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mirror of git://git.suckless.org/sbase synced 2024-12-23 15:34:38 +00:00
sbase/tail.c
sin b8edf3b4ee Add weprintf() and replace fprintf(stderr, ...) calls
There is still some programs left to be updated for this.

Many of these programs would stop on the first file that they
could not open.
2013-11-13 11:41:43 +00:00

90 lines
1.6 KiB
C

/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "text.h"
#include "util.h"
static void dropinit(FILE *, const char *, long);
static void taketail(FILE *, const char *, long);
static void
usage(void)
{
eprintf("usage: %s [-n lines] [file]\n", argv0);
}
int
main(int argc, char *argv[])
{
long n = 10;
FILE *fp;
void (*tail)(FILE *, const char *, long) = taketail;
char *lines;
ARGBEGIN {
case 'n':
lines = EARGF(usage());
n = abs(estrtol(lines, 0));
if(lines[0] == '+')
tail = dropinit;
break;
ARGNUM:
n = ARGNUMF(0);
break;
default:
usage();
} ARGEND;
if(argc == 0) {
tail(stdin, "<stdin>", n);
} else {
for (; argc > 0; argc--, argv++) {
if(!(fp = fopen(argv[0], "r"))) {
weprintf("fopen %s:", argv[0]);
continue;
}
tail(fp, argv[0], n);
fclose(fp);
}
}
return EXIT_SUCCESS;
}
void
dropinit(FILE *fp, const char *str, long n)
{
char buf[BUFSIZ];
long i = 0;
while(i < n && fgets(buf, sizeof buf, fp))
if(buf[strlen(buf)-1] == '\n')
i++;
concat(fp, str, stdout, "<stdout>");
}
void
taketail(FILE *fp, const char *str, long n)
{
char **ring;
long i, j;
size_t *size = NULL;
if(!(ring = calloc(n, sizeof *ring)) || !(size = calloc(n, sizeof *size)))
eprintf("calloc:");
for(i = j = 0; afgets(&ring[i], &size[i], fp); i = j = (i+1)%n)
;
if(ferror(fp))
eprintf("%s: read error:", str);
do {
if(ring[j]) {
fputs(ring[j], stdout);
free(ring[j]);
}
} while((j = (j+1)%n) != i);
free(ring);
free(size);
}