libdeflate/NEWS.md

# libdeflate release notes

## Version 1.8

* Added `-t` (test) option to `libdeflate-gunzip`.

* Unaligned access optimizations are now enabled on WebAssembly builds.

* Fixed a build error when building with the Intel C Compiler (ICC).

* Fixed a build error when building with uClibc.

* libdeflate's CI system has switched from Travis CI to GitHub Actions.

* Made some improvements to test scripts.

## Version 1.7

* Added support for compression level 0, "no compression".

* Added an ARM CRC32 instruction accelerated implementation of CRC32.

* Added support for linking the programs to the shared library version of
  libdeflate rather than to the static library version.

* Made the compression level affect the minimum input size at which compression
  is attempted.

* Fixed undefined behavior in x86 Adler32 implementation.  (No miscompilations
  were observed in practice.)

* Fixed undefined behavior in x86 CPU feature code.  (No miscompilations were
  observed in practice.)

* Fixed installing shared lib symlink on macOS.

* Documented third-party bindings.

* Made a lot of improvements to the testing scripts and the CI configuration
  file.

* Lots of other small improvements and cleanups.

## Version 1.6

* Prevented gcc 10 from miscompiling libdeflate (workaround for
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94994).

* Removed workaround for gcc 5 and earlier producing slow code on ARM32.  If
  this affects you, please upgrade your compiler.

* New API function: `libdeflate_zlib_decompress_ex()`.  It provides the actual
  size of the stream that was decompressed, like the gzip and DEFLATE
  equivalents.

* `libdeflate_zlib_decompress()` now accepts trailing bytes after the end of the
  stream, like the gzip and DEFLATE equivalents.

* Added support for custom memory allocators.  (New API function:
  `libdeflate_set_memory_allocator()`)

* Added support for building the library in freestanding mode.

* Building libdeflate no longer requires `CPPFLAGS=-Icommon`.

## Version 1.5

* Fixed up stdcall support on 32-bit Windows: the functions are now exported
  using both suffixed and non-suffixed names, and fixed `libdeflate.h` to be
  MSVC-compatible again.

## Version 1.4

* The 32-bit Windows build of libdeflate now uses the "stdcall" calling
  convention instead of "cdecl".  If you're calling `libdeflate.dll` directly
  from C or C++, you'll need to recompile your code.  If you're calling it from
  another language, or calling it indirectly using `LoadLibrary()`, you'll need
  to update your code to use the stdcall calling convention.

* The Makefile now supports building libdeflate as a shared
  library (`.dylib`) on macOS.

* Fixed a bug where support for certain optimizations and optional features
  (file access hints and more precise timestamps) was incorrectly omitted when
  libdeflate was compiled with `-Werror`.

* Added `make check` target to the Makefile.

* Added CI configuration files.

## Version 1.3

* `make install` now supports customizing the directories into which binaries,
  headers, and libraries are installed.

* `make install` now installs into `/usr/local` by default.  To change it, use
  e.g. `make install PREFIX=/usr`.

* `make install` now works on more platforms.

* The Makefile now supports overriding the optimization flags.

* The compression functions now correctly handle an output data buffer >= 4 GiB
  in size, and `gzip` and `gunzip` now correctly handle multi-gigabyte files (if
  enough memory is available).

## Version 1.2

* Slight improvements to decompression speed.

* Added an AVX-512BW implementation of Adler-32.

* The Makefile now supports a user-specified installation `PREFIX`.

* Fixed build error with some Visual Studio versions.

## Version 1.1

* Fixed crash in CRC-32 code when the prebuilt libdeflate for 32-bit Windows was
  called by a program built with Visual Studio.

* Improved the worst-case decompression speed of malicious data.

* Fixed build error when compiling for an ARM processor without hardware
  floating point support.

* Improved performance on the PowerPC64 architecture.

* Added soname to `libdeflate.so`, to make packaging easier.

* Added `make install` target to the Makefile.

* The Makefile now supports user-specified `CPPFLAGS`.

* The Windows binary releases now include the import library for
  `libdeflate.dll`.  `libdeflate.lib` is now the import library, and
  `libdeflatestatic.lib` is the static library.

## Version 1.0

* Added support for multi-member gzip files.

* Moved architecture-specific code into subdirectories.  If you aren't using the
  provided Makefile to build libdeflate, you now need to compile `lib/*.c` and
  `lib/*/*.c` instead of just `lib/*.c`.

* Added an ARM PMULL implementation of CRC-32, which speeds up gzip compression
  and decompression on 32-bit and 64-bit ARM processors that have the
  Cryptography Extensions.

* Improved detection of CPU features, resulting in accelerated functions being
  used in more cases.  This includes:

  * Detect CPU features on 32-bit x86, not just 64-bit as was done previously.

  * Detect CPU features on ARM, both 32 and 64-bit.  (Limited to Linux only
    currently.)

## Version 0.8

* Build fixes for certain platforms and compilers.

* libdeflate now produces the same output on all CPU architectures.

* Improved documentation for building libdeflate on Windows.

## Version 0.7

* Fixed a very rare bug that caused data to be compressed incorrectly.  The bug
  affected compression levels 7 and below since libdeflate v0.2.  Although there
  have been no user reports of the bug, and I believe it would have been highly
  unlikely to encounter on realistic data, it could occur on data specially
  crafted to reproduce it.

* Fixed a compilation error when building with clang 3.7.

## Version 0.6

* Various improvements to the gzip program's behavior.

* Faster CRC-32 on AVX-capable processors.

* Other minor changes.

## Version 0.5

* The CRC-32 checksum algorithm has been optimized with carryless multiplication
  instructions for `x86_64` (PCLMUL).  This speeds up gzip compression and
  decompression.

* Build fixes for certain platforms and compilers.

* Added more test programs and scripts.

* libdeflate is now entirely MIT-licensed.

## Version 0.4

* The Adler-32 checksum algorithm has been optimized with vector instructions
  for `x86_64` (SSE2 and AVX2) and ARM (NEON).  This speeds up zlib compression
  and decompression.

* To avoid naming collisions, functions and definitions in libdeflate's API have
  been renamed to be prefixed with `libdeflate_` or `LIBDEFLATE_`.  Programs
  using the old API will need to be updated.

* Various bug fixes and other improvements.

## Version 0.3

* Some bug fixes and other minor changes.

## Version 0.2

* Implemented a new block splitting algorithm which typically improves the
  compression ratio slightly at all compression levels.

* The compressor now outputs each block using the cheapest type (dynamic
  Huffman, static Huffman, or uncompressed).

* The gzip program has received an overhaul and now behaves more like the
  standard version.

* Build system updates, including: some build options were changed and some
  build options were removed, and the default 'make' target now includes the
  gzip program as well as the library.

## Version 0.1

* Initial official release.