dcrd/txscript
Dave Collins 462eea3b82
txscript: Optimize IsMultisigSigScript.
This converts the IsMultisigSigScript function to analyze the raw script
and make use of the new tokenizer instead of the far less efficient
parseScript thereby significantly optimizing the function.

In order to accomplish this, it first rejects scripts that can't
possibly fit the bill due to the final byte of what would be the redeem
script not being the appropriate opcode or the overall script not having
enough bytes.  Then, it uses a new function that is introduced named
finalOpcodeData that uses the tokenizer to return any data associated
with the final opcode in the signature script (which will be nil for
non-push opcodes or if the script fails to parse) and analyzes it as if
it were a redeem script when it is non nil.

It is also worth noting that this new implementation intentionally has
the same semantic difference from the existing implementation as the
updated IsMultisigScript function in regards to allowing zero pubkeys
whereas previously it incorrectly required at least one pubkey.

Finally, the comment is modified to explicitly call out the script
version semantics.

The following is a before and after comparison of analyzing a large
script that is not a multisig script and both a 1-of-2 multisig public
key script (which should be false) and a signature script comprised of a
pay-to-script-hash 1-of-2 multisig redeem script (which should be true):

benchmark                           old ns/op    new ns/op     delta
-----------------------------------------------------------------------
BenchmarkIsMultisigSigScriptLarge   158149       4             -100.00%
BenchmarkIsMultisigSigScript        3445         202           -94.14%

benchmark                           old allocs   new allocs    delta
-----------------------------------------------------------------------
BenchmarkIsMultisigSigScriptLarge   9            0             -100.00%
BenchmarkIsMultisigSigScript        3            0             -100.00%

benchmark                           old bytes    new bytes     delta
-----------------------------------------------------------------------
BenchmarkIsMultisigSigScriptLarge   533189       0             -100.00%
BenchmarkIsMultisigSigScript        9472         0             -100.00%
2019-03-26 14:51:04 -05:00
..
data txscript: Add remove signature reference test. 2019-02-14 14:10:12 -06:00
bench_test.go txscript: Add benchmarks for IsMutlsigSigScript. 2019-03-26 14:51:04 -05:00
consensus_test.go multi: Break coinbase dep on standardness rules. 2018-05-08 12:49:40 -05:00
consensus.go txscript: Significantly improve errors. 2018-07-01 15:04:59 -05:00
doc.go txscript: Significantly improve errors. 2018-07-01 15:04:59 -05:00
engine_test.go txscript: Remove DER signature verification flag. 2018-07-02 12:02:28 -05:00
engine.go txscript: Tighten standardness pubkey checks. 2019-03-11 19:33:27 -05:00
error_test.go txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00
error.go txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00
example_test.go txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00
go.mod multi: Add go 1.11 directive to all modules. 2019-03-18 02:02:35 -05:00
go.sum multi: Remove non-root module replacements. 2019-02-08 18:01:43 -06:00
log.go multi: deprecate DisableLog 2019-03-18 11:16:35 -05:00
opcode_test.go multi: cleanup linter warnings 2019-02-13 08:38:25 -05:00
opcode.go txscript: Optimize script disasm. 2019-03-26 14:50:57 -05:00
README.md txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00
reference_test.go txscript: Convert sighash calc tests. 2019-03-26 14:50:59 -05:00
script_test.go txscript: Introduce raw script sighash calc func. 2019-03-26 14:50:57 -05:00
script.go txscript: Optimize IsMultisigSigScript. 2019-03-26 14:51:04 -05:00
scriptbuilder_test.go txscript: Significantly improve errors. 2018-07-01 15:04:59 -05:00
scriptbuilder.go txscript: code cleanup 2019-02-08 09:18:53 -05:00
scriptnum_test.go txscript: Remove script num require minimal flag. 2018-07-02 12:14:15 -05:00
scriptnum.go txscript: Introduce constant for max CSV bytes. 2019-03-12 10:26:04 -05:00
sigcache_test.go multi: Remove unused secp256k1 sig parse parameter. 2018-07-04 12:27:34 -05:00
sigcache.go multi: release the mutex earlier 2018-02-13 13:55:02 -06:00
sighash_test.go txscript: Decouple and optimize sighash calc. 2018-05-01 08:51:41 -05:00
sighash.go txscript: Optimize CalcSignatureHash. 2019-03-26 14:50:58 -05:00
sign_test.go txscript: code cleanup 2019-02-08 09:18:53 -05:00
sign.go txscript: code cleanup 2019-02-08 09:18:53 -05:00
stack_test.go txscript: Make PeekInt consistent with PopInt. 2018-07-02 12:14:37 -05:00
stack.go txscript: code cleanup 2019-02-08 09:18:53 -05:00
standard_test.go txscript: Tighten standardness pubkey checks. 2019-03-11 19:33:27 -05:00
standard.go txscript: Optimize IsMultisigSigScript. 2019-03-26 14:51:04 -05:00
tokenizer_test.go txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00
tokenizer.go txscript: Introduce zero-alloc script tokenizer. 2019-03-26 14:50:56 -05:00

txscript

Build Status ISC License GoDoc

Package txscript implements the Decred transaction script language. There is a comprehensive test suite.

This package has intentionally been designed so it can be used as a standalone package for any projects needing to use or validate Decred transaction scripts.

Decred Scripts

Decred provides a stack-based, FORTH-like language for the scripts in the Decred transactions. This language is not turing complete although it is still fairly powerful.

Installation and Updating

$ go get -u github.com/decred/dcrd/txscript

Examples

License

Package txscript is licensed under the copyfree ISC License.