linksocket.c

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

int ReadChar(LinkSocket *socket, char *c){
    return ReadChars(socket, c, 1);
}

int WriteChars(LinkSocket *socket, char buffer[], int nchartowrite){    
    int nbyteswritten;
    
    if(Debug(LINKSOCKET))
    {
        printf("LinkSocket.c WriteChars-- %s %d\n", buffer, nchartowrite);
    }

    if (nchartowrite == 0){
        socket->error = LINK_FALSE;
        return OK;
    }
        
    if((LINK_TRUE == socket->isBuffered) && (OK == WriteToBuffer(socket, nchartowrite)) )
    {
        nbyteswritten = BufferedWriteChars(&(socket->writebuffer[socket->currentbuffer]),
                                           buffer, nchartowrite);
        socket->currentbuffer += nbyteswritten;
    }
    else
        nbyteswritten = socket_send(socket->sd, buffer, nchartowrite); 
    
    if(nchartowrite == nbyteswritten)
    {   
        socket->error = LINK_FALSE;
        return OK;
    }
    /*system error */
    socket->error = LINK_TRUE;
    return NOK;
}

int WriteChar(LinkSocket *socket, char *c){
    return WriteChars(socket, c, 1);
}

int BufferedWriteChars(char *toBuffer, char *fromBuffer, int nchartowrite){
    
    memcpy(toBuffer,fromBuffer,nchartowrite);
    /*
      int i = 0;
      while(i < nchartowrite)
      {
      toBuffer[i] = fromBuffer[i];
      i++;
      }
    */
    return nchartowrite;
}

/*
 * bmackiew: This function originally translated the Unicode characters
 * to ASCII for use by the calling function.  Since we deal with stored
 * strings in Unicode only, there's no need to do the translation.
 */

int ReadUnicodeChars(LinkSocket *socket, char *buffer, int nchartoread){
    int ncharread = 0;
    int i;
    char *inbuffer;
    
    /*
     * ### bmackiew: Make sure we read in the proper number of characters!
     */

    /* bmackiew: The numbers of characters to read was originally multiplied
     * by two since strings were stored in ASCII.  We've stored them as 
     * Unicode already, so we know how many characters were needed for
     * storage and readback.
     */

#if 0
    nchartoread = nchartoread*2;
#endif

    inbuffer = (char *)malloc(sizeof(char) * nchartoread);
    if (inbuffer == NULL)
      return -1; /* Memory allocation error */

    ncharread = socket_receive(socket->sd, inbuffer, nchartoread);
    if(nchartoread == ncharread)
    {
      /*
       * This was originally done by a strcpy(), but that fails with
       * English Unicode characters.
       */

      for (i = 0; i < nchartoread; i++) {
        buffer[i] = inbuffer[i];
      }

      buffer[ncharread] = '\0';
      free(inbuffer);
      socket->error = LINK_FALSE;
      return OK;
    }        
    /*error condition */
    free(inbuffer);
    socket->error = LINK_TRUE;
    return NOK;
}

/*
 * bmackiew: Modified to not use ASCIIToUnicode(), as by the time
 * characters are sent here, they are already in Unicode.
 */

int WriteUnicodeChars(LinkSocket *socket, char buffer[], int nchartowrite){
    int ncharwritten = 0;
    /*Internal buffer for holding unicode characters*/   
    char *inbuffer;
 
    if (nchartowrite == 0){
        socket->error = LINK_FALSE;
        return OK;
    }
    
    inbuffer = (char *)malloc(nchartowrite);
    
    if (inbuffer == NULL)
      return -1; /* Memory allocation error */
             
    if((LINK_TRUE == socket->isBuffered) && (OK == WriteToBuffer(socket, nchartowrite)) ) {
      ncharwritten = BufferedWriteUnicodeChars(&(socket->writebuffer[socket->currentbuffer]),
                                               buffer, nchartowrite);   
      socket->currentbuffer += ncharwritten;
      nchartowrite = N_CHARS_PER_UNICODE_CHAR * nchartowrite;
    } 
    else {
      ncharwritten = socket_send(socket->sd, buffer, nchartowrite);
    }

    if(nchartowrite == ncharwritten){
        /*error condition */            
        socket->error = LINK_FALSE;
        free(inbuffer);
        return OK;
    }
       
    socket->error = LINK_TRUE;
    free(inbuffer);

    return NOK;
}

int BufferedWriteUnicodeChars(char *toBuffer,
                              char *fromBuffer,
                              int nchartowrite){
    
    return ASCIIToUnicode(fromBuffer,toBuffer, nchartowrite);
}


/*
 * Converts Unicode characters to _English_ ASCII characters by
 * stripping them of their first byte.  Note that this is not a
 * comprehensive solution for other language stored in ASCII.
 *
 */
char *EnglishUnicodeToASCII(char unicodechar[], int len) {
    int i, length;
    char *cchar;
    
    cchar = (char *)malloc(length/2);
    for( i = 0; i< length/2;i++){
        cchar[i] = unicodechar[i*2 + 1];      
    }
    return cchar;
}

/*
 * Converts ASCII characters to Unicode Chars by prefixing them with 0x00;
 */

char *ASCIIToEnglishUnicode(char cchar[]) {
  
  int i, length;
  char *unicodechar;

  length = strlen(cchar);
  unicodechar = (char *)malloc(length * 2);

  if(Debug(LINKSOCKET))
    printf("LinkSocket.c::ASCIITOUnicode \n");
  for(i=0;i<length;i++)
    {
      unicodechar[i*2]=0x0;
      unicodechar[i*2 + 1] = cchar[i];
      if(Debug(LINKSOCKET))
        {
          printf("Unicode char %d = %c %0x\n",i*2,unicodechar[i*2],
                 unicodechar[i*2]);
          printf("Unicode char %d = %c %0x\n",(i*2 + 1),unicodechar[i*2+1],
                 unicodechar[i*2+1]);
        }
    }
  return unicodechar;
}

/*
 * unicodecmp()
 *
 * This was written to supplement the strcmp() standard C function.
 * Instead of comparing two strings for to see if there is a match,
 * it is designed to take two strings which may be Unicode strings,
 * and compares character by character.  
 *
 * This function was written to support OpenMap's C-side link server
 * code.  The protocol requires that Unicode be sent across the link 
 * so the Java-side client can easily parse the data being sent.
 * However, our server implementation takes in ASCII strings and
 * then converts them to Unicode.  For the time being, we make the
 * assumption that we are passed English ASCII only, which may be
 * converted to Unicode by prepending the 0x0 byte to each ASCII
 * character.
 *
 * Unfortunately, C's standard strcmp() function will fail when
 * comparing two of our Unicode'd strings, as the first character
 * read in will be the \0 character, and strcmp() will terminate
 * immediately.  This is a quick fix to get around that problem.
 *
 */

int unicodecmp(const char *s1, const char *s2, int length) {
  int i;

  for (i = 0; i < length; i++) {
    if (s1[i] != s2[i]) {
      return 1;
    }
  }
  return 0;
}

/*
 * The functions listed below are deprecated, and are included only until
 * the redundant buffering code has been eliminated from the link server.
 *
 */

/*
  Converts Unicode(ASCII in 2 bytes) Characters to ASCII Characters 
  by stripping them of their 1st byte
*/
int UnicodeToASCII(char unicodechar[], char cchar[], int length){
    int i;
    for( i = 0; i< length/2;i++){
        cchar[i] = unicodechar[i*2 + 1];      
    }
    return length/2;
}

/*
  Converts ASCII Charecters to Unicode Chars by prefixing them with 0x00;
*/
int ASCIIToUnicode(const char cchar[], char unicodechar[], int length ){
    int i;
    if(Debug(LINKSOCKET))
        printf("LinkSocket.c::ASCIITOUnicode \n");
    for(i=0;i<length;i++)
    {
        unicodechar[i*2]=0x0;
        unicodechar[i*2 + 1] = cchar[i];
        if(Debug(LINKSOCKET))
        {
            printf("Unicode char %d = %c %0x\n",i*2,unicodechar[i*2],unicodechar[i*2]);
            printf("Unicode char %d = %c %0x\n",(i*2 + 1),unicodechar[i*2+1],unicodechar[i*2+1]);
        }
    }
    return length*2;
}