf("DecMode() returned error %v", err)
-	}
-	var readback TestNode
-	err = dm.Unmarshal(data, &readback)
-	if err != nil {
-		t.Errorf("Unmarshal() of deeply nested object returned error: %v", err)
-	}
-	if !reflect.DeepEqual(root, &readback) {
-		t.Errorf("Unmarshal() of deeply nested object did not match\nGot: %#v\n Want: %#v\n",
-			&readback, root)
-	}
-}
-
-func TestUnmarshalRegisteredTagToInterface(t *testing.T) {
-	var err error
-	tags := NewTagSet()
-	err = tags.Add(TagOptions{EncTag: EncTagRequired, DecTag: DecTagRequired}, reflect.TypeOf(C{}), 279)
-	if err != nil {
-		t.Error(err)
-	}
-	err = tags.Add(TagOptions{EncTag: EncTagRequired, DecTag: DecTagRequired}, reflect.TypeOf(D{}), 280)
-	if err != nil {
-		t.Error(err)
-	}
-
-	encMode, _ := PreferredUnsortedEncOptions().EncModeWithTags(tags)
-	decMode, _ := DecOptions{}.DecModeWithTags(tags)
-
-	v1 := A1{Field: &C{Field: 5}}
-	data1, err := encMode.Marshal(v1)
-	if err != nil {
-		t.Fatalf("Marshal(%+v) returned error %v", v1, err)
-	}
-
-	v2 := A2{Fields: []B{&C{Field: 5}, &D{Field: "a"}}}
-	data2, err := encMode.Marshal(v2)
-	if err != nil {
-		t.Fatalf("Marshal(%+v) returned error %v", v2, err)
-	}
-
-	testCases := []struct {
-		name           string
-		data           []byte
-		unmarshalToObj interface{}
-		wantValue      interface{}
-	}{
-		{
-			name:           "interface type",
-			data:           data1,
-			unmarshalToObj: &A1{},
-			wantValue:      &v1,
-		},
-		{
-			name:           "slice of interface type",
-			data:           data2,
-			unmarshalToObj: &A2{},
-			wantValue:      &v2,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			err = decMode.Unmarshal(tc.data, tc.unmarshalToObj)
-			if err != nil {
-				t.Errorf("Unmarshal(0x%x) returned error %v", tc.data, err)
-			}
-			if !reflect.DeepEqual(tc.unmarshalToObj, tc.wantValue) {
-				t.Errorf("Unmarshal(0x%x) = %v, want %v", tc.data, tc.unmarshalToObj, tc.wantValue)
-			}
-		})
-	}
-}

decode_tinygo.go

@@ -1,24 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build tinygo
-
-package cbor
-
-import "reflect"
-
-const (
-	defaultMaxNestedLevels = 16    // was 32 for non-tinygo (24+ for tinygo v0.33 panics tests)
-	minMaxNestedLevels     = 4     // same as non-tinygo
-	maxMaxNestedLevels     = 65535 // same as non-tinygo (to allow testing)
-)
-
-// tinygo v0.33 doesn't implement Type.AssignableTo() and it panics.
-// Type.AssignableTo() is used under the hood for Type.Implements().
-//
-// More details in https://github.com/tinygo-org/tinygo/issues/4277.
-//
-// implements() always returns false until tinygo implements Type.AssignableTo().
-func implements(concreteType reflect.Type, interfaceType reflect.Type) bool {
-	return false
-}

decode_tinygo_test.go

@@ -1,111 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build tinygo
-
-package cbor
-
-import (
-	"reflect"
-	"testing"
-)
-
-// TestUnmarshalDeepNesting tests marshaling and unmarshaling of deeply nesting objects.
-// tinygo v0.33 fails with roughly 24+ levels of nested objects.
-func TestUnmarshalDeepNesting(t *testing.T) {
-	// Construct this object rather than embed such a large constant in the code.
-	type TestNode struct {
-		Value int
-		Child *TestNode
-	}
-	n := &TestNode{Value: 0}
-	root := n
-	const tinygoNestedLevels = 24
-	for i := 1; i < tinygoNestedLevels; i++ {
-		child := &TestNode{Value: i}
-		n.Child = child
-		n = child
-	}
-	em, err := EncOptions{}.EncMode()
-	if err != nil {
-		t.Errorf("EncMode() returned error %v", err)
-	}
-	data, err := em.Marshal(root)
-	if err != nil {
-		t.Errorf("Marshal() deeply nested object returned error %v", err)
-	}
-
-	// Try unmarshal it
-	dm, err := DecOptions{MaxNestedLevels: tinygoNestedLevels}.DecMode()
-	if err != nil {
-		t.Errorf("DecMode() returned error %v", err)
-	}
-	var readback TestNode
-	err = dm.Unmarshal(data, &readback)
-	if err != nil {
-		t.Errorf("Unmarshal() of deeply nested object returned error: %v", err)
-	}
-	if !reflect.DeepEqual(root, &readback) {
-		t.Errorf("Unmarshal() of deeply nested object did not match\nGot: %#v\n Want: %#v\n",
-			&readback, root)
-	}
-}
-
-func TestUnmarshalRegisteredTagToInterface(t *testing.T) {
-	var err error
-	tags := NewTagSet()
-	err = tags.Add(TagOptions{EncTag: EncTagRequired, DecTag: DecTagRequired}, reflect.TypeOf(C{}), 279)
-	if err != nil {
-		t.Error(err)
-	}
-	err = tags.Add(TagOptions{EncTag: EncTagRequired, DecTag: DecTagRequired}, reflect.TypeOf(D{}), 280)
-	if err != nil {
-		t.Error(err)
-	}
-
-	encMode, _ := PreferredUnsortedEncOptions().EncModeWithTags(tags)
-	decMode, _ := DecOptions{}.DecModeWithTags(tags)
-
-	v1 := A1{Field: &C{Field: 5}}
-	data1, err := encMode.Marshal(v1)
-	if err != nil {
-		t.Fatalf("Marshal(%+v) returned error %v", v1, err)
-	}
-
-	v2 := A2{Fields: []B{&C{Field: 5}, &D{Field: "a"}}}
-	data2, err := encMode.Marshal(v2)
-	if err != nil {
-		t.Fatalf("Marshal(%+v) returned error %v", v2, err)
-	}
-
-	testCases := []struct {
-		name           string
-		data           []byte
-		unmarshalToObj interface{}
-		wantValue      interface{}
-	}{
-		{
-			name:           "interface type",
-			data:           data1,
-			unmarshalToObj: &A1{},
-			wantValue:      &v1,
-		},
-		{
-			name:           "slice of interface type",
-			data:           data2,
-			unmarshalToObj: &A2{},
-			wantValue:      &v2,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			err = decMode.Unmarshal(tc.data, tc.unmarshalToObj)
-			if err == nil {
-				t.Errorf("Unmarshal(0x%x) returned no error, expect error", tc.data)
-			} else if _, ok := err.(*UnmarshalTypeError); !ok {
-				t.Errorf("Unmarshal(0x%x) returned wrong error type %T, want (*UnmarshalTypeError)", tc.data, err)
-			}
-		})
-	}
-}

doc.go

@@ -2,15 +2,15 @@
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 /*
-Package cbor is a modern CBOR codec (RFC 8949 & RFC 7049) with CBOR tags,
-Go struct tags (toarray/keyasint/omitempty), Core Deterministic Encoding,
+Package cbor is a modern CBOR codec (RFC 8949 & RFC 8742) with CBOR tags,
+Go struct tag options (toarray/keyasint/omitempty/omitzero), Core Deterministic Encoding,
 CTAP2, Canonical CBOR, float64->32->16, and duplicate map key detection.
 
 Encoding options allow "preferred serialization" by encoding integers and floats
 to their smallest forms (e.g. float16) when values fit.
 
-Struct tags like "keyasint", "toarray" and "omitempty" make CBOR data smaller
-and easier to use with structs.
+Struct tag options "keyasint", "toarray", "omitempty", and "omitzero" reduce encoding size
+and reduce programming effort.
 
 For example, "toarray" tag makes struct fields encode to CBOR array elements.  And
 "keyasint" makes a field encode to an element of CBOR map with specified int key.
@@ -23,11 +23,19 @@ The Quick Start guide is at https://github.com/fxamacker/cbor#quick-start
 
 Function signatures identical to encoding/json include:
 
-	Marshal, Unmarshal, NewEncoder, NewDecoder, (*Encoder).Encode, (*Decoder).Decode.
+	Marshal, Unmarshal, NewEncoder, NewDecoder, (*Encoder).Encode, (*Decoder).Decode
 
 Standard interfaces include:
 
-	BinaryMarshaler, BinaryUnmarshaler, Marshaler, and Unmarshaler.
+	BinaryMarshaler, BinaryUnmarshaler, Marshaler, and Unmarshaler
+
+Diagnostic functions translate CBOR data item into Diagnostic Notation:
+
+	Diagnose, DiagnoseFirst
+
+Functions that simplify using CBOR Sequences (RFC 8742) include:
+
+	UnmarshalFirst
 
 Custom encoding and decoding is possible by implementing standard interfaces for
 user-defined Go types.
@@ -50,19 +58,19 @@ Modes are intended to be reused and are safe for concurrent use.
 
 EncMode and DecMode Interfaces
 
-	    // EncMode interface uses immutable options and is safe for concurrent use.
-	    type EncMode interface {
+	// EncMode interface uses immutable options and is safe for concurrent use.
+	type EncMode interface {
 		Marshal(v interface{}) ([]byte, error)
 		NewEncoder(w io.Writer) *Encoder
 		EncOptions() EncOptions  // returns copy of options
-	    }
+	}
 
-	    // DecMode interface uses immutable options and is safe for concurrent use.
-	    type DecMode interface {
+	// DecMode interface uses immutable options and is safe for concurrent use.
+	type DecMode interface {
 		Unmarshal(data []byte, v interface{}) error
 		NewDecoder(r io.Reader) *Decoder
 		DecOptions() DecOptions  // returns copy of options
-	    }
+	}
 
 Using Default Encoding Mode
 
@@ -78,6 +86,16 @@ Using Default Decoding Mode
 	decoder := cbor.NewDecoder(r)
 	err = decoder.Decode(&v)
 
+Using Default Mode of UnmarshalFirst to Decode CBOR Sequences
+
+	// Decode the first CBOR data item and return remaining bytes:
+	rest, err = cbor.UnmarshalFirst(b, &v)   // decode []byte b to v
+
+Using Extended Diagnostic Notation (EDN) to represent CBOR data
+
+	// Translate the first CBOR data item into text and return remaining bytes.
+	text, rest, err = cbor.DiagnoseFirst(b)  // decode []byte b to text
+
 Creating and Using Encoding Modes
 
 	// Create EncOptions using either struct literal or a function.
@@ -111,15 +129,20 @@ Decoding Options: https://github.com/fxamacker/cbor#decoding-options
 Struct tags like `cbor:"name,omitempty"` and `json:"name,omitempty"` work as expected.
 If both struct tags are specified then `cbor` is used.
 
-Struct tags like "keyasint", "toarray", and "omitempty" make it easy to use
+Struct tag options like "keyasint", "toarray", "omitempty", and "omitzero" make it easy to use
 very compact formats like COSE and CWT (CBOR Web Tokens) with structs.
 
+The "omitzero" option omits zero values from encoding, matching
+[stdlib encoding/json behavior](https://pkg.go.dev/encoding/json#Marshal).
+When specified in the `cbor` tag, the option is always honored.
+When specified in the `json` tag, the option is honored when building with Go 1.24+.
+
 For example, "toarray" makes struct fields encode to array elements.  And "keyasint"
 makes struct fields encode to elements of CBOR map with int keys.
 
 https://raw.githubusercontent.com/fxamacker/images/master/cbor/v2.0.0/cbor_easy_api.png
 
-Struct tags are listed at https://github.com/fxamacker/cbor#struct-tags-1
+Struct tag options are listed at https://github.com/fxamacker/cbor#struct-tags-1
 
 # Tests and Fuzzing
 

encode.go

@@ -58,8 +58,10 @@ import (
 //
 // Marshal supports format string stored under the "cbor" key in the struct
 // field's tag.  CBOR format string can specify the name of the field,
-// "omitempty" and "keyasint" options, and special case "-" for field omission.
-// If "cbor" key is absent, Marshal uses "json" key.
+// "omitempty", "omitzero" and "keyasint" options, and special case "-" for
+// field omission. If "cbor" key is absent, Marshal uses "json" key.
+// When using the "json" key, the "omitzero" option is honored when building
+// with Go 1.24+ to match stdlib encoding/json behavior.
 //
 // Struct field name is treated as integer if it has "keyasint" option in
 // its format string.  The format string must specify an integer as its
@@ -67,8 +69,8 @@ import (
 //
 // Special struct field "_" is used to specify struct level options, such as
 // "toarray". "toarray" option enables Go struct to be encoded as CBOR array.
-// "omitempty" is disabled by "toarray" to ensure that the same number
-// of elements are encoded every time.
+// "omitempty" and "omitzero" are disabled by "toarray" to ensure that the
+// same number of elements are encoded every time.
 //
 // Anonymous struct fields are marshaled as if their exported fields
 // were fields in the outer struct.  Marshal follows the same struct fields
@@ -92,7 +94,7 @@ import (
 //
 // Values of other types cannot be encoded in CBOR.  Attempting
 // to encode such a value causes Marshal to return an UnsupportedTypeError.
-func Marshal(v interface{}) ([]byte, error) {
+func Marshal(v any) ([]byte, error) {
 	return defaultEncMode.Marshal(v)
 }
 
@@ -103,7 +105,7 @@ func Marshal(v interface{}) ([]byte, error) {
 // partially encoded data if error is returned.
 //
 // See Marshal for more details.
-func MarshalToBuffer(v interface{}, buf *bytes.Buffer) error {
+func MarshalToBuffer(v any, buf *bytes.Buffer) error {
 	return defaultEncMode.MarshalToBuffer(v, buf)
 }
 
@@ -773,8 +775,9 @@ func (opts EncOptions) encMode() (*encMode, error) { //nolint:gocritic // ignore
 
 // EncMode is the main interface for CBOR encoding.
 type EncMode interface {
-	Marshal(v interface{}) ([]byte, error)
+	Marshal(v any) ([]byte, error)
 	NewEncoder(w io.Writer) *Encoder
+	NewStreamEncoder(w io.Writer) *StreamEncoder
 	EncOptions() EncOptions
 }
 
@@ -783,7 +786,7 @@ type EncMode interface {
 // into the built-in buffer pool.
 type UserBufferEncMode interface {
 	EncMode
-	MarshalToBuffer(v interface{}, buf *bytes.Buffer) error
+	MarshalToBuffer(v any, buf *bytes.Buffer) error
 
 	// This private method is to prevent users implementing
 	// this interface and so future additions to it will
@@ -921,7 +924,7 @@ func (em *encMode) encTagBytes(t reflect.Type) []byte {
 // Marshal returns the CBOR encoding of v using em encoding mode.
 //
 // See the documentation for Marshal for details.
-func (em *encMode) Marshal(v interface{}) ([]byte, error) {
+func (em *encMode) Marshal(v any) ([]byte, error) {
 	e := getEncodeBuffer()
 
 	if err := encode(e, em, reflect.ValueOf(v)); err != nil {
@@ -943,7 +946,7 @@ func (em *encMode) Marshal(v interface{}) ([]byte, error) {
 // partially encoded data if error is returned.
 //
 // See Marshal for more details.
-func (em *encMode) MarshalToBuffer(v interface{}, buf *bytes.Buffer) error {
+func (em *encMode) MarshalToBuffer(v any, buf *bytes.Buffer) error {
 	if buf == nil {
 		return fmt.Errorf("cbor: encoding buffer provided by user is nil")
 	}
@@ -955,11 +958,19 @@ func (em *encMode) NewEncoder(w io.Writer) *Encoder {
 	return &Encoder{w: w, em: em}
 }
 
+// NewStreamEncoder returns a new stream encoder that writes sequentially to w using em EncMode.
+func (em *encMode) NewStreamEncoder(w io.Writer) *StreamEncoder {
+	return &StreamEncoder{
+		Encoder: em.NewEncoder(w),
+		buf:     getEncodeBuffer(),
+	}
+}
+
 // encodeBufferPool caches unused bytes.Buffer objects for later reuse.
 var encodeBufferPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		e := new(bytes.Buffer)
-		e.Grow(32) // TODO: make this configurable
+		e.Grow(64) // TODO: make this configurable
 		return e
 	},
 }
@@ -975,6 +986,7 @@ func putEncodeBuffer(e *bytes.Buffer) {
 
 type encodeFunc func(e *bytes.Buffer, em *encMode, v reflect.Value) error
 type isEmptyFunc func(em *encMode, v reflect.Value) (empty bool, err error)
+type isZeroFunc func(v reflect.Value) (zero bool, err error)
 
 func encode(e *bytes.Buffer, em *encMode, v reflect.Value) error {
 	if !v.IsValid() {
@@ -983,7 +995,7 @@ func encode(e *bytes.Buffer, em *encMode, v reflect.Value) error {
 		return nil
 	}
 	vt := v.Type()
-	f, _ := getEncodeFunc(vt)
+	f, _, _ := getEncodeFunc(vt)
 	if f == nil {
 		return &UnsupportedTypeError{vt}
 	}
@@ -1483,6 +1495,15 @@ func encodeStruct(e *bytes.Buffer, em *encMode, v reflect.Value) (err error) {
 				continue
 			}
 		}
+		if f.omitZero {
+			zero, err := f.izf(fv)
+			if err != nil {
+				return err
+			}
+			if zero {
+				continue
+			}
+		}
 
 		if !f.keyAsInt && em.fieldName == FieldNameToByteString {
 			e.Write(f.cborNameByteString)
@@ -1775,34 +1796,34 @@ var (
 	typeByteString      = reflect.TypeOf(ByteString(""))
 )
 
-func getEncodeFuncInternal(t reflect.Type) (ef encodeFunc, ief isEmptyFunc) {
+func getEncodeFuncInternal(t reflect.Type) (ef encodeFunc, ief isEmptyFunc, izf isZeroFunc) {
 	k := t.Kind()
-	if k == reflect.Ptr {
-		return getEncodeIndirectValueFunc(t), isEmptyPtr
+	if k == reflect.Pointer {
+		return getEncodeIndirectValueFunc(t), isEmptyPtr, getIsZeroFunc(t)
 	}
 	switch t {
 	case typeSimpleValue:
-		return encodeMarshalerType, isEmptyUint
+		return encodeMarshalerType, isEmptyUint, getIsZeroFunc(t)
 
 	case typeTag:
-		return encodeTag, alwaysNotEmpty
+		return encodeTag, alwaysNotEmpty, getIsZeroFunc(t)
 
 	case typeTime:
-		return encodeTime, alwaysNotEmpty
+		return encodeTime, alwaysNotEmpty, getIsZeroFunc(t)
 
 	case typeBigInt:
-		return encodeBigInt, alwaysNotEmpty
+		return encodeBigInt, alwaysNotEmpty, getIsZeroFunc(t)
 
 	case typeRawMessage:
-		return encodeMarshalerType, isEmptySlice
+		return encodeMarshalerType, isEmptySlice, getIsZeroFunc(t)
 
 	case typeByteString:
-		return encodeMarshalerType, isEmptyString
+		return encodeMarshalerType, isEmptyString, getIsZeroFunc(t)
 	}
-	if reflect.PtrTo(t).Implements(typeMarshaler) {
-		return encodeMarshalerType, alwaysNotEmpty
+	if reflect.PointerTo(t).Implements(typeMarshaler) {
+		return encodeMarshalerType, alwaysNotEmpty, getIsZeroFunc(t)
 	}
-	if reflect.PtrTo(t).Implements(typeBinaryMarshaler) {
+	if reflect.PointerTo(t).Implements(typeBinaryMarshaler) {
 		defer func() {
 			// capture encoding method used for modes that disable BinaryMarshaler
 			bme := binaryMarshalerEncoder{
@@ -1815,39 +1836,39 @@ func getEncodeFuncInternal(t reflect.Type) (ef encodeFunc, ief isEmptyFunc) {
 	}
 	switch k {
 	case reflect.Bool:
-		return encodeBool, isEmptyBool
+		return encodeBool, isEmptyBool, getIsZeroFunc(t)
 
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return encodeInt, isEmptyInt
+		return encodeInt, isEmptyInt, getIsZeroFunc(t)
 
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-		return encodeUint, isEmptyUint
+		return encodeUint, isEmptyUint, getIsZeroFunc(t)
 
 	case reflect.Float32, reflect.Float64:
-		return encodeFloat, isEmptyFloat
+		return encodeFloat, isEmptyFloat, getIsZeroFunc(t)
 
 	case reflect.String:
-		return encodeString, isEmptyString
+		return encodeString, isEmptyString, getIsZeroFunc(t)
 
 	case reflect.Slice:
 		if t.Elem().Kind() == reflect.Uint8 {
-			return encodeByteString, isEmptySlice
+			return encodeByteString, isEmptySlice, getIsZeroFunc(t)
 		}
 		fallthrough
 
 	case reflect.Array:
-		f, _ := getEncodeFunc(t.Elem())
+		f, _, _ := getEncodeFunc(t.Elem())
 		if f == nil {
-			return nil, nil
+			return nil, nil, nil
 		}
-		return arrayEncodeFunc{f: f}.encode, isEmptySlice
+		return arrayEncodeFunc{f: f}.encode, isEmptySlice, getIsZeroFunc(t)
 
 	case reflect.Map:
 		f := getEncodeMapFunc(t)
 		if f == nil {
-			return nil, nil
+			return nil, nil, nil
 		}
-		return f, isEmptyMap
+		return f, isEmptyMap, getIsZeroFunc(t)
 
 	case reflect.Struct:
 		// Get struct's special field "_" tag options
@@ -1855,31 +1876,31 @@ func getEncodeFuncInternal(t reflect.Type) (ef encodeFunc, ief isEmptyFunc) {
 			tag := f.Tag.Get("cbor")
 			if tag != "-" {
 				if hasToArrayOption(tag) {
-					return encodeStructToArray, isEmptyStruct
+					return encodeStructToArray, isEmptyStruct, isZeroFieldStruct
 				}
 			}
 		}
-		return encodeStruct, isEmptyStruct
+		return encodeStruct, isEmptyStruct, getIsZeroFunc(t)
 
 	case reflect.Interface:
-		return encodeIntf, isEmptyIntf
+		return encodeIntf, isEmptyIntf, getIsZeroFunc(t)
 	}
-	return nil, nil
+	return nil, nil, nil
 }
 
 func getEncodeIndirectValueFunc(t reflect.Type) encodeFunc {
-	for t.Kind() == reflect.Ptr {
+	for t.Kind() == reflect.Pointer {
 		t = t.Elem()
 	}
-	f, _ := getEncodeFunc(t)
+	f, _, _ := getEncodeFunc(t)
 	if f == nil {
 		return nil
 	}
 	return func(e *bytes.Buffer, em *encMode, v reflect.Value) error {
-		for v.Kind() == reflect.Ptr && !v.IsNil() {
+		for v.Kind() == reflect.Pointer && !v.IsNil() {
 			v = v.Elem()
 		}
-		if v.Kind() == reflect.Ptr && v.IsNil() {
+		if v.Kind() == reflect.Pointer && v.IsNil() {
 			e.Write(cborNil)
 			return nil
 		}
@@ -1987,3 +2008,96 @@ func float32NaNFromReflectValue(v reflect.Value) float32 {
 	f32 := p.Convert(reflect.TypeOf((*float32)(nil))).Elem().Interface().(float32)
 	return f32
 }
+
+type isZeroer interface {
+	IsZero() bool
+}
+
+var isZeroerType = reflect.TypeOf((*isZeroer)(nil)).Elem()
+
+// getIsZeroFunc returns a function for the given type that can be called to determine if a given value is zero.
+// Types that implement `IsZero() bool` are delegated to for non-nil values.
+// Types that do not implement `IsZero() bool` use the reflect.Value#IsZero() implementation.
+// The returned function matches behavior of stdlib encoding/json behavior in Go 1.24+.
+func getIsZeroFunc(t reflect.Type) isZeroFunc {
+	// Provide a function that uses a type's IsZero method if defined.
+	switch {
+	case t == nil:
+		return isZeroDefault
+	case t.Kind() == reflect.Interface && t.Implements(isZeroerType):
+		return isZeroInterfaceCustom
+	case t.Kind() == reflect.Pointer && t.Implements(isZeroerType):
+		return isZeroPointerCustom
+	case t.Implements(isZeroerType):
+		return isZeroCustom
+	case reflect.PointerTo(t).Implements(isZeroerType):
+		return isZeroAddrCustom
+	default:
+		return isZeroDefault
+	}
+}
+
+// isZeroInterfaceCustom returns true for nil or pointer-to-nil values,
+// and delegates to the custom IsZero() implementation otherwise.
+func isZeroInterfaceCustom(v reflect.Value) (bool, error) {
+	kind := v.Kind()
+
+	switch kind {
+	case reflect.Chan, reflect.Func, reflect.Map, reflect.Pointer, reflect.Interface, reflect.Slice:
+		if v.IsNil() {
+			return true, nil
+		}
+	}
+
+	switch kind {
+	case reflect.Interface, reflect.Pointer:
+		if elem := v.Elem(); elem.Kind() == reflect.Pointer && elem.IsNil() {
+			return true, nil
+		}
+	}
+
+	return v.Interface().(isZeroer).IsZero(), nil
+}
+
+// isZeroPointerCustom returns true for nil values,
+// and delegates to the custom IsZero() implementation otherwise.
+func isZeroPointerCustom(v reflect.Value) (bool, error) {
+	if v.IsNil() {
+		return true, nil
+	}
+	return v.Interface().(isZeroer).IsZero(), nil
+}
+
+// isZeroCustom delegates to the custom IsZero() implementation.
+func isZeroCustom(v reflect.Value) (bool, error) {
+	return v.Interface().(isZeroer).IsZero(), nil
+}
+
+// isZeroAddrCustom delegates to the custom IsZero() implementation of the addr of the value.
+func isZeroAddrCustom(v reflect.Value) (bool, error) {
+	if !v.CanAddr() {
+		// Temporarily box v so we can take the address.
+		v2 := reflect.New(v.Type()).Elem()
+		v2.Set(v)
+		v = v2
+	}
+	return v.Addr().Interface().(isZeroer).IsZero(), nil
+}
+
+// isZeroDefault calls reflect.Value#IsZero()
+func isZeroDefault(v reflect.Value) (bool, error) {
+	if !v.IsValid() {
+		// v is zero value
+		return true, nil
+	}
+	return v.IsZero(), nil
+}
+
+// isZeroFieldStruct is used to determine whether to omit toarray structs
+func isZeroFieldStruct(v reflect.Value) (bool, error) {
+	structType, err := getEncodingStructType(v.Type())
+	if err != nil {
+		return false, err
+	}
+	return len(structType.fields) == 0, nil
+}

encode_map.go

@@ -1,8 +1,6 @@
 // Copyright (c) Faye Amacker. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
-//go:build go1.20 && !tinygo
-
 package cbor
 
 import (
@@ -67,8 +65,8 @@ func (me *mapKeyValueEncodeFunc) encodeKeyValues(e *bytes.Buffer, em *encMode, v
 }
 
 func getEncodeMapFunc(t reflect.Type) encodeFunc {
-	kf, _ := getEncodeFunc(t.Key())
-	ef, _ := getEncodeFunc(t.Elem())
+	kf, _, _ := getEncodeFunc(t.Key())
+	ef, _, _ := getEncodeFunc(t.Elem())
 	if kf == nil || ef == nil {
 		return nil
 	}
@@ -76,13 +74,13 @@ func getEncodeMapFunc(t reflect.Type) encodeFunc {
 		kf: kf,
 		ef: ef,
 		kpool: sync.Pool{
-			New: func() interface{} {
+			New: func() any {
 				rk := reflect.New(t.Key()).Elem()
 				return &rk
 			},
 		},
 		vpool: sync.Pool{
-			New: func() interface{} {
+			New: func() any {
 				rv := reflect.New(t.Elem()).Elem()
 				return &rv
 			},

encode_map_go117.go

@@ -1,60 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build !go1.20 || tinygo
-
-package cbor
-
-import (
-	"bytes"
-	"reflect"
-)
-
-type mapKeyValueEncodeFunc struct {
-	kf, ef encodeFunc
-}
-
-func (me *mapKeyValueEncodeFunc) encodeKeyValues(e *bytes.Buffer, em *encMode, v reflect.Value, kvs []keyValue) error {
-	if kvs == nil {
-		for i, iter := 0, v.MapRange(); iter.Next(); i++ {
-			if err := me.kf(e, em, iter.Key()); err != nil {
-				return err
-			}
-			if err := me.ef(e, em, iter.Value()); err != nil {
-				return err
-			}
-		}
-		return nil
-	}
-
-	initial := e.Len()
-	for i, iter := 0, v.MapRange(); iter.Next(); i++ {
-		offset := e.Len()
-		if err := me.kf(e, em, iter.Key()); err != nil {
-			return err
-		}
-		valueOffset := e.Len()
-		if err := me.ef(e, em, iter.Value()); err != nil {
-			return err
-		}
-		kvs[i] = keyValue{
-			offset:      offset - initial,
-			valueOffset: valueOffset - initial,
-			nextOffset:  e.Len() - initial,
-		}
-	}
-
-	return nil
-}
-
-func getEncodeMapFunc(t reflect.Type) encodeFunc {
-	kf, _ := getEncodeFunc(t.Key())
-	ef, _ := getEncodeFunc(t.Elem())
-	if kf == nil || ef == nil {
-		return nil
-	}
-	mkv := &mapKeyValueEncodeFunc{kf: kf, ef: ef}
-	return mapEncodeFunc{
-		e: mkv.encodeKeyValues,
-	}.encode
-}

example_test.go

@@ -82,7 +82,7 @@ func ExampleMarshal_canonical() {
 	// a46341676504644d616c65f4644e616d656543616e647968436f6e7461637473a2634a6f656c3232322d3232322d32323232644d6172796c3131312d3131312d31313131
 }
 
-// This example uses "toarray" struct tag to encode struct as CBOR array.
+// This example uses "toarray" struct tag option to encode struct as CBOR array.
 func ExampleMarshal_toarray() {
 	type Record struct {
 		_           struct{} `cbor:",toarray"`
@@ -100,7 +100,7 @@ func ExampleMarshal_toarray() {
 	// 836763757272656e74615601
 }
 
-// This example uses "keyasint" struct tag to encode struct's fiele names as integer.
+// This example uses "keyasint" struct tag option to encode struct's field names as integer.
 // This feautre is very useful in handling COSE, CWT, SenML data.
 func ExampleMarshal_keyasint() {
 	type Record struct {
@@ -353,7 +353,7 @@ func ExampleDecoder() {
 }
 
 func Example_cWT() {
-	// Use "keyasint" struct tag to encode/decode struct to/from CBOR map.
+	// Use "keyasint" struct tag option to encode/decode struct to/from CBOR map.
 	type claims struct {
 		Iss string `cbor:"1,keyasint"`
 		Sub string `cbor:"2,keyasint"`
@@ -403,14 +403,14 @@ func Example_cWTWithDupMapKeyOption() {
 }
 
 func Example_signedCWT() {
-	// Use "keyasint" struct tag to encode/decode struct to/from CBOR map.
+	// Use "keyasint" struct tag option to encode/decode struct to/from CBOR map.
 	// Partial COSE header definition
 	type coseHeader struct {
 		Alg int    `cbor:"1,keyasint,omitempty"`
 		Kid []byte `cbor:"4,keyasint,omitempty"`
 		IV  []byte `cbor:"5,keyasint,omitempty"`
 	}
-	// Use "toarray" struct tag to encode/decode struct to/from CBOR array.
+	// Use "toarray" struct tag option to encode/decode struct to/from CBOR array.
 	type signedCWT struct {
 		_           struct{} `cbor:",toarray"`
 		Protected   []byte
@@ -433,14 +433,14 @@ func Example_signedCWT() {
 }
 
 func Example_signedCWTWithTag() {
-	// Use "keyasint" struct tag to encode/decode struct to/from CBOR map.
+	// Use "keyasint" struct tag option to encode/decode struct to/from CBOR map.
 	// Partial COSE header definition
 	type coseHeader struct {
 		Alg int    `cbor:"1,keyasint,omitempty"`
 		Kid []byte `cbor:"4,keyasint,omitempty"`
 		IV  []byte `cbor:"5,keyasint,omitempty"`
 	}
-	// Use "toarray" struct tag to encode/decode struct to/from CBOR array.
+	// Use "toarray" struct tag option to encode/decode struct to/from CBOR array.
 	type signedCWT struct {
 		_           struct{} `cbor:",toarray"`
 		Protected   []byte
@@ -478,7 +478,7 @@ func Example_signedCWTWithTag() {
 }
 
 func Example_cOSE() {
-	// Use "keyasint" struct tag to encode/decode struct to/from CBOR map.
+	// Use "keyasint" struct tag option to encode/decode struct to/from CBOR map.
 	// Use cbor.RawMessage to delay unmarshaling (CrvOrNOrK's data type depends on Kty's value).
 	type coseKey struct {
 		Kty       int             `cbor:"1,keyasint,omitempty"`
@@ -507,7 +507,7 @@ func Example_cOSE() {
 }
 
 func Example_senML() {
-	// Use "keyasint" struct tag to encode/decode struct to/from CBOR map.
+	// Use "keyasint" struct tag option to encode/decode struct to/from CBOR map.
 	type SenMLRecord struct {
 		BaseName    string  `cbor:"-2,keyasint,omitempty"`
 		BaseTime    float64 `cbor:"-3,keyasint,omitempty"`

go.mod

@@ -1,5 +1,5 @@
 module github.com/fxamacker/cbor/v2
 
-go 1.17 // Compiling with go 1.20+ uses new features and optimizations
+go 1.20
 
 require github.com/x448/float16 v0.8.4

json_test.go

@@ -1,3 +1,6 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
 package cbor_test
 
 import (
@@ -34,7 +37,7 @@ func TestStdlibJSONCompatibility(t *testing.T) {
 
 	for _, tc := range []struct {
 		name       string
-		original   interface{}
+		original   any
 		ifaceEqual bool // require equal intermediate interface{} values from both protocols
 	}{
 		{
@@ -67,14 +70,14 @@ func TestStdlibJSONCompatibility(t *testing.T) {
 			}
 			t.Logf("original to cbor: %s", diag1)
 
-			var jintf interface{}
+			var jintf any
 			err = json.Unmarshal(j1, &jintf)
 			if err != nil {
 				t.Fatal(err)
 			}
 			t.Logf("json to interface{} (%T): %#v", jintf, jintf)
 
-			var cintf interface{}
+			var cintf any
 			err = dec.Unmarshal(c1, &cintf)
 			if err != nil {
 				t.Fatal(err)

omitzero_go124.go

@@ -0,0 +1,8 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+//go:build go1.24
+
+package cbor
+
+var jsonStdlibSupportsOmitzero = true

omitzero_pre_go124.go

@@ -0,0 +1,8 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+//go:build !go1.24
+
+package cbor
+
+var jsonStdlibSupportsOmitzero = false

simplevalue.go

@@ -1,3 +1,6 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
 package cbor
 
 import (
@@ -45,6 +48,9 @@ func (sv SimpleValue) MarshalCBOR() ([]byte, error) {
 }
 
 // UnmarshalCBOR decodes CBOR simple value (major type 7) to SimpleValue.
+//
+// Deprecated: No longer used by this codec; kept for compatibility
+// with user apps that directly call this function.
 func (sv *SimpleValue) UnmarshalCBOR(data []byte) error {
 	if sv == nil {
 		return errors.New("cbor.SimpleValue: UnmarshalCBOR on nil pointer")
@@ -52,6 +58,29 @@ func (sv *SimpleValue) UnmarshalCBOR(data []byte) error {
 
 	d := decoder{data: data, dm: defaultDecMode}
 
+	// Check well-formedness of CBOR data item.
+	// SimpleValue.UnmarshalCBOR() is exported, so
+	// the codec needs to support same behavior for:
+	// - Unmarshal(data, *SimpleValue)
+	// - SimpleValue.UnmarshalCBOR(data)
+	err := d.wellformed(false, false)
+	if err != nil {
+		return err
+	}
+
+	return sv.unmarshalCBOR(data)
+}
+
+// unmarshalCBOR decodes CBOR simple value (major type 7) to SimpleValue.
+// This function assumes data is well-formed, and does not perform bounds checking.
+// This function is called by Unmarshal().
+func (sv *SimpleValue) unmarshalCBOR(data []byte) error {
+	if sv == nil {
+		return errors.New("cbor.SimpleValue: UnmarshalCBOR on nil pointer")
+	}
+
+	d := decoder{data: data, dm: defaultDecMode}
+
 	typ, ai, val := d.getHead()
 
 	if typ != cborTypePrimitives {

simplevalue_test.go

@@ -5,7 +5,9 @@ package cbor
 
 import (
 	"bytes"
+	"io"
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -51,8 +53,127 @@ func TestUnmarshalSimpleValue(t *testing.T) {
 	})
 }
 
+func TestUnmarshalSimpleValueOnBadData(t *testing.T) {
+	testCases := []struct {
+		name   string
+		data   []byte
+		errMsg string
+	}{
+		// Empty data
+		{
+			name:   "nil data",
+			data:   nil,
+			errMsg: io.EOF.Error(),
+		},
+		{
+			name:   "empty data",
+			data:   []byte{},
+			errMsg: io.EOF.Error(),
+		},
+
+		// Wrong CBOR types
+		{
+			name:   "uint type",
+			data:   hexDecode("01"),
+			errMsg: "cbor: cannot unmarshal positive integer into Go value of type SimpleValue",
+		},
+		{
+			name:   "int type",
+			data:   hexDecode("20"),
+			errMsg: "cbor: cannot unmarshal negative integer into Go value of type SimpleValue",
+		},
+		{
+			name:   "byte string type",
+			data:   hexDecode("40"),
+			errMsg: "cbor: cannot unmarshal byte string into Go value of type SimpleValue",
+		},
+		{
+			name:   "string type",
+			data:   hexDecode("60"),
+			errMsg: "cbor: cannot unmarshal UTF-8 text string into Go value of type SimpleValue",
+		},
+		{
+			name:   "array type",
+			data:   hexDecode("80"),
+			errMsg: "cbor: cannot unmarshal array into Go value of type SimpleValue",
+		},
+		{
+			name:   "map type",
+			data:   hexDecode("a0"),
+			errMsg: "cbor: cannot unmarshal map into Go value of type SimpleValue",
+		},
+		{
+			name:   "tag type",
+			data:   hexDecode("c074323031332d30332d32315432303a30343a30305a"),
+			errMsg: "cbor: cannot unmarshal tag into Go value of type SimpleValue",
+		},
+		{
+			name:   "float type",
+			data:   hexDecode("f90000"),
+			errMsg: "cbor: cannot unmarshal primitives into Go value of type SimpleValue",
+		},
+
+		// Truncated CBOR data
+		{
+			name:   "truncated head",
+			data:   hexDecode("18"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Truncated CBOR simple value
+		{
+			name:   "truncated simple value",
+			data:   hexDecode("f8"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Invalid simple value
+		{
+			name:   "invalid simple value",
+			data:   hexDecode("f800"),
+			errMsg: "cbor: invalid simple value 0 for type primitives",
+		},
+
+		// Extraneous CBOR data
+		{
+			name:   "extraneous data",
+			data:   hexDecode("f4f5"),
+			errMsg: "cbor: 1 bytes of extraneous data starting at index 1",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Test SimpleValue.UnmarshalCBOR(data)
+			{
+				var v SimpleValue
+
+				err := v.UnmarshalCBOR(tc.data)
+				if err == nil {
+					t.Errorf("UnmarshalCBOR(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("UnmarshalCBOR(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+			// Test Unmarshal(data, *SimpleValue), which calls SimpleValue.unmarshalCBOR() under the hood
+			{
+				var v SimpleValue
+
+				err := Unmarshal(tc.data, &v)
+				if err == nil {
+					t.Errorf("Unmarshal(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("Unmarshal(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+		})
+	}
+}
+
 func testUnmarshalInvalidSimpleValueToEmptyInterface(t *testing.T, data []byte) {
-	var v interface{}
+	var v any
 	if err := Unmarshal(data, v); err == nil {
 		t.Errorf("Unmarshal(0x%x) didn't return an error", data)
 	} else if _, ok := err.(*SyntaxError); !ok {
@@ -69,8 +190,8 @@ func testUnmarshalInvalidSimpleValue(t *testing.T, data []byte) {
 	}
 }
 
-func testUnmarshalSimpleValueToEmptyInterface(t *testing.T, data []byte, want interface{}) {
-	var v interface{}
+func testUnmarshalSimpleValueToEmptyInterface(t *testing.T, data []byte, want any) {
+	var v any
 	if err := Unmarshal(data, &v); err != nil {
 		t.Errorf("Unmarshal(0x%x) returned error %v", data, err)
 		return

stream.go

@@ -13,7 +13,7 @@ import (
 // Decoder reads and decodes CBOR values from io.Reader.
 type Decoder struct {
 	r         io.Reader
-	d         decoder
+	d         *decoder
 	buf       []byte
 	off       int // next read offset in buf
 	bytesRead int
@@ -26,7 +26,7 @@ func NewDecoder(r io.Reader) *Decoder {
 }
 
 // Decode reads CBOR value and decodes it into the value pointed to by v.
-func (dec *Decoder) Decode(v interface{}) error {
+func (dec *Decoder) Decode(v any) error {
 	_, err := dec.readNext()
 	if err != nil {
 		// Return validation error or read error.
@@ -132,8 +132,14 @@ func (dec *Decoder) readNext() (int, error) {
 // - dec.buf contains previously unread data and new data.
 // - dec.off is 0.
 func (dec *Decoder) read() (int, error) {
-	// Grow buf if needed.
+	if dec.r == nil {
+		// buf contains all the data, can't read more.
+		return 0, io.EOF
+	}
+
 	const minRead = 512
+
+	// Grow buf if needed.
 	if cap(dec.buf)-len(dec.buf)+dec.off < minRead {
 		oldUnreadBuf := dec.buf[dec.off:]
 		dec.buf = make([]byte, len(dec.buf)-dec.off, 2*cap(dec.buf)+minRead)
@@ -169,22 +175,38 @@ func NewEncoder(w io.Writer) *Encoder {
 	return defaultEncMode.NewEncoder(w)
 }
 
+func (enc *Encoder) checkIndefiniteLengthDataItemTypeIfNeeded(v interface{}) error {
+	if len(enc.indefTypes) == 0 || v == nil {
+		return nil
+	}
+
+	indefType := enc.indefTypes[len(enc.indefTypes)-1]
+	return checkIndefiniteLengthDataItemType(indefType, v)
+}
+
+func checkIndefiniteLengthDataItemType(indefType cborType, v interface{}) error {
+	switch indefType {
+	case cborTypeTextString:
+		k := reflect.TypeOf(v).Kind()
+		if k != reflect.String {
+			return errors.New("cbor: cannot encode item type " + k.String() + " for indefinite-length text string")
+		}
+
+	case cborTypeByteString:
+		t := reflect.TypeOf(v)
+		k := t.Kind()
+		if (k != reflect.Array && k != reflect.Slice) || t.Elem().Kind() != reflect.Uint8 {
+			return errors.New("cbor: cannot encode item type " + k.String() + " for indefinite-length byte string")
+		}
+	}
+
+	return nil
+}
+
 // Encode writes the CBOR encoding of v.
 func (enc *Encoder) Encode(v interface{}) error {
-	if len(enc.indefTypes) > 0 && v != nil {
-		indefType := enc.indefTypes[len(enc.indefTypes)-1]
-		if indefType == cborTypeTextString {
-			k := reflect.TypeOf(v).Kind()
-			if k != reflect.String {
-				return errors.New("cbor: cannot encode item type " + k.String() + " for indefinite-length text string")
-			}
-		} else if indefType == cborTypeByteString {
-			t := reflect.TypeOf(v)
-			k := t.Kind()
-			if (k != reflect.Array && k != reflect.Slice) || t.Elem().Kind() != reflect.Uint8 {
-				return errors.New("cbor: cannot encode item type " + k.String() + " for indefinite-length byte string")
-			}
-		}
+	if err := enc.checkIndefiniteLengthDataItemTypeIfNeeded(v); err != nil {
+		return err
 	}
 
 	buf := getEncodeBuffer()

stream_decode.go

@@ -0,0 +1,641 @@
+package cbor
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"math/big"
+	"unicode/utf8"
+)
+
+// Type represents CBOR type.
+type Type uint8
+
+const (
+	UndefinedType Type = iota
+
+	// CBOR major types
+	UintType       // CBOR major type 0
+	IntType        // CBOR major type 1
+	ByteStringType // CBOR major type 2
+	TextStringType // CBOR major type 3
+	ArrayType      // CBOR major type 4
+	MapType        // CBOR major type 5
+	TagType        // CBOR major type 6
+	// OtherType is CBOR major type 7.  It is for two types of data:
+	// floating-point numbers and "simple values" that do not need any content.
+	OtherType
+
+	// Non-major types
+	BigNumType // BigNumType is specified as part of CBOR major type 6
+	NilType    // NilType is specified as part of CBOR major type 7
+	BoolType   // BoolType is specified as part of CBOR major type 7
+)
+
+func (t Type) String() string {
+	switch t {
+	case UintType:
+		return "CBOR uint type"
+	case IntType:
+		return "CBOR int type"
+	case ByteStringType:
+		return "CBOR byte string type"
+	case TextStringType:
+		return "CBOR text string type"
+	case ArrayType:
+		return "CBOR array type"
+	case MapType:
+		return "CBOR map type"
+	case TagType:
+		return "CBOR tag type"
+	case OtherType:
+		return "CBOR other type"
+	case NilType:
+		return "CBOR nil type"
+	case BoolType:
+		return "CBOR boolean type"
+	case BigNumType:
+		return "CBOR bignum type"
+	default:
+		return "undefined CBOR type"
+	}
+}
+
+type WrongTypeError struct {
+	ActualType   Type
+	ExpectedType string
+}
+
+func (e *WrongTypeError) Error() string {
+	return fmt.Sprintf("cbor: cannot decode %s to %s", e.ActualType.String(), e.ExpectedType)
+}
+
+// IndefiniteLengthNotSupportedError is returned by NextSize() if next CBOR data
+// is indefinite length.
+type IndefiniteLengthNotSupportedError struct {
+	t Type
+}
+
+func (e *IndefiniteLengthNotSupportedError) Error() string {
+	return fmt.Sprintf("cbor: size is unavailable for indefinite length %s", e.t)
+}
+
+// TypeNotSupportedError is returned by NextSize() if next CBOR type
+// is not supported/implemented by NextSize().
+type TypeNotSupportedError struct {
+	t Type
+}
+
+func (e *TypeNotSupportedError) Error() string {
+	return fmt.Sprintf("cbor: size operation is not supported for %s", e.t)
+}
+
+// StreamDecoder validates complete CBOR data and decodes it in chunks.
+//
+// If CBOR data is malformed or fails decoding checks (set by options),
+// validation error is saved and all subseqent decoding functions
+// return the saved error.
+//
+// If DecodeXXX() tries to decode CBOR data of mismatched type,
+// WrongTypeError is returned.  Caller can retry to decode the same
+// data with a different DecodeXXX().
+//
+// If DecodeXXX() function returns other types of error,
+// CBOR data is skipped.  User can decode next CBOR data.
+type StreamDecoder struct {
+	dec             *Decoder
+	err             error
+	remainingBytes  int // remaining bytes of a complete and validated CBOR data
+	decodedMsgBytes int // number of bytes of decoded CBOR messages
+}
+
+// NewStreamDecoder returns a new StreamDecoder that reads from r using default DecMode.
+func NewStreamDecoder(r io.Reader) *StreamDecoder {
+	return defaultDecMode.NewStreamDecoder(r)
+}
+
+// NewByteStreamDecoder returns a new StreamDecoder that reads from data using default DecMode.
+func NewByteStreamDecoder(data []byte) *StreamDecoder {
+	return defaultDecMode.NewByteStreamDecoder(data)
+}
+
+// NextType returns the next CBOR type.
+func (sd *StreamDecoder) NextType() (Type, error) {
+	if err := sd.prepareNext(); err != nil {
+		return UndefinedType, err
+	}
+
+	b := sd.dec.d.data[sd.dec.d.off]
+	switch b & 0xe0 {
+	case 0x00:
+		return UintType, nil
+	case 0x20:
+		return IntType, nil
+	case 0x40:
+		return ByteStringType, nil
+	case 0x60:
+		return TextStringType, nil
+	case 0x80:
+		return ArrayType, nil
+	case 0xa0:
+		return MapType, nil
+	case 0xc0:
+		if b == 0xc2 || b == 0xc3 {
+			return BigNumType, nil
+		}
+		return TagType, nil
+	case 0xe0:
+		switch b {
+		case 0xf4, 0xf5:
+			return BoolType, nil
+		case 0xf6:
+			return NilType, nil
+		}
+		return OtherType, nil
+	}
+	return UndefinedType, errors.New("cbor: unrecognized type")
+}
+
+// NextSize returns the next CBOR data size for five types.
+// Returned uint64 represents different kind of size depending on
+// the type:
+// - ByteStringType : length (in bytes) of byte string
+// - TextStringType : length (in bytes) of text string
+// - ArrayType      : number of array elements
+// - MapType        : number of key/value pairs
+// - BigNumType     : length (in bytes) of encoded big number
+// Error is returned for indef length data and unsupported types.
+// Support for additional types wasn't added for simplicity.
+func (sd *StreamDecoder) NextSize() (uint64, error) {
+	t, err := sd.NextType()
+	if err != nil {
+		return 0, err
+	}
+
+	off := sd.dec.d.off
+
+	if t == BigNumType {
+		// NextType() validates CBOR tag data (tag number + tag content),
+		// so it's safe to increment offset to access tag content.
+		off++              // Increment offset to point to tag content
+		t = ByteStringType // tag content type is CBOR byte string
+	}
+
+	switch t {
+
+	case ByteStringType, TextStringType, ArrayType, MapType:
+		ai := sd.dec.d.data[off] & 0x1f
+		off++
+
+		// This function only interprets valid head because
+		// CBOR data is validated in NextType().
+		var size uint64
+		if ai < 24 {
+			size = uint64(ai)
+		} else if ai == 24 {
+			size = uint64(sd.dec.d.data[off])
+		} else if ai == 25 {
+			size = uint64(binary.BigEndian.Uint16(sd.dec.d.data[off : off+2]))
+		} else if ai == 26 {
+			size = uint64(binary.BigEndian.Uint32(sd.dec.d.data[off : off+4]))
+		} else if ai == 27 {
+			size = binary.BigEndian.Uint64(sd.dec.d.data[off : off+8])
+		} else if ai == 31 {
+			return 0, &IndefiniteLengthNotSupportedError{t}
+		}
+		return size, nil
+	}
+
+	return 0, &TypeNotSupportedError{t}
+}
+
+// Skip skips next CBOR data.
+func (sd *StreamDecoder) Skip() error {
+	if err := sd.prepareNext(); err != nil {
+		return err
+	}
+
+	d := sd.dec.d
+
+	start := d.off
+	d.skip()
+	end := d.off
+
+	sd.updateState(end - start)
+
+	return nil
+}
+
+// DecodeRawBytes returns a copy of next CBOR data as raw bytes.
+func (sd *StreamDecoder) DecodeRawBytes() ([]byte, error) {
+	if err := sd.prepareNext(); err != nil {
+		return nil, err
+	}
+
+	d := sd.dec.d
+
+	start := d.off
+	d.skip()
+	end := d.off
+
+	b := make([]byte, end-start)
+	copy(b, d.data[start:end])
+
+	sd.updateState(end - start)
+
+	return b, nil
+}
+
+// DecodeRawBytesZeroCopy returns next CBOR data as raw bytes pointing to underlying data.
+// It is only available for StreamDecoder created with NewByteStreamDecoder.
+func (sd *StreamDecoder) DecodeRawBytesZeroCopy() ([]byte, error) {
+	if sd.dec.r != nil {
+		return nil, errors.New("cbor: DecodeRawBytesZeroCopy is only supported for StreamDecoder created with NewByteStreamDecoder")
+	}
+
+	if err := sd.prepareNext(); err != nil {
+		return nil, err
+	}
+
+	d := sd.dec.d
+
+	start := d.off
+	d.skip()
+	end := d.off
+
+	b := d.data[start:end]
+
+	sd.updateState(end - start)
+
+	return b, nil
+}
+
+// DecodeNil decodes next CBOR data as nil.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeNil() error {
+	if err := sd.prepareNext(); err != nil {
+		return err
+	}
+
+	d := sd.dec.d
+
+	if d.data[d.off] == 0xf6 {
+		d.off++
+		sd.updateState(1)
+		return nil
+	}
+
+	t, _ := sd.NextType()
+	return &WrongTypeError{t, "nil"}
+}
+
+// DecodeBool decodes next CBOR data as bool.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeBool() (bool, error) {
+	if err := sd.prepareNext(); err != nil {
+		return false, err
+	}
+
+	d := sd.dec.d
+
+	b := d.data[d.off]
+	switch b {
+
+	case 0xf4, 0xf5:
+		d.off++
+		sd.updateState(1)
+		return b == 0xf5, nil
+
+	default:
+		t, _ := sd.NextType()
+		return false, &WrongTypeError{t, "bool"}
+	}
+}
+
+// DecodeUint64 decodes next CBOR data as uint64.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeUint64() (uint64, error) {
+	if err := sd.prepareNext(); err != nil {
+		return 0, err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypePositiveInt {
+		t, _ := sd.NextType()
+		return 0, &WrongTypeError{t, "uint64"}
+	}
+
+	start := d.off
+	_, _, val := d.getHead()
+	end := d.off
+
+	sd.updateState(end - start)
+
+	return val, nil
+}
+
+// DecodeInt64 decodes next CBOR data as int64.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeInt64() (int64, error) {
+	if err := sd.prepareNext(); err != nil {
+		return 0, err
+	}
+
+	d := sd.dec.d
+
+	switch nt := d.nextCBORType(); nt {
+
+	case cborTypePositiveInt, cborTypeNegativeInt:
+		start := d.off
+		_, _, val := d.getHead()
+		end := d.off
+
+		sd.updateState(end - start)
+
+		if val > math.MaxInt64 {
+			return 0, fmt.Errorf("cbor: %d overflow Go's int64", val)
+		}
+
+		if nt == cborTypePositiveInt {
+			return int64(val), nil
+		}
+
+		nValue := int64(-1) ^ int64(val)
+		return nValue, nil
+
+	default:
+		t, _ := sd.NextType()
+		return 0, &WrongTypeError{t, "int64"}
+	}
+}
+
+// DecodeBytes decodes next CBOR data as []byte.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeBytes() ([]byte, error) {
+	if err := sd.prepareNext(); err != nil {
+		return nil, err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypeByteString {
+		t, _ := sd.NextType()
+		return nil, &WrongTypeError{t, "bytes"}
+	}
+
+	start := d.off
+	_, ai, val := d.getHead()
+
+	if ai == 31 {
+		// Indefinite length byte string isn't supported in StreamDecoder.  Skip it.
+		d.off = start
+		_ = sd.Skip()
+		return nil, errors.New("cbor: indefinite length byte string isn't supported")
+	}
+
+	b := make([]byte, int(val))
+	copy(b, d.data[d.off:d.off+int(val)])
+	d.off += int(val)
+
+	end := d.off
+
+	sd.updateState(end - start)
+
+	return b, nil
+}
+
+// DecodeString decodes next CBOR data as string.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeString() (string, error) {
+	if err := sd.prepareNext(); err != nil {
+		return "", err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypeTextString {
+		t, _ := sd.NextType()
+		return "", &WrongTypeError{t, "string"}
+	}
+
+	start := d.off
+	_, ai, val := d.getHead()
+
+	if ai == 31 {
+		// Indefinite length text string isn't supported in StreamDecoder.  Skip it.
+		d.off = start
+		_ = sd.Skip()
+		return "", errors.New("cbor: indefinite length text string isn't supported")
+	}
+
+	b := d.data[d.off : d.off+int(val)]
+
+	d.off += int(val)
+	end := d.off
+
+	sd.updateState(end - start)
+
+	if d.dm.utf8 == UTF8RejectInvalid && !utf8.Valid(b) {
+		return "", &SemanticError{"cbor: invalid UTF-8 string"}
+	}
+
+	return string(b), nil
+}
+
+// DecodeBigInt decodes next CBOR data as *big.Int.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeBigInt() (*big.Int, error) {
+	if err := sd.prepareNext(); err != nil {
+		return nil, err
+	}
+
+	d := sd.dec.d
+
+	t := d.data[d.off]
+	if t != 0xc2 && t != 0xc3 {
+		t, _ := sd.NextType()
+		return nil, &WrongTypeError{t, "big.Int"}
+	}
+
+	d.off++
+	sd.updateState(1)
+
+	b, err := sd.DecodeBytes()
+	if err != nil {
+		return nil, err
+	}
+
+	bi := new(big.Int).SetBytes(b)
+
+	if t == 0xc3 {
+		bi.Add(bi, bigOne)
+		bi.Neg(bi)
+	}
+
+	return bi, nil
+}
+
+// DecodeTagNumber decodes next CBOR data as tag number.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeTagNumber() (uint64, error) {
+	if err := sd.prepareNext(); err != nil {
+		return 0, err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypeTag {
+		t, _ := sd.NextType()
+		return 0, &WrongTypeError{t, "tag"}
+	}
+
+	start := d.off
+	_, _, val := d.getHead()
+	end := d.off
+
+	sd.updateState(end - start)
+
+	return val, nil
+}
+
+// DecodeArrayHead decodes next CBOR data as array size.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeArrayHead() (uint64, error) {
+	if err := sd.prepareNext(); err != nil {
+		return 0, err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypeArray {
+		t, _ := sd.NextType()
+		return 0, &WrongTypeError{t, "array"}
+	}
+
+	start := d.off
+	_, ai, val := d.getHead()
+	end := d.off
+
+	if ai == 31 {
+		// Indefinite length array isn't supported in StreamDecoder.  Skip it.
+		d.off = start
+		_ = sd.Skip()
+		return 0, errors.New("cbor: indefinite length array isn't supported")
+	}
+
+	sd.updateState(end - start)
+
+	return val, nil
+}
+
+// DecodeMapHead decodes next CBOR data as map size.  WrongType error is returned if type is mismatched.
+func (sd *StreamDecoder) DecodeMapHead() (uint64, error) {
+	if err := sd.prepareNext(); err != nil {
+		return 0, err
+	}
+
+	d := sd.dec.d
+
+	if d.nextCBORType() != cborTypeMap {
+		t, _ := sd.NextType()
+		return 0, &WrongTypeError{t, "map"}
+	}
+
+	start := d.off
+	_, ai, val := d.getHead()
+	end := d.off
+
+	if ai == 31 {
+		// Indefinite length map isn't supported in StreamDecoder.  Skip it.
+		d.off = start
+		_ = sd.Skip()
+		return 0, errors.New("cbor: indefinite length map isn't supported")
+	}
+
+	sd.updateState(end - start)
+
+	return val, nil
+}
+
+// prepareNext reads and validates next CBOR data.
+// prepareNext can return io error or CBOR validation error.
+func (sd *StreamDecoder) prepareNext() error {
+	if sd.err != nil {
+		return sd.err
+	}
+
+	if sd.remainingBytes > 0 {
+		return nil
+	}
+
+	return sd.readAndValidateNext()
+}
+
+func (sd *StreamDecoder) readAndValidateNext() error {
+
+	lastMsgBytes := sd.dec.d.off
+
+	length, err := sd._readAndValidateNext()
+	if err != nil {
+		sd.err = err
+		return err
+	}
+
+	sd.decodedMsgBytes += lastMsgBytes
+
+	sd.remainingBytes = length
+
+	sd.dec.off += length
+	sd.dec.bytesRead += length
+
+	return nil
+}
+
+func (sd *StreamDecoder) _readAndValidateNext() (int, error) {
+	if len(sd.dec.buf) == sd.dec.off {
+		n, err := sd.dec.read()
+		if err != nil && err != io.EOF {
+			return 0, err
+		}
+		if n == 0 {
+			return 0, io.EOF
+		}
+	}
+
+	for {
+		sd.dec.d.reset(sd.dec.buf[sd.dec.off:])
+
+		start := sd.dec.d.off
+		err := sd.dec.d.wellformed(true, false)
+		end := sd.dec.d.off
+
+		// Restore decoder offset after validation
+		sd.dec.d.off = start
+
+		if err == nil {
+			// Next complete data is read and validated
+			return end - start, nil
+		}
+
+		if err != io.ErrUnexpectedEOF {
+			return 0, err
+		}
+
+		// valid() returned io.ErrUnexpectedEOF.
+		// Read more data and try again.
+		n, err := sd.dec.read()
+		if n == 0 {
+			// No more data, it is incomplete CBOR.
+			return 0, io.ErrUnexpectedEOF
+		}
+		if err != nil {
+			return 0, err
+		}
+	}
+}
+
+func (sd *StreamDecoder) updateState(bytesRead int) {
+	sd.remainingBytes -= bytesRead
+	if sd.remainingBytes < 0 {
+		sd.err = errors.New("remaining bytes are out of sync")
+	}
+}
+
+// NumBytesDecoded returns the accumulated number of bytes decoded using "DecodeXXX()"
+func (sd *StreamDecoder) NumBytesDecoded() int {
+	return sd.decodedMsgBytes + sd.dec.d.off
+}

stream_encode.go

@@ -0,0 +1,266 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+package cbor
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math/big"
+	"reflect"
+)
+
+// ErrStreamClosed is the error indicating operations on a closed stream.
+// E.g. any call to encode after a call to Close will return ErrStreamClosed.
+var ErrStreamClosed = errors.New("cbor: operation on closed stream")
+
+// StreamEncoder provides low-level API for sequential encoding.
+//
+// Users of StreamEncoder should be familiar with CBOR data models.
+// When in doubt, please use Encoder instead.
+//
+// IMPORTANT: Use Valid() to check whether generated CBOR data is
+// complete and well-formed.
+type StreamEncoder struct {
+	*Encoder
+	buf    *bytes.Buffer
+	closed bool
+}
+
+// NewStreamEncoder returns a new StreamEncoder for sequential encoding.
+func NewStreamEncoder(w io.Writer) *StreamEncoder {
+	return defaultEncMode.NewStreamEncoder(w)
+}
+
+// Close closes StreamEncoder and subsequence operations (except for Close)
+// will return ErrStreamClosed.
+func (se *StreamEncoder) Close() {
+	if se.closed {
+		return
+	}
+	putEncodeBuffer(se.buf)
+	se.Encoder = nil
+	se.closed = true
+}
+
+// Flush writes streamed data to underlying io.Writer.
+func (se *StreamEncoder) Flush() error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	_, err := se.buf.WriteTo(se.Encoder.w)
+	return err
+}
+
+// Encode writes the CBOR encoding of v.
+func (se *StreamEncoder) Encode(v interface{}) error {
+	if err := se.checkIndefiniteLengthDataItemTypeIfNeeded(v); err != nil {
+		return err
+	}
+
+	return encode(se.buf, se.em, reflect.ValueOf(v))
+}
+
+// EncodeMapHead encodes CBOR map head of specified size.
+func (se *StreamEncoder) EncodeMapHead(size uint64) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypeMap), size)
+	return nil
+}
+
+// EncodeArrayHead encodes CBOR array head of specified size.
+func (se *StreamEncoder) EncodeArrayHead(size uint64) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypeArray), size)
+	return nil
+}
+
+// EncodeTagHead encodes CBOR tag head with num as tag number.
+func (se *StreamEncoder) EncodeTagHead(num uint64) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypeTag), num)
+	return nil
+}
+
+// EncodeRawBytes writes b to the underlying writer.
+// If b is an empty or nil byte slice, it is a no-op.
+func (se *StreamEncoder) EncodeRawBytes(b []byte) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	se.buf.Write(b)
+	return nil
+}
+
+// EncodeNil encodes CBOR nil.
+func (se *StreamEncoder) EncodeNil() error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	se.buf.Write(cborNil)
+	return nil
+}
+
+// EncodeBool encodes bool as CBOR bool.
+func (se *StreamEncoder) EncodeBool(b bool) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	bBytes := cborTrue
+	if !b {
+		bBytes = cborFalse
+	}
+	se.buf.Write(bBytes)
+	return nil
+}
+
+// EncodeUint encodes uint as CBOR positive integer.
+func (se *StreamEncoder) EncodeUint(i uint) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypePositiveInt), uint64(i))
+	return nil
+}
+
+// EncodeUint8 encodes uint8 as CBOR positive integer.
+func (se *StreamEncoder) EncodeUint8(i uint8) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypePositiveInt), uint64(i))
+	return nil
+}
+
+// EncodeUint16 encodes uint16 as CBOR positive integer.
+func (se *StreamEncoder) EncodeUint16(i uint16) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypePositiveInt), uint64(i))
+	return nil
+}
+
+// EncodeUint32 encodes uint32 as CBOR positive integer.
+func (se *StreamEncoder) EncodeUint32(i uint32) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypePositiveInt), uint64(i))
+	return nil
+}
+
+// EncodeUint64 encodes uint64 as CBOR positive integer.
+func (se *StreamEncoder) EncodeUint64(i uint64) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypePositiveInt), i)
+	return nil
+}
+
+// EncodeInt encodes int as CBOR positive or negtive integer.
+func (se *StreamEncoder) EncodeInt(i int) error {
+	return se.EncodeInt64(int64(i))
+}
+
+// EncodeInt8 encodes int8 as CBOR positive or negtive integer.
+func (se *StreamEncoder) EncodeInt8(i int8) error {
+	return se.EncodeInt64(int64(i))
+}
+
+// EncodeInt16 encodes int16 as CBOR positive or negtive integer.
+func (se *StreamEncoder) EncodeInt16(i int16) error {
+	return se.EncodeInt64(int64(i))
+}
+
+// EncodeInt32 encodes int32 as CBOR positive or negtive integer.
+func (se *StreamEncoder) EncodeInt32(i int32) error {
+	return se.EncodeInt64(int64(i))
+}
+
+// EncodeInt64 encodes int64 as CBOR positive or negtive integer.
+func (se *StreamEncoder) EncodeInt64(i int64) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	t := cborTypePositiveInt
+	if i < 0 {
+		t = cborTypeNegativeInt
+		i = i*(-1) - 1
+	}
+	encodeHead(se.buf, byte(t), uint64(i))
+	return nil
+}
+
+// EncodeBytes encodes byte slice as CBOR byte string.
+func (se *StreamEncoder) EncodeBytes(b []byte) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	if b == nil {
+		se.buf.Write(cborNil)
+		return nil
+	}
+
+	encodeHead(se.buf, byte(cborTypeByteString), uint64(len(b)))
+	se.buf.Write(b)
+	return nil
+}
+
+// EncodeString encodes string as CBOR string.
+func (se *StreamEncoder) EncodeString(s string) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	encodeHead(se.buf, byte(cborTypeTextString), uint64(len(s)))
+	se.buf.WriteString(s)
+	return nil
+}
+
+var bigOne = big.NewInt(1)
+
+// EncodeBigInt encodes big.Int as CBOR bignum (tag number 2 and 3).
+func (se *StreamEncoder) EncodeBigInt(v *big.Int) error {
+	if se.closed {
+		return ErrStreamClosed
+	}
+	if se.em.bigIntConvert == BigIntConvertShortest {
+		if v.IsUint64() {
+			encodeHead(se.buf, byte(cborTypePositiveInt), v.Uint64())
+			return nil
+		}
+		if v.IsInt64() {
+			return se.EncodeInt64(v.Int64())
+		}
+	}
+
+	tagNum := 2
+	sign := v.Sign()
+	if sign < 0 {
+		tagNum = 3
+
+		// Create a new big.Int with value of -1 - v
+		v = new(big.Int).Abs(v)
+		v.Sub(v, bigOne)
+	}
+
+	b := v.Bytes()
+
+	// Write tag number
+	encodeHead(se.buf, byte(cborTypeTag), uint64(tagNum))
+	// Write bignum byte string
+	encodeHead(se.buf, byte(cborTypeByteString), uint64(len(b)))
+	se.buf.Write(b)
+	return nil
+}

stream_test.go

@@ -37,7 +37,7 @@ func TestDecoder(t *testing.T) {
 			bytesRead := 0
 			for i := 0; i < 5; i++ {
 				for _, tc := range unmarshalTests {
-					var v interface{}
+					var v any
 					if err := decoder.Decode(&v); err != nil {
 						t.Fatalf("Decode() returned error %v", err)
 					}
@@ -56,7 +56,7 @@ func TestDecoder(t *testing.T) {
 			}
 			for i := 0; i < 2; i++ {
 				// no more data
-				var v interface{}
+				var v any
 				err := decoder.Decode(&v)
 				if v != nil {
 					t.Errorf("Decode() = %v (%T), want nil (no more data)", v, v)
@@ -106,7 +106,7 @@ func TestDecoderUnmarshalTypeError(t *testing.T) {
 							t.Errorf("NumBytesRead() = %v, want %v", decoder.NumBytesRead(), bytesRead)
 						}
 
-						var vi interface{}
+						var vi any
 						if err := decoder.Decode(&vi); err != nil {
 							t.Errorf("Decode() returned error %v", err)
 						}
@@ -126,7 +126,7 @@ func TestDecoderUnmarshalTypeError(t *testing.T) {
 			}
 			for i := 0; i < 2; i++ {
 				// no more data
-				var v interface{}
+				var v any
 				err := decoder.Decode(&v)
 				if v != nil {
 					t.Errorf("Decode() = %v (%T), want nil (no more data)", v, v)
@@ -162,7 +162,7 @@ func TestDecoderUnexpectedEOFError(t *testing.T) {
 			bytesRead := 0
 			for i := 0; i < len(unmarshalTests)-1; i++ {
 				tc := unmarshalTests[i]
-				var v interface{}
+				var v any
 				if err := decoder.Decode(&v); err != nil {
 					t.Fatalf("Decode() returned error %v", err)
 				}
@@ -180,7 +180,7 @@ func TestDecoderUnexpectedEOFError(t *testing.T) {
 			}
 			for i := 0; i < 2; i++ {
 				// truncated data
-				var v interface{}
+				var v any
 				err := decoder.Decode(&v)
 				if v != nil {
 					t.Errorf("Decode() = %v (%T), want nil (no more data)", v, v)
@@ -217,7 +217,7 @@ func TestDecoderReadError(t *testing.T) {
 			bytesRead := 0
 			for i := 0; i < len(unmarshalTests)-1; i++ {
 				tc := unmarshalTests[i]
-				var v interface{}
+				var v any
 				if err := decoder.Decode(&v); err != nil {
 					t.Fatalf("Decode() returned error %v", err)
 				}
@@ -235,7 +235,7 @@ func TestDecoderReadError(t *testing.T) {
 			}
 			for i := 0; i < 2; i++ {
 				// truncated data because Reader returned error
-				var v interface{}
+				var v any
 				err := decoder.Decode(&v)
 				if v != nil {
 					t.Errorf("Decode() = %v (%T), want nil (no more data)", v, v)
@@ -265,7 +265,7 @@ func TestDecoderNoData(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			decoder := NewDecoder(tc.reader)
 			for i := 0; i < 2; i++ {
-				var v interface{}
+				var v any
 				err := decoder.Decode(&v)
 				if v != nil {
 					t.Errorf("Decode() = %v (%T), want nil", v, v)
@@ -280,12 +280,12 @@ func TestDecoderNoData(t *testing.T) {
 
 func TestDecoderRecoverableReadError(t *testing.T) {
 	data := hexDecode("83010203") // [1,2,3]
-	wantValue := []interface{}{uint64(1), uint64(2), uint64(3)}
+	wantValue := []any{uint64(1), uint64(2), uint64(3)}
 	recoverableReaderErr := errors.New("recoverable reader error")
 
 	decoder := NewDecoder(newRecoverableReader(data, 1, recoverableReaderErr))
 
-	var v interface{}
+	var v any
 	err := decoder.Decode(&v)
 	if err != recoverableReaderErr {
 		t.Fatalf("Decode() returned error %v, want error %v", err, recoverableReaderErr)
@@ -303,7 +303,7 @@ func TestDecoderRecoverableReadError(t *testing.T) {
 	}
 
 	// no more data
-	v = interface{}(nil)
+	v = any(nil)
 	err = decoder.Decode(&v)
 	if v != nil {
 		t.Errorf("Decode() = %v (%T), want nil (no more data)", v, v)
@@ -317,13 +317,13 @@ func TestDecoderInvalidData(t *testing.T) {
 	data := []byte{0x01, 0x3e}
 	decoder := NewDecoder(bytes.NewReader(data))
 
-	var v1 interface{}
+	var v1 any
 	err := decoder.Decode(&v1)
 	if err != nil {
 		t.Errorf("Decode() returned error %v when decoding valid data item", err)
 	}
 
-	var v2 interface{}
+	var v2 any
 	err = decoder.Decode(&v2)
 	if err == nil {
 		t.Errorf("Decode() didn't return error when decoding invalid data item")
@@ -645,7 +645,7 @@ func TestDecoderBuffered(t *testing.T) {
 				t.Errorf("Buffered() = 0x%x (%d bytes), want 0 bytes", buffered, len(buffered))
 			}
 
-			var v interface{}
+			var v any
 			err = decoder.Decode(&v)
 			if err != tc.decodeErr {
 				t.Errorf("Decode() returned error %v, want %v", err, tc.decodeErr)
@@ -688,11 +688,11 @@ func TestEncoder(t *testing.T) {
 func TestEncoderError(t *testing.T) {
 	testcases := []struct {
 		name         string
-		value        interface{}
+		value        any
 		wantErrorMsg string
 	}{
 		{"channel cannot be marshaled", make(chan bool), "cbor: unsupported type: chan bool"},
-		{"function cannot be marshaled", func(i int) int { return i * i }, "cbor: unsupported type: func"},
+		{"function cannot be marshaled", func(i int) int { return i * i }, "cbor: unsupported type: func(int) int"},
 		{"complex cannot be marshaled", complex(100, 8), "cbor: unsupported type: complex128"},
 	}
 	var w bytes.Buffer
@@ -705,7 +705,7 @@ func TestEncoderError(t *testing.T) {
 				t.Errorf("Encode(%v) didn't return an error, want error %q", tc.value, tc.wantErrorMsg)
 			} else if _, ok := err.(*UnsupportedTypeError); !ok {
 				t.Errorf("Encode(%v) error type %T, want *UnsupportedTypeError", tc.value, err)
-			} else if !strings.HasPrefix(err.Error(), tc.wantErrorMsg) {
+			} else if err.Error() != tc.wantErrorMsg {
 				t.Errorf("Encode(%v) error %q, want %q", tc.value, err.Error(), tc.wantErrorMsg)
 			}
 		})

structfields.go

@@ -18,9 +18,11 @@ type field struct {
 	typ                reflect.Type
 	ef                 encodeFunc
 	ief                isEmptyFunc
+	izf                isZeroFunc
 	typInfo            *typeInfo // used to decoder to reuse type info
 	tagged             bool      // used to choose dominant field (at the same level tagged fields dominate untagged fields)
 	omitEmpty          bool      // used to skip empty field
+	omitZero           bool      // used to skip zero field
 	keyAsInt           bool      // used to encode/decode field name as int
 }
 
@@ -157,7 +159,7 @@ func appendFields(
 		f := t.Field(i)
 
 		ft := f.Type
-		for ft.Kind() == reflect.Ptr {
+		for ft.Kind() == reflect.Pointer {
 			ft = ft.Elem()
 		}
 
@@ -165,9 +167,11 @@ func appendFields(
 			continue
 		}
 
+		cborTag := true
 		tag := f.Tag.Get("cbor")
 		if tag == "" {
 			tag = f.Tag.Get("json")
+			cborTag = false
 		}
 		if tag == "-" {
 			continue
@@ -177,7 +181,7 @@ func appendFields(
 
 		// Parse field tag options
 		var tagFieldName string
-		var omitempty, keyasint bool
+		var omitempty, omitzero, keyasint bool
 		for j := 0; tag != ""; j++ {
 			var token string
 			idx := strings.IndexByte(tag, ',')
@@ -192,6 +196,10 @@ func appendFields(
 				switch token {
 				case "omitempty":
 					omitempty = true
+				case "omitzero":
+					if cborTag || jsonStdlibSupportsOmitzero {
+						omitzero = true
+					}
 				case "keyasint":
 					keyasint = true
 				}
@@ -213,6 +221,7 @@ func appendFields(
 				idx:       fIdx,
 				typ:       f.Type,
 				omitEmpty: omitempty,
+				omitZero:  omitzero,
 				keyAsInt:  keyasint,
 				tagged:    tagged})
 		} else {
@@ -244,7 +253,7 @@ func getFieldValue(v reflect.Value, idx []int, f embeddedFieldNullPtrFunc) (fv r
 		fv = fv.Field(n)
 
 		if i < len(idx)-1 {
-			if fv.Kind() == reflect.Ptr && fv.Type().Elem().Kind() == reflect.Struct {
+			if fv.Kind() == reflect.Pointer && fv.Type().Elem().Kind() == reflect.Struct {
 				if fv.IsNil() {
 					// Null pointer to embedded struct field
 					fv, err = f(fv)

tag.go

@@ -1,3 +1,6 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
 package cbor
 
 import (
@@ -12,7 +15,7 @@ import (
 // enclosed data item if it were to appear outside of a tag.
 type Tag struct {
 	Number  uint64
-	Content interface{}
+	Content any
 }
 
 // RawTag represents CBOR tag data, including tag number and raw tag content.
@@ -23,11 +26,37 @@ type RawTag struct {
 }
 
 // UnmarshalCBOR sets *t with tag number and raw tag content copied from data.
+//
+// Deprecated: No longer used by this codec; kept for compatibility
+// with user apps that directly call this function.
 func (t *RawTag) UnmarshalCBOR(data []byte) error {
 	if t == nil {
 		return errors.New("cbor.RawTag: UnmarshalCBOR on nil pointer")
 	}
 
+	d := decoder{data: data, dm: defaultDecMode}
+
+	// Check if data is a well-formed CBOR data item.
+	// RawTag.UnmarshalCBOR() is exported, so
+	// the codec needs to support same behavior for:
+	// - Unmarshal(data, *RawTag)
+	// - RawTag.UnmarshalCBOR(data)
+	err := d.wellformed(false, false)
+	if err != nil {
+		return err
+	}
+
+	return t.unmarshalCBOR(data)
+}
+
+// unmarshalCBOR sets *t with tag number and raw tag content copied from data.
+// This function assumes data is well-formed, and does not perform bounds checking.
+// This function is called by Unmarshal().
+func (t *RawTag) unmarshalCBOR(data []byte) error {
+	if t == nil {
+		return errors.New("cbor.RawTag: UnmarshalCBOR on nil pointer")
+	}
+
 	// Decoding CBOR null and undefined to cbor.RawTag is no-op.
 	if len(data) == 1 && (data[0] == 0xf6 || data[0] == 0xf7) {
 		return nil
@@ -193,7 +222,7 @@ func (t *syncTagSet) Add(opts TagOptions, contentType reflect.Type, num uint64,
 	if contentType == nil {
 		return errors.New("cbor: cannot add nil content type to TagSet")
 	}
-	for contentType.Kind() == reflect.Ptr {
+	for contentType.Kind() == reflect.Pointer {
 		contentType = contentType.Elem()
 	}
 	tag, err := newTagItem(opts, contentType, num, nestedNum...)
@@ -216,7 +245,7 @@ func (t *syncTagSet) Add(opts TagOptions, contentType reflect.Type, num uint64,
 
 // Remove removes given tag content type from TagSet.
 func (t *syncTagSet) Remove(contentType reflect.Type) {
-	for contentType.Kind() == reflect.Ptr {
+	for contentType.Kind() == reflect.Pointer {
 		contentType = contentType.Elem()
 	}
 	t.Lock()

tag_test.go

@@ -1,3 +1,6 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
 package cbor
 
 import (
@@ -905,7 +908,7 @@ func TestDecodeWrongTag(t *testing.T) {
 
 	testCases := []struct {
 		name         string
-		obj          interface{}
+		obj          any
 		data         []byte
 		wantErrorMsg string
 	}{
@@ -1240,7 +1243,7 @@ func TestMarshalRawTagWithEmptyContent(t *testing.T) {
 }
 
 func TestEncodeTag(t *testing.T) {
-	m := make(map[interface{}]bool)
+	m := make(map[any]bool)
 	m[10] = true
 	m[100] = true
 	m[-1] = true
@@ -1295,7 +1298,7 @@ func TestDecodeTagToEmptyIface(t *testing.T) {
 	testCases := []struct {
 		name    string
 		data    []byte
-		wantObj interface{}
+		wantObj any
 	}{
 		{
 			name:    "registered myBool",
@@ -1326,7 +1329,7 @@ func TestDecodeTagToEmptyIface(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			var v1 interface{}
+			var v1 any
 			if err := dm.Unmarshal(tc.data, &v1); err != nil {
 				t.Errorf("Unmarshal() returned error %v", err)
 			}
@@ -1334,7 +1337,7 @@ func TestDecodeTagToEmptyIface(t *testing.T) {
 				t.Errorf("Unmarshal to interface{} returned different values: %v, %v", tc.wantObj, v1)
 			}
 
-			var v2 interface{}
+			var v2 any
 			if err := dmSharedTags.Unmarshal(tc.data, &v2); err != nil {
 				t.Errorf("Unmarshal() returned error %v", err)
 			}
@@ -1359,7 +1362,7 @@ func TestDecodeRegisteredTagToEmptyIfaceError(t *testing.T) {
 
 	data := hexDecode("d865d8663bffffffffffffffff") // 101(102(-18446744073709551616))
 
-	var v interface{}
+	var v any
 	if err := dm.Unmarshal(data, &v); err == nil {
 		t.Errorf("Unmarshal(0x%x) didn't return an error", data)
 	} else if _, ok := err.(*UnmarshalTypeError); !ok {
@@ -1415,7 +1418,7 @@ func TestDecodeRegisterTagForUnmarshaler(t *testing.T) {
 	em, _ := EncOptions{}.EncModeWithTags(tags)
 
 	// Decode to empty interface.  Unmarshal() should return object of registered type.
-	var v1 interface{}
+	var v1 any
 	if err := dm.Unmarshal(data, &v1); err != nil {
 		t.Errorf("Unmarshal() returned error %v", err)
 	}
@@ -1448,7 +1451,7 @@ func TestDecodeRegisterTagForUnmarshaler(t *testing.T) {
 func TestMarshalRawTagContainingMalformedCBORData(t *testing.T) {
 	testCases := []struct {
 		name         string
-		value        interface{}
+		value        any
 		wantErrorMsg string
 	}{
 		// Nil RawMessage and empty RawMessage are encoded as CBOR nil.
@@ -1536,3 +1539,125 @@ func TestEncodeBuiltinTag(t *testing.T) {
 		})
 	}
 }
+
+func TestUnmarshalRawTagOnBadData(t *testing.T) {
+	testCases := []struct {
+		name   string
+		data   []byte
+		errMsg string
+	}{
+		// Empty data
+		{
+			name:   "nil data",
+			data:   nil,
+			errMsg: io.EOF.Error(),
+		},
+		{
+			name:   "empty data",
+			data:   []byte{},
+			errMsg: io.EOF.Error(),
+		},
+
+		// Wrong CBOR types
+		{
+			name:   "uint type",
+			data:   hexDecode("01"),
+			errMsg: "cbor: cannot unmarshal positive integer into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "int type",
+			data:   hexDecode("20"),
+			errMsg: "cbor: cannot unmarshal negative integer into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "byte string type",
+			data:   hexDecode("40"),
+			errMsg: "cbor: cannot unmarshal byte string into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "string type",
+			data:   hexDecode("60"),
+			errMsg: "cbor: cannot unmarshal UTF-8 text string into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "array type",
+			data:   hexDecode("80"),
+			errMsg: "cbor: cannot unmarshal array into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "map type",
+			data:   hexDecode("a0"),
+			errMsg: "cbor: cannot unmarshal map into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "primitive type",
+			data:   hexDecode("f4"),
+			errMsg: "cbor: cannot unmarshal primitives into Go value of type cbor.RawTag",
+		},
+		{
+			name:   "float type",
+			data:   hexDecode("f90000"),
+			errMsg: "cbor: cannot unmarshal primitives into Go value of type cbor.RawTag",
+		},
+
+		// Truncated CBOR data
+		{
+			name:   "truncated head",
+			data:   hexDecode("18"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Truncated CBOR tag data
+		{
+			name:   "truncated tag number",
+			data:   hexDecode("d8"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+		{
+			name:   "tag number not followed by tag content",
+			data:   hexDecode("da"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+		{
+			name:   "truncated tag content",
+			data:   hexDecode("c074323031332d30332d32315432303a30343a3030"),
+			errMsg: io.ErrUnexpectedEOF.Error(),
+		},
+
+		// Extraneous CBOR data
+		{
+			name:   "extraneous data",
+			data:   hexDecode("c074323031332d30332d32315432303a30343a30305a00"),
+			errMsg: "cbor: 1 bytes of extraneous data starting at index 22",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Test RawTag.UnmarshalCBOR(data)
+			{
+				var v RawTag
+
+				err := v.UnmarshalCBOR(tc.data)
+				if err == nil {
+					t.Errorf("UnmarshalCBOR(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("UnmarshalCBOR(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+			// Test Unmarshal(data, *RawTag), which calls RawTag.unmarshalCBOR() under the hood
+			{
+				var v RawTag
+
+				err := Unmarshal(tc.data, &v)
+				if err == nil {
+					t.Errorf("Unmarshal(%x) didn't return error", tc.data)
+				}
+				if !strings.HasPrefix(err.Error(), tc.errMsg) {
+					t.Errorf("Unmarshal(%x) returned error %q, want %q", tc.data, err.Error(), tc.errMsg)
+				}
+			}
+		})
+	}
+}

valid_not_tinygo_test.go

@@ -1,34 +0,0 @@
-// Copyright (c) Faye Amacker. All rights reserved.
-// Licensed under the MIT License. See LICENSE in the project root for license information.
-
-//go:build !tinygo
-
-package cbor
-
-import "testing"
-
-func Test32Depth(t *testing.T) {
-	testCases := []struct {
-		name      string
-		data      []byte
-		wantDepth int
-	}{
-		{"32-level array", hexDecode("82018181818181818181818181818181818181818181818181818181818181818101"), 32},
-		{"32-level indefinite length array", hexDecode("9f018181818181818181818181818181818181818181818181818181818181818101ff"), 32},
-		{"32-level map", hexDecode("a1018181818181818181818181818181818181818181818181818181818181818101"), 32},
-		{"32-level indefinite length map", hexDecode("bf018181818181818181818181818181818181818181818181818181818181818101ff"), 32},
-		{"32-level tag", hexDecode("d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d86474323031332d30332d32315432303a30343a30305a"), 32}, // 100(100(...("2013-03-21T20:04:00Z")))
-	}
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			d := decoder{data: tc.data, dm: defaultDecMode}
-			depth, err := d.wellformedInternal(0, false)
-			if err != nil {
-				t.Errorf("wellformed(0x%x) returned error %v", tc.data, err)
-			}
-			if depth != tc.wantDepth {
-				t.Errorf("wellformed(0x%x) returned depth %d, want %d", tc.data, depth, tc.wantDepth)
-			}
-		})
-	}
-}

valid_test.go

@@ -5,7 +5,6 @@ package cbor
 
 import (
 	"bytes"
-	"strconv"
 	"testing"
 )
 
@@ -103,11 +102,11 @@ func TestDepth(t *testing.T) {
 		{"tagged map and array", hexDecode("d864a26161016162d865820203"), 2},                                    // 100({"a": 1, "b": 101([2, 3])})
 		{"tagged map and array", hexDecode("d864a26161016162d865d866820203"), 3},                                // 100({"a": 1, "b": 101(102([2, 3]))})
 		{"nested tag", hexDecode("d864d865d86674323031332d30332d32315432303a30343a30305a"), 2},                  // 100(101(102("2013-03-21T20:04:00Z")))
-		{"16-level array", hexDecode("820181818181818181818181818181818101"), 16},
-		{"16-level indefinite length array", hexDecode("9f0181818181818181818181818181818101ff"), 16},
-		{"16-level map", hexDecode("a10181818181818181818181818181818101"), 16},
-		{"16-level indefinite length map", hexDecode("bf0181818181818181818181818181818101ff"), 16},
-		{"16-level tag", hexDecode("d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d86474323031332d30332d32315432303a30343a30305a"), 16}, // 100(100(...("2013-03-21T20:04:00Z")))
+		{"32-level array", hexDecode("82018181818181818181818181818181818181818181818181818181818181818101"), 32},
+		{"32-level indefinite length array", hexDecode("9f018181818181818181818181818181818181818181818181818181818181818101ff"), 32},
+		{"32-level map", hexDecode("a1018181818181818181818181818181818181818181818181818181818181818101"), 32},
+		{"32-level indefinite length map", hexDecode("bf018181818181818181818181818181818181818181818181818181818181818101ff"), 32},
+		{"32-level tag", hexDecode("d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d86474323031332d30332d32315432303a30343a30305a"), 32}, // 100(100(...("2013-03-21T20:04:00Z")))
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -146,31 +145,31 @@ func TestDepthError(t *testing.T) {
 			name:         "33-level array",
 			data:         hexDecode("8201818181818181818181818181818181818181818181818181818181818181818101"),
 			opts:         DecOptions{},
-			wantErrorMsg: "cbor: exceeded max nested level " + strconv.Itoa(defaultMaxNestedLevels),
+			wantErrorMsg: "cbor: exceeded max nested level 32",
 		},
 		{
 			name:         "33-level indefinite length array",
 			data:         hexDecode("9f01818181818181818181818181818181818181818181818181818181818181818101ff"),
 			opts:         DecOptions{},
-			wantErrorMsg: "cbor: exceeded max nested level " + strconv.Itoa(defaultMaxNestedLevels),
+			wantErrorMsg: "cbor: exceeded max nested level 32",
 		},
 		{
 			name:         "33-level map",
 			data:         hexDecode("a101818181818181818181818181818181818181818181818181818181818181818101"),
 			opts:         DecOptions{},
-			wantErrorMsg: "cbor: exceeded max nested level " + strconv.Itoa(defaultMaxNestedLevels),
+			wantErrorMsg: "cbor: exceeded max nested level 32",
 		},
 		{
 			name:         "33-level indefinite length map",
 			data:         hexDecode("bf01818181818181818181818181818181818181818181818181818181818181818101ff"),
 			opts:         DecOptions{},
-			wantErrorMsg: "cbor: exceeded max nested level " + strconv.Itoa(defaultMaxNestedLevels),
+			wantErrorMsg: "cbor: exceeded max nested level 32",
 		},
 		{
 			name:         "33-level tag",
 			data:         hexDecode("d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d864d86474323031332d30332d32315432303a30343a30305a"),
 			opts:         DecOptions{},
-			wantErrorMsg: "cbor: exceeded max nested level " + strconv.Itoa(defaultMaxNestedLevels),
+			wantErrorMsg: "cbor: exceeded max nested level 32",
 		},
 	}
 	for _, tc := range testCases {