Method find

src/function/find_function.cpp:95–127

Returns the position of the first occurrence of needle in the haystack. If haystack doesn't contain needle, it returns -1.

// Returns the position of the first occurrence of needle in the haystack. If haystack doesn't
// contain needle, it returns -1.
int64_t Find::find(const uint8_t* haystack, uint32_t haystackLen, const uint8_t* needle,
    uint32_t needleLen) {
    auto firstMatchCharPos = (uint8_t*)memchr(haystack, needle[0], haystackLen);
    if (firstMatchCharPos == nullptr) {
        return -1;
    }
    auto firstMatchCharOffset = firstMatchCharPos - haystack;
    auto numCharsToMatch = haystackLen - firstMatchCharOffset;
    switch (needleLen) {
    case 1:
        return firstMatchCharOffset;
    case 2:
        return alignedNeedleSizeFind<uint16_t>(firstMatchCharPos, numCharsToMatch, needle,
            firstMatchCharOffset);
    case 3:
        return unalignedNeedleSizeFind<uint32_t>(firstMatchCharPos, numCharsToMatch, needle, 3,
            firstMatchCharOffset);
    case 4:
        return alignedNeedleSizeFind<uint32_t>(firstMatchCharPos, numCharsToMatch, needle,
            firstMatchCharOffset);
    case 5:
    case 6:
    case 7:
        return unalignedNeedleSizeFind<uint64_t>(firstMatchCharPos, numCharsToMatch, needle,
            needleLen, firstMatchCharOffset);
    case 8:
        return alignedNeedleSizeFind<uint64_t>(firstMatchCharPos, numCharsToMatch, needle,
            firstMatchCharOffset);
    default:
        return genericFind(firstMatchCharPos, numCharsToMatch, needle, needleLen,
            firstMatchCharOffset);
    }
}

} // namespace function
} // namespace lbug