inline ssize_t phr_decode_chunked()

in include/ylt/standalone/cinatra/picohttpparser.h [1083:1197]

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

inline ssize_t phr_decode_chunked(struct phr_chunked_decoder *decoder,
                                  char *buf, size_t *_bufsz) {
  size_t dst = 0, src = 0, bufsz = *_bufsz;
  ssize_t ret = -2; /* incomplete */

  while (1) {
    switch (decoder->_state) {
      case CHUNKED_IN_CHUNK_SIZE:
        for (;; ++src) {
          int v;
          if (src == bufsz)
            goto Exit;
          if ((v = decode_hex(buf[src])) == -1) {
            if (decoder->_hex_count == 0) {
              ret = -1;
              goto Exit;
            }
            break;
          }
          if (decoder->_hex_count == sizeof(size_t) * 2) {
            ret = -1;
            goto Exit;
          }
          decoder->bytes_left_in_chunk = decoder->bytes_left_in_chunk * 16 + v;
          ++decoder->_hex_count;
        }
        decoder->_hex_count = 0;
        decoder->_state = CHUNKED_IN_CHUNK_EXT;
        /* fallthru */
      case CHUNKED_IN_CHUNK_EXT:
        /* RFC 7230 A.2 "Line folding in chunk extensions is disallowed" */
        for (;; ++src) {
          if (src == bufsz)
            goto Exit;
          if (buf[src] == '\012')
            break;
        }
        ++src;
        if (decoder->bytes_left_in_chunk == 0) {
          if (decoder->consume_trailer) {
            decoder->_state = CHUNKED_IN_TRAILERS_LINE_HEAD;
            break;
          }
          else {
            goto Complete;
          }
        }
        decoder->_state = CHUNKED_IN_CHUNK_DATA;
        /* fallthru */
      case CHUNKED_IN_CHUNK_DATA: {
        size_t avail = bufsz - src;
        if (avail < decoder->bytes_left_in_chunk) {
          if (dst != src)
            memmove(buf + dst, buf + src, avail);
          src += avail;
          dst += avail;
          decoder->bytes_left_in_chunk -= avail;
          goto Exit;
        }
        if (dst != src)
          memmove(buf + dst, buf + src, decoder->bytes_left_in_chunk);
        src += decoder->bytes_left_in_chunk;
        dst += decoder->bytes_left_in_chunk;
        decoder->bytes_left_in_chunk = 0;
        decoder->_state = CHUNKED_IN_CHUNK_CRLF;
      }
        /* fallthru */
      case CHUNKED_IN_CHUNK_CRLF:
        for (;; ++src) {
          if (src == bufsz)
            goto Exit;
          if (buf[src] != '\015')
            break;
        }
        if (buf[src] != '\012') {
          ret = -1;
          goto Exit;
        }
        ++src;
        decoder->_state = CHUNKED_IN_CHUNK_SIZE;
        break;
      case CHUNKED_IN_TRAILERS_LINE_HEAD:
        for (;; ++src) {
          if (src == bufsz)
            goto Exit;
          if (buf[src] != '\015')
            break;
        }
        if (buf[src++] == '\012')
          goto Complete;
        decoder->_state = CHUNKED_IN_TRAILERS_LINE_MIDDLE;
        /* fallthru */
      case CHUNKED_IN_TRAILERS_LINE_MIDDLE:
        for (;; ++src) {
          if (src == bufsz)
            goto Exit;
          if (buf[src] == '\012')
            break;
        }
        ++src;
        decoder->_state = CHUNKED_IN_TRAILERS_LINE_HEAD;
        break;
      default:
        assert(!"decoder is corrupt");
    }
  }

Complete:
  ret = bufsz - src;
Exit:
  if (dst != src)
    memmove(buf + dst, buf + src, bufsz - src);
  *_bufsz = dst;
  return ret;
}