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#include <assert.h>
#include <getopt.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include "io/read_file.h"
#include "util/debug.h"
#include "util/error.h"
#include "util/loop_files.h"
#include "util/versie.h"
static int gn, gc;
static void usage(FILE *f) {
fprintf(f,
"Gebruik: staart [-nchV] [BESTAND]...\n"
"\n"
"Toon de laatste 10 regels van elk BESTAND naar standaard uitvoer\n"
"\n"
" -n AANTAL Aantal regels om weer te geven\n"
" -c AANTAL Aantal karakters om weer te geven\n"
" -h Toon deze hulptekst\n"
" -V Toon versienummer\n");
}
// Returns pointer to argument array containing the file names
static char** parse_options(int argc, char **argv, int *n, int *c) {
int opt;
while ((opt = getopt(argc, argv, "n:c:hV")) != -1) {
switch (opt) {
case 'c':
*c = atoi(optarg);
*n = -1;
break;
case 'n':
*c = -1;
*n = atoi(optarg);
break;
case 'h':
usage(stdout);
exit(0);
case 'V':
drukkedoos_print_versie(stdout);
exit(0);
case '?':
usage(stderr);
exit(1);
}
}
return argv + optind;
}
static int process(struct filebuf *fb, char*, bool) {
// handle byte limits
if (gc != -1) {
assert(gc >= 0);
fwrite(fb->buf+fb->sz-gc, 1, gc, stdout);
goto done;
}
assert(gn >= 0);
size_t n = gn;
if (fb->buf[fb->sz - 1] == '\n') {
// if the file has a trailing newline, we should ignore it. So we should
// except one newline more
n += 1;
}
ssize_t i;
for (i = fb->sz - 1; i >= 0; i--) {
if (fb->buf[i] == '\n') n--;
if (n == 0) break;
}
if (i < 0) {
// we haven't encountered the maximum of newlines, write everything
fwrite(fb->buf, 1, fb->sz, stdout);
goto done;
}
fwrite(fb->buf + i + 1, 1, fb->sz - i, stdout);
done:
free_filebuf(fb);
return 0;
}
int entry_staart(int argc, char **argv) {
gn = 10;
gc = -1;
char **args = parse_options(argc, argv, &gn, &gc);
return loop_files(args, process);
}
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