FreeTDS Development Group

[ZIGLIO Frediano <Frediano.Ziglio AT vodafoneomnitel.it>]

> 
> not much to it really.  The biggest problem is do you have the buffer
> space big enough to handle the escaped string, here's a quick 
> and dirty
> implementation, calling program is responsible for free()ing 
> the string
> when done.  The API's don't really do much of anything with 
> the SQL, they
> just take it directly from the application and pass it on to 
> the server
> without processing, so I suppose that is why nothing is there.
> 
> char *escape_string(char *instr)
> {
> char *outstr;
> int i, j=0, need = 0;
> 
>    for (i=0;i<strlen(instr);i++)
>       if (instr[i]=='\'') need++;
> 
>    outstr = malloc(strlen(outstr) + need + 1);
> 
>    for (i=0;i<strlen(instr);i++) {
>      if (instr[i]=='\'') {
>         outstr[j++]='\'';
>      outstr[j++]=instr[i];
>    }
>    return outstr;
> }
> 
> 
> This of course assumes that you are using single quotes for string
> literals.  Sybase allows use of double quotes if 
> quoted_indentifier is set
> to off (which it is by default) but it's non-portable and 
> make break in
> the future (jConnect turns it off on connect for instance).
> 
> Brian
> 

I prefer also to handle NULL case and quote all string

/**
 * Escape a string using SQL syntax
 * Return NULL if out of memory
 */
char *escape_string(const char *instr)
{
char *outstr,  *pdst;
const char *psrc;
int need;

   /* null string, return NULL */
   if (!instr) 
      return strdup("NULL");

   need = 0;
   for (psrc=instr; *psrc; ++psrc,++need)
      if (*psrc=='\'') ++need;

   outstr = malloc(need + 3);
   if (!outstr) return NULL;
   pdst = outstr;

   *pdst++ = '\'';
   for (psrc=instr; *psrc; ++psrc) {
     if (*psrc=='\'') {
        *pdst++='\'';
     *pdst++ = *psrc;
   }
   *pdst++ = '\'';
   *pdst++ = '\0';
   return outstr;
}

Perhaps some other optimization can be done...
I have also a version of a sqlnprintf...

freddy77

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