minix/commands/fold/fold.c
2010-05-12 16:28:54 +00:00

70 lines
1.1 KiB
C

/* fold - folds long lines Author: Terrence W. Holm */
/* Usage: fold [ -width ] [ file ... ] */
#include <stdlib.h>
#include <stdio.h>
#define TAB 8
#define DEFAULT_WIDTH 80
int column = 0; /* Current column, retained between files */
_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void Fold, (FILE *f, int width));
int main(argc, argv)
int argc;
char *argv[];
{
int width = DEFAULT_WIDTH;
int i;
FILE *f;
if (argc > 1 && argv[1][0] == '-') {
if ((width = atoi(&argv[1][1])) <= 0) {
fprintf(stderr, "Bad number for fold\n");
exit(1);
}
--argc;
++argv;
}
if (argc == 1)
Fold(stdin, width);
else {
for (i = 1; i < argc; ++i) {
if ((f = fopen(argv[i], "r")) == NULL) {
perror(argv[i]);
exit(1);
}
Fold(f, width);
fclose(f);
}
}
return(0);
}
void Fold(f, width)
FILE *f;
int width;
{
int c;
while ((c = getc(f)) != EOF) {
if (c == '\t')
column = (column / TAB + 1) * TAB;
else if (c == '\b')
column = column > 0 ? column - 1 : 0;
else if (c == '\n' || c == '\r')
column = 0;
else
++column;
if (column > width) {
putchar('\n');
column = c == '\t' ? TAB : 1;
}
putchar(c);
}
}