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dcrd/gcs
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Dave Collins 7f402345f0
stake: Convert to use new stdaddr package. 
This converts the blockchain/stake package to use the stdaddr package
instead of dcrutil.Address as well as to support script versions.

All callers that use the package in the repository are updated
accordingly to maintain code that continues to build and work properly
as well as pass all tests.  In order to achieve this, it introduces
temporary address conversion code that will be removed in future
commits.

This is part of a series of commits to convert all packages in the
repository to make use of the new stdaddr package.
2021-04-09 13:39:16 -05:00
..
blockcf2 multi: Rework utxoset/view to use outpoints. 2021-01-14 17:25:06 -06:00
bench_test.go gcs: Implement version 2 filters. 2019-09-03 10:30:31 -05:00
bits_test.go gcs: update error types. 2020-11-11 14:12:03 -06:00
bits.go gcs: Overhaul tests and benchmarks. 2019-08-20 09:36:10 -05:00
doc.go multi: Fix various typos. 2021-03-01 10:57:51 -06:00
error_test.go gcs: update error types. 2020-11-11 14:12:03 -06:00
error.go gcs: update error types. 2020-11-11 14:12:03 -06:00
fastreduce_old.go gcs: Implement version 2 filters. 2019-09-03 10:30:31 -05:00
fastreduce.go gcs: Implement version 2 filters. 2019-09-03 10:30:31 -05:00
gcs_test.go gcs: update error types. 2020-11-11 14:12:03 -06:00
gcs.go multi: Address a bunch of lint issues. 2019-12-30 13:54:41 -06:00
go.mod stake: Convert to use new stdaddr package. 2021-04-09 13:39:16 -05:00
go.sum multi: Update to siphash v1.2.2. 2021-01-30 18:32:35 -06:00
README.md multi: Update README.md files for go modules. 2021-01-22 14:39:23 -06:00

README.md

gcs

Build Status ISC License Doc

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 B that defines the remainder code bit size
  • A parameter M that defines the false positive rate as 1/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.