NetBSD/usr.bin/more/filename.c

106 lines
1.8 KiB
C

/* $NetBSD: filename.c,v 1.2 1994/12/24 17:17:06 cgd Exp $ */
#include <stdlib.h>
#include <string.h>
/*
* Expand a string, substituting any "%" with the current filename,
* and any "#" with the previous filename and an initial "!" with
* the second string.
*/
char *
fexpand(s, t)
char *s;
char *t;
{
extern char *current_file, *previous_file;
register char *fr, *to;
register int n;
register char *e;
if (*s == '\0')
return ((char *) 0);
/*
* Make one pass to see how big a buffer we
* need to allocate for the expanded string.
*/
n = 0;
for (fr = s; *fr != '\0'; fr++)
{
switch (*fr)
{
case '!':
if (s == fr && t == (char *) 0) {
error("no previous command");
return ((char *) 0);
}
n += (s == fr) ? strlen(t) : 1;
break;
case '%':
n += (current_file != (char *) 0) ?
strlen(current_file) : 1;
break;
case '#':
n += (previous_file != (char *) 0) ?
strlen(previous_file) : 1;
break;
default:
n++;
if (*fr == '\\') {
n++;
if (*++fr == '\0') {
error("syntax error");
return ((char *) 0);
}
}
break;
}
}
if ((e = (char *) calloc(n+1, sizeof(char))) == (char *) 0) {
error("cannot allocate memory");
quit();
}
/*
* Now copy the string, expanding any "%" or "#".
*/
to = e;
for (fr = s; *fr != '\0'; fr++)
{
switch (*fr)
{
case '!':
if (s == fr) {
strcpy(to, t);
to += strlen(to);
} else
*to++ = *fr;
break;
case '%':
if (current_file == (char *) 0)
*to++ = *fr;
else {
strcpy(to, current_file);
to += strlen(to);
}
break;
case '#':
if (previous_file == (char *) 0)
*to++ = *fr;
else {
strcpy(to, previous_file);
to += strlen(to);
}
break;
default:
*to++ = *fr;
if (*fr == '\\')
*to++ = *++fr;
break;
}
}
*to = '\0';
return (e);
}