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- /*
- * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of https://github.com/facebook/zstd.
- * An additional grant of patent rights can be found in the PATENTS file in the
- * same directory.
- *
- * This program is free software; you can redistribute it and/or modify it under
- * the terms of the GNU General Public License version 2 as published by the
- * Free Software Foundation. This program is dual-licensed; you may select
- * either version 2 of the GNU General Public License ("GPL") or BSD license
- * ("BSD").
- */
- #ifndef ZSTD_H
- #define ZSTD_H
- /* ====== Dependency ======*/
- #include <linux/types.h> /* size_t */
- /*-*****************************************************************************
- * Introduction
- *
- * zstd, short for Zstandard, is a fast lossless compression algorithm,
- * targeting real-time compression scenarios at zlib-level and better
- * compression ratios. The zstd compression library provides in-memory
- * compression and decompression functions. The library supports compression
- * levels from 1 up to ZSTD_maxCLevel() which is 22. Levels >= 20, labeled
- * ultra, should be used with caution, as they require more memory.
- * Compression can be done in:
- * - a single step, reusing a context (described as Explicit memory management)
- * - unbounded multiple steps (described as Streaming compression)
- * The compression ratio achievable on small data can be highly improved using
- * compression with a dictionary in:
- * - a single step (described as Simple dictionary API)
- * - a single step, reusing a dictionary (described as Fast dictionary API)
- ******************************************************************************/
- /*====== Helper functions ======*/
- /**
- * enum ZSTD_ErrorCode - zstd error codes
- *
- * Functions that return size_t can be checked for errors using ZSTD_isError()
- * and the ZSTD_ErrorCode can be extracted using ZSTD_getErrorCode().
- */
- typedef enum {
- ZSTD_error_no_error,
- ZSTD_error_GENERIC,
- ZSTD_error_prefix_unknown,
- ZSTD_error_version_unsupported,
- ZSTD_error_parameter_unknown,
- ZSTD_error_frameParameter_unsupported,
- ZSTD_error_frameParameter_unsupportedBy32bits,
- ZSTD_error_frameParameter_windowTooLarge,
- ZSTD_error_compressionParameter_unsupported,
- ZSTD_error_init_missing,
- ZSTD_error_memory_allocation,
- ZSTD_error_stage_wrong,
- ZSTD_error_dstSize_tooSmall,
- ZSTD_error_srcSize_wrong,
- ZSTD_error_corruption_detected,
- ZSTD_error_checksum_wrong,
- ZSTD_error_tableLog_tooLarge,
- ZSTD_error_maxSymbolValue_tooLarge,
- ZSTD_error_maxSymbolValue_tooSmall,
- ZSTD_error_dictionary_corrupted,
- ZSTD_error_dictionary_wrong,
- ZSTD_error_dictionaryCreation_failed,
- ZSTD_error_maxCode
- } ZSTD_ErrorCode;
- /**
- * ZSTD_maxCLevel() - maximum compression level available
- *
- * Return: Maximum compression level available.
- */
- int ZSTD_maxCLevel(void);
- /**
- * ZSTD_compressBound() - maximum compressed size in worst case scenario
- * @srcSize: The size of the data to compress.
- *
- * Return: The maximum compressed size in the worst case scenario.
- */
- size_t ZSTD_compressBound(size_t srcSize);
- /**
- * ZSTD_isError() - tells if a size_t function result is an error code
- * @code: The function result to check for error.
- *
- * Return: Non-zero iff the code is an error.
- */
- static __attribute__((unused)) unsigned int ZSTD_isError(size_t code)
- {
- return code > (size_t)-ZSTD_error_maxCode;
- }
- /**
- * ZSTD_getErrorCode() - translates an error function result to a ZSTD_ErrorCode
- * @functionResult: The result of a function for which ZSTD_isError() is true.
- *
- * Return: The ZSTD_ErrorCode corresponding to the functionResult or 0
- * if the functionResult isn't an error.
- */
- static __attribute__((unused)) ZSTD_ErrorCode ZSTD_getErrorCode(
- size_t functionResult)
- {
- if (!ZSTD_isError(functionResult))
- return (ZSTD_ErrorCode)0;
- return (ZSTD_ErrorCode)(0 - functionResult);
- }
- /**
- * enum ZSTD_strategy - zstd compression search strategy
- *
- * From faster to stronger.
- */
- typedef enum {
- ZSTD_fast,
- ZSTD_dfast,
- ZSTD_greedy,
- ZSTD_lazy,
- ZSTD_lazy2,
- ZSTD_btlazy2,
- ZSTD_btopt,
- ZSTD_btopt2
- } ZSTD_strategy;
- /**
- * struct ZSTD_compressionParameters - zstd compression parameters
- * @windowLog: Log of the largest match distance. Larger means more
- * compression, and more memory needed during decompression.
- * @chainLog: Fully searched segment. Larger means more compression, slower,
- * and more memory (useless for fast).
- * @hashLog: Dispatch table. Larger means more compression,
- * slower, and more memory.
- * @searchLog: Number of searches. Larger means more compression and slower.
- * @searchLength: Match length searched. Larger means faster decompression,
- * sometimes less compression.
- * @targetLength: Acceptable match size for optimal parser (only). Larger means
- * more compression, and slower.
- * @strategy: The zstd compression strategy.
- */
- typedef struct {
- unsigned int windowLog;
- unsigned int chainLog;
- unsigned int hashLog;
- unsigned int searchLog;
- unsigned int searchLength;
- unsigned int targetLength;
- ZSTD_strategy strategy;
- } ZSTD_compressionParameters;
- /**
- * struct ZSTD_frameParameters - zstd frame parameters
- * @contentSizeFlag: Controls whether content size will be present in the frame
- * header (when known).
- * @checksumFlag: Controls whether a 32-bit checksum is generated at the end
- * of the frame for error detection.
- * @noDictIDFlag: Controls whether dictID will be saved into the frame header
- * when using dictionary compression.
- *
- * The default value is all fields set to 0.
- */
- typedef struct {
- unsigned int contentSizeFlag;
- unsigned int checksumFlag;
- unsigned int noDictIDFlag;
- } ZSTD_frameParameters;
- /**
- * struct ZSTD_parameters - zstd parameters
- * @cParams: The compression parameters.
- * @fParams: The frame parameters.
- */
- typedef struct {
- ZSTD_compressionParameters cParams;
- ZSTD_frameParameters fParams;
- } ZSTD_parameters;
- /**
- * ZSTD_getCParams() - returns ZSTD_compressionParameters for selected level
- * @compressionLevel: The compression level from 1 to ZSTD_maxCLevel().
- * @estimatedSrcSize: The estimated source size to compress or 0 if unknown.
- * @dictSize: The dictionary size or 0 if a dictionary isn't being used.
- *
- * Return: The selected ZSTD_compressionParameters.
- */
- ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel,
- unsigned long long estimatedSrcSize, size_t dictSize);
- /**
- * ZSTD_getParams() - returns ZSTD_parameters for selected level
- * @compressionLevel: The compression level from 1 to ZSTD_maxCLevel().
- * @estimatedSrcSize: The estimated source size to compress or 0 if unknown.
- * @dictSize: The dictionary size or 0 if a dictionary isn't being used.
- *
- * The same as ZSTD_getCParams() except also selects the default frame
- * parameters (all zero).
- *
- * Return: The selected ZSTD_parameters.
- */
- ZSTD_parameters ZSTD_getParams(int compressionLevel,
- unsigned long long estimatedSrcSize, size_t dictSize);
- /*-*************************************
- * Explicit memory management
- **************************************/
- /**
- * ZSTD_CCtxWorkspaceBound() - amount of memory needed to initialize a ZSTD_CCtx
- * @cParams: The compression parameters to be used for compression.
- *
- * If multiple compression parameters might be used, the caller must call
- * ZSTD_CCtxWorkspaceBound() for each set of parameters and use the maximum
- * size.
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initCCtx().
- */
- size_t ZSTD_CCtxWorkspaceBound(ZSTD_compressionParameters cParams);
- /**
- * struct ZSTD_CCtx - the zstd compression context
- *
- * When compressing many times it is recommended to allocate a context just once
- * and reuse it for each successive compression operation.
- */
- typedef struct ZSTD_CCtx_s ZSTD_CCtx;
- /**
- * ZSTD_initCCtx() - initialize a zstd compression context
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace. Use ZSTD_CCtxWorkspaceBound() to
- * determine how large the workspace must be.
- *
- * Return: A compression context emplaced into workspace.
- */
- ZSTD_CCtx *ZSTD_initCCtx(void *workspace, size_t workspaceSize);
- /**
- * ZSTD_compressCCtx() - compress src into dst
- * @ctx: The context. Must have been initialized with a workspace at
- * least as large as ZSTD_CCtxWorkspaceBound(params.cParams).
- * @dst: The buffer to compress src into.
- * @dstCapacity: The size of the destination buffer. May be any size, but
- * ZSTD_compressBound(srcSize) is guaranteed to be large enough.
- * @src: The data to compress.
- * @srcSize: The size of the data to compress.
- * @params: The parameters to use for compression. See ZSTD_getParams().
- *
- * Return: The compressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_compressCCtx(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize, ZSTD_parameters params);
- /**
- * ZSTD_DCtxWorkspaceBound() - amount of memory needed to initialize a ZSTD_DCtx
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initDCtx().
- */
- size_t ZSTD_DCtxWorkspaceBound(void);
- /**
- * struct ZSTD_DCtx - the zstd decompression context
- *
- * When decompressing many times it is recommended to allocate a context just
- * once and reuse it for each successive decompression operation.
- */
- typedef struct ZSTD_DCtx_s ZSTD_DCtx;
- /**
- * ZSTD_initDCtx() - initialize a zstd decompression context
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace. Use ZSTD_DCtxWorkspaceBound() to
- * determine how large the workspace must be.
- *
- * Return: A decompression context emplaced into workspace.
- */
- ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize);
- /**
- * ZSTD_decompressDCtx() - decompress zstd compressed src into dst
- * @ctx: The decompression context.
- * @dst: The buffer to decompress src into.
- * @dstCapacity: The size of the destination buffer. Must be at least as large
- * as the decompressed size. If the caller cannot upper bound the
- * decompressed size, then it's better to use the streaming API.
- * @src: The zstd compressed data to decompress. Multiple concatenated
- * frames and skippable frames are allowed.
- * @srcSize: The exact size of the data to decompress.
- *
- * Return: The decompressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_decompressDCtx(ZSTD_DCtx *ctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- /*-************************
- * Simple dictionary API
- **************************/
- /**
- * ZSTD_compress_usingDict() - compress src into dst using a dictionary
- * @ctx: The context. Must have been initialized with a workspace at
- * least as large as ZSTD_CCtxWorkspaceBound(params.cParams).
- * @dst: The buffer to compress src into.
- * @dstCapacity: The size of the destination buffer. May be any size, but
- * ZSTD_compressBound(srcSize) is guaranteed to be large enough.
- * @src: The data to compress.
- * @srcSize: The size of the data to compress.
- * @dict: The dictionary to use for compression.
- * @dictSize: The size of the dictionary.
- * @params: The parameters to use for compression. See ZSTD_getParams().
- *
- * Compression using a predefined dictionary. The same dictionary must be used
- * during decompression.
- *
- * Return: The compressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_compress_usingDict(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize, const void *dict, size_t dictSize,
- ZSTD_parameters params);
- /**
- * ZSTD_decompress_usingDict() - decompress src into dst using a dictionary
- * @ctx: The decompression context.
- * @dst: The buffer to decompress src into.
- * @dstCapacity: The size of the destination buffer. Must be at least as large
- * as the decompressed size. If the caller cannot upper bound the
- * decompressed size, then it's better to use the streaming API.
- * @src: The zstd compressed data to decompress. Multiple concatenated
- * frames and skippable frames are allowed.
- * @srcSize: The exact size of the data to decompress.
- * @dict: The dictionary to use for decompression. The same dictionary
- * must've been used to compress the data.
- * @dictSize: The size of the dictionary.
- *
- * Return: The decompressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_decompress_usingDict(ZSTD_DCtx *ctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize, const void *dict, size_t dictSize);
- /*-**************************
- * Fast dictionary API
- ***************************/
- /**
- * ZSTD_CDictWorkspaceBound() - memory needed to initialize a ZSTD_CDict
- * @cParams: The compression parameters to be used for compression.
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initCDict().
- */
- size_t ZSTD_CDictWorkspaceBound(ZSTD_compressionParameters cParams);
- /**
- * struct ZSTD_CDict - a digested dictionary to be used for compression
- */
- typedef struct ZSTD_CDict_s ZSTD_CDict;
- /**
- * ZSTD_initCDict() - initialize a digested dictionary for compression
- * @dictBuffer: The dictionary to digest. The buffer is referenced by the
- * ZSTD_CDict so it must outlive the returned ZSTD_CDict.
- * @dictSize: The size of the dictionary.
- * @params: The parameters to use for compression. See ZSTD_getParams().
- * @workspace: The workspace. It must outlive the returned ZSTD_CDict.
- * @workspaceSize: The workspace size. Must be at least
- * ZSTD_CDictWorkspaceBound(params.cParams).
- *
- * When compressing multiple messages / blocks with the same dictionary it is
- * recommended to load it just once. The ZSTD_CDict merely references the
- * dictBuffer, so it must outlive the returned ZSTD_CDict.
- *
- * Return: The digested dictionary emplaced into workspace.
- */
- ZSTD_CDict *ZSTD_initCDict(const void *dictBuffer, size_t dictSize,
- ZSTD_parameters params, void *workspace, size_t workspaceSize);
- /**
- * ZSTD_compress_usingCDict() - compress src into dst using a ZSTD_CDict
- * @ctx: The context. Must have been initialized with a workspace at
- * least as large as ZSTD_CCtxWorkspaceBound(cParams) where
- * cParams are the compression parameters used to initialize the
- * cdict.
- * @dst: The buffer to compress src into.
- * @dstCapacity: The size of the destination buffer. May be any size, but
- * ZSTD_compressBound(srcSize) is guaranteed to be large enough.
- * @src: The data to compress.
- * @srcSize: The size of the data to compress.
- * @cdict: The digested dictionary to use for compression.
- * @params: The parameters to use for compression. See ZSTD_getParams().
- *
- * Compression using a digested dictionary. The same dictionary must be used
- * during decompression.
- *
- * Return: The compressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_compress_usingCDict(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize, const ZSTD_CDict *cdict);
- /**
- * ZSTD_DDictWorkspaceBound() - memory needed to initialize a ZSTD_DDict
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initDDict().
- */
- size_t ZSTD_DDictWorkspaceBound(void);
- /**
- * struct ZSTD_DDict - a digested dictionary to be used for decompression
- */
- typedef struct ZSTD_DDict_s ZSTD_DDict;
- /**
- * ZSTD_initDDict() - initialize a digested dictionary for decompression
- * @dictBuffer: The dictionary to digest. The buffer is referenced by the
- * ZSTD_DDict so it must outlive the returned ZSTD_DDict.
- * @dictSize: The size of the dictionary.
- * @workspace: The workspace. It must outlive the returned ZSTD_DDict.
- * @workspaceSize: The workspace size. Must be at least
- * ZSTD_DDictWorkspaceBound().
- *
- * When decompressing multiple messages / blocks with the same dictionary it is
- * recommended to load it just once. The ZSTD_DDict merely references the
- * dictBuffer, so it must outlive the returned ZSTD_DDict.
- *
- * Return: The digested dictionary emplaced into workspace.
- */
- ZSTD_DDict *ZSTD_initDDict(const void *dictBuffer, size_t dictSize,
- void *workspace, size_t workspaceSize);
- /**
- * ZSTD_decompress_usingDDict() - decompress src into dst using a ZSTD_DDict
- * @ctx: The decompression context.
- * @dst: The buffer to decompress src into.
- * @dstCapacity: The size of the destination buffer. Must be at least as large
- * as the decompressed size. If the caller cannot upper bound the
- * decompressed size, then it's better to use the streaming API.
- * @src: The zstd compressed data to decompress. Multiple concatenated
- * frames and skippable frames are allowed.
- * @srcSize: The exact size of the data to decompress.
- * @ddict: The digested dictionary to use for decompression. The same
- * dictionary must've been used to compress the data.
- *
- * Return: The decompressed size or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_decompress_usingDDict(ZSTD_DCtx *dctx, void *dst,
- size_t dstCapacity, const void *src, size_t srcSize,
- const ZSTD_DDict *ddict);
- /*-**************************
- * Streaming
- ***************************/
- /**
- * struct ZSTD_inBuffer - input buffer for streaming
- * @src: Start of the input buffer.
- * @size: Size of the input buffer.
- * @pos: Position where reading stopped. Will be updated.
- * Necessarily 0 <= pos <= size.
- */
- typedef struct ZSTD_inBuffer_s {
- const void *src;
- size_t size;
- size_t pos;
- } ZSTD_inBuffer;
- /**
- * struct ZSTD_outBuffer - output buffer for streaming
- * @dst: Start of the output buffer.
- * @size: Size of the output buffer.
- * @pos: Position where writing stopped. Will be updated.
- * Necessarily 0 <= pos <= size.
- */
- typedef struct ZSTD_outBuffer_s {
- void *dst;
- size_t size;
- size_t pos;
- } ZSTD_outBuffer;
- /*-*****************************************************************************
- * Streaming compression - HowTo
- *
- * A ZSTD_CStream object is required to track streaming operation.
- * Use ZSTD_initCStream() to initialize a ZSTD_CStream object.
- * ZSTD_CStream objects can be reused multiple times on consecutive compression
- * operations. It is recommended to re-use ZSTD_CStream in situations where many
- * streaming operations will be achieved consecutively. Use one separate
- * ZSTD_CStream per thread for parallel execution.
- *
- * Use ZSTD_compressStream() repetitively to consume input stream.
- * The function will automatically update both `pos` fields.
- * Note that it may not consume the entire input, in which case `pos < size`,
- * and it's up to the caller to present again remaining data.
- * It returns a hint for the preferred number of bytes to use as an input for
- * the next function call.
- *
- * At any moment, it's possible to flush whatever data remains within internal
- * buffer, using ZSTD_flushStream(). `output->pos` will be updated. There might
- * still be some content left within the internal buffer if `output->size` is
- * too small. It returns the number of bytes left in the internal buffer and
- * must be called until it returns 0.
- *
- * ZSTD_endStream() instructs to finish a frame. It will perform a flush and
- * write frame epilogue. The epilogue is required for decoders to consider a
- * frame completed. Similar to ZSTD_flushStream(), it may not be able to flush
- * the full content if `output->size` is too small. In which case, call again
- * ZSTD_endStream() to complete the flush. It returns the number of bytes left
- * in the internal buffer and must be called until it returns 0.
- ******************************************************************************/
- /**
- * ZSTD_CStreamWorkspaceBound() - memory needed to initialize a ZSTD_CStream
- * @cParams: The compression parameters to be used for compression.
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initCStream() and ZSTD_initCStream_usingCDict().
- */
- size_t ZSTD_CStreamWorkspaceBound(ZSTD_compressionParameters cParams);
- /**
- * struct ZSTD_CStream - the zstd streaming compression context
- */
- typedef struct ZSTD_CStream_s ZSTD_CStream;
- /*===== ZSTD_CStream management functions =====*/
- /**
- * ZSTD_initCStream() - initialize a zstd streaming compression context
- * @params: The zstd compression parameters.
- * @pledgedSrcSize: If params.fParams.contentSizeFlag == 1 then the caller must
- * pass the source size (zero means empty source). Otherwise,
- * the caller may optionally pass the source size, or zero if
- * unknown.
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace.
- * Use ZSTD_CStreamWorkspaceBound(params.cParams) to determine
- * how large the workspace must be.
- *
- * Return: The zstd streaming compression context.
- */
- ZSTD_CStream *ZSTD_initCStream(ZSTD_parameters params,
- unsigned long long pledgedSrcSize, void *workspace,
- size_t workspaceSize);
- /**
- * ZSTD_initCStream_usingCDict() - initialize a streaming compression context
- * @cdict: The digested dictionary to use for compression.
- * @pledgedSrcSize: Optionally the source size, or zero if unknown.
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace. Call ZSTD_CStreamWorkspaceBound()
- * with the cParams used to initialize the cdict to determine
- * how large the workspace must be.
- *
- * Return: The zstd streaming compression context.
- */
- ZSTD_CStream *ZSTD_initCStream_usingCDict(const ZSTD_CDict *cdict,
- unsigned long long pledgedSrcSize, void *workspace,
- size_t workspaceSize);
- /*===== Streaming compression functions =====*/
- /**
- * ZSTD_resetCStream() - reset the context using parameters from creation
- * @zcs: The zstd streaming compression context to reset.
- * @pledgedSrcSize: Optionally the source size, or zero if unknown.
- *
- * Resets the context using the parameters from creation. Skips dictionary
- * loading, since it can be reused. If `pledgedSrcSize` is non-zero the frame
- * content size is always written into the frame header.
- *
- * Return: Zero or an error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_resetCStream(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize);
- /**
- * ZSTD_compressStream() - streaming compress some of input into output
- * @zcs: The zstd streaming compression context.
- * @output: Destination buffer. `output->pos` is updated to indicate how much
- * compressed data was written.
- * @input: Source buffer. `input->pos` is updated to indicate how much data was
- * read. Note that it may not consume the entire input, in which case
- * `input->pos < input->size`, and it's up to the caller to present
- * remaining data again.
- *
- * The `input` and `output` buffers may be any size. Guaranteed to make some
- * forward progress if `input` and `output` are not empty.
- *
- * Return: A hint for the number of bytes to use as the input for the next
- * function call or an error, which can be checked using
- * ZSTD_isError().
- */
- size_t ZSTD_compressStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output,
- ZSTD_inBuffer *input);
- /**
- * ZSTD_flushStream() - flush internal buffers into output
- * @zcs: The zstd streaming compression context.
- * @output: Destination buffer. `output->pos` is updated to indicate how much
- * compressed data was written.
- *
- * ZSTD_flushStream() must be called until it returns 0, meaning all the data
- * has been flushed. Since ZSTD_flushStream() causes a block to be ended,
- * calling it too often will degrade the compression ratio.
- *
- * Return: The number of bytes still present within internal buffers or an
- * error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_flushStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output);
- /**
- * ZSTD_endStream() - flush internal buffers into output and end the frame
- * @zcs: The zstd streaming compression context.
- * @output: Destination buffer. `output->pos` is updated to indicate how much
- * compressed data was written.
- *
- * ZSTD_endStream() must be called until it returns 0, meaning all the data has
- * been flushed and the frame epilogue has been written.
- *
- * Return: The number of bytes still present within internal buffers or an
- * error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_endStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output);
- /**
- * ZSTD_CStreamInSize() - recommended size for the input buffer
- *
- * Return: The recommended size for the input buffer.
- */
- size_t ZSTD_CStreamInSize(void);
- /**
- * ZSTD_CStreamOutSize() - recommended size for the output buffer
- *
- * When the output buffer is at least this large, it is guaranteed to be large
- * enough to flush at least one complete compressed block.
- *
- * Return: The recommended size for the output buffer.
- */
- size_t ZSTD_CStreamOutSize(void);
- /*-*****************************************************************************
- * Streaming decompression - HowTo
- *
- * A ZSTD_DStream object is required to track streaming operations.
- * Use ZSTD_initDStream() to initialize a ZSTD_DStream object.
- * ZSTD_DStream objects can be re-used multiple times.
- *
- * Use ZSTD_decompressStream() repetitively to consume your input.
- * The function will update both `pos` fields.
- * If `input->pos < input->size`, some input has not been consumed.
- * It's up to the caller to present again remaining data.
- * If `output->pos < output->size`, decoder has flushed everything it could.
- * Returns 0 iff a frame is completely decoded and fully flushed.
- * Otherwise it returns a suggested next input size that will never load more
- * than the current frame.
- ******************************************************************************/
- /**
- * ZSTD_DStreamWorkspaceBound() - memory needed to initialize a ZSTD_DStream
- * @maxWindowSize: The maximum window size allowed for compressed frames.
- *
- * Return: A lower bound on the size of the workspace that is passed to
- * ZSTD_initDStream() and ZSTD_initDStream_usingDDict().
- */
- size_t ZSTD_DStreamWorkspaceBound(size_t maxWindowSize);
- /**
- * struct ZSTD_DStream - the zstd streaming decompression context
- */
- typedef struct ZSTD_DStream_s ZSTD_DStream;
- /*===== ZSTD_DStream management functions =====*/
- /**
- * ZSTD_initDStream() - initialize a zstd streaming decompression context
- * @maxWindowSize: The maximum window size allowed for compressed frames.
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace.
- * Use ZSTD_DStreamWorkspaceBound(maxWindowSize) to determine
- * how large the workspace must be.
- *
- * Return: The zstd streaming decompression context.
- */
- ZSTD_DStream *ZSTD_initDStream(size_t maxWindowSize, void *workspace,
- size_t workspaceSize);
- /**
- * ZSTD_initDStream_usingDDict() - initialize streaming decompression context
- * @maxWindowSize: The maximum window size allowed for compressed frames.
- * @ddict: The digested dictionary to use for decompression.
- * @workspace: The workspace to emplace the context into. It must outlive
- * the returned context.
- * @workspaceSize: The size of workspace.
- * Use ZSTD_DStreamWorkspaceBound(maxWindowSize) to determine
- * how large the workspace must be.
- *
- * Return: The zstd streaming decompression context.
- */
- ZSTD_DStream *ZSTD_initDStream_usingDDict(size_t maxWindowSize,
- const ZSTD_DDict *ddict, void *workspace, size_t workspaceSize);
- /*===== Streaming decompression functions =====*/
- /**
- * ZSTD_resetDStream() - reset the context using parameters from creation
- * @zds: The zstd streaming decompression context to reset.
- *
- * Resets the context using the parameters from creation. Skips dictionary
- * loading, since it can be reused.
- *
- * Return: Zero or an error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_resetDStream(ZSTD_DStream *zds);
- /**
- * ZSTD_decompressStream() - streaming decompress some of input into output
- * @zds: The zstd streaming decompression context.
- * @output: Destination buffer. `output.pos` is updated to indicate how much
- * decompressed data was written.
- * @input: Source buffer. `input.pos` is updated to indicate how much data was
- * read. Note that it may not consume the entire input, in which case
- * `input.pos < input.size`, and it's up to the caller to present
- * remaining data again.
- *
- * The `input` and `output` buffers may be any size. Guaranteed to make some
- * forward progress if `input` and `output` are not empty.
- * ZSTD_decompressStream() will not consume the last byte of the frame until
- * the entire frame is flushed.
- *
- * Return: Returns 0 iff a frame is completely decoded and fully flushed.
- * Otherwise returns a hint for the number of bytes to use as the input
- * for the next function call or an error, which can be checked using
- * ZSTD_isError(). The size hint will never load more than the frame.
- */
- size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output,
- ZSTD_inBuffer *input);
- /**
- * ZSTD_DStreamInSize() - recommended size for the input buffer
- *
- * Return: The recommended size for the input buffer.
- */
- size_t ZSTD_DStreamInSize(void);
- /**
- * ZSTD_DStreamOutSize() - recommended size for the output buffer
- *
- * When the output buffer is at least this large, it is guaranteed to be large
- * enough to flush at least one complete decompressed block.
- *
- * Return: The recommended size for the output buffer.
- */
- size_t ZSTD_DStreamOutSize(void);
- /* --- Constants ---*/
- #define ZSTD_MAGICNUMBER 0xFD2FB528 /* >= v0.8.0 */
- #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
- #define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
- #define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
- #define ZSTD_WINDOWLOG_MAX_32 27
- #define ZSTD_WINDOWLOG_MAX_64 27
- #define ZSTD_WINDOWLOG_MAX \
- ((unsigned int)(sizeof(size_t) == 4 \
- ? ZSTD_WINDOWLOG_MAX_32 \
- : ZSTD_WINDOWLOG_MAX_64))
- #define ZSTD_WINDOWLOG_MIN 10
- #define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX
- #define ZSTD_HASHLOG_MIN 6
- #define ZSTD_CHAINLOG_MAX (ZSTD_WINDOWLOG_MAX+1)
- #define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN
- #define ZSTD_HASHLOG3_MAX 17
- #define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
- #define ZSTD_SEARCHLOG_MIN 1
- /* only for ZSTD_fast, other strategies are limited to 6 */
- #define ZSTD_SEARCHLENGTH_MAX 7
- /* only for ZSTD_btopt, other strategies are limited to 4 */
- #define ZSTD_SEARCHLENGTH_MIN 3
- #define ZSTD_TARGETLENGTH_MIN 4
- #define ZSTD_TARGETLENGTH_MAX 999
- /* for static allocation */
- #define ZSTD_FRAMEHEADERSIZE_MAX 18
- #define ZSTD_FRAMEHEADERSIZE_MIN 6
- static const size_t ZSTD_frameHeaderSize_prefix = 5;
- static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
- static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
- /* magic number + skippable frame length */
- static const size_t ZSTD_skippableHeaderSize = 8;
- /*-*************************************
- * Compressed size functions
- **************************************/
- /**
- * ZSTD_findFrameCompressedSize() - returns the size of a compressed frame
- * @src: Source buffer. It should point to the start of a zstd encoded frame
- * or a skippable frame.
- * @srcSize: The size of the source buffer. It must be at least as large as the
- * size of the frame.
- *
- * Return: The compressed size of the frame pointed to by `src` or an error,
- * which can be check with ZSTD_isError().
- * Suitable to pass to ZSTD_decompress() or similar functions.
- */
- size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize);
- /*-*************************************
- * Decompressed size functions
- **************************************/
- /**
- * ZSTD_getFrameContentSize() - returns the content size in a zstd frame header
- * @src: It should point to the start of a zstd encoded frame.
- * @srcSize: The size of the source buffer. It must be at least as large as the
- * frame header. `ZSTD_frameHeaderSize_max` is always large enough.
- *
- * Return: The frame content size stored in the frame header if known.
- * `ZSTD_CONTENTSIZE_UNKNOWN` if the content size isn't stored in the
- * frame header. `ZSTD_CONTENTSIZE_ERROR` on invalid input.
- */
- unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
- /**
- * ZSTD_findDecompressedSize() - returns decompressed size of a series of frames
- * @src: It should point to the start of a series of zstd encoded and/or
- * skippable frames.
- * @srcSize: The exact size of the series of frames.
- *
- * If any zstd encoded frame in the series doesn't have the frame content size
- * set, `ZSTD_CONTENTSIZE_UNKNOWN` is returned. But frame content size is always
- * set when using ZSTD_compress(). The decompressed size can be very large.
- * If the source is untrusted, the decompressed size could be wrong or
- * intentionally modified. Always ensure the result fits within the
- * application's authorized limits. ZSTD_findDecompressedSize() handles multiple
- * frames, and so it must traverse the input to read each frame header. This is
- * efficient as most of the data is skipped, however it does mean that all frame
- * data must be present and valid.
- *
- * Return: Decompressed size of all the data contained in the frames if known.
- * `ZSTD_CONTENTSIZE_UNKNOWN` if the decompressed size is unknown.
- * `ZSTD_CONTENTSIZE_ERROR` if an error occurred.
- */
- unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize);
- /*-*************************************
- * Advanced compression functions
- **************************************/
- /**
- * ZSTD_checkCParams() - ensure parameter values remain within authorized range
- * @cParams: The zstd compression parameters.
- *
- * Return: Zero or an error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams);
- /**
- * ZSTD_adjustCParams() - optimize parameters for a given srcSize and dictSize
- * @srcSize: Optionally the estimated source size, or zero if unknown.
- * @dictSize: Optionally the estimated dictionary size, or zero if unknown.
- *
- * Return: The optimized parameters.
- */
- ZSTD_compressionParameters ZSTD_adjustCParams(
- ZSTD_compressionParameters cParams, unsigned long long srcSize,
- size_t dictSize);
- /*--- Advanced decompression functions ---*/
- /**
- * ZSTD_isFrame() - returns true iff the buffer starts with a valid frame
- * @buffer: The source buffer to check.
- * @size: The size of the source buffer, must be at least 4 bytes.
- *
- * Return: True iff the buffer starts with a zstd or skippable frame identifier.
- */
- unsigned int ZSTD_isFrame(const void *buffer, size_t size);
- /**
- * ZSTD_getDictID_fromDict() - returns the dictionary id stored in a dictionary
- * @dict: The dictionary buffer.
- * @dictSize: The size of the dictionary buffer.
- *
- * Return: The dictionary id stored within the dictionary or 0 if the
- * dictionary is not a zstd dictionary. If it returns 0 the
- * dictionary can still be loaded as a content-only dictionary.
- */
- unsigned int ZSTD_getDictID_fromDict(const void *dict, size_t dictSize);
- /**
- * ZSTD_getDictID_fromDDict() - returns the dictionary id stored in a ZSTD_DDict
- * @ddict: The ddict to find the id of.
- *
- * Return: The dictionary id stored within `ddict` or 0 if the dictionary is not
- * a zstd dictionary. If it returns 0 `ddict` will be loaded as a
- * content-only dictionary.
- */
- unsigned int ZSTD_getDictID_fromDDict(const ZSTD_DDict *ddict);
- /**
- * ZSTD_getDictID_fromFrame() - returns the dictionary id stored in a zstd frame
- * @src: Source buffer. It must be a zstd encoded frame.
- * @srcSize: The size of the source buffer. It must be at least as large as the
- * frame header. `ZSTD_frameHeaderSize_max` is always large enough.
- *
- * Return: The dictionary id required to decompress the frame stored within
- * `src` or 0 if the dictionary id could not be decoded. It can return
- * 0 if the frame does not require a dictionary, the dictionary id
- * wasn't stored in the frame, `src` is not a zstd frame, or `srcSize`
- * is too small.
- */
- unsigned int ZSTD_getDictID_fromFrame(const void *src, size_t srcSize);
- /**
- * struct ZSTD_frameParams - zstd frame parameters stored in the frame header
- * @frameContentSize: The frame content size, or 0 if not present.
- * @windowSize: The window size, or 0 if the frame is a skippable frame.
- * @dictID: The dictionary id, or 0 if not present.
- * @checksumFlag: Whether a checksum was used.
- */
- typedef struct {
- unsigned long long frameContentSize;
- unsigned int windowSize;
- unsigned int dictID;
- unsigned int checksumFlag;
- } ZSTD_frameParams;
- /**
- * ZSTD_getFrameParams() - extracts parameters from a zstd or skippable frame
- * @fparamsPtr: On success the frame parameters are written here.
- * @src: The source buffer. It must point to a zstd or skippable frame.
- * @srcSize: The size of the source buffer. `ZSTD_frameHeaderSize_max` is
- * always large enough to succeed.
- *
- * Return: 0 on success. If more data is required it returns how many bytes
- * must be provided to make forward progress. Otherwise it returns
- * an error, which can be checked using ZSTD_isError().
- */
- size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src,
- size_t srcSize);
- /*-*****************************************************************************
- * Buffer-less and synchronous inner streaming functions
- *
- * This is an advanced API, giving full control over buffer management, for
- * users which need direct control over memory.
- * But it's also a complex one, with many restrictions (documented below).
- * Prefer using normal streaming API for an easier experience
- ******************************************************************************/
- /*-*****************************************************************************
- * Buffer-less streaming compression (synchronous mode)
- *
- * A ZSTD_CCtx object is required to track streaming operations.
- * Use ZSTD_initCCtx() to initialize a context.
- * ZSTD_CCtx object can be re-used multiple times within successive compression
- * operations.
- *
- * Start by initializing a context.
- * Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary
- * compression,
- * or ZSTD_compressBegin_advanced(), for finer parameter control.
- * It's also possible to duplicate a reference context which has already been
- * initialized, using ZSTD_copyCCtx()
- *
- * Then, consume your input using ZSTD_compressContinue().
- * There are some important considerations to keep in mind when using this
- * advanced function :
- * - ZSTD_compressContinue() has no internal buffer. It uses externally provided
- * buffer only.
- * - Interface is synchronous : input is consumed entirely and produce 1+
- * (or more) compressed blocks.
- * - Caller must ensure there is enough space in `dst` to store compressed data
- * under worst case scenario. Worst case evaluation is provided by
- * ZSTD_compressBound().
- * ZSTD_compressContinue() doesn't guarantee recover after a failed
- * compression.
- * - ZSTD_compressContinue() presumes prior input ***is still accessible and
- * unmodified*** (up to maximum distance size, see WindowLog).
- * It remembers all previous contiguous blocks, plus one separated memory
- * segment (which can itself consists of multiple contiguous blocks)
- * - ZSTD_compressContinue() detects that prior input has been overwritten when
- * `src` buffer overlaps. In which case, it will "discard" the relevant memory
- * section from its history.
- *
- * Finish a frame with ZSTD_compressEnd(), which will write the last block(s)
- * and optional checksum. It's possible to use srcSize==0, in which case, it
- * will write a final empty block to end the frame. Without last block mark,
- * frames will be considered unfinished (corrupted) by decoders.
- *
- * `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress some new
- * frame.
- ******************************************************************************/
- /*===== Buffer-less streaming compression functions =====*/
- size_t ZSTD_compressBegin(ZSTD_CCtx *cctx, int compressionLevel);
- size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx *cctx, const void *dict,
- size_t dictSize, int compressionLevel);
- size_t ZSTD_compressBegin_advanced(ZSTD_CCtx *cctx, const void *dict,
- size_t dictSize, ZSTD_parameters params,
- unsigned long long pledgedSrcSize);
- size_t ZSTD_copyCCtx(ZSTD_CCtx *cctx, const ZSTD_CCtx *preparedCCtx,
- unsigned long long pledgedSrcSize);
- size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx *cctx, const ZSTD_CDict *cdict,
- unsigned long long pledgedSrcSize);
- size_t ZSTD_compressContinue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- size_t ZSTD_compressEnd(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- /*-*****************************************************************************
- * Buffer-less streaming decompression (synchronous mode)
- *
- * A ZSTD_DCtx object is required to track streaming operations.
- * Use ZSTD_initDCtx() to initialize a context.
- * A ZSTD_DCtx object can be re-used multiple times.
- *
- * First typical operation is to retrieve frame parameters, using
- * ZSTD_getFrameParams(). It fills a ZSTD_frameParams structure which provide
- * important information to correctly decode the frame, such as the minimum
- * rolling buffer size to allocate to decompress data (`windowSize`), and the
- * dictionary ID used.
- * Note: content size is optional, it may not be present. 0 means unknown.
- * Note that these values could be wrong, either because of data malformation,
- * or because an attacker is spoofing deliberate false information. As a
- * consequence, check that values remain within valid application range,
- * especially `windowSize`, before allocation. Each application can set its own
- * limit, depending on local restrictions. For extended interoperability, it is
- * recommended to support at least 8 MB.
- * Frame parameters are extracted from the beginning of the compressed frame.
- * Data fragment must be large enough to ensure successful decoding, typically
- * `ZSTD_frameHeaderSize_max` bytes.
- * Result: 0: successful decoding, the `ZSTD_frameParams` structure is filled.
- * >0: `srcSize` is too small, provide at least this many bytes.
- * errorCode, which can be tested using ZSTD_isError().
- *
- * Start decompression, with ZSTD_decompressBegin() or
- * ZSTD_decompressBegin_usingDict(). Alternatively, you can copy a prepared
- * context, using ZSTD_copyDCtx().
- *
- * Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue()
- * alternatively.
- * ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize'
- * to ZSTD_decompressContinue().
- * ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will
- * fail.
- *
- * The result of ZSTD_decompressContinue() is the number of bytes regenerated
- * within 'dst' (necessarily <= dstCapacity). It can be zero, which is not an
- * error; it just means ZSTD_decompressContinue() has decoded some metadata
- * item. It can also be an error code, which can be tested with ZSTD_isError().
- *
- * ZSTD_decompressContinue() needs previous data blocks during decompression, up
- * to `windowSize`. They should preferably be located contiguously, prior to
- * current block. Alternatively, a round buffer of sufficient size is also
- * possible. Sufficient size is determined by frame parameters.
- * ZSTD_decompressContinue() is very sensitive to contiguity, if 2 blocks don't
- * follow each other, make sure that either the compressor breaks contiguity at
- * the same place, or that previous contiguous segment is large enough to
- * properly handle maximum back-reference.
- *
- * A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
- * Context can then be reset to start a new decompression.
- *
- * Note: it's possible to know if next input to present is a header or a block,
- * using ZSTD_nextInputType(). This information is not required to properly
- * decode a frame.
- *
- * == Special case: skippable frames ==
- *
- * Skippable frames allow integration of user-defined data into a flow of
- * concatenated frames. Skippable frames will be ignored (skipped) by a
- * decompressor. The format of skippable frames is as follows:
- * a) Skippable frame ID - 4 Bytes, Little endian format, any value from
- * 0x184D2A50 to 0x184D2A5F
- * b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
- * c) Frame Content - any content (User Data) of length equal to Frame Size
- * For skippable frames ZSTD_decompressContinue() always returns 0.
- * For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0
- * what means that a frame is skippable.
- * Note: If fparamsPtr->frameContentSize==0, it is ambiguous: the frame might
- * actually be a zstd encoded frame with no content. For purposes of
- * decompression, it is valid in both cases to skip the frame using
- * ZSTD_findFrameCompressedSize() to find its size in bytes.
- * It also returns frame size as fparamsPtr->frameContentSize.
- ******************************************************************************/
- /*===== Buffer-less streaming decompression functions =====*/
- size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx);
- size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx *dctx, const void *dict,
- size_t dictSize);
- void ZSTD_copyDCtx(ZSTD_DCtx *dctx, const ZSTD_DCtx *preparedDCtx);
- size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx *dctx);
- size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- typedef enum {
- ZSTDnit_frameHeader,
- ZSTDnit_blockHeader,
- ZSTDnit_block,
- ZSTDnit_lastBlock,
- ZSTDnit_checksum,
- ZSTDnit_skippableFrame
- } ZSTD_nextInputType_e;
- ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx *dctx);
- /*-*****************************************************************************
- * Block functions
- *
- * Block functions produce and decode raw zstd blocks, without frame metadata.
- * Frame metadata cost is typically ~18 bytes, which can be non-negligible for
- * very small blocks (< 100 bytes). User will have to take in charge required
- * information to regenerate data, such as compressed and content sizes.
- *
- * A few rules to respect:
- * - Compressing and decompressing require a context structure
- * + Use ZSTD_initCCtx() and ZSTD_initDCtx()
- * - It is necessary to init context before starting
- * + compression : ZSTD_compressBegin()
- * + decompression : ZSTD_decompressBegin()
- * + variants _usingDict() are also allowed
- * + copyCCtx() and copyDCtx() work too
- * - Block size is limited, it must be <= ZSTD_getBlockSizeMax()
- * + If you need to compress more, cut data into multiple blocks
- * + Consider using the regular ZSTD_compress() instead, as frame metadata
- * costs become negligible when source size is large.
- * - When a block is considered not compressible enough, ZSTD_compressBlock()
- * result will be zero. In which case, nothing is produced into `dst`.
- * + User must test for such outcome and deal directly with uncompressed data
- * + ZSTD_decompressBlock() doesn't accept uncompressed data as input!!!
- * + In case of multiple successive blocks, decoder must be informed of
- * uncompressed block existence to follow proper history. Use
- * ZSTD_insertBlock() in such a case.
- ******************************************************************************/
- /* Define for static allocation */
- #define ZSTD_BLOCKSIZE_ABSOLUTEMAX (128 * 1024)
- /*===== Raw zstd block functions =====*/
- size_t ZSTD_getBlockSizeMax(ZSTD_CCtx *cctx);
- size_t ZSTD_compressBlock(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- size_t ZSTD_decompressBlock(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity,
- const void *src, size_t srcSize);
- size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart,
- size_t blockSize);
- #endif /* ZSTD_H */
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