Function Base64DecodeBufLen

be/src/util/coding-util.cc:196–218

}

bool Base64DecodeBufLen(const char* in, int64_t in_len, int64_t* out_max) {
  // Base64 decoding turns every 4 characters into 3 bytes. If the last character of the
  // encoded string is '=', that character (which represents 6 bits) and the last two bits
  // of the previous character is ignored, for a total of 8 ignored bits, therefore
  // producing one fewer byte of output. This is repeated if the second-to-last character
  // is '='. One more byte must be allocated to account for Base64Decode's null-padding
  // of its output.
  if (UNLIKELY(in_len == 0)) {
    *out_max = 0;
    return true;
  }
  if (UNLIKELY((in_len & 3) != 0)) return false;
  *out_max = 1 + 3 * (in_len / 4);
  DCHECK_GE(in_len, 1);
  if (in[in_len - 1] == '=') {
    --(*out_max);
    DCHECK_GE(in_len, 2);
    if (in[in_len - 2] == '=') {
      --(*out_max);
    }
  }
  return true;
}

bool Base64Decode(const char* in, int64_t in_len, int64_t out_max, char* out,
    unsigned* out_len) {