lib/zstd/decompress/zstd_ddict.c

Source file repositories/reference/linux-study-clean/lib/zstd/decompress/zstd_ddict.c

File Facts

System
Linux kernel
Corpus path
lib/zstd/decompress/zstd_ddict.c
Extension
.c
Size
9130 bytes
Lines
243
Domain
Kernel Services
Bucket
lib
Inferred role
Kernel Services: implementation source
Status
source implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ZSTD_DDict_s {
    void* dictBuffer;
    const void* dictContent;
    size_t dictSize;
    ZSTD_entropyDTables_t entropy;
    U32 dictID;
    U32 entropyPresent;
    ZSTD_customMem cMem;
};  /* typedef'd to ZSTD_DDict within "zstd.h" */

const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
{
    assert(ddict != NULL);
    return ddict->dictContent;
}

size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
{
    assert(ddict != NULL);
    return ddict->dictSize;
}

void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{
    DEBUGLOG(4, "ZSTD_copyDDictParameters");
    assert(dctx != NULL);
    assert(ddict != NULL);
    dctx->dictID = ddict->dictID;
    dctx->prefixStart = ddict->dictContent;
    dctx->virtualStart = ddict->dictContent;
    dctx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
    dctx->previousDstEnd = dctx->dictEnd;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    dctx->dictContentBeginForFuzzing = dctx->prefixStart;
    dctx->dictContentEndForFuzzing = dctx->previousDstEnd;
#endif
    if (ddict->entropyPresent) {
        dctx->litEntropy = 1;
        dctx->fseEntropy = 1;
        dctx->LLTptr = ddict->entropy.LLTable;
        dctx->MLTptr = ddict->entropy.MLTable;
        dctx->OFTptr = ddict->entropy.OFTable;
        dctx->HUFptr = ddict->entropy.hufTable;
        dctx->entropy.rep[0] = ddict->entropy.rep[0];
        dctx->entropy.rep[1] = ddict->entropy.rep[1];
        dctx->entropy.rep[2] = ddict->entropy.rep[2];
    } else {
        dctx->litEntropy = 0;
        dctx->fseEntropy = 0;
    }
}


static size_t
ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
                           ZSTD_dictContentType_e dictContentType)
{
    ddict->dictID = 0;
    ddict->entropyPresent = 0;
    if (dictContentType == ZSTD_dct_rawContent) return 0;

    if (ddict->dictSize < 8) {
        if (dictContentType == ZSTD_dct_fullDict)
            return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
        return 0;   /* pure content mode */
    }
    {   U32 const magic = MEM_readLE32(ddict->dictContent);
        if (magic != ZSTD_MAGIC_DICTIONARY) {
            if (dictContentType == ZSTD_dct_fullDict)
                return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
            return 0;   /* pure content mode */
        }
    }
    ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_FRAMEIDSIZE);

    /* load entropy tables */
    RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
            &ddict->entropy, ddict->dictContent, ddict->dictSize)),
        dictionary_corrupted, "");
    ddict->entropyPresent = 1;
    return 0;
}


static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
                                      const void* dict, size_t dictSize,
                                      ZSTD_dictLoadMethod_e dictLoadMethod,
                                      ZSTD_dictContentType_e dictContentType)
{
    if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {

Annotation

Implementation Notes