9144d51594
It's not useful when 0 is returned anyway, so be sure that we have a string with length > 0, this also solves some indexing-gotchas like "len - 1" and so on. Also, add checked getline()'s whenever it has been forgotten and clean up the error-messages.
71 lines
1.1 KiB
C
71 lines
1.1 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "util.h"
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static void
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head(FILE *fp, const char *fname, size_t n)
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{
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char *buf = NULL;
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size_t i = 0, size = 0;
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ssize_t len;
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while (i < n && (len = getline(&buf, &size, fp)) > 0) {
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fputs(buf, stdout);
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i += (len && (buf[len - 1] == '\n'));
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}
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free(buf);
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if (ferror(fp))
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eprintf("getline %s:", fname);
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}
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static void
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usage(void)
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{
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eprintf("usage: %s [-num | -n num] [file ...]\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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size_t n = 10;
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FILE *fp;
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int ret = 0, newline, many;
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ARGBEGIN {
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case 'n':
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n = estrtonum(EARGF(usage()), 0, MIN(LLONG_MAX, SIZE_MAX));
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break;
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ARGNUM:
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n = ARGNUMF();
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break;
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default:
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usage();
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} ARGEND;
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if (!argc) {
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head(stdin, "<stdin>", n);
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} else {
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many = argc > 1;
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for (newline = 0; *argv; argc--, argv++) {
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if (!(fp = fopen(*argv, "r"))) {
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weprintf("fopen %s:", *argv);
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ret = 1;
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continue;
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}
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if (many) {
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if (newline)
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putchar('\n');
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printf("==> %s <==\n", *argv);
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}
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newline = 1;
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head(fp, *argv, n);
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fclose(fp);
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}
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}
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return ret;
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}
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