libds

simple data structures library and utility functions
git clone git@git.2f30.org/libds.git
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str.c (904B)


      1 /* Taken from: http://creativeandcritical.net/str-replace-c/ */
      2 /* Released in the public domain */
      3 #include <stddef.h>
      4 #include <stdlib.h>
      5 #include <string.h>
      6 
      7 char *
      8 replace_str(const char *str, const char *old, const char *new)
      9 {
     10 	char *ret, *r;
     11 	const char *p, *q;
     12 	size_t oldlen = strlen(old);
     13 	size_t count, retlen, newlen = strlen(new);
     14 
     15 	if (oldlen != newlen) {
     16 		for (count = 0, p = str; (q = strstr(p, old)) != NULL; p = q + oldlen)
     17 			count++;
     18 		/* this is undefined if p - str > PTRDIFF_MAX */
     19 		retlen = p - str + strlen(p) + count * (newlen - oldlen);
     20 	} else
     21 		retlen = strlen(str);
     22 
     23 	if ((ret = malloc(retlen + 1)) == NULL)
     24 		return NULL;
     25 
     26 	for (r = ret, p = str; (q = strstr(p, old)) != NULL; p = q + oldlen) {
     27 		/* this is undefined if q - p > PTRDIFF_MAX */
     28 		ptrdiff_t l = q - p;
     29 		memcpy(r, p, l);
     30 		r += l;
     31 		memcpy(r, new, newlen);
     32 		r += newlen;
     33 	}
     34 	strcpy(r, p);
     35 
     36 	return ret;
     37 }