| 1 |
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| 2 | |
| 3 | * Copyright (c) Yann Collet, Facebook, Inc.
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| 4 | * All rights reserved.
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| 5 | *
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| 6 | * This source code is licensed under both the BSD-style license (found in the
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| 7 | * LICENSE file in the root directory of https://github.com/facebook/zstd) and
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| 8 | * the GPLv2 (found in the COPYING file in the root directory of
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| 9 | * https://github.com/facebook/zstd). You may select, at your option, one of the
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| 10 | * above-listed licenses.
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| 11 |
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| 12 |
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| 13 | #ifndef LINUX_ZSTD_H
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| 14 | #define LINUX_ZSTD_H
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| 15 |
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| 16 | |
| 17 | * This is a kernel-style API that wraps the upstream zstd API, which cannot be
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| 18 | * used directly because the symbols aren't exported. It exposes the minimal
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| 19 | * functionality which is currently required by users of zstd in the kernel.
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| 20 | * Expose extra functions from lib/zstd/zstd.h as needed.
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| 21 |
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| 22 |
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| 23 | |
| 24 | #include <linux/types.h>
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| 25 | #include <linux/zstd_errors.h>
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| 26 | #include <linux/zstd_lib.h>
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| 27 |
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| 28 | |
| 29 | |
| 30 | * zstd_compress_bound() - maximum compressed size in worst case scenario
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| 31 | * @src_size: The size of the data to compress.
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| 32 | *
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| 33 | * Return: The maximum compressed size in the worst case scenario.
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| 34 |
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| 35 | size_t zstd_compress_bound(size_t src_size);
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| 36 |
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| 37 | |
| 38 | * zstd_is_error() - tells if a size_t function result is an error code
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| 39 | * @code: The function result to check for error.
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| 40 | *
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| 41 | * Return: Non-zero iff the code is an error.
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| 42 |
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| 43 | unsigned int zstd_is_error(size_t code);
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| 44 |
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| 45 | |
| 46 | * enum zstd_error_code - zstd error codes
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| 47 |
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| 48 | typedef ZSTD_ErrorCode zstd_error_code;
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| 49 |
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| 50 | |
| 51 | * zstd_get_error_code() - translates an error function result to an error code
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| 52 | * @code: The function result for which zstd_is_error(code) is true.
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| 53 | *
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| 54 | * Return: A unique error code for this error.
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| 55 |
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| 56 | zstd_error_code zstd_get_error_code(size_t code);
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| 57 |
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| 58 | |
| 59 | * zstd_get_error_name() - translates an error function result to a string
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| 60 | * @code: The function result for which zstd_is_error(code) is true.
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| 61 | *
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| 62 | * Return: An error string corresponding to the error code.
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| 63 |
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| 64 | const char *zstd_get_error_name(size_t code);
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| 65 |
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| 66 | |
| 67 | * zstd_min_clevel() - minimum allowed compression level
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| 68 | *
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| 69 | * Return: The minimum allowed compression level.
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| 70 |
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| 71 | int zstd_min_clevel(void);
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| 72 |
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| 73 | |
| 74 | * zstd_max_clevel() - maximum allowed compression level
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| 75 | *
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| 76 | * Return: The maximum allowed compression level.
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| 77 |
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| 78 | int zstd_max_clevel(void);
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| 79 |
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| 80 | |
| 81 |
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| 82 | |
| 83 | * enum zstd_strategy - zstd compression search strategy
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| 84 | *
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| 85 | * From faster to stronger. See zstd_lib.h.
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| 86 |
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| 87 | typedef ZSTD_strategy zstd_strategy;
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| 88 |
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| 89 | |
| 90 | * struct zstd_compression_parameters - zstd compression parameters
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| 91 | * @windowLog: Log of the largest match distance. Larger means more
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| 92 | * compression, and more memory needed during decompression.
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| 93 | * @chainLog: Fully searched segment. Larger means more compression,
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| 94 | * slower, and more memory (useless for fast).
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| 95 | * @hashLog: Dispatch table. Larger means more compression,
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| 96 | * slower, and more memory.
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| 97 | * @searchLog: Number of searches. Larger means more compression and slower.
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| 98 | * @searchLength: Match length searched. Larger means faster decompression,
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| 99 | * sometimes less compression.
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| 100 | * @targetLength: Acceptable match size for optimal parser (only). Larger means
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| 101 | * more compression, and slower.
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| 102 | * @strategy: The zstd compression strategy.
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| 103 | *
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| 104 | * See zstd_lib.h.
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| 105 |
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| 106 | typedef ZSTD_compressionParameters zstd_compression_parameters;
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| 107 |
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| 108 | |
| 109 | * struct zstd_frame_parameters - zstd frame parameters
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| 110 | * @contentSizeFlag: Controls whether content size will be present in the
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| 111 | * frame header (when known).
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| 112 | * @checksumFlag: Controls whether a 32-bit checksum is generated at the
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| 113 | * end of the frame for error detection.
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| 114 | * @noDictIDFlag: Controls whether dictID will be saved into the frame
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| 115 | * header when using dictionary compression.
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| 116 | *
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| 117 | * The default value is all fields set to 0. See zstd_lib.h.
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| 118 |
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| 119 | typedef ZSTD_frameParameters zstd_frame_parameters;
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| 120 |
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| 121 | |
| 122 | * struct zstd_parameters - zstd parameters
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| 123 | * @cParams: The compression parameters.
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| 124 | * @fParams: The frame parameters.
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| 125 |
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| 126 | typedef ZSTD_parameters zstd_parameters;
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| 127 |
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| 128 | |
| 129 | * zstd_get_params() - returns zstd_parameters for selected level
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| 130 | * @level: The compression level
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| 131 | * @estimated_src_size: The estimated source size to compress or 0
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| 132 | * if unknown.
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| 133 | *
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| 134 | * Return: The selected zstd_parameters.
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| 135 |
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| 136 | zstd_parameters zstd_get_params(int level,
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| 137 | unsigned long long estimated_src_size);
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| 138 |
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| 139 | |
| 140 |
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| 141 | typedef ZSTD_CCtx zstd_cctx;
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| 142 |
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| 143 | |
| 144 | * zstd_cctx_workspace_bound() - max memory needed to initialize a zstd_cctx
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| 145 | * @parameters: The compression parameters to be used.
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| 146 | *
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| 147 | * If multiple compression parameters might be used, the caller must call
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| 148 | * zstd_cctx_workspace_bound() for each set of parameters and use the maximum
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| 149 | * size.
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| 150 | *
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| 151 | * Return: A lower bound on the size of the workspace that is passed to
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| 152 | * zstd_init_cctx().
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| 153 |
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| 154 | size_t zstd_cctx_workspace_bound(const zstd_compression_parameters *parameters);
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| 155 |
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| 156 | |
| 157 | * zstd_init_cctx() - initialize a zstd compression context
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| 158 | * @workspace: The workspace to emplace the context into. It must outlive
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| 159 | * the returned context.
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| 160 | * @workspace_size: The size of workspace. Use zstd_cctx_workspace_bound() to
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| 161 | * determine how large the workspace must be.
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| 162 | *
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| 163 | * Return: A zstd compression context or NULL on error.
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| 164 |
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| 165 | zstd_cctx *zstd_init_cctx(void *workspace, size_t workspace_size);
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| 166 |
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| 167 | |
| 168 | * zstd_compress_cctx() - compress src into dst with the initialized parameters
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| 169 | * @cctx: The context. Must have been initialized with zstd_init_cctx().
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| 170 | * @dst: The buffer to compress src into.
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| 171 | * @dst_capacity: The size of the destination buffer. May be any size, but
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| 172 | * ZSTD_compressBound(srcSize) is guaranteed to be large enough.
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| 173 | * @src: The data to compress.
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| 174 | * @src_size: The size of the data to compress.
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| 175 | * @parameters: The compression parameters to be used.
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| 176 | *
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| 177 | * Return: The compressed size or an error, which can be checked using
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| 178 | * zstd_is_error().
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| 179 |
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| 180 | size_t zstd_compress_cctx(zstd_cctx *cctx, void *dst, size_t dst_capacity,
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| 181 | const void *src, size_t src_size, const zstd_parameters *parameters);
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| 182 |
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| 183 | |
| 184 |
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| 185 | typedef ZSTD_DCtx zstd_dctx;
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| 186 |
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| 187 | |
| 188 | * zstd_dctx_workspace_bound() - max memory needed to initialize a zstd_dctx
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| 189 | *
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| 190 | * Return: A lower bound on the size of the workspace that is passed to
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| 191 | * zstd_init_dctx().
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| 192 |
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| 193 | size_t zstd_dctx_workspace_bound(void);
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| 194 |
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| 195 | |
| 196 | * zstd_init_dctx() - initialize a zstd decompression context
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| 197 | * @workspace: The workspace to emplace the context into. It must outlive
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| 198 | * the returned context.
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| 199 | * @workspace_size: The size of workspace. Use zstd_dctx_workspace_bound() to
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| 200 | * determine how large the workspace must be.
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| 201 | *
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| 202 | * Return: A zstd decompression context or NULL on error.
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| 203 |
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| 204 | zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size);
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| 205 |
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| 206 | |
| 207 | * zstd_decompress_dctx() - decompress zstd compressed src into dst
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| 208 | * @dctx: The decompression context.
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| 209 | * @dst: The buffer to decompress src into.
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| 210 | * @dst_capacity: The size of the destination buffer. Must be at least as large
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| 211 | * as the decompressed size. If the caller cannot upper bound the
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| 212 | * decompressed size, then it's better to use the streaming API.
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| 213 | * @src: The zstd compressed data to decompress. Multiple concatenated
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| 214 | * frames and skippable frames are allowed.
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| 215 | * @src_size: The exact size of the data to decompress.
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| 216 | *
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| 217 | * Return: The decompressed size or an error, which can be checked using
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| 218 | * zstd_is_error().
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| 219 |
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| 220 | size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity,
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| 221 | const void *src, size_t src_size);
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| 222 |
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| 223 | |
| 224 |
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| 225 | |
| 226 | * struct zstd_in_buffer - input buffer for streaming
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| 227 | * @src: Start of the input buffer.
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| 228 | * @size: Size of the input buffer.
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| 229 | * @pos: Position where reading stopped. Will be updated.
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| 230 | * Necessarily 0 <= pos <= size.
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| 231 | *
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| 232 | * See zstd_lib.h.
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| 233 |
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| 234 | typedef ZSTD_inBuffer zstd_in_buffer;
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| 235 |
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| 236 | |
| 237 | * struct zstd_out_buffer - output buffer for streaming
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| 238 | * @dst: Start of the output buffer.
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| 239 | * @size: Size of the output buffer.
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| 240 | * @pos: Position where writing stopped. Will be updated.
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| 241 | * Necessarily 0 <= pos <= size.
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| 242 | *
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| 243 | * See zstd_lib.h.
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| 244 |
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| 245 | typedef ZSTD_outBuffer zstd_out_buffer;
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| 246 |
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| 247 | |
| 248 |
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| 249 | typedef ZSTD_CStream zstd_cstream;
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| 250 |
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| 251 | |
| 252 | * zstd_cstream_workspace_bound() - memory needed to initialize a zstd_cstream
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| 253 | * @cparams: The compression parameters to be used for compression.
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| 254 | *
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| 255 | * Return: A lower bound on the size of the workspace that is passed to
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| 256 | * zstd_init_cstream().
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| 257 |
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| 258 | size_t zstd_cstream_workspace_bound(const zstd_compression_parameters *cparams);
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| 259 |
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| 260 | |
| 261 | * zstd_init_cstream() - initialize a zstd streaming compression context
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| 262 | * @parameters The zstd parameters to use for compression.
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| 263 | * @pledged_src_size: If params.fParams.contentSizeFlag == 1 then the caller
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| 264 | * must pass the source size (zero means empty source).
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| 265 | * Otherwise, the caller may optionally pass the source
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| 266 | * size, or zero if unknown.
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| 267 | * @workspace: The workspace to emplace the context into. It must outlive
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| 268 | * the returned context.
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| 269 | * @workspace_size: The size of workspace.
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| 270 | * Use zstd_cstream_workspace_bound(params->cparams) to
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| 271 | * determine how large the workspace must be.
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| 272 | *
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| 273 | * Return: The zstd streaming compression context or NULL on error.
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| 274 |
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| 275 | zstd_cstream *zstd_init_cstream(const zstd_parameters *parameters,
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| 276 | unsigned long long pledged_src_size, void *workspace, size_t workspace_size);
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| 277 |
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| 278 | |
| 279 | * zstd_reset_cstream() - reset the context using parameters from creation
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| 280 | * @cstream: The zstd streaming compression context to reset.
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| 281 | * @pledged_src_size: Optionally the source size, or zero if unknown.
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| 282 | *
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| 283 | * Resets the context using the parameters from creation. Skips dictionary
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| 284 | * loading, since it can be reused. If `pledged_src_size` is non-zero the frame
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| 285 | * content size is always written into the frame header.
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| 286 | *
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| 287 | * Return: Zero or an error, which can be checked using
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| 288 | * zstd_is_error().
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| 289 |
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| 290 | size_t zstd_reset_cstream(zstd_cstream *cstream,
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| 291 | unsigned long long pledged_src_size);
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| 292 |
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| 293 | |
| 294 | * zstd_compress_stream() - streaming compress some of input into output
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| 295 | * @cstream: The zstd streaming compression context.
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| 296 | * @output: Destination buffer. `output->pos` is updated to indicate how much
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| 297 | * compressed data was written.
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| 298 | * @input: Source buffer. `input->pos` is updated to indicate how much data
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| 299 | * was read. Note that it may not consume the entire input, in which
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| 300 | * case `input->pos < input->size`, and it's up to the caller to
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| 301 | * present remaining data again.
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| 302 | *
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| 303 | * The `input` and `output` buffers may be any size. Guaranteed to make some
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| 304 | * forward progress if `input` and `output` are not empty.
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| 305 | *
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| 306 | * Return: A hint for the number of bytes to use as the input for the next
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| 307 | * function call or an error, which can be checked using
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| 308 | * zstd_is_error().
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| 309 |
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| 310 | size_t zstd_compress_stream(zstd_cstream *cstream, zstd_out_buffer *output,
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| 311 | zstd_in_buffer *input);
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| 312 |
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| 313 | |
| 314 | * zstd_flush_stream() - flush internal buffers into output
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| 315 | * @cstream: The zstd streaming compression context.
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| 316 | * @output: Destination buffer. `output->pos` is updated to indicate how much
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| 317 | * compressed data was written.
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| 318 | *
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| 319 | * zstd_flush_stream() must be called until it returns 0, meaning all the data
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| 320 | * has been flushed. Since zstd_flush_stream() causes a block to be ended,
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| 321 | * calling it too often will degrade the compression ratio.
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| 322 | *
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| 323 | * Return: The number of bytes still present within internal buffers or an
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| 324 | * error, which can be checked using zstd_is_error().
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| 325 |
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| 326 | size_t zstd_flush_stream(zstd_cstream *cstream, zstd_out_buffer *output);
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| 327 |
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| 328 | |
| 329 | * zstd_end_stream() - flush internal buffers into output and end the frame
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| 330 | * @cstream: The zstd streaming compression context.
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| 331 | * @output: Destination buffer. `output->pos` is updated to indicate how much
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| 332 | * compressed data was written.
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| 333 | *
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| 334 | * zstd_end_stream() must be called until it returns 0, meaning all the data has
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| 335 | * been flushed and the frame epilogue has been written.
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| 336 | *
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| 337 | * Return: The number of bytes still present within internal buffers or an
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| 338 | * error, which can be checked using zstd_is_error().
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| 339 |
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| 340 | size_t zstd_end_stream(zstd_cstream *cstream, zstd_out_buffer *output);
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| 341 |
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| 342 | |
| 343 |
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| 344 | typedef ZSTD_DStream zstd_dstream;
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| 345 |
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| 346 | |
| 347 | * zstd_dstream_workspace_bound() - memory needed to initialize a zstd_dstream
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| 348 | * @max_window_size: The maximum window size allowed for compressed frames.
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| 349 | *
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| 350 | * Return: A lower bound on the size of the workspace that is passed
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| 351 | * to zstd_init_dstream().
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| 352 |
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| 353 | size_t zstd_dstream_workspace_bound(size_t max_window_size);
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| 354 |
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| 355 | |
| 356 | * zstd_init_dstream() - initialize a zstd streaming decompression context
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| 357 | * @max_window_size: The maximum window size allowed for compressed frames.
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| 358 | * @workspace: The workspace to emplace the context into. It must outlive
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| 359 | * the returned context.
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| 360 | * @workspaceSize: The size of workspace.
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| 361 | * Use zstd_dstream_workspace_bound(max_window_size) to
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| 362 | * determine how large the workspace must be.
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| 363 | *
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| 364 | * Return: The zstd streaming decompression context.
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| 365 |
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| 366 | zstd_dstream *zstd_init_dstream(size_t max_window_size, void *workspace,
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| 367 | size_t workspace_size);
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| 368 |
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| 369 | |
| 370 | * zstd_reset_dstream() - reset the context using parameters from creation
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| 371 | * @dstream: The zstd streaming decompression context to reset.
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| 372 | *
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| 373 | * Resets the context using the parameters from creation. Skips dictionary
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| 374 | * loading, since it can be reused.
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| 375 | *
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| 376 | * Return: Zero or an error, which can be checked using zstd_is_error().
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| 377 |
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| 378 | size_t zstd_reset_dstream(zstd_dstream *dstream);
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| 379 |
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| 380 | |
| 381 | * zstd_decompress_stream() - streaming decompress some of input into output
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| 382 | * @dstream: The zstd streaming decompression context.
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| 383 | * @output: Destination buffer. `output.pos` is updated to indicate how much
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| 384 | * decompressed data was written.
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| 385 | * @input: Source buffer. `input.pos` is updated to indicate how much data was
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| 386 | * read. Note that it may not consume the entire input, in which case
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| 387 | * `input.pos < input.size`, and it's up to the caller to present
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| 388 | * remaining data again.
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| 389 | *
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| 390 | * The `input` and `output` buffers may be any size. Guaranteed to make some
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| 391 | * forward progress if `input` and `output` are not empty.
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| 392 | * zstd_decompress_stream() will not consume the last byte of the frame until
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| 393 | * the entire frame is flushed.
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| 394 | *
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| 395 | * Return: Returns 0 iff a frame is completely decoded and fully flushed.
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| 396 | * Otherwise returns a hint for the number of bytes to use as the
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| 397 | * input for the next function call or an error, which can be checked
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| 398 | * using zstd_is_error(). The size hint will never load more than the
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| 399 | * frame.
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| 400 |
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| 401 | size_t zstd_decompress_stream(zstd_dstream *dstream, zstd_out_buffer *output,
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| 402 | zstd_in_buffer *input);
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| 403 |
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| 404 | |
| 405 |
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| 406 | |
| 407 | * zstd_find_frame_compressed_size() - returns the size of a compressed frame
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| 408 | * @src: Source buffer. It should point to the start of a zstd encoded
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| 409 | * frame or a skippable frame.
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| 410 | * @src_size: The size of the source buffer. It must be at least as large as the
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| 411 | * size of the frame.
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| 412 | *
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| 413 | * Return: The compressed size of the frame pointed to by `src` or an error,
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| 414 | * which can be check with zstd_is_error().
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| 415 | * Suitable to pass to ZSTD_decompress() or similar functions.
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| 416 |
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| 417 | size_t zstd_find_frame_compressed_size(const void *src, size_t src_size);
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| 418 |
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| 419 | |
| 420 | * struct zstd_frame_params - zstd frame parameters stored in the frame header
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| 421 | * @frameContentSize: The frame content size, or ZSTD_CONTENTSIZE_UNKNOWN if not
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| 422 | * present.
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| 423 | * @windowSize: The window size, or 0 if the frame is a skippable frame.
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| 424 | * @blockSizeMax: The maximum block size.
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| 425 | * @frameType: The frame type (zstd or skippable)
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| 426 | * @headerSize: The size of the frame header.
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| 427 | * @dictID: The dictionary id, or 0 if not present.
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| 428 | * @checksumFlag: Whether a checksum was used.
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| 429 | *
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| 430 | * See zstd_lib.h.
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| 431 |
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| 432 | typedef ZSTD_frameHeader zstd_frame_header;
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| 433 |
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| 434 | |
| 435 | * zstd_get_frame_header() - extracts parameters from a zstd or skippable frame
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| 436 | * @params: On success the frame parameters are written here.
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| 437 | * @src: The source buffer. It must point to a zstd or skippable frame.
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| 438 | * @src_size: The size of the source buffer.
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| 439 | *
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| 440 | * Return: 0 on success. If more data is required it returns how many bytes
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| 441 | * must be provided to make forward progress. Otherwise it returns
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| 442 | * an error, which can be checked using zstd_is_error().
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| 443 |
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| 444 | size_t zstd_get_frame_header(zstd_frame_header *params, const void *src,
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| 445 | size_t src_size);
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| 446 |
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| 447 | #endif
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