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ext/zstd/lib/compress/zstd_compress.c  view on Meta::CPAN

                      const void* src, size_t srcSize, size_t* srcPos,
                            ZSTD_EndDirective endOp)
{
    ZSTD_outBuffer output;
    ZSTD_inBuffer  input;
    output.dst = dst;
    output.size = dstCapacity;
    output.pos = *dstPos;
    input.src = src;
    input.size = srcSize;
    input.pos = *srcPos;
    /* ZSTD_compressStream2() will check validity of dstPos and srcPos */
    {   size_t const cErr = ZSTD_compressStream2(cctx, &output, &input, endOp);
        *dstPos = output.pos;
        *srcPos = input.pos;
        return cErr;
    }
}

size_t ZSTD_compress2(ZSTD_CCtx* cctx,
                      void* dst, size_t dstCapacity,
                      const void* src, size_t srcSize)
{
    ZSTD_bufferMode_e const originalInBufferMode = cctx->requestedParams.inBufferMode;
    ZSTD_bufferMode_e const originalOutBufferMode = cctx->requestedParams.outBufferMode;
    DEBUGLOG(4, "ZSTD_compress2 (srcSize=%u)", (unsigned)srcSize);
    ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
    /* Enable stable input/output buffers. */
    cctx->requestedParams.inBufferMode = ZSTD_bm_stable;
    cctx->requestedParams.outBufferMode = ZSTD_bm_stable;
    {   size_t oPos = 0;
        size_t iPos = 0;
        size_t const result = ZSTD_compressStream2_simpleArgs(cctx,
                                        dst, dstCapacity, &oPos,
                                        src, srcSize, &iPos,
                                        ZSTD_e_end);
        /* Reset to the original values. */
        cctx->requestedParams.inBufferMode = originalInBufferMode;
        cctx->requestedParams.outBufferMode = originalOutBufferMode;

        FORWARD_IF_ERROR(result, "ZSTD_compressStream2_simpleArgs failed");
        if (result != 0) {  /* compression not completed, due to lack of output space */
            assert(oPos == dstCapacity);
            RETURN_ERROR(dstSize_tooSmall, "");
        }
        assert(iPos == srcSize);   /* all input is expected consumed */
        return oPos;
    }
}

/* ZSTD_validateSequence() :
 * @offCode : is presumed to follow format required by ZSTD_storeSeq()
 * @returns a ZSTD error code if sequence is not valid
 */
static size_t
ZSTD_validateSequence(U32 offCode, U32 matchLength, U32 minMatch,
                      size_t posInSrc, U32 windowLog, size_t dictSize, int useSequenceProducer)
{
    U32 const windowSize = 1u << windowLog;
    /* posInSrc represents the amount of data the decoder would decode up to this point.
     * As long as the amount of data decoded is less than or equal to window size, offsets may be
     * larger than the total length of output decoded in order to reference the dict, even larger than
     * window size. After output surpasses windowSize, we're limited to windowSize offsets again.
     */
    size_t const offsetBound = posInSrc > windowSize ? (size_t)windowSize : posInSrc + (size_t)dictSize;
    size_t const matchLenLowerBound = (minMatch == 3 || useSequenceProducer) ? 3 : 4;
    RETURN_ERROR_IF(offCode > OFFSET_TO_OFFBASE(offsetBound), externalSequences_invalid, "Offset too large!");
    /* Validate maxNbSeq is large enough for the given matchLength and minMatch */
    RETURN_ERROR_IF(matchLength < matchLenLowerBound, externalSequences_invalid, "Matchlength too small for the minMatch");
    return 0;
}

/* Returns an offset code, given a sequence's raw offset, the ongoing repcode array, and whether litLength == 0 */
static U32 ZSTD_finalizeOffBase(U32 rawOffset, const U32 rep[ZSTD_REP_NUM], U32 ll0)
{
    U32 offBase = OFFSET_TO_OFFBASE(rawOffset);

    if (!ll0 && rawOffset == rep[0]) {
        offBase = REPCODE1_TO_OFFBASE;
    } else if (rawOffset == rep[1]) {
        offBase = REPCODE_TO_OFFBASE(2 - ll0);
    } else if (rawOffset == rep[2]) {
        offBase = REPCODE_TO_OFFBASE(3 - ll0);
    } else if (ll0 && rawOffset == rep[0] - 1) {
        offBase = REPCODE3_TO_OFFBASE;
    }
    return offBase;
}

size_t
ZSTD_copySequencesToSeqStoreExplicitBlockDelim(ZSTD_CCtx* cctx,
                                              ZSTD_sequencePosition* seqPos,
                                        const ZSTD_Sequence* const inSeqs, size_t inSeqsSize,
                                        const void* src, size_t blockSize,
                                        ZSTD_paramSwitch_e externalRepSearch)
{
    U32 idx = seqPos->idx;
    U32 const startIdx = idx;
    BYTE const* ip = (BYTE const*)(src);
    const BYTE* const iend = ip + blockSize;
    repcodes_t updatedRepcodes;
    U32 dictSize;

    DEBUGLOG(5, "ZSTD_copySequencesToSeqStoreExplicitBlockDelim (blockSize = %zu)", blockSize);

    if (cctx->cdict) {
        dictSize = (U32)cctx->cdict->dictContentSize;
    } else if (cctx->prefixDict.dict) {
        dictSize = (U32)cctx->prefixDict.dictSize;
    } else {
        dictSize = 0;
    }
    ZSTD_memcpy(updatedRepcodes.rep, cctx->blockState.prevCBlock->rep, sizeof(repcodes_t));
    for (; idx < inSeqsSize && (inSeqs[idx].matchLength != 0 || inSeqs[idx].offset != 0); ++idx) {
        U32 const litLength = inSeqs[idx].litLength;
        U32 const matchLength = inSeqs[idx].matchLength;
        U32 offBase;

        if (externalRepSearch == ZSTD_ps_disable) {
            offBase = OFFSET_TO_OFFBASE(inSeqs[idx].offset);
        } else {
            U32 const ll0 = (litLength == 0);