c_cpp/readscorr/gtools.c

   1 #include <locale.h>
   2 #include <limits.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5
   6 // http://c-faq.com/stdio/commaprint.html
   7 char *commaprint(unsigned long n)
   8 {
   9         static int comma = '\0';
  10         static char retbuf[4*(sizeof(unsigned long)*CHAR_BIT+2)/3/3+1]; // size=30
  11         char *p = &retbuf[sizeof(retbuf)-1];
  12         int i = 0;
  13
  14         if(comma == '\0') {
  15                 struct lconv *lcp = localeconv();
  16                 if(lcp != NULL) {
  17                         if(lcp->thousands_sep != NULL &&
  18                                 *lcp->thousands_sep != '\0')
  19                                 comma = *lcp->thousands_sep;
  20                         else    comma = ',';
  21                 }
  22         }
  23
  24         *p = '\0';
  25
  26         do {
  27                 if(i%3 == 0 && i != 0)
  28                         *--p = comma;
  29                 *--p = '0' + n % 10;
  30                 n /= 10;
  31                 i++;
  32         } while(n != 0);
  33
  34     //return p;
  35     char *pret = malloc(&retbuf[sizeof(retbuf)]-p); // well, just a tiny leak ...
  36     return strcpy(pret,p);
  37 }
  38