459 lines
17 KiB
C
459 lines
17 KiB
C
|
/*
|
||
|
|
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
|
||
|
|
* All rights reserved.
|
||
|
|
*
|
||
|
|
* This source code is licensed under the BSD-style license found in the
|
||
|
|
* LICENSE file in the root directory of https://github.com/facebook/zstd.
|
||
|
|
* An additional grant of patent rights can be found in the PATENTS file in the
|
||
|
|
* same directory.
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify it under
|
||
|
|
* the terms of the GNU General Public License version 2 as published by the
|
||
|
|
* Free Software Foundation. This program is dual-licensed; you may select
|
||
|
|
* either version 2 of the GNU General Public License ("GPL") or BSD license
|
||
|
|
* ("BSD").
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef LINUX_ZSTD_H
|
||
|
|
#define LINUX_ZSTD_H
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This is a kernel-style API that wraps the upstream zstd API, which cannot be
|
||
|
|
* used directly because the symbols aren't exported. It exposes the minimal
|
||
|
|
* functionality which is currently required by users of zstd in the kernel.
|
||
|
|
* Expose extra functions from lib/zstd/zstd.h as needed.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* ====== Dependency ====== */
|
||
|
|
#include <linux/types.h>
|
||
|
|
|
||
|
|
/* ====== Helper Functions ====== */
|
||
|
|
/**
|
||
|
|
* zstd_compress_bound() - maximum compressed size in worst case scenario
|
||
|
|
* @src_size: The size of the data to compress.
|
||
|
|
*
|
||
|
|
* Return: The maximum compressed size in the worst case scenario.
|
||
|
|
*/
|
||
|
|
size_t zstd_compress_bound(size_t src_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_is_error() - tells if a size_t function result is an error code
|
||
|
|
* @code: The function result to check for error.
|
||
|
|
*
|
||
|
|
* Return: Non-zero iff the code is an error.
|
||
|
|
*/
|
||
|
|
unsigned int zstd_is_error(size_t code);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_get_error_code() - translates an error function result to an error code
|
||
|
|
* @code: The function result for which zstd_is_error(code) is true.
|
||
|
|
*
|
||
|
|
* Return: A unique error code for this error.
|
||
|
|
*/
|
||
|
|
int zstd_get_error_code(size_t code);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_get_error_name() - translates an error function result to a string
|
||
|
|
* @code: The function result for which zstd_is_error(code) is true.
|
||
|
|
*
|
||
|
|
* Return: An error string corresponding to the error code.
|
||
|
|
*/
|
||
|
|
const char* zstd_get_error_name(size_t code);
|
||
|
|
|
||
|
|
/* ====== Parameter Selection ====== */
|
||
|
|
|
||
|
|
/**
|
||
|
|
* enum zstd_strategy - zstd compression search strategy
|
||
|
|
*
|
||
|
|
* From faster to stronger.
|
||
|
|
*/
|
||
|
|
enum zstd_strategy {
|
||
|
|
zstd_fast = 1,
|
||
|
|
zstd_dfast = 2,
|
||
|
|
zstd_greedy = 3,
|
||
|
|
zstd_lazy = 4,
|
||
|
|
zstd_lazy2 = 5,
|
||
|
|
zstd_btlazy2 = 6,
|
||
|
|
zstd_btopt = 7,
|
||
|
|
zstd_btultra = 8,
|
||
|
|
zstd_btultra2 = 9
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_compression_parameters - zstd compression parameters
|
||
|
|
* @window_log: Log of the largest match distance. Larger means more
|
||
|
|
* compression, and more memory needed during decompression.
|
||
|
|
* @chain_log: Fully searched segment. Larger means more compression,
|
||
|
|
* slower, and more memory (useless for fast).
|
||
|
|
* @hash_log: Dispatch table. Larger means more compression,
|
||
|
|
* slower, and more memory.
|
||
|
|
* @search_log: Number of searches. Larger means more compression and slower.
|
||
|
|
* @search_length: Match length searched. Larger means faster decompression,
|
||
|
|
* sometimes less compression.
|
||
|
|
* @target_length: Acceptable match size for optimal parser (only). Larger means
|
||
|
|
* more compression, and slower.
|
||
|
|
* @strategy: The zstd compression strategy.
|
||
|
|
*/
|
||
|
|
struct zstd_compression_parameters {
|
||
|
|
unsigned int window_log;
|
||
|
|
unsigned int chain_log;
|
||
|
|
unsigned int hash_log;
|
||
|
|
unsigned int search_log;
|
||
|
|
unsigned int search_length;
|
||
|
|
unsigned int target_length;
|
||
|
|
enum zstd_strategy strategy;
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_frame_parameters - zstd frame parameters
|
||
|
|
* @content_size_flag: Controls whether content size will be present in the
|
||
|
|
* frame header (when known).
|
||
|
|
* @checksum_flag: Controls whether a 32-bit checksum is generated at the
|
||
|
|
* end of the frame for error detection.
|
||
|
|
* @no_dict_id_flag: Controls whether dictID will be saved into the frame
|
||
|
|
* header when using dictionary compression.
|
||
|
|
*
|
||
|
|
* The default value is all fields set to 0.
|
||
|
|
*/
|
||
|
|
struct zstd_frame_parameters {
|
||
|
|
unsigned int content_size_flag;
|
||
|
|
unsigned int checksum_flag;
|
||
|
|
unsigned int no_dict_id_flag;
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_parameters - zstd parameters
|
||
|
|
* @cparams: The compression parameters.
|
||
|
|
* @fparams: The frame parameters.
|
||
|
|
*/
|
||
|
|
struct zstd_parameters {
|
||
|
|
struct zstd_compression_parameters cparams;
|
||
|
|
struct zstd_frame_parameters fparams;
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_get_params() - returns zstd_parameters for selected level
|
||
|
|
* @level: The compression level
|
||
|
|
* @estimated_src_size: The estimated source size to compress or 0
|
||
|
|
* if unknown.
|
||
|
|
*
|
||
|
|
* Return: The selected zstd_parameters.
|
||
|
|
*/
|
||
|
|
struct zstd_parameters zstd_get_params(int level,
|
||
|
|
unsigned long long estimated_src_size);
|
||
|
|
|
||
|
|
/* ====== Single-pass Compression ====== */
|
||
|
|
|
||
|
|
typedef struct ZSTD_CCtx_s zstd_cctx;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_cctx_workspace_bound() - max memory needed to initialize a zstd_cctx
|
||
|
|
* @parameters: The compression parameters to be used.
|
||
|
|
*
|
||
|
|
* If multiple compression parameters might be used, the caller must call
|
||
|
|
* zstd_cctx_workspace_bound() for each set of parameters and use the maximum
|
||
|
|
* size.
|
||
|
|
*
|
||
|
|
* Return: A lower bound on the size of the workspace that is passed to
|
||
|
|
* zstd_init_cctx().
|
||
|
|
*/
|
||
|
|
size_t zstd_cctx_workspace_bound(
|
||
|
|
const struct zstd_compression_parameters *parameters);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_init_cctx() - initialize a zstd compression context
|
||
|
|
* @workspace: The workspace to emplace the context into. It must outlive
|
||
|
|
* the returned context.
|
||
|
|
* @workspace_size: The size of workspace. Use zstd_cctx_workspace_bound() to
|
||
|
|
* determine how large the workspace must be.
|
||
|
|
*
|
||
|
|
* Return: A zstd compression context or NULL on error.
|
||
|
|
*/
|
||
|
|
zstd_cctx *zstd_init_cctx(void *workspace, size_t workspace_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_compress_cctx() - compress src into dst with the initialized parameters
|
||
|
|
* @cctx: The context. Must have been initialized with zstd_init_cctx().
|
||
|
|
* @dst: The buffer to compress src into.
|
||
|
|
* @dst_capacity: The size of the destination buffer. May be any size, but
|
||
|
|
* ZSTD_compressBound(srcSize) is guaranteed to be large enough.
|
||
|
|
* @src: The data to compress.
|
||
|
|
* @src_size: The size of the data to compress.
|
||
|
|
* @parameters: The compression parameters to be used.
|
||
|
|
*
|
||
|
|
* Return: The compressed size or an error, which can be checked using
|
||
|
|
* zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_compress_cctx(zstd_cctx *cctx, void *dst, size_t dst_capacity,
|
||
|
|
const void *src, size_t src_size, const struct zstd_parameters* parameters);
|
||
|
|
|
||
|
|
/* ====== Single-pass Decompression ====== */
|
||
|
|
|
||
|
|
typedef struct ZSTD_DCtx_s zstd_dctx;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_dctx_workspace_bound() - max memory needed to initialize a zstd_dctx
|
||
|
|
*
|
||
|
|
* Return: A lower bound on the size of the workspace that is passed to
|
||
|
|
* zstd_init_dctx().
|
||
|
|
*/
|
||
|
|
size_t zstd_dctx_workspace_bound(void);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_init_dctx() - initialize a zstd decompression context
|
||
|
|
* @workspace: The workspace to emplace the context into. It must outlive
|
||
|
|
* the returned context.
|
||
|
|
* @workspace_size: The size of workspace. Use zstd_dctx_workspace_bound() to
|
||
|
|
* determine how large the workspace must be.
|
||
|
|
*
|
||
|
|
* Return: A zstd decompression context or NULL on error.
|
||
|
|
*/
|
||
|
|
zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_decompress_dctx() - decompress zstd compressed src into dst
|
||
|
|
* @dctx: The decompression context.
|
||
|
|
* @dst: The buffer to decompress src into.
|
||
|
|
* @dst_capacity: The size of the destination buffer. Must be at least as large
|
||
|
|
* as the decompressed size. If the caller cannot upper bound the
|
||
|
|
* decompressed size, then it's better to use the streaming API.
|
||
|
|
* @src: The zstd compressed data to decompress. Multiple concatenated
|
||
|
|
* frames and skippable frames are allowed.
|
||
|
|
* @src_size: The exact size of the data to decompress.
|
||
|
|
*
|
||
|
|
* Return: The decompressed size or an error, which can be checked using
|
||
|
|
* zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity,
|
||
|
|
const void *src, size_t src_size);
|
||
|
|
|
||
|
|
/* ====== Streaming Buffers ====== */
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_in_buffer - input buffer for streaming
|
||
|
|
* @src: Start of the input buffer.
|
||
|
|
* @size: Size of the input buffer.
|
||
|
|
* @pos: Position where reading stopped. Will be updated.
|
||
|
|
* Necessarily 0 <= pos <= size.
|
||
|
|
*/
|
||
|
|
struct zstd_in_buffer {
|
||
|
|
const void *src;
|
||
|
|
size_t size;
|
||
|
|
size_t pos;
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_out_buffer - output buffer for streaming
|
||
|
|
* @dst: Start of the output buffer.
|
||
|
|
* @size: Size of the output buffer.
|
||
|
|
* @pos: Position where writing stopped. Will be updated.
|
||
|
|
* Necessarily 0 <= pos <= size.
|
||
|
|
*/
|
||
|
|
struct zstd_out_buffer {
|
||
|
|
void *dst;
|
||
|
|
size_t size;
|
||
|
|
size_t pos;
|
||
|
|
};
|
||
|
|
|
||
|
|
/* ====== Streaming Compression ====== */
|
||
|
|
|
||
|
|
typedef struct ZSTD_CCtx_s zstd_cstream;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_cstream_workspace_bound() - memory needed to initialize a zstd_cstream
|
||
|
|
* @cparams: The compression parameters to be used for compression.
|
||
|
|
*
|
||
|
|
* Return: A lower bound on the size of the workspace that is passed to
|
||
|
|
* zstd_init_cstream().
|
||
|
|
*/
|
||
|
|
size_t zstd_cstream_workspace_bound(
|
||
|
|
const struct zstd_compression_parameters *cparams);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_init_cstream() - initialize a zstd streaming compression context
|
||
|
|
* @parameters The zstd parameters to use for compression.
|
||
|
|
* @pledged_src_size: If params.fParams.contentSizeFlag == 1 then the caller
|
||
|
|
* must pass the source size (zero means empty source).
|
||
|
|
* Otherwise, the caller may optionally pass the source
|
||
|
|
* size, or zero if unknown.
|
||
|
|
* @workspace: The workspace to emplace the context into. It must outlive
|
||
|
|
* the returned context.
|
||
|
|
* @workspace_size: The size of workspace.
|
||
|
|
* Use zstd_cstream_workspace_bound(params->cparams) to
|
||
|
|
* determine how large the workspace must be.
|
||
|
|
*
|
||
|
|
* Return: The zstd streaming compression context or NULL on error.
|
||
|
|
*/
|
||
|
|
zstd_cstream *zstd_init_cstream(const struct zstd_parameters *parameters,
|
||
|
|
unsigned long long pledged_src_size, void *workspace, size_t workspace_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_reset_cstream() - reset the context using parameters from creation
|
||
|
|
* @cstream: The zstd streaming compression context to reset.
|
||
|
|
* @pledged_src_size: Optionally the source size, or zero if unknown.
|
||
|
|
*
|
||
|
|
* Resets the context using the parameters from creation. Skips dictionary
|
||
|
|
* loading, since it can be reused. If `pledged_src_size` is non-zero the frame
|
||
|
|
* content size is always written into the frame header.
|
||
|
|
*
|
||
|
|
* Return: Zero or an error, which can be checked using
|
||
|
|
* zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_reset_cstream(zstd_cstream *cstream,
|
||
|
|
unsigned long long pledged_src_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_compress_stream() - streaming compress some of input into output
|
||
|
|
* @cstream: The zstd streaming compression context.
|
||
|
|
* @output: Destination buffer. `output->pos` is updated to indicate how much
|
||
|
|
* compressed data was written.
|
||
|
|
* @input: Source buffer. `input->pos` is updated to indicate how much data
|
||
|
|
* was read. Note that it may not consume the entire input, in which
|
||
|
|
* case `input->pos < input->size`, and it's up to the caller to
|
||
|
|
* present remaining data again.
|
||
|
|
*
|
||
|
|
* The `input` and `output` buffers may be any size. Guaranteed to make some
|
||
|
|
* forward progress if `input` and `output` are not empty.
|
||
|
|
*
|
||
|
|
* Return: A hint for the number of bytes to use as the input for the next
|
||
|
|
* function call or an error, which can be checked using
|
||
|
|
* zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_compress_stream(zstd_cstream *cstream,
|
||
|
|
struct zstd_out_buffer *output, struct zstd_in_buffer *input);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_flush_stream() - flush internal buffers into output
|
||
|
|
* @cstream: The zstd streaming compression context.
|
||
|
|
* @output: Destination buffer. `output->pos` is updated to indicate how much
|
||
|
|
* compressed data was written.
|
||
|
|
*
|
||
|
|
* zstd_flush_stream() must be called until it returns 0, meaning all the data
|
||
|
|
* has been flushed. Since zstd_flush_stream() causes a block to be ended,
|
||
|
|
* calling it too often will degrade the compression ratio.
|
||
|
|
*
|
||
|
|
* Return: The number of bytes still present within internal buffers or an
|
||
|
|
* error, which can be checked using zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_flush_stream(zstd_cstream *cstream, struct zstd_out_buffer *output);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_end_stream() - flush internal buffers into output and end the frame
|
||
|
|
* @cstream: The zstd streaming compression context.
|
||
|
|
* @output: Destination buffer. `output->pos` is updated to indicate how much
|
||
|
|
* compressed data was written.
|
||
|
|
*
|
||
|
|
* zstd_end_stream() must be called until it returns 0, meaning all the data has
|
||
|
|
* been flushed and the frame epilogue has been written.
|
||
|
|
*
|
||
|
|
* Return: The number of bytes still present within internal buffers or an
|
||
|
|
* error, which can be checked using zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_end_stream(zstd_cstream *cstream, struct zstd_out_buffer *output);
|
||
|
|
|
||
|
|
/* ====== Streaming Decompression ====== */
|
||
|
|
|
||
|
|
typedef struct ZSTD_DCtx_s zstd_dstream;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_dstream_workspace_bound() - memory needed to initialize a zstd_dstream
|
||
|
|
* @max_window_size: The maximum window size allowed for compressed frames.
|
||
|
|
*
|
||
|
|
* Return: A lower bound on the size of the workspace that is passed
|
||
|
|
* to zstd_init_dstream().
|
||
|
|
*/
|
||
|
|
size_t zstd_dstream_workspace_bound(size_t max_window_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_init_dstream() - initialize a zstd streaming decompression context
|
||
|
|
* @max_window_size: The maximum window size allowed for compressed frames.
|
||
|
|
* @workspace: The workspace to emplace the context into. It must outlive
|
||
|
|
* the returned context.
|
||
|
|
* @workspaceSize: The size of workspace.
|
||
|
|
* Use zstd_dstream_workspace_bound(max_window_size) to
|
||
|
|
* determine how large the workspace must be.
|
||
|
|
*
|
||
|
|
* Return: The zstd streaming decompression context.
|
||
|
|
*/
|
||
|
|
zstd_dstream *zstd_init_dstream(size_t max_window_size, void* workspace,
|
||
|
|
size_t workspace_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_reset_dstream() - reset the context using parameters from creation
|
||
|
|
* @dstream: The zstd streaming decompression context to reset.
|
||
|
|
*
|
||
|
|
* Resets the context using the parameters from creation. Skips dictionary
|
||
|
|
* loading, since it can be reused.
|
||
|
|
*
|
||
|
|
* Return: Zero or an error, which can be checked using zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_reset_dstream(zstd_dstream *dstream);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_decompress_stream() - streaming decompress some of input into output
|
||
|
|
* @dstream: The zstd streaming decompression context.
|
||
|
|
* @output: Destination buffer. `output.pos` is updated to indicate how much
|
||
|
|
* decompressed data was written.
|
||
|
|
* @input: Source buffer. `input.pos` is updated to indicate how much data was
|
||
|
|
* read. Note that it may not consume the entire input, in which case
|
||
|
|
* `input.pos < input.size`, and it's up to the caller to present
|
||
|
|
* remaining data again.
|
||
|
|
*
|
||
|
|
* The `input` and `output` buffers may be any size. Guaranteed to make some
|
||
|
|
* forward progress if `input` and `output` are not empty.
|
||
|
|
* zstd_decompress_stream() will not consume the last byte of the frame until
|
||
|
|
* the entire frame is flushed.
|
||
|
|
*
|
||
|
|
* Return: Returns 0 iff a frame is completely decoded and fully flushed.
|
||
|
|
* Otherwise returns a hint for the number of bytes to use as the
|
||
|
|
* input for the next function call or an error, which can be checked
|
||
|
|
* using zstd_is_error(). The size hint will never load more than the
|
||
|
|
* frame.
|
||
|
|
*/
|
||
|
|
size_t zstd_decompress_stream(zstd_dstream *dstream,
|
||
|
|
struct zstd_out_buffer *output, struct zstd_in_buffer *input);
|
||
|
|
|
||
|
|
/* ====== Frame Inspection Functions ====== */
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_find_frame_compressed_size() - returns the size of a compressed frame
|
||
|
|
* @src: Source buffer. It should point to the start of a zstd encoded
|
||
|
|
* frame or a skippable frame.
|
||
|
|
* @src_size: The size of the source buffer. It must be at least as large as the
|
||
|
|
* size of the frame.
|
||
|
|
*
|
||
|
|
* Return: The compressed size of the frame pointed to by `src` or an error,
|
||
|
|
* which can be check with zstd_is_error().
|
||
|
|
* Suitable to pass to ZSTD_decompress() or similar functions.
|
||
|
|
*/
|
||
|
|
size_t zstd_find_frame_compressed_size(const void *src, size_t src_size);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* struct zstd_frame_params - zstd frame parameters stored in the frame header
|
||
|
|
* @frame_content_size: The frame content size, or 0 if not present.
|
||
|
|
* @window_size: The window size, or 0 if the frame is a skippable frame.
|
||
|
|
* @dict_id: The dictionary id, or 0 if not present.
|
||
|
|
* @checksum_flag: Whether a checksum was used.
|
||
|
|
*/
|
||
|
|
struct zstd_frame_params {
|
||
|
|
unsigned long long frame_content_size;
|
||
|
|
unsigned int window_size;
|
||
|
|
unsigned int dict_id;
|
||
|
|
unsigned int checksum_flag;
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* zstd_get_frame_params() - extracts parameters from a zstd or skippable frame
|
||
|
|
* @params: On success the frame parameters are written here.
|
||
|
|
* @src: The source buffer. It must point to a zstd or skippable frame.
|
||
|
|
* @src_size: The size of the source buffer.
|
||
|
|
*
|
||
|
|
* Return: 0 on success. If more data is required it returns how many bytes
|
||
|
|
* must be provided to make forward progress. Otherwise it returns
|
||
|
|
* an error, which can be checked using zstd_is_error().
|
||
|
|
*/
|
||
|
|
size_t zstd_get_frame_params(struct zstd_frame_params *params, const void *src,
|
||
|
|
size_t src_size);
|
||
|
|
|
||
|
|
#endif /* LINUX_ZSTD_H */
|