private int decodeOutLength()

in encode/java/src/main/java/com/aliyun/darabonba/encode/Encoder.java [261:297]

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

        private int decodeOutLength(byte[] src, int sp, int sl) {
            int[] base64 = isURL ? fromBase64URL : fromBase64;
            int paddings = 0;
            int len = sl - sp;
            if (len == 0)
                return 0;
            if (len < 2) {
                if (isMIME && base64[0] == -1)
                    return 0;
                throw new IllegalArgumentException(
                        "Input byte[] should at least have 2 bytes for base64 bytes");
            }
            if (isMIME) {
                // scan all bytes to fill out all non-alphabet. a performance
                // trade-off of pre-scan or Arrays.copyOf
                int n = 0;
                while (sp < sl) {
                    int b = src[sp++] & 0xff;
                    if (b == '=') {
                        len -= (sl - sp + 1);
                        break;
                    }
                    if ((b = base64[b]) == -1)
                        n++;
                }
                len -= n;
            } else {
                if (src[sl - 1] == '=') {
                    paddings++;
                    if (src[sl - 2] == '=')
                        paddings++;
                }
            }
            if (paddings == 0 && (len & 0x3) !=  0)
                paddings = 4 - (len & 0x3);
            return 3 * ((len + 3) / 4) - paddings;
        }