README

lzma2-delphi

Native Delphi LZMA, LZMA2, XZ, and limited 7z implementation aligned with 7-Zip/LZMA SDK 26.01. The runtime is source-only Delphi code: it does not load 7z.dll, lzma.dll, liblzma, .obj, .lib, or spawn compressor helper processes at runtime.

This project is intended for applications that need a Delphi-native compression stack with stream APIs, deterministic release tooling, cross-tool compatibility tests, and reproducible performance evidence.

Highlights

• TStream first API through TLzma2 and Delphi-native SDK facade calls in Lzma.Sdk.
• Raw LZMA2, raw/standalone LZMA, XZ with one LZMA2 filter per block, and 7z archives using LZMA/LZMA2 folders.
• Multi-threaded LZMA2 encode with deterministic output ordering.
• Multi-threaded raw LZMA2 and XZ decode for independent reset chunks/blocks, with ordered output and explicit fallback diagnostics.
• XZ checks: none, crc32, crc64, and sha256.
• CLI and VCL tools under tools/, plus DUnitX, cross-tool, benchmark, and release-validator tiers under tests/.
• Runtime purity audit: external 7-Zip/xz/LZMA SDK tools are allowed only in tests, fixtures, CI, and benchmarks.

Format Support

Out of scope: encrypted 7z archives, non-LZMA/LZMA2 7z coders, arbitrary 7z filter graphs, ZIP, TAR, gzip, bzip2, zstd, PPMd, and AES.

Install

Add the src units to your Delphi project search path or include the units directly. The public API is intentionally small:

uses
  System.Classes,
  Lzma.Api,
  Lzma.Types;

var
  Options: TLzma2Options;
begin
  Options := TLzma2.XzOptions(1, 4, lzCheckCrc64);

  TLzma2.Compress(SourceStream, PackedStream, Options);
  PackedStream.Position := 0;
  TLzma2.Decompress(PackedStream, OutputStream, Options);
end;

Stream ownership stays with the caller. The library never closes caller-owned input or output streams.

CLI Quick Start

Build tools/Lzma2.dproj for Win64 Release, then use the 7-Zip-style command surface:

.\Lzma2.exe a data.xz data.bin -txz -mx=1 -md=1m -mmt=4 -mcheck=crc64
.\Lzma2.exe t data.xz -txz
.\Lzma2.exe x data.xz unpacked.bin -txz

.\Lzma2.exe a data.lzma data.bin -tlzma -mx=1 -md=1m
.\Lzma2.exe a tree.7z .\data-dir -t7z -mx=1 -md=1m -m0=LZMA2:d=1m
.\Lzma2.exe x tree.7z -o.\out -t7z

.\Lzma2.exe benchmark silesia.tar -T2 -D2 -1 -e9 -i2 -t3 -txz
.\Lzma2.exe --version

Common switches:

The legacy script-compatible form remains available:

.\Lzma2.exe compress input.bin output.xz xz 1 1048576 4 crc64
.\Lzma2.exe decompress output.xz roundtrip.bin xz

Performance Snapshot

Measured on 2026-05-02 with Delphi 13.1 Win64 and the official LZMA SDK 26.01 7zr.exe baseline on an AMD Ryzen 9 9950X3D. Throughput is end-to-end MiB/s. Ratio is compressed / original, lower is better.

Quality Gates

Use the same tiers as CI:

.\tests\run-ci.ps1 -Mode inner
.\tests\run-ci.ps1 -Mode quick -PerformanceWorkRoot <PERFORMANCE_WORK_ROOT>
.\tests\run-ci.ps1 -Mode release -PerformanceWorkRoot <PERFORMANCE_WORK_ROOT>

The release tier validates DUnitX, cross-tool compatibility, runtime purity, artifact manifests, SDK trace evidence, malformed-format behavior, and performance gates against the configured 7-Zip/LZMA SDK 26.01 and xz-utils tools from tests/qa-tools.json.

Performance evidence is intentionally data-only:

• artifacts/perf/lzma2-benchmark.csv
• artifacts/perf/lzma2-benchmark.json
• artifacts/perf/lzma2-benchmark.samples.csv
• artifacts/perf/lzma2-benchmark.summary.json

Charts are generated outside release validation from those files.

Release

Current project version: 26.01, matching the LZMA SDK baseline.

The public release asset set is:

• lzma2-delphi-26.01-win64.zip
• lzma2-delphi-26.01-win64.zip.sha256

The ZIP contains the Win64 command-line tool, the GUI tool, the Skia runtime DLL used by the GUI, and license notices: Lzma2.exe, Lzma2_GUI.exe, sk4d.dll, LICENSE, and THIRD-PARTY-NOTICES.md.

License

Project source code is licensed under the MIT License. Binary release packages can include third-party runtime files that remain under their own license terms; see THIRD-PARTY-NOTICES.md.

Documentation

• docs/api.md - public API and examples.
• docs/build.md - compiler, platform, and test requirements.
• docs/options.md - option semantics and normalization.
• docs/compatibility.md - format scope and cross-tool behavior.
• docs/memory.md - memory accounting.
• docs/performance.md - benchmark and artifact methodology.
• docs/release-scope.md - public release scope and assets.