Zstd

perf: much faster dictionary builder, by jenniferliu
perf: faster dictionary compression on small data when using multiple contexts, by felixhandte
perf: faster dictionary decompression when using a very large number of dictionaries simultaneously
cli : fix : does no longer overwrite destination when source does not exist (1082)
cli : new command --adapt, for automatic compression level adaptation
api : fix : block api can be streamed with > 4 GB, reported by catid
api : reduced ZSTD_DDict size by 2 KB
api : minimum negative compression level is defined, and can be queried using ZSTD_minCLevel().
build: support Haiku target, by korli
build: Read Legacy format is limited to v0.5+ by default. Can be changed at compile time with macro ZSTD_LEGACY_SUPPORT.
doc : zstd_compression_format.md updated to match wording in IETF RFC 8478
misc: tests/paramgrill, a parameter optimizer, by GeorgeLu97

perf: much faster dictionary compression, by felixhandte
perf: small quality improvement for dictionary generation, by terrelln
perf: slightly improved high compression levels (notably level 19)
mem : automatic memory release for long duration contexts
cli : fix : overlapLog can be manually set
cli : fix : decoding invalid lz4 frames
api : fix : performance degradation for dictionary compression when using advanced API, by terrelln
api : change : clarify ZSTD_CCtx_reset() vs ZSTD_CCtx_resetParameters(), by terrelln
build: select custom libzstd scope through control macros, by GeorgeLu97
build: OpenBSD patch, by bket
build: make and make all are compatible with -j
doc : clarify zstd_compression_format.md, updated for IETF RFC process
misc: pzstd compatible with reproducible compilation, by lamby

perf: faster speed (especially decoding speed) on recent cpus (haswell+)
perf: much better performance associating --long with multi-threading, by terrelln
perf: better compression at levels 13-15
cli : asynchronous compression by default, for faster experience (use --single-thread for former behavior)
cli : smoother status report in multi-threading mode
cli : added command --fast=, for faster compression modes
cli : fix crash when not overwriting existing files, by Pádraig Brady (pixelb)
api : `nbThreads` becomes `nbWorkers` : 1 triggers asynchronous mode
api : compression levels can be negative, for even more speed
api : ZSTD_getFrameProgression() : get precise progress status of ZSTDMT anytime
api : ZSTDMT can accept new compression parameters during compression
api : implemented all advanced dictionary decompression prototypes
build: improved meson recipe, by Shawn Landden (shawnl)
build: VS2017 scripts, by HaydnTrigg
misc: all /contrib projects fixed
misc: added /contrib/docker script by gyscos

perf: faster zstd_opt strategy (levels 16-19)
fix : bug 944 : multithreading with shared ditionary and large data, reported by gsliepen
cli : fix : content size written in header by default
cli : fix : improved LZ4 format support, by felixhandte
cli : new : hidden command `-S`, to benchmark multiple files while generating one result per file
api : fix : support large skippable frames, by terrelln
api : fix : streaming interface was adding a useless 3-bytes null block to small frames
api : change : when setting `pledgedSrcSize`, use `ZSTD_CONTENTSIZE_UNKNOWN` macro value to mean "unknown"
build: fix : compilation under rhel6 and centos6, reported by pixelb
build: added `check` target

new : long range mode, using --long command, by Stella Lau (stellamplau)
new : ability to generate and decode magicless frames (591)
changed : maximum nb of threads reduced to 200, to avoid address space exhaustion in 32-bits mode
fix : multi-threading compression works with custom allocators
fix : ZSTD_sizeof_CStream() was over-evaluating memory usage
fix : a rare compression bug when compression generates very large distances and bunch of other conditions (only possible at --ultra -22)
fix : 32-bits build can now decode large offsets (levels 21+)
cli : added LZ4 frame support by default, by Felix Handte (felixhandte)
cli : improved --list output
cli : new : can split input file for dictionary training, using command -B
cli : new : clean operation artefact on Ctrl-C interruption
cli : fix : do not change /dev/null permissions when using command -t with root access, reported by mike155 (851)
cli : fix : write file size in header in multiple-files mode
api : added macro ZSTD_COMPRESSBOUND() for static allocation
api : experimental : new advanced decompression API
api : fix : sizeof_CCtx() used to over-estimate
build: fix : no-multithread variant compiles without pool.c dependency, reported by Mitchell Blank Jr (mitchblank) (819)
build: better compatibility with reproducible builds, by Bernhard M. Wiedemann (bmwiedemann) (818)
example : added streaming_memory_usage
license : changed /examples license to BSD + GPLv2
license : fix a few header files to reflect new license (825)

New license : BSD + GPLv2
perf: substantially decreased memory usage in Multi-threading mode, thanks to reports by Tino Reichardt (mcmilk)
perf: Multi-threading supports up to 256 threads. Cap at 256 when more are requested (760)
cli : improved and fixed --list command, by ib (772)
cli : command -vV to list supported formats, by ib (771)
build : fixed binary variants, reported by svenha (788)
build : fix Visual compilation for non x86/x64 targets, reported by Greg Slazinski (GregSlazinski) (718)
API exp : breaking change : ZSTD_getframeHeader() provides more information
API exp : breaking change : pinned down values of error codes
doc : fixed huffman example, by Ulrich Kunitz (ulikunitz)
new : contrib/adaptive-compression, I/O driven compression strength, by Paul Cruz (paulcruz74)
new : contrib/long_distance_matching, statistics by Stella Lau (stellamplau)
updated : contrib/linux-kernel, by Nick Terrell (terrelln)