Mike Smith authored on 29/11/2020 12:26:04 | 1 | 1 |
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+/* |
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+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. |
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+ * All rights reserved. |
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+ * |
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+ * This source code is licensed under both the BSD-style license (found in the |
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+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
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+ * in the COPYING file in the root directory of this source tree). |
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+ * You may select, at your option, one of the above-listed licenses. |
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+ */ |
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+#if defined (__cplusplus) |
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+extern "C" {
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+#endif |
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+ |
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+#ifndef ZSTD_H_235446 |
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+#define ZSTD_H_235446 |
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+ |
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+/* ====== Dependency ======*/ |
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+#include <limits.h> /* INT_MAX */ |
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+#include <stddef.h> /* size_t */ |
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+ |
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+ |
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+/* ===== ZSTDLIB_API : control library symbols visibility ===== */ |
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+#ifndef ZSTDLIB_VISIBILITY |
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+# if defined(__GNUC__) && (__GNUC__ >= 4) |
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+# define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default")))
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+# else |
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+# define ZSTDLIB_VISIBILITY |
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+# endif |
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+#endif |
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+#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) |
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+# define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY |
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+#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) |
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+# define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ |
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+#else |
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+# define ZSTDLIB_API ZSTDLIB_VISIBILITY |
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+#endif |
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+ |
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+ |
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+/******************************************************************************* |
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+ Introduction |
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+ |
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+ zstd, short for Zstandard, is a fast lossless compression algorithm, targeting |
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+ real-time compression scenarios at zlib-level and better compression ratios. |
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+ The zstd compression library provides in-memory compression and decompression |
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+ functions. |
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+ |
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+ The library supports regular compression levels from 1 up to ZSTD_maxCLevel(), |
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+ which is currently 22. Levels >= 20, labeled `--ultra`, should be used with |
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+ caution, as they require more memory. The library also offers negative |
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+ compression levels, which extend the range of speed vs. ratio preferences. |
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+ The lower the level, the faster the speed (at the cost of compression). |
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+ |
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+ Compression can be done in: |
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+ - a single step (described as Simple API) |
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+ - a single step, reusing a context (described as Explicit context) |
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+ - unbounded multiple steps (described as Streaming compression) |
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+ |
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+ The compression ratio achievable on small data can be highly improved using |
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+ a dictionary. Dictionary compression can be performed in: |
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+ - a single step (described as Simple dictionary API) |
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+ - a single step, reusing a dictionary (described as Bulk-processing |
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+ dictionary API) |
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+ |
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+ Advanced experimental functions can be accessed using |
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+ `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. |
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+ |
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+ Advanced experimental APIs should never be used with a dynamically-linked |
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+ library. They are not "stable"; their definitions or signatures may change in |
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+ the future. Only static linking is allowed. |
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+*******************************************************************************/ |
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+ |
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+/*------ Version ------*/ |
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+#define ZSTD_VERSION_MAJOR 1 |
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+#define ZSTD_VERSION_MINOR 4 |
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+#define ZSTD_VERSION_RELEASE 5 |
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+ |
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+#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) |
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+ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< to check runtime library version */ |
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+ |
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+#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE |
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+#define ZSTD_QUOTE(str) #str |
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+#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str) |
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+#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION) |
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+ZSTDLIB_API const char* ZSTD_versionString(void); /* requires v1.3.0+ */ |
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+ |
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+/* ************************************* |
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+ * Default constant |
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+ ***************************************/ |
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+#ifndef ZSTD_CLEVEL_DEFAULT |
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+# define ZSTD_CLEVEL_DEFAULT 3 |
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+#endif |
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+ |
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+/* ************************************* |
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+ * Constants |
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+ ***************************************/ |
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+ |
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+/* All magic numbers are supposed read/written to/from files/memory using little-endian convention */ |
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+#define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */ |
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+#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */ |
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+#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */ |
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+#define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0 |
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+ |
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+#define ZSTD_BLOCKSIZELOG_MAX 17 |
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+#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) |
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+ |
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+ |
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+ |
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+/*************************************** |
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+* Simple API |
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+***************************************/ |
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+/*! ZSTD_compress() : |
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+ * Compresses `src` content as a single zstd compressed frame into already allocated `dst`. |
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+ * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. |
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+ * @return : compressed size written into `dst` (<= `dstCapacity), |
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+ * or an error code if it fails (which can be tested using ZSTD_isError()). */ |
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+ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, |
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+ const void* src, size_t srcSize, |
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+ int compressionLevel); |
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+ |
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+/*! ZSTD_decompress() : |
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+ * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames. |
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+ * `dstCapacity` is an upper bound of originalSize to regenerate. |
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+ * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. |
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+ * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`), |
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+ * or an errorCode if it fails (which can be tested using ZSTD_isError()). */ |
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+ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, |
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+ const void* src, size_t compressedSize); |
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+ |
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+/*! ZSTD_getFrameContentSize() : requires v1.3.0+ |
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+ * `src` should point to the start of a ZSTD encoded frame. |
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+ * `srcSize` must be at least as large as the frame header. |
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+ * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. |
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+ * @return : - decompressed size of `src` frame content, if known |
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+ * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined |
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+ * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) |
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+ * note 1 : a 0 return value means the frame is valid but "empty". |
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+ * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. |
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+ * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. |
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+ * In which case, it's necessary to use streaming mode to decompress data. |
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+ * Optionally, application can rely on some implicit limit, |
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+ * as ZSTD_decompress() only needs an upper bound of decompressed size. |
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+ * (For example, data could be necessarily cut into blocks <= 16 KB). |
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+ * note 3 : decompressed size is always present when compression is completed using single-pass functions, |
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+ * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). |
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+ * note 4 : decompressed size can be very large (64-bits value), |
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+ * potentially larger than what local system can handle as a single memory segment. |
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+ * In which case, it's necessary to use streaming mode to decompress data. |
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+ * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. |
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+ * Always ensure return value fits within application's authorized limits. |
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+ * Each application can set its own limits. |
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+ * note 6 : This function replaces ZSTD_getDecompressedSize() */ |
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+#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) |
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+#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) |
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+ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); |
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+ |
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+/*! ZSTD_getDecompressedSize() : |
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+ * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). |
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+ * Both functions work the same way, but ZSTD_getDecompressedSize() blends |
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+ * "empty", "unknown" and "error" results to the same return value (0), |
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+ * while ZSTD_getFrameContentSize() gives them separate return values. |
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+ * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ |
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+ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); |
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+ |
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+/*! ZSTD_findFrameCompressedSize() : |
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+ * `src` should point to the start of a ZSTD frame or skippable frame. |
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+ * `srcSize` must be >= first frame size |
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+ * @return : the compressed size of the first frame starting at `src`, |
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+ * suitable to pass as `srcSize` to `ZSTD_decompress` or similar, |
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+ * or an error code if input is invalid */ |
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+ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); |
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+ |
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+ |
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+/*====== Helper functions ======*/ |
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+#define ZSTD_COMPRESSBOUND(srcSize) ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */ |
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+ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ |
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+ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ |
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+ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ |
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+ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */ |
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+ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ |
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+ |
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+ |
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+/*************************************** |
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+* Explicit context |
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+***************************************/ |
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+/*= Compression context |
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+ * When compressing many times, |
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+ * it is recommended to allocate a context just once, |
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+ * and re-use it for each successive compression operation. |
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+ * This will make workload friendlier for system's memory. |
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+ * Note : re-using context is just a speed / resource optimization. |
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+ * It doesn't change the compression ratio, which remains identical. |
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+ * Note 2 : In multi-threaded environments, |
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+ * use one different context per thread for parallel execution. |
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+ */ |
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+typedef struct ZSTD_CCtx_s ZSTD_CCtx; |
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+ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); |
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+ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); |
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+ |
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+/*! ZSTD_compressCCtx() : |
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+ * Same as ZSTD_compress(), using an explicit ZSTD_CCtx. |
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+ * Important : in order to behave similarly to `ZSTD_compress()`, |
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+ * this function compresses at requested compression level, |
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+ * __ignoring any other parameter__ . |
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+ * If any advanced parameter was set using the advanced API, |
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+ * they will all be reset. Only `compressionLevel` remains. |
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+ */ |
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+ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx, |
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+ void* dst, size_t dstCapacity, |
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+ const void* src, size_t srcSize, |
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+ int compressionLevel); |
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+ |
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+/*= Decompression context |
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+ * When decompressing many times, |
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+ * it is recommended to allocate a context only once, |
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+ * and re-use it for each successive compression operation. |
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+ * This will make workload friendlier for system's memory. |
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+ * Use one context per thread for parallel execution. */ |
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+typedef struct ZSTD_DCtx_s ZSTD_DCtx; |
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+ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void); |
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+ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); |
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+ |
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+/*! ZSTD_decompressDCtx() : |
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+ * Same as ZSTD_decompress(), |
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+ * requires an allocated ZSTD_DCtx. |
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+ * Compatible with sticky parameters. |
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+ */ |
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+ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, |
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+ void* dst, size_t dstCapacity, |
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+ const void* src, size_t srcSize); |
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+ |
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+ |
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+/*************************************** |
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+* Advanced compression API |
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+***************************************/ |
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+ |
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+/* API design : |
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+ * Parameters are pushed one by one into an existing context, |
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+ * using ZSTD_CCtx_set*() functions. |
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+ * Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame. |
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+ * "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` ! |
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+ * __They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx()__ . |
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+ * |
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+ * It's possible to reset all parameters to "default" using ZSTD_CCtx_reset(). |
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+ * |
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+ * This API supercedes all other "advanced" API entry points in the experimental section. |
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+ * In the future, we expect to remove from experimental API entry points which are redundant with this API. |
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+ */ |
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+ |
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+ |
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+/* Compression strategies, listed from fastest to strongest */ |
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+typedef enum { ZSTD_fast=1,
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+ ZSTD_dfast=2, |
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+ ZSTD_greedy=3, |
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+ ZSTD_lazy=4, |
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+ ZSTD_lazy2=5, |
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+ ZSTD_btlazy2=6, |
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+ ZSTD_btopt=7, |
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+ ZSTD_btultra=8, |
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+ ZSTD_btultra2=9 |
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+ /* note : new strategies _might_ be added in the future. |
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+ Only the order (from fast to strong) is guaranteed */ |
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+} ZSTD_strategy; |
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+ |
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+ |
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+typedef enum {
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+ |
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+ /* compression parameters |
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+ * Note: When compressing with a ZSTD_CDict these parameters are superseded |
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+ * by the parameters used to construct the ZSTD_CDict. |
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+ * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */ |
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+ ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table. |
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+ * Note that exact compression parameters are dynamically determined, |
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+ * depending on both compression level and srcSize (when known). |
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+ * Default level is ZSTD_CLEVEL_DEFAULT==3. |
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+ * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. |
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+ * Note 1 : it's possible to pass a negative compression level. |
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+ * Note 2 : setting a level does not automatically set all other compression parameters |
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+ * to default. Setting this will however eventually dynamically impact the compression |
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+ * parameters which have not been manually set. The manually set |
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+ * ones will 'stick'. */ |
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+ /* Advanced compression parameters : |
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+ * It's possible to pin down compression parameters to some specific values. |
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+ * In which case, these values are no longer dynamically selected by the compressor */ |
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+ ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2. |
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+ * This will set a memory budget for streaming decompression, |
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+ * with larger values requiring more memory |
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+ * and typically compressing more. |
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+ * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX. |
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+ * Special: value 0 means "use default windowLog". |
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+ * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT |
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+ * requires explicitly allowing such size at streaming decompression stage. */ |
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+ ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2. |
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+ * Resulting memory usage is (1 << (hashLog+2)). |
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+ * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX. |
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+ * Larger tables improve compression ratio of strategies <= dFast, |
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+ * and improve speed of strategies > dFast. |
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+ * Special: value 0 means "use default hashLog". */ |
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+ ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2. |
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+ * Resulting memory usage is (1 << (chainLog+2)). |
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+ * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. |
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+ * Larger tables result in better and slower compression. |
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+ * This parameter is useless for "fast" strategy. |
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+ * It's still useful when using "dfast" strategy, |
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+ * in which case it defines a secondary probe table. |
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+ * Special: value 0 means "use default chainLog". */ |
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+ ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2. |
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+ * More attempts result in better and slower compression. |
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+ * This parameter is useless for "fast" and "dFast" strategies. |
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+ * Special: value 0 means "use default searchLog". */ |
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+ ZSTD_c_minMatch=105, /* Minimum size of searched matches. |
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+ * Note that Zstandard can still find matches of smaller size, |
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+ * it just tweaks its search algorithm to look for this size and larger. |
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+ * Larger values increase compression and decompression speed, but decrease ratio. |
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+ * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX. |
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+ * Note that currently, for all strategies < btopt, effective minimum is 4. |
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+ * , for all strategies > fast, effective maximum is 6. |
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+ * Special: value 0 means "use default minMatchLength". */ |
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+ ZSTD_c_targetLength=106, /* Impact of this field depends on strategy. |
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+ * For strategies btopt, btultra & btultra2: |
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+ * Length of Match considered "good enough" to stop search. |
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+ * Larger values make compression stronger, and slower. |
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+ * For strategy fast: |
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+ * Distance between match sampling. |
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+ * Larger values make compression faster, and weaker. |
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+ * Special: value 0 means "use default targetLength". */ |
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+ ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition. |
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+ * The higher the value of selected strategy, the more complex it is, |
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+ * resulting in stronger and slower compression. |
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+ * Special: value 0 means "use default strategy". */ |
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+ |
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+ /* LDM mode parameters */ |
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+ ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching. |
|
| 333 |
+ * This parameter is designed to improve compression ratio |
|
| 334 |
+ * for large inputs, by finding large matches at long distance. |
|
| 335 |
+ * It increases memory usage and window size. |
|
| 336 |
+ * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB |
|
| 337 |
+ * except when expressly set to a different value. */ |
|
| 338 |
+ ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2. |
|
| 339 |
+ * Larger values increase memory usage and compression ratio, |
|
| 340 |
+ * but decrease compression speed. |
|
| 341 |
+ * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX |
|
| 342 |
+ * default: windowlog - 7. |
|
| 343 |
+ * Special: value 0 means "automatically determine hashlog". */ |
|
| 344 |
+ ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher. |
|
| 345 |
+ * Larger/too small values usually decrease compression ratio. |
|
| 346 |
+ * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. |
|
| 347 |
+ * Special: value 0 means "use default value" (default: 64). */ |
|
| 348 |
+ ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution. |
|
| 349 |
+ * Larger values improve collision resolution but decrease compression speed. |
|
| 350 |
+ * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX. |
|
| 351 |
+ * Special: value 0 means "use default value" (default: 3). */ |
|
| 352 |
+ ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table. |
|
| 353 |
+ * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). |
|
| 354 |
+ * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. |
|
| 355 |
+ * Larger values improve compression speed. |
|
| 356 |
+ * Deviating far from default value will likely result in a compression ratio decrease. |
|
| 357 |
+ * Special: value 0 means "automatically determine hashRateLog". */ |
|
| 358 |
+ |
|
| 359 |
+ /* frame parameters */ |
|
| 360 |
+ ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) |
|
| 361 |
+ * Content size must be known at the beginning of compression. |
|
| 362 |
+ * This is automatically the case when using ZSTD_compress2(), |
|
| 363 |
+ * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */ |
|
| 364 |
+ ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */ |
|
| 365 |
+ ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */ |
|
| 366 |
+ |
|
| 367 |
+ /* multi-threading parameters */ |
|
| 368 |
+ /* These parameters are only useful if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD). |
|
| 369 |
+ * They return an error otherwise. */ |
|
| 370 |
+ ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. |
|
| 371 |
+ * When nbWorkers >= 1, triggers asynchronous mode when used with ZSTD_compressStream*() : |
|
| 372 |
+ * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller, |
|
| 373 |
+ * while compression work is performed in parallel, within worker threads. |
|
| 374 |
+ * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end : |
|
| 375 |
+ * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call). |
|
| 376 |
+ * More workers improve speed, but also increase memory usage. |
|
| 377 |
+ * Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */ |
|
| 378 |
+ ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1. |
|
| 379 |
+ * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads. |
|
| 380 |
+ * 0 means default, which is dynamically determined based on compression parameters. |
|
| 381 |
+ * Job size must be a minimum of overlap size, or 1 MB, whichever is largest. |
|
| 382 |
+ * The minimum size is automatically and transparently enforced. */ |
|
| 383 |
+ ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size. |
|
| 384 |
+ * The overlap size is an amount of data reloaded from previous job at the beginning of a new job. |
|
| 385 |
+ * It helps preserve compression ratio, while each job is compressed in parallel. |
|
| 386 |
+ * This value is enforced only when nbWorkers >= 1. |
|
| 387 |
+ * Larger values increase compression ratio, but decrease speed. |
|
| 388 |
+ * Possible values range from 0 to 9 : |
|
| 389 |
+ * - 0 means "default" : value will be determined by the library, depending on strategy |
|
| 390 |
+ * - 1 means "no overlap" |
|
| 391 |
+ * - 9 means "full overlap", using a full window size. |
|
| 392 |
+ * Each intermediate rank increases/decreases load size by a factor 2 : |
|
| 393 |
+ * 9: full window; 8: w/2; 7: w/4; 6: w/8; 5:w/16; 4: w/32; 3:w/64; 2:w/128; 1:no overlap; 0:default |
|
| 394 |
+ * default value varies between 6 and 9, depending on strategy */ |
|
| 395 |
+ |
|
| 396 |
+ /* note : additional experimental parameters are also available |
|
| 397 |
+ * within the experimental section of the API. |
|
| 398 |
+ * At the time of this writing, they include : |
|
| 399 |
+ * ZSTD_c_rsyncable |
|
| 400 |
+ * ZSTD_c_format |
|
| 401 |
+ * ZSTD_c_forceMaxWindow |
|
| 402 |
+ * ZSTD_c_forceAttachDict |
|
| 403 |
+ * ZSTD_c_literalCompressionMode |
|
| 404 |
+ * ZSTD_c_targetCBlockSize |
|
| 405 |
+ * ZSTD_c_srcSizeHint |
|
| 406 |
+ * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. |
|
| 407 |
+ * note : never ever use experimentalParam? names directly; |
|
| 408 |
+ * also, the enums values themselves are unstable and can still change. |
|
| 409 |
+ */ |
|
| 410 |
+ ZSTD_c_experimentalParam1=500, |
|
| 411 |
+ ZSTD_c_experimentalParam2=10, |
|
| 412 |
+ ZSTD_c_experimentalParam3=1000, |
|
| 413 |
+ ZSTD_c_experimentalParam4=1001, |
|
| 414 |
+ ZSTD_c_experimentalParam5=1002, |
|
| 415 |
+ ZSTD_c_experimentalParam6=1003, |
|
| 416 |
+ ZSTD_c_experimentalParam7=1004 |
|
| 417 |
+} ZSTD_cParameter; |
|
| 418 |
+ |
|
| 419 |
+typedef struct {
|
|
| 420 |
+ size_t error; |
|
| 421 |
+ int lowerBound; |
|
| 422 |
+ int upperBound; |
|
| 423 |
+} ZSTD_bounds; |
|
| 424 |
+ |
|
| 425 |
+/*! ZSTD_cParam_getBounds() : |
|
| 426 |
+ * All parameters must belong to an interval with lower and upper bounds, |
|
| 427 |
+ * otherwise they will either trigger an error or be automatically clamped. |
|
| 428 |
+ * @return : a structure, ZSTD_bounds, which contains |
|
| 429 |
+ * - an error status field, which must be tested using ZSTD_isError() |
|
| 430 |
+ * - lower and upper bounds, both inclusive |
|
| 431 |
+ */ |
|
| 432 |
+ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam); |
|
| 433 |
+ |
|
| 434 |
+/*! ZSTD_CCtx_setParameter() : |
|
| 435 |
+ * Set one compression parameter, selected by enum ZSTD_cParameter. |
|
| 436 |
+ * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). |
|
| 437 |
+ * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). |
|
| 438 |
+ * Setting a parameter is generally only possible during frame initialization (before starting compression). |
|
| 439 |
+ * Exception : when using multi-threading mode (nbWorkers >= 1), |
|
| 440 |
+ * the following parameters can be updated _during_ compression (within same frame): |
|
| 441 |
+ * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. |
|
| 442 |
+ * new parameters will be active for next job only (after a flush()). |
|
| 443 |
+ * @return : an error code (which can be tested using ZSTD_isError()). |
|
| 444 |
+ */ |
|
| 445 |
+ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value); |
|
| 446 |
+ |
|
| 447 |
+/*! ZSTD_CCtx_setPledgedSrcSize() : |
|
| 448 |
+ * Total input data size to be compressed as a single frame. |
|
| 449 |
+ * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. |
|
| 450 |
+ * This value will also be controlled at end of frame, and trigger an error if not respected. |
|
| 451 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 452 |
+ * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. |
|
| 453 |
+ * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. |
|
| 454 |
+ * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. |
|
| 455 |
+ * Note 2 : pledgedSrcSize is only valid once, for the next frame. |
|
| 456 |
+ * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. |
|
| 457 |
+ * Note 3 : Whenever all input data is provided and consumed in a single round, |
|
| 458 |
+ * for example with ZSTD_compress2(), |
|
| 459 |
+ * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), |
|
| 460 |
+ * this value is automatically overridden by srcSize instead. |
|
| 461 |
+ */ |
|
| 462 |
+ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); |
|
| 463 |
+ |
|
| 464 |
+typedef enum {
|
|
| 465 |
+ ZSTD_reset_session_only = 1, |
|
| 466 |
+ ZSTD_reset_parameters = 2, |
|
| 467 |
+ ZSTD_reset_session_and_parameters = 3 |
|
| 468 |
+} ZSTD_ResetDirective; |
|
| 469 |
+ |
|
| 470 |
+/*! ZSTD_CCtx_reset() : |
|
| 471 |
+ * There are 2 different things that can be reset, independently or jointly : |
|
| 472 |
+ * - The session : will stop compressing current frame, and make CCtx ready to start a new one. |
|
| 473 |
+ * Useful after an error, or to interrupt any ongoing compression. |
|
| 474 |
+ * Any internal data not yet flushed is cancelled. |
|
| 475 |
+ * Compression parameters and dictionary remain unchanged. |
|
| 476 |
+ * They will be used to compress next frame. |
|
| 477 |
+ * Resetting session never fails. |
|
| 478 |
+ * - The parameters : changes all parameters back to "default". |
|
| 479 |
+ * This removes any reference to any dictionary too. |
|
| 480 |
+ * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing) |
|
| 481 |
+ * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError()) |
|
| 482 |
+ * - Both : similar to resetting the session, followed by resetting parameters. |
|
| 483 |
+ */ |
|
| 484 |
+ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); |
|
| 485 |
+ |
|
| 486 |
+/*! ZSTD_compress2() : |
|
| 487 |
+ * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. |
|
| 488 |
+ * ZSTD_compress2() always starts a new frame. |
|
| 489 |
+ * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. |
|
| 490 |
+ * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() |
|
| 491 |
+ * - The function is always blocking, returns when compression is completed. |
|
| 492 |
+ * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. |
|
| 493 |
+ * @return : compressed size written into `dst` (<= `dstCapacity), |
|
| 494 |
+ * or an error code if it fails (which can be tested using ZSTD_isError()). |
|
| 495 |
+ */ |
|
| 496 |
+ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx, |
|
| 497 |
+ void* dst, size_t dstCapacity, |
|
| 498 |
+ const void* src, size_t srcSize); |
|
| 499 |
+ |
|
| 500 |
+ |
|
| 501 |
+/*************************************** |
|
| 502 |
+* Advanced decompression API |
|
| 503 |
+***************************************/ |
|
| 504 |
+ |
|
| 505 |
+/* The advanced API pushes parameters one by one into an existing DCtx context. |
|
| 506 |
+ * Parameters are sticky, and remain valid for all following frames |
|
| 507 |
+ * using the same DCtx context. |
|
| 508 |
+ * It's possible to reset parameters to default values using ZSTD_DCtx_reset(). |
|
| 509 |
+ * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream(). |
|
| 510 |
+ * Therefore, no new decompression function is necessary. |
|
| 511 |
+ */ |
|
| 512 |
+ |
|
| 513 |
+typedef enum {
|
|
| 514 |
+ |
|
| 515 |
+ ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which |
|
| 516 |
+ * the streaming API will refuse to allocate memory buffer |
|
| 517 |
+ * in order to protect the host from unreasonable memory requirements. |
|
| 518 |
+ * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. |
|
| 519 |
+ * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT). |
|
| 520 |
+ * Special: value 0 means "use default maximum windowLog". */ |
|
| 521 |
+ |
|
| 522 |
+ /* note : additional experimental parameters are also available |
|
| 523 |
+ * within the experimental section of the API. |
|
| 524 |
+ * At the time of this writing, they include : |
|
| 525 |
+ * ZSTD_d_format |
|
| 526 |
+ * ZSTD_d_stableOutBuffer |
|
| 527 |
+ * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. |
|
| 528 |
+ * note : never ever use experimentalParam? names directly |
|
| 529 |
+ */ |
|
| 530 |
+ ZSTD_d_experimentalParam1=1000, |
|
| 531 |
+ ZSTD_d_experimentalParam2=1001 |
|
| 532 |
+ |
|
| 533 |
+} ZSTD_dParameter; |
|
| 534 |
+ |
|
| 535 |
+/*! ZSTD_dParam_getBounds() : |
|
| 536 |
+ * All parameters must belong to an interval with lower and upper bounds, |
|
| 537 |
+ * otherwise they will either trigger an error or be automatically clamped. |
|
| 538 |
+ * @return : a structure, ZSTD_bounds, which contains |
|
| 539 |
+ * - an error status field, which must be tested using ZSTD_isError() |
|
| 540 |
+ * - both lower and upper bounds, inclusive |
|
| 541 |
+ */ |
|
| 542 |
+ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam); |
|
| 543 |
+ |
|
| 544 |
+/*! ZSTD_DCtx_setParameter() : |
|
| 545 |
+ * Set one compression parameter, selected by enum ZSTD_dParameter. |
|
| 546 |
+ * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). |
|
| 547 |
+ * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). |
|
| 548 |
+ * Setting a parameter is only possible during frame initialization (before starting decompression). |
|
| 549 |
+ * @return : 0, or an error code (which can be tested using ZSTD_isError()). |
|
| 550 |
+ */ |
|
| 551 |
+ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value); |
|
| 552 |
+ |
|
| 553 |
+/*! ZSTD_DCtx_reset() : |
|
| 554 |
+ * Return a DCtx to clean state. |
|
| 555 |
+ * Session and parameters can be reset jointly or separately. |
|
| 556 |
+ * Parameters can only be reset when no active frame is being decompressed. |
|
| 557 |
+ * @return : 0, or an error code, which can be tested with ZSTD_isError() |
|
| 558 |
+ */ |
|
| 559 |
+ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); |
|
| 560 |
+ |
|
| 561 |
+ |
|
| 562 |
+/**************************** |
|
| 563 |
+* Streaming |
|
| 564 |
+****************************/ |
|
| 565 |
+ |
|
| 566 |
+typedef struct ZSTD_inBuffer_s {
|
|
| 567 |
+ const void* src; /**< start of input buffer */ |
|
| 568 |
+ size_t size; /**< size of input buffer */ |
|
| 569 |
+ size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ |
|
| 570 |
+} ZSTD_inBuffer; |
|
| 571 |
+ |
|
| 572 |
+typedef struct ZSTD_outBuffer_s {
|
|
| 573 |
+ void* dst; /**< start of output buffer */ |
|
| 574 |
+ size_t size; /**< size of output buffer */ |
|
| 575 |
+ size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ |
|
| 576 |
+} ZSTD_outBuffer; |
|
| 577 |
+ |
|
| 578 |
+ |
|
| 579 |
+ |
|
| 580 |
+/*-*********************************************************************** |
|
| 581 |
+* Streaming compression - HowTo |
|
| 582 |
+* |
|
| 583 |
+* A ZSTD_CStream object is required to track streaming operation. |
|
| 584 |
+* Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. |
|
| 585 |
+* ZSTD_CStream objects can be reused multiple times on consecutive compression operations. |
|
| 586 |
+* It is recommended to re-use ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. |
|
| 587 |
+* |
|
| 588 |
+* For parallel execution, use one separate ZSTD_CStream per thread. |
|
| 589 |
+* |
|
| 590 |
+* note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing. |
|
| 591 |
+* |
|
| 592 |
+* Parameters are sticky : when starting a new compression on the same context, |
|
| 593 |
+* it will re-use the same sticky parameters as previous compression session. |
|
| 594 |
+* When in doubt, it's recommended to fully initialize the context before usage. |
|
| 595 |
+* Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(), |
|
| 596 |
+* ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to |
|
| 597 |
+* set more specific parameters, the pledged source size, or load a dictionary. |
|
| 598 |
+* |
|
| 599 |
+* Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to |
|
| 600 |
+* consume input stream. The function will automatically update both `pos` |
|
| 601 |
+* fields within `input` and `output`. |
|
| 602 |
+* Note that the function may not consume the entire input, for example, because |
|
| 603 |
+* the output buffer is already full, in which case `input.pos < input.size`. |
|
| 604 |
+* The caller must check if input has been entirely consumed. |
|
| 605 |
+* If not, the caller must make some room to receive more compressed data, |
|
| 606 |
+* and then present again remaining input data. |
|
| 607 |
+* note: ZSTD_e_continue is guaranteed to make some forward progress when called, |
|
| 608 |
+* but doesn't guarantee maximal forward progress. This is especially relevant |
|
| 609 |
+* when compressing with multiple threads. The call won't block if it can |
|
| 610 |
+* consume some input, but if it can't it will wait for some, but not all, |
|
| 611 |
+* output to be flushed. |
|
| 612 |
+* @return : provides a minimum amount of data remaining to be flushed from internal buffers |
|
| 613 |
+* or an error code, which can be tested using ZSTD_isError(). |
|
| 614 |
+* |
|
| 615 |
+* At any moment, it's possible to flush whatever data might remain stuck within internal buffer, |
|
| 616 |
+* using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated. |
|
| 617 |
+* Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0). |
|
| 618 |
+* In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush. |
|
| 619 |
+* You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the |
|
| 620 |
+* operation. |
|
| 621 |
+* note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will |
|
| 622 |
+* block until the flush is complete or the output buffer is full. |
|
| 623 |
+* @return : 0 if internal buffers are entirely flushed, |
|
| 624 |
+* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), |
|
| 625 |
+* or an error code, which can be tested using ZSTD_isError(). |
|
| 626 |
+* |
|
| 627 |
+* Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame. |
|
| 628 |
+* It will perform a flush and write frame epilogue. |
|
| 629 |
+* The epilogue is required for decoders to consider a frame completed. |
|
| 630 |
+* flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush. |
|
| 631 |
+* You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to |
|
| 632 |
+* start a new frame. |
|
| 633 |
+* note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will |
|
| 634 |
+* block until the flush is complete or the output buffer is full. |
|
| 635 |
+* @return : 0 if frame fully completed and fully flushed, |
|
| 636 |
+* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), |
|
| 637 |
+* or an error code, which can be tested using ZSTD_isError(). |
|
| 638 |
+* |
|
| 639 |
+* *******************************************************************/ |
|
| 640 |
+ |
|
| 641 |
+typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */ |
|
| 642 |
+ /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ |
|
| 643 |
+/*===== ZSTD_CStream management functions =====*/ |
|
| 644 |
+ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); |
|
| 645 |
+ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); |
|
| 646 |
+ |
|
| 647 |
+/*===== Streaming compression functions =====*/ |
|
| 648 |
+typedef enum {
|
|
| 649 |
+ ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */ |
|
| 650 |
+ ZSTD_e_flush=1, /* flush any data provided so far, |
|
| 651 |
+ * it creates (at least) one new block, that can be decoded immediately on reception; |
|
| 652 |
+ * frame will continue: any future data can still reference previously compressed data, improving compression. |
|
| 653 |
+ * note : multithreaded compression will block to flush as much output as possible. */ |
|
| 654 |
+ ZSTD_e_end=2 /* flush any remaining data _and_ close current frame. |
|
| 655 |
+ * note that frame is only closed after compressed data is fully flushed (return value == 0). |
|
| 656 |
+ * After that point, any additional data starts a new frame. |
|
| 657 |
+ * note : each frame is independent (does not reference any content from previous frame). |
|
| 658 |
+ : note : multithreaded compression will block to flush as much output as possible. */ |
|
| 659 |
+} ZSTD_EndDirective; |
|
| 660 |
+ |
|
| 661 |
+/*! ZSTD_compressStream2() : |
|
| 662 |
+ * Behaves about the same as ZSTD_compressStream, with additional control on end directive. |
|
| 663 |
+ * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() |
|
| 664 |
+ * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode) |
|
| 665 |
+ * - output->pos must be <= dstCapacity, input->pos must be <= srcSize |
|
| 666 |
+ * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. |
|
| 667 |
+ * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller. |
|
| 668 |
+ * - When nbWorkers>=1, function is non-blocking : it just acquires a copy of input, and distributes jobs to internal worker threads, flush whatever is available, |
|
| 669 |
+ * and then immediately returns, just indicating that there is some data remaining to be flushed. |
|
| 670 |
+ * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. |
|
| 671 |
+ * - Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking. |
|
| 672 |
+ * - @return provides a minimum amount of data remaining to be flushed from internal buffers |
|
| 673 |
+ * or an error code, which can be tested using ZSTD_isError(). |
|
| 674 |
+ * if @return != 0, flush is not fully completed, there is still some data left within internal buffers. |
|
| 675 |
+ * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. |
|
| 676 |
+ * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. |
|
| 677 |
+ * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), |
|
| 678 |
+ * only ZSTD_e_end or ZSTD_e_flush operations are allowed. |
|
| 679 |
+ * Before starting a new compression job, or changing compression parameters, |
|
| 680 |
+ * it is required to fully flush internal buffers. |
|
| 681 |
+ */ |
|
| 682 |
+ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx, |
|
| 683 |
+ ZSTD_outBuffer* output, |
|
| 684 |
+ ZSTD_inBuffer* input, |
|
| 685 |
+ ZSTD_EndDirective endOp); |
|
| 686 |
+ |
|
| 687 |
+ |
|
| 688 |
+/* These buffer sizes are softly recommended. |
|
| 689 |
+ * They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output. |
|
| 690 |
+ * Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(), |
|
| 691 |
+ * reducing the amount of memory shuffling and buffering, resulting in minor performance savings. |
|
| 692 |
+ * |
|
| 693 |
+ * However, note that these recommendations are from the perspective of a C caller program. |
|
| 694 |
+ * If the streaming interface is invoked from some other language, |
|
| 695 |
+ * especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo, |
|
| 696 |
+ * a major performance rule is to reduce crossing such interface to an absolute minimum. |
|
| 697 |
+ * It's not rare that performance ends being spent more into the interface, rather than compression itself. |
|
| 698 |
+ * In which cases, prefer using large buffers, as large as practical, |
|
| 699 |
+ * for both input and output, to reduce the nb of roundtrips. |
|
| 700 |
+ */ |
|
| 701 |
+ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */ |
|
| 702 |
+ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */ |
|
| 703 |
+ |
|
| 704 |
+ |
|
| 705 |
+/* ***************************************************************************** |
|
| 706 |
+ * This following is a legacy streaming API. |
|
| 707 |
+ * It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2(). |
|
| 708 |
+ * It is redundant, but remains fully supported. |
|
| 709 |
+ * Advanced parameters and dictionary compression can only be used through the |
|
| 710 |
+ * new API. |
|
| 711 |
+ ******************************************************************************/ |
|
| 712 |
+ |
|
| 713 |
+/*! |
|
| 714 |
+ * Equivalent to: |
|
| 715 |
+ * |
|
| 716 |
+ * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
|
| 717 |
+ * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) |
|
| 718 |
+ * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); |
|
| 719 |
+ */ |
|
| 720 |
+ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); |
|
| 721 |
+/*! |
|
| 722 |
+ * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue). |
|
| 723 |
+ * NOTE: The return value is different. ZSTD_compressStream() returns a hint for |
|
| 724 |
+ * the next read size (if non-zero and not an error). ZSTD_compressStream2() |
|
| 725 |
+ * returns the minimum nb of bytes left to flush (if non-zero and not an error). |
|
| 726 |
+ */ |
|
| 727 |
+ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); |
|
| 728 |
+/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */ |
|
| 729 |
+ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); |
|
| 730 |
+/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ |
|
| 731 |
+ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); |
|
| 732 |
+ |
|
| 733 |
+ |
|
| 734 |
+/*-*************************************************************************** |
|
| 735 |
+* Streaming decompression - HowTo |
|
| 736 |
+* |
|
| 737 |
+* A ZSTD_DStream object is required to track streaming operations. |
|
| 738 |
+* Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. |
|
| 739 |
+* ZSTD_DStream objects can be re-used multiple times. |
|
| 740 |
+* |
|
| 741 |
+* Use ZSTD_initDStream() to start a new decompression operation. |
|
| 742 |
+* @return : recommended first input size |
|
| 743 |
+* Alternatively, use advanced API to set specific properties. |
|
| 744 |
+* |
|
| 745 |
+* Use ZSTD_decompressStream() repetitively to consume your input. |
|
| 746 |
+* The function will update both `pos` fields. |
|
| 747 |
+* If `input.pos < input.size`, some input has not been consumed. |
|
| 748 |
+* It's up to the caller to present again remaining data. |
|
| 749 |
+* The function tries to flush all data decoded immediately, respecting output buffer size. |
|
| 750 |
+* If `output.pos < output.size`, decoder has flushed everything it could. |
|
| 751 |
+* But if `output.pos == output.size`, there might be some data left within internal buffers., |
|
| 752 |
+* In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer. |
|
| 753 |
+* Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX. |
|
| 754 |
+* @return : 0 when a frame is completely decoded and fully flushed, |
|
| 755 |
+* or an error code, which can be tested using ZSTD_isError(), |
|
| 756 |
+* or any other value > 0, which means there is still some decoding or flushing to do to complete current frame : |
|
| 757 |
+* the return value is a suggested next input size (just a hint for better latency) |
|
| 758 |
+* that will never request more than the remaining frame size. |
|
| 759 |
+* *******************************************************************************/ |
|
| 760 |
+ |
|
| 761 |
+typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */ |
|
| 762 |
+ /* For compatibility with versions <= v1.2.0, prefer differentiating them. */ |
|
| 763 |
+/*===== ZSTD_DStream management functions =====*/ |
|
| 764 |
+ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); |
|
| 765 |
+ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); |
|
| 766 |
+ |
|
| 767 |
+/*===== Streaming decompression functions =====*/ |
|
| 768 |
+ |
|
| 769 |
+/* This function is redundant with the advanced API and equivalent to: |
|
| 770 |
+ * |
|
| 771 |
+ * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); |
|
| 772 |
+ * ZSTD_DCtx_refDDict(zds, NULL); |
|
| 773 |
+ */ |
|
| 774 |
+ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); |
|
| 775 |
+ |
|
| 776 |
+ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); |
|
| 777 |
+ |
|
| 778 |
+ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ |
|
| 779 |
+ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ |
|
| 780 |
+ |
|
| 781 |
+ |
|
| 782 |
+/************************** |
|
| 783 |
+* Simple dictionary API |
|
| 784 |
+***************************/ |
|
| 785 |
+/*! ZSTD_compress_usingDict() : |
|
| 786 |
+ * Compression at an explicit compression level using a Dictionary. |
|
| 787 |
+ * A dictionary can be any arbitrary data segment (also called a prefix), |
|
| 788 |
+ * or a buffer with specified information (see dictBuilder/zdict.h). |
|
| 789 |
+ * Note : This function loads the dictionary, resulting in significant startup delay. |
|
| 790 |
+ * It's intended for a dictionary used only once. |
|
| 791 |
+ * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */ |
|
| 792 |
+ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, |
|
| 793 |
+ void* dst, size_t dstCapacity, |
|
| 794 |
+ const void* src, size_t srcSize, |
|
| 795 |
+ const void* dict,size_t dictSize, |
|
| 796 |
+ int compressionLevel); |
|
| 797 |
+ |
|
| 798 |
+/*! ZSTD_decompress_usingDict() : |
|
| 799 |
+ * Decompression using a known Dictionary. |
|
| 800 |
+ * Dictionary must be identical to the one used during compression. |
|
| 801 |
+ * Note : This function loads the dictionary, resulting in significant startup delay. |
|
| 802 |
+ * It's intended for a dictionary used only once. |
|
| 803 |
+ * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ |
|
| 804 |
+ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, |
|
| 805 |
+ void* dst, size_t dstCapacity, |
|
| 806 |
+ const void* src, size_t srcSize, |
|
| 807 |
+ const void* dict,size_t dictSize); |
|
| 808 |
+ |
|
| 809 |
+ |
|
| 810 |
+/*********************************** |
|
| 811 |
+ * Bulk processing dictionary API |
|
| 812 |
+ **********************************/ |
|
| 813 |
+typedef struct ZSTD_CDict_s ZSTD_CDict; |
|
| 814 |
+ |
|
| 815 |
+/*! ZSTD_createCDict() : |
|
| 816 |
+ * When compressing multiple messages or blocks using the same dictionary, |
|
| 817 |
+ * it's recommended to digest the dictionary only once, since it's a costly operation. |
|
| 818 |
+ * ZSTD_createCDict() will create a state from digesting a dictionary. |
|
| 819 |
+ * The resulting state can be used for future compression operations with very limited startup cost. |
|
| 820 |
+ * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. |
|
| 821 |
+ * @dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict. |
|
| 822 |
+ * Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content. |
|
| 823 |
+ * Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer, |
|
| 824 |
+ * in which case the only thing that it transports is the @compressionLevel. |
|
| 825 |
+ * This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively, |
|
| 826 |
+ * expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */ |
|
| 827 |
+ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, |
|
| 828 |
+ int compressionLevel); |
|
| 829 |
+ |
|
| 830 |
+/*! ZSTD_freeCDict() : |
|
| 831 |
+ * Function frees memory allocated by ZSTD_createCDict(). */ |
|
| 832 |
+ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); |
|
| 833 |
+ |
|
| 834 |
+/*! ZSTD_compress_usingCDict() : |
|
| 835 |
+ * Compression using a digested Dictionary. |
|
| 836 |
+ * Recommended when same dictionary is used multiple times. |
|
| 837 |
+ * Note : compression level is _decided at dictionary creation time_, |
|
| 838 |
+ * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */ |
|
| 839 |
+ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, |
|
| 840 |
+ void* dst, size_t dstCapacity, |
|
| 841 |
+ const void* src, size_t srcSize, |
|
| 842 |
+ const ZSTD_CDict* cdict); |
|
| 843 |
+ |
|
| 844 |
+ |
|
| 845 |
+typedef struct ZSTD_DDict_s ZSTD_DDict; |
|
| 846 |
+ |
|
| 847 |
+/*! ZSTD_createDDict() : |
|
| 848 |
+ * Create a digested dictionary, ready to start decompression operation without startup delay. |
|
| 849 |
+ * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */ |
|
| 850 |
+ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); |
|
| 851 |
+ |
|
| 852 |
+/*! ZSTD_freeDDict() : |
|
| 853 |
+ * Function frees memory allocated with ZSTD_createDDict() */ |
|
| 854 |
+ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); |
|
| 855 |
+ |
|
| 856 |
+/*! ZSTD_decompress_usingDDict() : |
|
| 857 |
+ * Decompression using a digested Dictionary. |
|
| 858 |
+ * Recommended when same dictionary is used multiple times. */ |
|
| 859 |
+ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, |
|
| 860 |
+ void* dst, size_t dstCapacity, |
|
| 861 |
+ const void* src, size_t srcSize, |
|
| 862 |
+ const ZSTD_DDict* ddict); |
|
| 863 |
+ |
|
| 864 |
+ |
|
| 865 |
+/******************************** |
|
| 866 |
+ * Dictionary helper functions |
|
| 867 |
+ *******************************/ |
|
| 868 |
+ |
|
| 869 |
+/*! ZSTD_getDictID_fromDict() : |
|
| 870 |
+ * Provides the dictID stored within dictionary. |
|
| 871 |
+ * if @return == 0, the dictionary is not conformant with Zstandard specification. |
|
| 872 |
+ * It can still be loaded, but as a content-only dictionary. */ |
|
| 873 |
+ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); |
|
| 874 |
+ |
|
| 875 |
+/*! ZSTD_getDictID_fromDDict() : |
|
| 876 |
+ * Provides the dictID of the dictionary loaded into `ddict`. |
|
| 877 |
+ * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. |
|
| 878 |
+ * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ |
|
| 879 |
+ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); |
|
| 880 |
+ |
|
| 881 |
+/*! ZSTD_getDictID_fromFrame() : |
|
| 882 |
+ * Provides the dictID required to decompressed the frame stored within `src`. |
|
| 883 |
+ * If @return == 0, the dictID could not be decoded. |
|
| 884 |
+ * This could for one of the following reasons : |
|
| 885 |
+ * - The frame does not require a dictionary to be decoded (most common case). |
|
| 886 |
+ * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information. |
|
| 887 |
+ * Note : this use case also happens when using a non-conformant dictionary. |
|
| 888 |
+ * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`). |
|
| 889 |
+ * - This is not a Zstandard frame. |
|
| 890 |
+ * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ |
|
| 891 |
+ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); |
|
| 892 |
+ |
|
| 893 |
+ |
|
| 894 |
+/******************************************************************************* |
|
| 895 |
+ * Advanced dictionary and prefix API |
|
| 896 |
+ * |
|
| 897 |
+ * This API allows dictionaries to be used with ZSTD_compress2(), |
|
| 898 |
+ * ZSTD_compressStream2(), and ZSTD_decompress(). Dictionaries are sticky, and |
|
| 899 |
+ * only reset with the context is reset with ZSTD_reset_parameters or |
|
| 900 |
+ * ZSTD_reset_session_and_parameters. Prefixes are single-use. |
|
| 901 |
+ ******************************************************************************/ |
|
| 902 |
+ |
|
| 903 |
+ |
|
| 904 |
+/*! ZSTD_CCtx_loadDictionary() : |
|
| 905 |
+ * Create an internal CDict from `dict` buffer. |
|
| 906 |
+ * Decompression will have to use same dictionary. |
|
| 907 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 908 |
+ * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, |
|
| 909 |
+ * meaning "return to no-dictionary mode". |
|
| 910 |
+ * Note 1 : Dictionary is sticky, it will be used for all future compressed frames. |
|
| 911 |
+ * To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters). |
|
| 912 |
+ * Note 2 : Loading a dictionary involves building tables. |
|
| 913 |
+ * It's also a CPU consuming operation, with non-negligible impact on latency. |
|
| 914 |
+ * Tables are dependent on compression parameters, and for this reason, |
|
| 915 |
+ * compression parameters can no longer be changed after loading a dictionary. |
|
| 916 |
+ * Note 3 :`dict` content will be copied internally. |
|
| 917 |
+ * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. |
|
| 918 |
+ * In such a case, dictionary buffer must outlive its users. |
|
| 919 |
+ * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() |
|
| 920 |
+ * to precisely select how dictionary content must be interpreted. */ |
|
| 921 |
+ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); |
|
| 922 |
+ |
|
| 923 |
+/*! ZSTD_CCtx_refCDict() : |
|
| 924 |
+ * Reference a prepared dictionary, to be used for all next compressed frames. |
|
| 925 |
+ * Note that compression parameters are enforced from within CDict, |
|
| 926 |
+ * and supersede any compression parameter previously set within CCtx. |
|
| 927 |
+ * The parameters ignored are labled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. |
|
| 928 |
+ * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode. |
|
| 929 |
+ * The dictionary will remain valid for future compressed frames using same CCtx. |
|
| 930 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 931 |
+ * Special : Referencing a NULL CDict means "return to no-dictionary mode". |
|
| 932 |
+ * Note 1 : Currently, only one dictionary can be managed. |
|
| 933 |
+ * Referencing a new dictionary effectively "discards" any previous one. |
|
| 934 |
+ * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */ |
|
| 935 |
+ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); |
|
| 936 |
+ |
|
| 937 |
+/*! ZSTD_CCtx_refPrefix() : |
|
| 938 |
+ * Reference a prefix (single-usage dictionary) for next compressed frame. |
|
| 939 |
+ * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end). |
|
| 940 |
+ * Decompression will need same prefix to properly regenerate data. |
|
| 941 |
+ * Compressing with a prefix is similar in outcome as performing a diff and compressing it, |
|
| 942 |
+ * but performs much faster, especially during decompression (compression speed is tunable with compression level). |
|
| 943 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 944 |
+ * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary |
|
| 945 |
+ * Note 1 : Prefix buffer is referenced. It **must** outlive compression. |
|
| 946 |
+ * Its content must remain unmodified during compression. |
|
| 947 |
+ * Note 2 : If the intention is to diff some large src data blob with some prior version of itself, |
|
| 948 |
+ * ensure that the window size is large enough to contain the entire source. |
|
| 949 |
+ * See ZSTD_c_windowLog. |
|
| 950 |
+ * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. |
|
| 951 |
+ * It's a CPU consuming operation, with non-negligible impact on latency. |
|
| 952 |
+ * If there is a need to use the same prefix multiple times, consider loadDictionary instead. |
|
| 953 |
+ * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent). |
|
| 954 |
+ * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */ |
|
| 955 |
+ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, |
|
| 956 |
+ const void* prefix, size_t prefixSize); |
|
| 957 |
+ |
|
| 958 |
+/*! ZSTD_DCtx_loadDictionary() : |
|
| 959 |
+ * Create an internal DDict from dict buffer, |
|
| 960 |
+ * to be used to decompress next frames. |
|
| 961 |
+ * The dictionary remains valid for all future frames, until explicitly invalidated. |
|
| 962 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 963 |
+ * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, |
|
| 964 |
+ * meaning "return to no-dictionary mode". |
|
| 965 |
+ * Note 1 : Loading a dictionary involves building tables, |
|
| 966 |
+ * which has a non-negligible impact on CPU usage and latency. |
|
| 967 |
+ * It's recommended to "load once, use many times", to amortize the cost |
|
| 968 |
+ * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading. |
|
| 969 |
+ * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. |
|
| 970 |
+ * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of |
|
| 971 |
+ * how dictionary content is loaded and interpreted. |
|
| 972 |
+ */ |
|
| 973 |
+ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); |
|
| 974 |
+ |
|
| 975 |
+/*! ZSTD_DCtx_refDDict() : |
|
| 976 |
+ * Reference a prepared dictionary, to be used to decompress next frames. |
|
| 977 |
+ * The dictionary remains active for decompression of future frames using same DCtx. |
|
| 978 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 979 |
+ * Note 1 : Currently, only one dictionary can be managed. |
|
| 980 |
+ * Referencing a new dictionary effectively "discards" any previous one. |
|
| 981 |
+ * Special: referencing a NULL DDict means "return to no-dictionary mode". |
|
| 982 |
+ * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. |
|
| 983 |
+ */ |
|
| 984 |
+ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); |
|
| 985 |
+ |
|
| 986 |
+/*! ZSTD_DCtx_refPrefix() : |
|
| 987 |
+ * Reference a prefix (single-usage dictionary) to decompress next frame. |
|
| 988 |
+ * This is the reverse operation of ZSTD_CCtx_refPrefix(), |
|
| 989 |
+ * and must use the same prefix as the one used during compression. |
|
| 990 |
+ * Prefix is **only used once**. Reference is discarded at end of frame. |
|
| 991 |
+ * End of frame is reached when ZSTD_decompressStream() returns 0. |
|
| 992 |
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
|
| 993 |
+ * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary |
|
| 994 |
+ * Note 2 : Prefix buffer is referenced. It **must** outlive decompression. |
|
| 995 |
+ * Prefix buffer must remain unmodified up to the end of frame, |
|
| 996 |
+ * reached when ZSTD_decompressStream() returns 0. |
|
| 997 |
+ * Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent). |
|
| 998 |
+ * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) |
|
| 999 |
+ * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. |
|
| 1000 |
+ * A full dictionary is more costly, as it requires building tables. |
|
| 1001 |
+ */ |
|
| 1002 |
+ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, |
|
| 1003 |
+ const void* prefix, size_t prefixSize); |
|
| 1004 |
+ |
|
| 1005 |
+/* === Memory management === */ |
|
| 1006 |
+ |
|
| 1007 |
+/*! ZSTD_sizeof_*() : |
|
| 1008 |
+ * These functions give the _current_ memory usage of selected object. |
|
| 1009 |
+ * Note that object memory usage can evolve (increase or decrease) over time. */ |
|
| 1010 |
+ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); |
|
| 1011 |
+ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); |
|
| 1012 |
+ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); |
|
| 1013 |
+ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); |
|
| 1014 |
+ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); |
|
| 1015 |
+ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); |
|
| 1016 |
+ |
|
| 1017 |
+#endif /* ZSTD_H_235446 */ |
|
| 1018 |
+ |
|
| 1019 |
+ |
|
| 1020 |
+/* ************************************************************************************** |
|
| 1021 |
+ * ADVANCED AND EXPERIMENTAL FUNCTIONS |
|
| 1022 |
+ **************************************************************************************** |
|
| 1023 |
+ * The definitions in the following section are considered experimental. |
|
| 1024 |
+ * They are provided for advanced scenarios. |
|
| 1025 |
+ * They should never be used with a dynamic library, as prototypes may change in the future. |
|
| 1026 |
+ * Use them only in association with static linking. |
|
| 1027 |
+ * ***************************************************************************************/ |
|
| 1028 |
+ |
|
| 1029 |
+#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) |
|
| 1030 |
+#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY |
|
| 1031 |
+ |
|
| 1032 |
+/**************************************************************************************** |
|
| 1033 |
+ * experimental API (static linking only) |
|
| 1034 |
+ **************************************************************************************** |
|
| 1035 |
+ * The following symbols and constants |
|
| 1036 |
+ * are not planned to join "stable API" status in the near future. |
|
| 1037 |
+ * They can still change in future versions. |
|
| 1038 |
+ * Some of them are planned to remain in the static_only section indefinitely. |
|
| 1039 |
+ * Some of them might be removed in the future (especially when redundant with existing stable functions) |
|
| 1040 |
+ * ***************************************************************************************/ |
|
| 1041 |
+ |
|
| 1042 |
+#define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */ |
|
| 1043 |
+#define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2) |
|
| 1044 |
+#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */ |
|
| 1045 |
+#define ZSTD_SKIPPABLEHEADERSIZE 8 |
|
| 1046 |
+ |
|
| 1047 |
+/* compression parameter bounds */ |
|
| 1048 |
+#define ZSTD_WINDOWLOG_MAX_32 30 |
|
| 1049 |
+#define ZSTD_WINDOWLOG_MAX_64 31 |
|
| 1050 |
+#define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) |
|
| 1051 |
+#define ZSTD_WINDOWLOG_MIN 10 |
|
| 1052 |
+#define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) |
|
| 1053 |
+#define ZSTD_HASHLOG_MIN 6 |
|
| 1054 |
+#define ZSTD_CHAINLOG_MAX_32 29 |
|
| 1055 |
+#define ZSTD_CHAINLOG_MAX_64 30 |
|
| 1056 |
+#define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) |
|
| 1057 |
+#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN |
|
| 1058 |
+#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) |
|
| 1059 |
+#define ZSTD_SEARCHLOG_MIN 1 |
|
| 1060 |
+#define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ |
|
| 1061 |
+#define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */ |
|
| 1062 |
+#define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX |
|
| 1063 |
+#define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ |
|
| 1064 |
+#define ZSTD_STRATEGY_MIN ZSTD_fast |
|
| 1065 |
+#define ZSTD_STRATEGY_MAX ZSTD_btultra2 |
|
| 1066 |
+ |
|
| 1067 |
+ |
|
| 1068 |
+#define ZSTD_OVERLAPLOG_MIN 0 |
|
| 1069 |
+#define ZSTD_OVERLAPLOG_MAX 9 |
|
| 1070 |
+ |
|
| 1071 |
+#define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame |
|
| 1072 |
+ * requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size, |
|
| 1073 |
+ * to preserve host's memory from unreasonable requirements. |
|
| 1074 |
+ * This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,). |
|
| 1075 |
+ * The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */ |
|
| 1076 |
+ |
|
| 1077 |
+ |
|
| 1078 |
+/* LDM parameter bounds */ |
|
| 1079 |
+#define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN |
|
| 1080 |
+#define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX |
|
| 1081 |
+#define ZSTD_LDM_MINMATCH_MIN 4 |
|
| 1082 |
+#define ZSTD_LDM_MINMATCH_MAX 4096 |
|
| 1083 |
+#define ZSTD_LDM_BUCKETSIZELOG_MIN 1 |
|
| 1084 |
+#define ZSTD_LDM_BUCKETSIZELOG_MAX 8 |
|
| 1085 |
+#define ZSTD_LDM_HASHRATELOG_MIN 0 |
|
| 1086 |
+#define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN) |
|
| 1087 |
+ |
|
| 1088 |
+/* Advanced parameter bounds */ |
|
| 1089 |
+#define ZSTD_TARGETCBLOCKSIZE_MIN 64 |
|
| 1090 |
+#define ZSTD_TARGETCBLOCKSIZE_MAX ZSTD_BLOCKSIZE_MAX |
|
| 1091 |
+#define ZSTD_SRCSIZEHINT_MIN 0 |
|
| 1092 |
+#define ZSTD_SRCSIZEHINT_MAX INT_MAX |
|
| 1093 |
+ |
|
| 1094 |
+/* internal */ |
|
| 1095 |
+#define ZSTD_HASHLOG3_MAX 17 |
|
| 1096 |
+ |
|
| 1097 |
+ |
|
| 1098 |
+/* --- Advanced types --- */ |
|
| 1099 |
+ |
|
| 1100 |
+typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; |
|
| 1101 |
+ |
|
| 1102 |
+typedef struct {
|
|
| 1103 |
+ unsigned int matchPos; /* Match pos in dst */ |
|
| 1104 |
+ /* If seqDef.offset > 3, then this is seqDef.offset - 3 |
|
| 1105 |
+ * If seqDef.offset < 3, then this is the corresponding repeat offset |
|
| 1106 |
+ * But if seqDef.offset < 3 and litLength == 0, this is the |
|
| 1107 |
+ * repeat offset before the corresponding repeat offset |
|
| 1108 |
+ * And if seqDef.offset == 3 and litLength == 0, this is the |
|
| 1109 |
+ * most recent repeat offset - 1 |
|
| 1110 |
+ */ |
|
| 1111 |
+ unsigned int offset; |
|
| 1112 |
+ unsigned int litLength; /* Literal length */ |
|
| 1113 |
+ unsigned int matchLength; /* Match length */ |
|
| 1114 |
+ /* 0 when seq not rep and seqDef.offset otherwise |
|
| 1115 |
+ * when litLength == 0 this will be <= 4, otherwise <= 3 like normal |
|
| 1116 |
+ */ |
|
| 1117 |
+ unsigned int rep; |
|
| 1118 |
+} ZSTD_Sequence; |
|
| 1119 |
+ |
|
| 1120 |
+typedef struct {
|
|
| 1121 |
+ unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */ |
|
| 1122 |
+ unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ |
|
| 1123 |
+ unsigned hashLog; /**< dispatch table : larger == faster, more memory */ |
|
| 1124 |
+ unsigned searchLog; /**< nb of searches : larger == more compression, slower */ |
|
| 1125 |
+ unsigned minMatch; /**< match length searched : larger == faster decompression, sometimes less compression */ |
|
| 1126 |
+ unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */ |
|
| 1127 |
+ ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */ |
|
| 1128 |
+} ZSTD_compressionParameters; |
|
| 1129 |
+ |
|
| 1130 |
+typedef struct {
|
|
| 1131 |
+ int contentSizeFlag; /**< 1: content size will be in frame header (when known) */ |
|
| 1132 |
+ int checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */ |
|
| 1133 |
+ int noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */ |
|
| 1134 |
+} ZSTD_frameParameters; |
|
| 1135 |
+ |
|
| 1136 |
+typedef struct {
|
|
| 1137 |
+ ZSTD_compressionParameters cParams; |
|
| 1138 |
+ ZSTD_frameParameters fParams; |
|
| 1139 |
+} ZSTD_parameters; |
|
| 1140 |
+ |
|
| 1141 |
+typedef enum {
|
|
| 1142 |
+ ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ |
|
| 1143 |
+ ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ |
|
| 1144 |
+ ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */ |
|
| 1145 |
+} ZSTD_dictContentType_e; |
|
| 1146 |
+ |
|
| 1147 |
+typedef enum {
|
|
| 1148 |
+ ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */ |
|
| 1149 |
+ ZSTD_dlm_byRef = 1 /**< Reference dictionary content -- the dictionary buffer must outlive its users. */ |
|
| 1150 |
+} ZSTD_dictLoadMethod_e; |
|
| 1151 |
+ |
|
| 1152 |
+typedef enum {
|
|
| 1153 |
+ ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ |
|
| 1154 |
+ ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number. |
|
| 1155 |
+ * Useful to save 4 bytes per generated frame. |
|
| 1156 |
+ * Decoder cannot recognise automatically this format, requiring this instruction. */ |
|
| 1157 |
+} ZSTD_format_e; |
|
| 1158 |
+ |
|
| 1159 |
+typedef enum {
|
|
| 1160 |
+ /* Note: this enum and the behavior it controls are effectively internal |
|
| 1161 |
+ * implementation details of the compressor. They are expected to continue |
|
| 1162 |
+ * to evolve and should be considered only in the context of extremely |
|
| 1163 |
+ * advanced performance tuning. |
|
| 1164 |
+ * |
|
| 1165 |
+ * Zstd currently supports the use of a CDict in three ways: |
|
| 1166 |
+ * |
|
| 1167 |
+ * - The contents of the CDict can be copied into the working context. This |
|
| 1168 |
+ * means that the compression can search both the dictionary and input |
|
| 1169 |
+ * while operating on a single set of internal tables. This makes |
|
| 1170 |
+ * the compression faster per-byte of input. However, the initial copy of |
|
| 1171 |
+ * the CDict's tables incurs a fixed cost at the beginning of the |
|
| 1172 |
+ * compression. For small compressions (< 8 KB), that copy can dominate |
|
| 1173 |
+ * the cost of the compression. |
|
| 1174 |
+ * |
|
| 1175 |
+ * - The CDict's tables can be used in-place. In this model, compression is |
|
| 1176 |
+ * slower per input byte, because the compressor has to search two sets of |
|
| 1177 |
+ * tables. However, this model incurs no start-up cost (as long as the |
|
| 1178 |
+ * working context's tables can be reused). For small inputs, this can be |
|
| 1179 |
+ * faster than copying the CDict's tables. |
|
| 1180 |
+ * |
|
| 1181 |
+ * - The CDict's tables are not used at all, and instead we use the working |
|
| 1182 |
+ * context alone to reload the dictionary and use params based on the source |
|
| 1183 |
+ * size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict(). |
|
| 1184 |
+ * This method is effective when the dictionary sizes are very small relative |
|
| 1185 |
+ * to the input size, and the input size is fairly large to begin with. |
|
| 1186 |
+ * |
|
| 1187 |
+ * Zstd has a simple internal heuristic that selects which strategy to use |
|
| 1188 |
+ * at the beginning of a compression. However, if experimentation shows that |
|
| 1189 |
+ * Zstd is making poor choices, it is possible to override that choice with |
|
| 1190 |
+ * this enum. |
|
| 1191 |
+ */ |
|
| 1192 |
+ ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */ |
|
| 1193 |
+ ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */ |
|
| 1194 |
+ ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */ |
|
| 1195 |
+ ZSTD_dictForceLoad = 3 /* Always reload the dictionary */ |
|
| 1196 |
+} ZSTD_dictAttachPref_e; |
|
| 1197 |
+ |
|
| 1198 |
+typedef enum {
|
|
| 1199 |
+ ZSTD_lcm_auto = 0, /**< Automatically determine the compression mode based on the compression level. |
|
| 1200 |
+ * Negative compression levels will be uncompressed, and positive compression |
|
| 1201 |
+ * levels will be compressed. */ |
|
| 1202 |
+ ZSTD_lcm_huffman = 1, /**< Always attempt Huffman compression. Uncompressed literals will still be |
|
| 1203 |
+ * emitted if Huffman compression is not profitable. */ |
|
| 1204 |
+ ZSTD_lcm_uncompressed = 2 /**< Always emit uncompressed literals. */ |
|
| 1205 |
+} ZSTD_literalCompressionMode_e; |
|
| 1206 |
+ |
|
| 1207 |
+ |
|
| 1208 |
+/*************************************** |
|
| 1209 |
+* Frame size functions |
|
| 1210 |
+***************************************/ |
|
| 1211 |
+ |
|
| 1212 |
+/*! ZSTD_findDecompressedSize() : |
|
| 1213 |
+ * `src` should point to the start of a series of ZSTD encoded and/or skippable frames |
|
| 1214 |
+ * `srcSize` must be the _exact_ size of this series |
|
| 1215 |
+ * (i.e. there should be a frame boundary at `src + srcSize`) |
|
| 1216 |
+ * @return : - decompressed size of all data in all successive frames |
|
| 1217 |
+ * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN |
|
| 1218 |
+ * - if an error occurred: ZSTD_CONTENTSIZE_ERROR |
|
| 1219 |
+ * |
|
| 1220 |
+ * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. |
|
| 1221 |
+ * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. |
|
| 1222 |
+ * In which case, it's necessary to use streaming mode to decompress data. |
|
| 1223 |
+ * note 2 : decompressed size is always present when compression is done with ZSTD_compress() |
|
| 1224 |
+ * note 3 : decompressed size can be very large (64-bits value), |
|
| 1225 |
+ * potentially larger than what local system can handle as a single memory segment. |
|
| 1226 |
+ * In which case, it's necessary to use streaming mode to decompress data. |
|
| 1227 |
+ * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified. |
|
| 1228 |
+ * Always ensure result fits within application's authorized limits. |
|
| 1229 |
+ * Each application can set its own limits. |
|
| 1230 |
+ * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to |
|
| 1231 |
+ * read each contained frame header. This is fast as most of the data is skipped, |
|
| 1232 |
+ * however it does mean that all frame data must be present and valid. */ |
|
| 1233 |
+ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); |
|
| 1234 |
+ |
|
| 1235 |
+/*! ZSTD_decompressBound() : |
|
| 1236 |
+ * `src` should point to the start of a series of ZSTD encoded and/or skippable frames |
|
| 1237 |
+ * `srcSize` must be the _exact_ size of this series |
|
| 1238 |
+ * (i.e. there should be a frame boundary at `src + srcSize`) |
|
| 1239 |
+ * @return : - upper-bound for the decompressed size of all data in all successive frames |
|
| 1240 |
+ * - if an error occured: ZSTD_CONTENTSIZE_ERROR |
|
| 1241 |
+ * |
|
| 1242 |
+ * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame. |
|
| 1243 |
+ * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`. |
|
| 1244 |
+ * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value. |
|
| 1245 |
+ * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by: |
|
| 1246 |
+ * upper-bound = # blocks * min(128 KB, Window_Size) |
|
| 1247 |
+ */ |
|
| 1248 |
+ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize); |
|
| 1249 |
+ |
|
| 1250 |
+/*! ZSTD_frameHeaderSize() : |
|
| 1251 |
+ * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. |
|
| 1252 |
+ * @return : size of the Frame Header, |
|
| 1253 |
+ * or an error code (if srcSize is too small) */ |
|
| 1254 |
+ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); |
|
| 1255 |
+ |
|
| 1256 |
+/*! ZSTD_getSequences() : |
|
| 1257 |
+ * Extract sequences from the sequence store |
|
| 1258 |
+ * zc can be used to insert custom compression params. |
|
| 1259 |
+ * This function invokes ZSTD_compress2 |
|
| 1260 |
+ * @return : number of sequences extracted |
|
| 1261 |
+ */ |
|
| 1262 |
+ZSTDLIB_API size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs, |
|
| 1263 |
+ size_t outSeqsSize, const void* src, size_t srcSize); |
|
| 1264 |
+ |
|
| 1265 |
+ |
|
| 1266 |
+/*************************************** |
|
| 1267 |
+* Memory management |
|
| 1268 |
+***************************************/ |
|
| 1269 |
+ |
|
| 1270 |
+/*! ZSTD_estimate*() : |
|
| 1271 |
+ * These functions make it possible to estimate memory usage |
|
| 1272 |
+ * of a future {D,C}Ctx, before its creation.
|
|
| 1273 |
+ * |
|
| 1274 |
+ * ZSTD_estimateCCtxSize() will provide a memory budget large enough |
|
| 1275 |
+ * for any compression level up to selected one. |
|
| 1276 |
+ * Note : Unlike ZSTD_estimateCStreamSize*(), this estimate |
|
| 1277 |
+ * does not include space for a window buffer. |
|
| 1278 |
+ * Therefore, the estimation is only guaranteed for single-shot compressions, not streaming. |
|
| 1279 |
+ * The estimate will assume the input may be arbitrarily large, |
|
| 1280 |
+ * which is the worst case. |
|
| 1281 |
+ * |
|
| 1282 |
+ * When srcSize can be bound by a known and rather "small" value, |
|
| 1283 |
+ * this fact can be used to provide a tighter estimation |
|
| 1284 |
+ * because the CCtx compression context will need less memory. |
|
| 1285 |
+ * This tighter estimation can be provided by more advanced functions |
|
| 1286 |
+ * ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(), |
|
| 1287 |
+ * and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter(). |
|
| 1288 |
+ * Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits. |
|
| 1289 |
+ * |
|
| 1290 |
+ * Note 2 : only single-threaded compression is supported. |
|
| 1291 |
+ * ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1. |
|
| 1292 |
+ */ |
|
| 1293 |
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); |
|
| 1294 |
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); |
|
| 1295 |
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); |
|
| 1296 |
+ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); |
|
| 1297 |
+ |
|
| 1298 |
+/*! ZSTD_estimateCStreamSize() : |
|
| 1299 |
+ * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. |
|
| 1300 |
+ * It will also consider src size to be arbitrarily "large", which is worst case. |
|
| 1301 |
+ * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. |
|
| 1302 |
+ * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. |
|
| 1303 |
+ * ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParams_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1. |
|
| 1304 |
+ * Note : CStream size estimation is only correct for single-threaded compression. |
|
| 1305 |
+ * ZSTD_DStream memory budget depends on window Size. |
|
| 1306 |
+ * This information can be passed manually, using ZSTD_estimateDStreamSize, |
|
| 1307 |
+ * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); |
|
| 1308 |
+ * Note : if streaming is init with function ZSTD_init?Stream_usingDict(), |
|
| 1309 |
+ * an internal ?Dict will be created, which additional size is not estimated here. |
|
| 1310 |
+ * In this case, get total size by adding ZSTD_estimate?DictSize */ |
|
| 1311 |
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel); |
|
| 1312 |
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); |
|
| 1313 |
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); |
|
| 1314 |
+ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize); |
|
| 1315 |
+ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); |
|
| 1316 |
+ |
|
| 1317 |
+/*! ZSTD_estimate?DictSize() : |
|
| 1318 |
+ * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). |
|
| 1319 |
+ * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). |
|
| 1320 |
+ * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller. |
|
| 1321 |
+ */ |
|
| 1322 |
+ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); |
|
| 1323 |
+ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); |
|
| 1324 |
+ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); |
|
| 1325 |
+ |
|
| 1326 |
+/*! ZSTD_initStatic*() : |
|
| 1327 |
+ * Initialize an object using a pre-allocated fixed-size buffer. |
|
| 1328 |
+ * workspace: The memory area to emplace the object into. |
|
| 1329 |
+ * Provided pointer *must be 8-bytes aligned*. |
|
| 1330 |
+ * Buffer must outlive object. |
|
| 1331 |
+ * workspaceSize: Use ZSTD_estimate*Size() to determine |
|
| 1332 |
+ * how large workspace must be to support target scenario. |
|
| 1333 |
+ * @return : pointer to object (same address as workspace, just different type), |
|
| 1334 |
+ * or NULL if error (size too small, incorrect alignment, etc.) |
|
| 1335 |
+ * Note : zstd will never resize nor malloc() when using a static buffer. |
|
| 1336 |
+ * If the object requires more memory than available, |
|
| 1337 |
+ * zstd will just error out (typically ZSTD_error_memory_allocation). |
|
| 1338 |
+ * Note 2 : there is no corresponding "free" function. |
|
| 1339 |
+ * Since workspace is allocated externally, it must be freed externally too. |
|
| 1340 |
+ * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level |
|
| 1341 |
+ * into its associated cParams. |
|
| 1342 |
+ * Limitation 1 : currently not compatible with internal dictionary creation, triggered by |
|
| 1343 |
+ * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). |
|
| 1344 |
+ * Limitation 2 : static cctx currently not compatible with multi-threading. |
|
| 1345 |
+ * Limitation 3 : static dctx is incompatible with legacy support. |
|
| 1346 |
+ */ |
|
| 1347 |
+ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); |
|
| 1348 |
+ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */ |
|
| 1349 |
+ |
|
| 1350 |
+ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); |
|
| 1351 |
+ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */ |
|