lib/zstd/compress/zstd_compress.c

Source file repositories/reference/linux-study-clean/lib/zstd/compress/zstd_compress.c

File Facts

System
Linux kernel
Corpus path
lib/zstd/compress/zstd_compress.c
Extension
.c
Size
337333 bytes
Lines
7635
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_CDict_s {
    const void* dictContent;
    size_t dictContentSize;
    ZSTD_dictContentType_e dictContentType; /* The dictContentType the CDict was created with */
    U32* entropyWorkspace; /* entropy workspace of HUF_WORKSPACE_SIZE bytes */
    ZSTD_cwksp workspace;
    ZSTD_MatchState_t matchState;
    ZSTD_compressedBlockState_t cBlockState;
    ZSTD_customMem customMem;
    U32 dictID;
    int compressionLevel; /* 0 indicates that advanced API was used to select CDict params */
    ZSTD_ParamSwitch_e useRowMatchFinder; /* Indicates whether the CDict was created with params that would use
                                           * row-based matchfinder. Unless the cdict is reloaded, we will use
                                           * the same greedy/lazy matchfinder at compression time.
                                           */
};  /* typedef'd to ZSTD_CDict within "zstd.h" */

ZSTD_CCtx* ZSTD_createCCtx(void)
{
    return ZSTD_createCCtx_advanced(ZSTD_defaultCMem);
}

static void ZSTD_initCCtx(ZSTD_CCtx* cctx, ZSTD_customMem memManager)
{
    assert(cctx != NULL);
    ZSTD_memset(cctx, 0, sizeof(*cctx));
    cctx->customMem = memManager;
    cctx->bmi2 = ZSTD_cpuSupportsBmi2();
    {   size_t const err = ZSTD_CCtx_reset(cctx, ZSTD_reset_parameters);
        assert(!ZSTD_isError(err));
        (void)err;
    }
}

ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
{
    ZSTD_STATIC_ASSERT(zcss_init==0);
    ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1));
    if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
    {   ZSTD_CCtx* const cctx = (ZSTD_CCtx*)ZSTD_customMalloc(sizeof(ZSTD_CCtx), customMem);
        if (!cctx) return NULL;
        ZSTD_initCCtx(cctx, customMem);
        return cctx;
    }
}

ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize)
{
    ZSTD_cwksp ws;
    ZSTD_CCtx* cctx;
    if (workspaceSize <= sizeof(ZSTD_CCtx)) return NULL;  /* minimum size */
    if ((size_t)workspace & 7) return NULL;  /* must be 8-aligned */
    ZSTD_cwksp_init(&ws, workspace, workspaceSize, ZSTD_cwksp_static_alloc);

    cctx = (ZSTD_CCtx*)ZSTD_cwksp_reserve_object(&ws, sizeof(ZSTD_CCtx));
    if (cctx == NULL) return NULL;

    ZSTD_memset(cctx, 0, sizeof(ZSTD_CCtx));
    ZSTD_cwksp_move(&cctx->workspace, &ws);
    cctx->staticSize = workspaceSize;

    /* statically sized space. tmpWorkspace never moves (but prev/next block swap places) */
    if (!ZSTD_cwksp_check_available(&cctx->workspace, TMP_WORKSPACE_SIZE + 2 * sizeof(ZSTD_compressedBlockState_t))) return NULL;
    cctx->blockState.prevCBlock = (ZSTD_compressedBlockState_t*)ZSTD_cwksp_reserve_object(&cctx->workspace, sizeof(ZSTD_compressedBlockState_t));
    cctx->blockState.nextCBlock = (ZSTD_compressedBlockState_t*)ZSTD_cwksp_reserve_object(&cctx->workspace, sizeof(ZSTD_compressedBlockState_t));
    cctx->tmpWorkspace = ZSTD_cwksp_reserve_object(&cctx->workspace, TMP_WORKSPACE_SIZE);
    cctx->tmpWkspSize = TMP_WORKSPACE_SIZE;
    cctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
    return cctx;
}

/*
 * Clears and frees all of the dictionaries in the CCtx.
 */
static void ZSTD_clearAllDicts(ZSTD_CCtx* cctx)
{
    ZSTD_customFree(cctx->localDict.dictBuffer, cctx->customMem);
    ZSTD_freeCDict(cctx->localDict.cdict);
    ZSTD_memset(&cctx->localDict, 0, sizeof(cctx->localDict));
    ZSTD_memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));
    cctx->cdict = NULL;
}

static size_t ZSTD_sizeof_localDict(ZSTD_localDict dict)
{
    size_t const bufferSize = dict.dictBuffer != NULL ? dict.dictSize : 0;
    size_t const cdictSize = ZSTD_sizeof_CDict(dict.cdict);
    return bufferSize + cdictSize;
}

Annotation

Implementation Notes