Category : C Source Code
Archive   : ECSTR.ZIP
Filename : STRREPL.C

Output of file : STRREPL.C contained in archive : ECSTR.ZIP
/* File : strrepl.c
Author : Richard A. O'Keefe.
Updated: 23 April 1984
Defines: strrepl()

strrepl(dst, src, pat, rep, times) copies src to dst, replacing the
first "times" non-overlapping instances of pat by rep. pat is not a
regex(3) pattern, it is a literal string which must be matched
exactly. As a special hack, since strfind claims to find "" just
once at the end of the src string, strrepl does a strcat when pat is
an empty string "". If times <= 0, it is just strmov.

The result is a pointer to the NUL which now terminates dst.

BEWARE: even when rep is shorter than pat it is NOT necessarily safe
for dst to be the same as src. ALWAYS make sure dst and src do not/
will not overlap. You have been warned.

There really ought to be a strnrepl with a bound for the size of the
destination string, but there isn't.

#include "strings.h"
#include "_str2pat.h"

char *strrepl(dst, src, pat, rep, times)
char *dst, *src, *pat, *rep;
int times;
register char *s, *p;
register int c, lastch;

pat = _str2pat(pat);
if (times <= 0) {
for (p = dst, s = src; *p++ = *s++; ) ;
return p-1;
if (_pat_lim < 0) {
for (p = dst, s = src; *p++ = *s++; ) ;
for (--p, s = rep; *p++ = *s++; ) ;
return p-1;
/* The pattern is non-empty and times is positive */
c = _pat_lim, lastch = pat[c];
for (;;) {
for (s = src, p = dst; --c >= 0; )
if (!(*p++ = *s++)) return p-1;
c = *s, src = s, dst = p;
if (c == lastch) {
for (s -= _pat_lim, p = pat; *p; )
if (*s++ != *p++) goto not_yet;
for (p = dst-_pat_lim, s = rep; *p++ = *s++; ) ;
if (--times == 0) {
for (s = src; *p++ = *++s; ) ;
return p-1;
dst = p, src++, c = _pat_lim;
} else {
not_yet: c = _pat_vec[c];

  3 Responses to “Category : C Source Code
Archive   : ECSTR.ZIP
Filename : STRREPL.C

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: