This commit was manufactured by cvs2svn to create tag 'FreeBSD-release/1.0'.

[unix-history] / usr.bin / more / filename.c

/*
* 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);
}