linux/lib/zstd/decompress/zstd_decompress_block.h
Nick Terrell 2aa14b1ab2 zstd: import usptream v1.5.2
Updates the kernel's zstd library to v1.5.2, the latest zstd release.
The upstream tag it is updated to is `v1.5.2-kernel`, which contains
several cherry-picked commits on top of the v1.5.2 release which are
required for the kernel update. I will create this tag once the PR is
ready to merge, until then reference the temporary upstream branch
`v1.5.2-kernel-cherrypicks`.

I plan to submit this patch as part of the v6.2 merge window.

I've done basic build testing & testing on x86-64, i386, and aarch64.
I'm merging these patches into my `zstd-next` branch, which is pulled
into `linux-next` for further testing.

I've benchmarked BtrFS with zstd compression on a x86-64 machine, and
saw these results. Decompression speed is a small win across the board.
The lower compression levels 1-4 see both compression speed and
compression ratio wins. The higher compression levels see a small
compression speed loss and about neutral ratio. I expect the lower
compression levels to be used much more heavily than the high
compression levels, so this should be a net win.

Level	CTime	DTime	Ratio
1	-2.95%	-1.1%	-0.7%
3	-3.5%	-1.2%	-0.5%
5	+3.7%	-1.0%	+0.0%
7	+3.2%	-0.9%	+0.0%
9	-4.3%	-0.8%	+0.1%

Signed-off-by: Nick Terrell <terrelln@fb.com>
2022-10-24 12:12:32 -07:00

69 lines
2.4 KiB
C

/*
* Copyright (c) Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
#ifndef ZSTD_DEC_BLOCK_H
#define ZSTD_DEC_BLOCK_H
/*-*******************************************************
* Dependencies
*********************************************************/
#include "../common/zstd_deps.h" /* size_t */
#include <linux/zstd.h> /* DCtx, and some public functions */
#include "../common/zstd_internal.h" /* blockProperties_t, and some public functions */
#include "zstd_decompress_internal.h" /* ZSTD_seqSymbol */
/* === Prototypes === */
/* note: prototypes already published within `zstd.h` :
* ZSTD_decompressBlock()
*/
/* note: prototypes already published within `zstd_internal.h` :
* ZSTD_getcBlockSize()
* ZSTD_decodeSeqHeaders()
*/
/* Streaming state is used to inform allocation of the literal buffer */
typedef enum {
not_streaming = 0,
is_streaming = 1
} streaming_operation;
/* ZSTD_decompressBlock_internal() :
* decompress block, starting at `src`,
* into destination buffer `dst`.
* @return : decompressed block size,
* or an error code (which can be tested using ZSTD_isError())
*/
size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize, const int frame, const streaming_operation streaming);
/* ZSTD_buildFSETable() :
* generate FSE decoding table for one symbol (ll, ml or off)
* this function must be called with valid parameters only
* (dt is large enough, normalizedCounter distribution total is a power of 2, max is within range, etc.)
* in which case it cannot fail.
* The workspace must be 4-byte aligned and at least ZSTD_BUILD_FSE_TABLE_WKSP_SIZE bytes, which is
* defined in zstd_decompress_internal.h.
* Internal use only.
*/
void ZSTD_buildFSETable(ZSTD_seqSymbol* dt,
const short* normalizedCounter, unsigned maxSymbolValue,
const U32* baseValue, const U8* nbAdditionalBits,
unsigned tableLog, void* wksp, size_t wkspSize,
int bmi2);
#endif /* ZSTD_DEC_BLOCK_H */