chromium/third_party/zstd/src/lib/decompress/zstd_ddict.c

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

/* zstd_ddict.c :
 * concentrates all logic that needs to know the internals of ZSTD_DDict object */

/*-*******************************************************
*  Dependencies
*********************************************************/
#include "../common/allocations.h"  /* ZSTD_customMalloc, ZSTD_customFree */
#include "../common/zstd_deps.h"   /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
#include "../common/cpu.h"         /* bmi2 */
#include "../common/mem.h"         /* low level memory routines */
#define FSE_STATIC_LINKING_ONLY
#include "../common/fse.h"
#include "../common/huf.h"
#include "zstd_decompress_internal.h"
#include "zstd_ddict.h"

#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
#  include "../legacy/zstd_legacy.h"
#endif



/*-*******************************************************
*  Types
*********************************************************/
struct ZSTD_DDict_s { … };  /* typedef'd to ZSTD_DDict within "zstd.h" */

const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
{ … }

size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
{ … }

void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{ … }


static size_t
ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
                           ZSTD_dictContentType_e dictContentType)
{ … }


static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
                                      const void* dict, size_t dictSize,
                                      ZSTD_dictLoadMethod_e dictLoadMethod,
                                      ZSTD_dictContentType_e dictContentType)
{ … }

ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
                                      ZSTD_dictLoadMethod_e dictLoadMethod,
                                      ZSTD_dictContentType_e dictContentType,
                                      ZSTD_customMem customMem)
{ … }

/*! ZSTD_createDDict() :
*   Create a digested dictionary, to start decompression without startup delay.
*   `dict` content is copied inside DDict.
*   Consequently, `dict` can be released after `ZSTD_DDict` creation */
ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
{ … }

/*! ZSTD_createDDict_byReference() :
 *  Create a digested dictionary, to start decompression without startup delay.
 *  Dictionary content is simply referenced, it will be accessed during decompression.
 *  Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
{ … }


const ZSTD_DDict* ZSTD_initStaticDDict(
                                void* sBuffer, size_t sBufferSize,
                                const void* dict, size_t dictSize,
                                ZSTD_dictLoadMethod_e dictLoadMethod,
                                ZSTD_dictContentType_e dictContentType)
{ … }


size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
{ … }

/*! ZSTD_estimateDDictSize() :
 *  Estimate amount of memory that will be needed to create a dictionary for decompression.
 *  Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
{ … }

size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
{ … }

/*! ZSTD_getDictID_fromDDict() :
 *  Provides the dictID of the dictionary loaded into `ddict`.
 *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
 *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
{ … }