101 lines
1.7 KiB
C
101 lines
1.7 KiB
C
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/*
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* Expand a string, substituting any "%" with the current filename,
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* and any "#" with the previous filename and an initial "!" with
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* the second string.
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*/
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char *
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fexpand(s, t)
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char *s;
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char *t;
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{
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extern char *current_file, *previous_file;
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register char *fr, *to;
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register int n;
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register char *e;
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if (*s == '\0')
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return ((char *) 0);
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/*
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* Make one pass to see how big a buffer we
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* need to allocate for the expanded string.
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*/
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n = 0;
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for (fr = s; *fr != '\0'; fr++)
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{
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switch (*fr)
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{
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case '!':
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if (s == fr && t == (char *) 0) {
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error("no previous command");
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return ((char *) 0);
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}
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n += (s == fr) ? strlen(t) : 1;
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break;
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case '%':
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n += (current_file != (char *) 0) ?
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strlen(current_file) : 1;
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break;
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case '#':
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n += (previous_file != (char *) 0) ?
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strlen(previous_file) : 1;
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break;
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default:
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n++;
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if (*fr == '\\') {
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n++;
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if (*++fr == '\0') {
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error("syntax error");
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return ((char *) 0);
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}
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}
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break;
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}
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}
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if ((e = (char *) calloc(n+1, sizeof(char))) == (char *) 0) {
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error("cannot allocate memory");
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quit();
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}
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/*
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* Now copy the string, expanding any "%" or "#".
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*/
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to = e;
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for (fr = s; *fr != '\0'; fr++)
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{
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switch (*fr)
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{
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case '!':
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if (s == fr) {
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strcpy(to, t);
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to += strlen(to);
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} else
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*to++ = *fr;
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break;
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case '%':
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if (current_file == (char *) 0)
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*to++ = *fr;
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else {
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strcpy(to, current_file);
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to += strlen(to);
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}
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break;
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case '#':
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if (previous_file == (char *) 0)
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*to++ = *fr;
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else {
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strcpy(to, previous_file);
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to += strlen(to);
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}
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break;
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default:
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*to++ = *fr;
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if (*fr == '\\')
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*to++ = *++fr;
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break;
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}
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}
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*to = '\0';
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return (e);
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}
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