Fix str_replace

readline.c

@@ -1,3 +1,4 @@
+#include <string.h>
 
 ssize_t
 readline(int fd, char *vptr, size_t maxlen)
@@ -24,46 +25,18 @@ readline(int fd, char *vptr, size_t maxlen)
 	return(n);
 }
 
-char *str_replace(char *orig, char *rep, char *with) {
-    char *result; // the return string
-    char *ins;    // the next insert point
-    char *tmp;    // varies
-    int len_rep;  // length of rep
-    int len_with; // length of with
-    int len_front; // distance between rep and end of last rep
-    int count;    // number of replacements
-
-    if (!orig)
-        return NULL;
-    if (!rep || !(len_rep = strlen(rep)))
-        return NULL;
-    if (!(ins = strstr(orig, rep))) 
-        return NULL;
-    if (!with)
-        with = "";
-    len_with = strlen(with);
+char *replace_str(char *str, char *orig, char *rep)
+{
+  static char buffer[4096];
+  char *p;
 
-    for (count = 0; tmp = strstr(ins, rep); ++count) {
-        ins = tmp + len_rep;
-    }
+  if(!(p = strstr(str, orig)))  // Is 'orig' even in 'str'?
+    return str;
 
-    // first time through the loop, all the variable are set correctly
-    // from here on,
-    //    tmp points to the end of the result string
-    //    ins points to the next occurrence of rep in orig
-    //    orig points to the remainder of orig after "end of rep"
-    tmp = result = malloc(strlen(orig) + (len_with - len_rep) * count + 1);
+  strncpy(buffer, str, p-str); // Copy characters from 'str' start to 'orig' st$
+  buffer[p-str] = '\0';
 
-    if (!result)
-        return NULL;
+  sprintf(buffer+(p-str), "%s%s", rep, p+strlen(orig));
 
-    while (count--) {
-        ins = strstr(orig, rep);
-        len_front = ins - orig;
-        tmp = strncpy(tmp, orig, len_front) + len_front;
-        tmp = strcpy(tmp, with) + len_with;
-        orig += len_front + len_rep; // move to next "end of rep"
-    }
-    strcpy(tmp, orig);
-    return result;
+  return buffer;
 }