int LZ4_decompress_safe_continue()

in lz4.cpp [2631:2668]

• 33 lines of code
• 8 McCabe index (conditional complexity)

int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize)
{
    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
    int result;

    if (lz4sd->prefixSize == 0) {
        /* The first call, no dictionary yet. */
        assert(lz4sd->extDictSize == 0);
        result = LZ4_decompress_safe(source, dest, compressedSize, maxOutputSize);
        if (result <= 0) return result;
        lz4sd->prefixSize = (size_t)result;
        lz4sd->prefixEnd = (BYTE*)dest + result;
    } else if (lz4sd->prefixEnd == (BYTE*)dest) {
        /* They're rolling the current segment. */
        if (lz4sd->prefixSize >= 64 KB - 1)
            result = LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize);
        else if (lz4sd->extDictSize == 0)
            result = LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize,
                                                         lz4sd->prefixSize);
        else
            result = LZ4_decompress_safe_doubleDict(source, dest, compressedSize, maxOutputSize,
                                                    lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize);
        if (result <= 0) return result;
        lz4sd->prefixSize += (size_t)result;
        lz4sd->prefixEnd  += result;
    } else {
        /* The buffer wraps around, or they're switching to another buffer. */
        lz4sd->extDictSize = lz4sd->prefixSize;
        lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
        result = LZ4_decompress_safe_forceExtDict(source, dest, compressedSize, maxOutputSize,
                                                  lz4sd->externalDict, lz4sd->extDictSize);
        if (result <= 0) return result;
        lz4sd->prefixSize = (size_t)result;
        lz4sd->prefixEnd  = (BYTE*)dest + result;
    }

    return result;
}