sbase/tail.c

94 lines
1.7 KiB
C
Raw Normal View History

2011-05-27 10:13:38 +00:00
/* See LICENSE file for copyright and license details. */
2011-05-26 17:18:42 +00:00
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
2011-05-26 17:18:42 +00:00
#include "text.h"
#include "util.h"
static void dropinit(FILE *, const char *, long);
static void taketail(FILE *, const char *, long);
2013-06-14 18:20:47 +00:00
static void
usage(void)
{
eprintf("usage: %s [-n lines] [file]\n", argv0);
}
2011-05-26 17:18:42 +00:00
int
main(int argc, char *argv[])
{
long n = 10;
FILE *fp;
2011-05-26 17:29:22 +00:00
void (*tail)(FILE *, const char *, long) = taketail;
char *lines;
2011-05-26 17:18:42 +00:00
2013-06-14 18:20:47 +00:00
ARGBEGIN {
case 'n':
lines = EARGF(usage());
n = abs(estrtol(lines, 0));
if (lines[0] == '+')
2013-06-14 18:20:47 +00:00
tail = dropinit;
break;
ARGNUM:
n = ARGNUMF(0);
break;
2013-06-14 18:20:47 +00:00
default:
usage();
} ARGEND;
if (argc == 0) {
2011-05-26 17:18:42 +00:00
tail(stdin, "<stdin>", n);
2013-11-12 10:45:18 +00:00
} else {
for (; argc > 0; argc--, argv++) {
if (!(fp = fopen(argv[0], "r"))) {
weprintf("fopen %s:", argv[0]);
2013-11-12 10:45:18 +00:00
continue;
}
tail(fp, argv[0], n);
fclose(fp);
}
}
2011-05-26 17:18:42 +00:00
2014-10-02 22:46:04 +00:00
return 0;
2011-05-26 17:18:42 +00:00
}
static void
2011-05-26 17:18:42 +00:00
dropinit(FILE *fp, const char *str, long n)
{
char *buf = NULL;
size_t size = 0;
ssize_t len;
unsigned long i = 0;
2011-05-26 17:18:42 +00:00
while (i < n && ((len = agetline(&buf, &size, fp)) != -1))
if (len && buf[len - 1] == '\n')
2011-05-26 17:18:42 +00:00
i++;
free(buf);
2011-05-26 17:18:42 +00:00
concat(fp, str, stdout, "<stdout>");
}
static void
2011-05-26 17:18:42 +00:00
taketail(FILE *fp, const char *str, long n)
{
char **ring = NULL;
2011-05-26 17:18:42 +00:00
long i, j;
2011-06-10 13:51:53 +00:00
size_t *size = NULL;
2011-05-26 17:18:42 +00:00
if (!(ring = calloc(n, sizeof *ring)) || !(size = calloc(n, sizeof *size)))
2011-05-26 17:18:42 +00:00
eprintf("calloc:");
for (i = j = 0; agetline(&ring[i], &size[i], fp) != -1; i = j = (i + 1) % n)
2011-05-26 17:18:42 +00:00
;
if (ferror(fp))
2011-05-26 17:29:22 +00:00
eprintf("%s: read error:", str);
2011-05-26 17:18:42 +00:00
do {
if (ring[j]) {
2011-05-26 17:18:42 +00:00
fputs(ring[j], stdout);
2011-05-26 17:24:56 +00:00
free(ring[j]);
}
} while ((j = (j+1)%n) != i);
2011-05-26 17:18:42 +00:00
free(ring);
free(size);
}