9f8114e53d
The moves the blockchain package from the blockchain module to an internal package of the root module meaning that it is no longer a part of the exported blockchain module. Nearly all of the logic it provides is really for the internal implementation of dcrd itself and thus having it exported module significantly increases the maintenance burden. Note that as of this change the blockchain module still exists and provides the chaingen and fullblocktests packages both or which are useful and used by external consumers. This is part of a continuing overall effort to reduce the total number of exported packages and modules and eventually get to the point it will be possible to follow semver for the root module. Overview of the major changes: - Move all go files from blockchain -> internal/blockchain - Move testdata from blockchain -> internal/blockchain - Remove doc.go in favor of the README.md since godoc now displays it - Move README.md from blockchain -> internal/blockchain and update to match the new reality - Add a new README.md in the exported blockchain module that documents it contains the remaining exported packages - Update all import paths in the repository accordingly - Run go mod tidy on all modules |
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|---|---|---|
| .. | ||
| blockcf2 | ||
| bench_test.go | ||
| bits_test.go | ||
| bits.go | ||
| doc.go | ||
| error_test.go | ||
| error.go | ||
| fastreduce_old.go | ||
| fastreduce.go | ||
| gcs_test.go | ||
| gcs.go | ||
| go.mod | ||
| go.sum | ||
| README.md | ||
gcs
Package gcs provides an API for building and using Golomb-coded sets.
A Golomb-Coded Set (GCS) is a space-efficient probabilistic data structure that is used to test set membership with a tunable false positive rate while simultaneously preventing false negatives. In other words, items that are in the set will always match, but items that are not in the set will also sometimes match with the chosen false positive rate.
This package currently implements two different versions for backwards compatibility. Version 1 is deprecated and therefore should no longer be used.
Version 2 is the GCS variation that follows the specification details in DCP0005.
Version 2 sets do not permit empty items (data of zero length) to be added and are parameterized by the following:
- A parameter
Bthat defines the remainder code bit size - A parameter
Mthat defines the false positive rate as1/M - A key for the SipHash-2-4 function
- The items to include in the set
A comprehensive suite of tests is provided to ensure proper functionality.
GCS use in Decred
GCS is used as a mechanism for storing, transmitting, and committing to per-block filters. Consensus-validating full nodes commit to a single filter for every block and serve the filter to SPV clients that match against the filter locally to determine if the block is potentially relevant. The required parameters for Decred are defined by the blockcf2 package.
For more details, see the Block Filters section of DCP0005.
Installation and Updating
This package is part of the github.com/decred/dcrd/gcs/v2 module. Use the
standard go tooling for working with modules to incorporate it.
License
Package blockchain is licensed under the copyfree ISC License.