mirror of https://github.com/metabarcoding/obitools4.git synced 2026-04-30 12:00:39 +00:00

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T

Eric Coissac 8c7017a99d ⬆️ version bump to v4.5

- Update obioptions.Version from "Release 4.4.29" to "/v/ Release v5"
- Update version.txt from 4.29 → .30
(automated by Makefile)

2026-04-13 13:34:53 +02:00

Variable-Length Integer Encoding/Decoding Utility

This Go package (obikmer) provides efficient serialization of uint64 integers using protobuf-style variable-length encoding (varint).

Core Features

✅ EncodeVarint(io.Writer, uint64) (n int, err error)
Writes a uint64 as a compact varint to any io.Writer. Uses 7 bits per byte, with the MSB as a continuation flag. Max 10 bytes for uint64.
✅ DecodeVarint(io.Reader) (val uint64, err error)
Reads and decodes a varint from any io.Reader. Handles multi-byte sequences safely; returns error on malformed input or overflow (>70 bits).
✅ VarintLen(uint64) int
Computes the exact byte length required to encode a value without performing I/O — useful for buffer preallocation or size estimation.

Each byte holds 7 bits of data; bit 8 (MSB) = 1 if more bytes follow, else 0.
Example:
- 0x7F → 1 byte: 0111_1111
- 0x80 → 2 bytes: 1000_0000 0000_0001

Network protocols & binary file formats requiring compact integer representation
Serialization frameworks (e.g., custom protobuf-like codecs)
Embedded systems or bandwidth-constrained environments where space efficiency matters

No external dependencies; uses only io from the standard library.
Thread-safe per call (no shared state), but io.Reader/Writer concurrency must be handled externally.
Compatible with standard protobuf varint format (e.g., interoperable with encoding/binary or gRPC).