static inline int32_t validate_dispatch_data_partial_string()

in SocketRocket/SRWebSocket.m [1566:1611]

• 35 lines of code
• 13 McCabe index (conditional complexity)

static inline int32_t validate_dispatch_data_partial_string(NSData *data) {
    if ([data length] > INT32_MAX) {
        // INT32_MAX is the limit so long as this Framework is using 32 bit ints everywhere.
        return -1;
    }

    int32_t size = (int32_t)[data length];

    const void * contents = [data bytes];
    const uint8_t *str = (const uint8_t *)contents;

    UChar32 codepoint = 1;
    int32_t offset = 0;
    int32_t lastOffset = 0;
    while(offset < size && codepoint > 0)  {
        lastOffset = offset;
        U8_NEXT(str, offset, size, codepoint);
    }

    if (codepoint == -1) {
        // Check to see if the last byte is valid or whether it was just continuing
        if (!U8_IS_LEAD(str[lastOffset]) || U8_COUNT_TRAIL_BYTES(str[lastOffset]) + lastOffset < (int32_t)size) {

            size = -1;
        } else {
            uint8_t leadByte = str[lastOffset];
            U8_MASK_LEAD_BYTE(leadByte, U8_COUNT_TRAIL_BYTES(leadByte));

            for (int i = lastOffset + 1; i < offset; i++) {
                if (U8_IS_SINGLE(str[i]) || U8_IS_LEAD(str[i]) || !U8_IS_TRAIL(str[i])) {
                    size = -1;
                }
            }

            if (size != -1) {
                size = lastOffset;
            }
        }
    }

    if (size != -1 && ![[NSString alloc] initWithBytesNoCopy:(char *)[data bytes] length:size encoding:NSUTF8StringEncoding freeWhenDone:NO]) {
        size = -1;
    }

    return size;
}