121 lines
2.2 KiB
C
121 lines
2.2 KiB
C
/* unexpand - convert spaces to tabs Author: Terrence W. Holm */
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/* Usage: unexpand [ -a ] [ file ... ] */
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#define TAB 8
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int column = 0; /* Current column, retained between files */
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int spaces = 0; /* Spaces since last tab stop */
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int leading_blank = 1; /* Only unexpand leading blanks, */
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/* Overruled by -a option */
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_PROTOTYPE(int main, (int argc, char **argv));
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_PROTOTYPE(void Unexpand, (FILE *f, int all));
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int main(argc, argv)
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int argc;
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char *argv[];
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{
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int all = 0; /* -a flag means unexpand all spaces */
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int i;
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FILE *f;
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if (argc > 1 && argv[1][0] == '-') {
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if (strcmp(argv[1], "-a") == 0)
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all = 1;
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else {
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fprintf(stderr, "Usage: unexpand [ -a ] [ file ... ]\n");
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exit(1);
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}
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--argc;
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++argv;
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}
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if (argc == 1)
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Unexpand(stdin, all);
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else
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for (i = 1; i < argc; ++i) {
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if ((f = fopen(argv[i], "r")) == NULL) {
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perror(argv[i]);
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exit(1);
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}
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Unexpand(f, all);
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fclose(f);
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}
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/* If there are pending spaces print them. */
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while (spaces > 0) {
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putchar(' ');
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--spaces;
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}
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return(0);
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}
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void Unexpand(f, all)
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FILE *f;
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int all;
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{
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int c;
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while ((c = getc(f)) != EOF) {
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if (c == ' ' && (all || leading_blank)) {
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++column;
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++spaces;
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/* If we have white space up to a tab stop, then output */
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/* A tab. If only one space is required, use a ' '. */
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if (column % TAB == 0) {
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if (spaces == 1)
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putchar(' ');
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else
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putchar('\t');
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spaces = 0;
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}
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continue;
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}
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/* If a tab character is encountered in the input then */
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/* Simply echo it. Any accumulated spaces can only be */
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/* Since the last tab stop, so ignore them. */
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if (c == '\t') {
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column = (column / TAB + 1) * TAB;
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spaces = 0;
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putchar('\t');
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continue;
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}
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/* A non-space character is to be printed. If there */
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/* Are pending spaces, then print them. There will be */
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/* At most TAB-1 spaces to print. */
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while (spaces > 0) {
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putchar(' ');
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--spaces;
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}
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if (c == '\n' || c == '\r') {
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column = 0;
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leading_blank = 1;
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putchar(c);
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continue;
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}
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if (c == '\b')
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column = column > 0 ? column - 1 : 0;
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else
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++column;
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leading_blank = 0;
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putchar(c);
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}
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}
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