local ZPOS64_T zip64local_SearchCentralDir()

in zlib/contrib/minizip/zip.c [686:739]

• 44 lines of code
• 15 McCabe index (conditional complexity)

local ZPOS64_T zip64local_SearchCentralDir(const zlib_filefunc64_32_def* pzlib_filefunc_def, voidpf filestream) {
  unsigned char* buf;
  ZPOS64_T uSizeFile;
  ZPOS64_T uBackRead;
  ZPOS64_T uMaxBack=0xffff; /* maximum size of global comment */
  ZPOS64_T uPosFound=0;

  if (ZSEEK64(*pzlib_filefunc_def,filestream,0,ZLIB_FILEFUNC_SEEK_END) != 0)
    return 0;


  uSizeFile = ZTELL64(*pzlib_filefunc_def,filestream);

  if (uMaxBack>uSizeFile)
    uMaxBack = uSizeFile;

  buf = (unsigned char*)ALLOC(BUFREADCOMMENT+4);
  if (buf==NULL)
    return 0;

  uBackRead = 4;
  while (uBackRead<uMaxBack)
  {
    uLong uReadSize;
    ZPOS64_T uReadPos ;
    int i;
    if (uBackRead+BUFREADCOMMENT>uMaxBack)
      uBackRead = uMaxBack;
    else
      uBackRead+=BUFREADCOMMENT;
    uReadPos = uSizeFile-uBackRead ;

    uReadSize = ((BUFREADCOMMENT+4) < (uSizeFile-uReadPos)) ?
      (BUFREADCOMMENT+4) : (uLong)(uSizeFile-uReadPos);
    if (ZSEEK64(*pzlib_filefunc_def,filestream,uReadPos,ZLIB_FILEFUNC_SEEK_SET)!=0)
      break;

    if (ZREAD64(*pzlib_filefunc_def,filestream,buf,uReadSize)!=uReadSize)
      break;

    for (i=(int)uReadSize-3; (i--)>0;)
      if (((*(buf+i))==0x50) && ((*(buf+i+1))==0x4b) &&
        ((*(buf+i+2))==0x05) && ((*(buf+i+3))==0x06))
      {
        uPosFound = uReadPos+(unsigned)i;
        break;
      }

    if (uPosFound!=0)
      break;
  }
  free(buf);
  return uPosFound;
}