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author | 2021-05-09 14:20:58 -0400 | |
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committer | 2021-05-09 14:20:58 -0400 | |
commit | 5fd83771641d15c418f747bd343ba6738d3875f7 (patch) | |
tree | 5abf0f78f680d9837dbd93d4d4c3933bb7509599 /text_cmds/head/head.c | |
download | apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.tar.gz apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.tar.zst apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.zip |
Import macOS userland
adv_cmds-176
basic_cmds-55
bootstrap_cmds-116.100.1
developer_cmds-66
diskdev_cmds-667.40.1
doc_cmds-53.60.1
file_cmds-321.40.3
mail_cmds-35
misc_cmds-34
network_cmds-606.40.1
patch_cmds-17
remote_cmds-63
shell_cmds-216.60.1
system_cmds-880.60.2
text_cmds-106
Diffstat (limited to 'text_cmds/head/head.c')
-rw-r--r-- | text_cmds/head/head.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/text_cmds/head/head.c b/text_cmds/head/head.c new file mode 100644 index 0000000..d798e78 --- /dev/null +++ b/text_cmds/head/head.c @@ -0,0 +1,199 @@ +/* + * Copyright (c) 1980, 1987, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +static const char copyright[] = +"@(#) Copyright (c) 1980, 1987, 1992, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; +#endif +#endif /* not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: src/usr.bin/head/head.c,v 1.20 2007/01/11 20:23:01 brooks Exp $"); + +#include <sys/types.h> + +#include <ctype.h> +#include <err.h> +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +/* + * head - give the first few lines of a stream or of each of a set of files + * + * Bill Joy UCB August 24, 1977 + */ + +static void head(FILE *, int); +static void head_bytes(FILE *, off_t); +static void obsolete(char *[]); +static void usage(void); + +int +main(int argc, char *argv[]) +{ + int ch; + FILE *fp; + int first, linecnt = -1, eval = 0; + off_t bytecnt = -1; + char *ep; + + obsolete(argv); + while ((ch = getopt(argc, argv, "n:c:")) != -1) + switch(ch) { + case 'c': + bytecnt = strtoimax(optarg, &ep, 10); + if (*ep || bytecnt <= 0) + errx(1, "illegal byte count -- %s", optarg); + break; + case 'n': + linecnt = strtol(optarg, &ep, 10); + if (*ep || linecnt <= 0) + errx(1, "illegal line count -- %s", optarg); + break; + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + if (linecnt != -1 && bytecnt != -1) + errx(1, "can't combine line and byte counts"); + if (linecnt == -1 ) + linecnt = 10; + if (*argv) { + for (first = 1; *argv; ++argv) { + if ((fp = fopen(*argv, "r")) == NULL) { + warn("%s", *argv); + eval = 1; + continue; + } + if (argc > 1) { + (void)printf("%s==> %s <==\n", + first ? "" : "\n", *argv); + first = 0; + } + if (bytecnt == -1) + head(fp, linecnt); + else + head_bytes(fp, bytecnt); + if (ferror(fp)) { + warnx("Error reading %s", *argv); + eval = 1; + } + (void)fclose(fp); + } + } else { + if (bytecnt == -1) { + head(stdin, linecnt); + } else { + head_bytes(stdin, bytecnt); + } + if (ferror(stdin)) { + warnx("Error reading stdin"); + eval = 1; + } + } + + exit(eval); +} + +static void +head(FILE *fp, int cnt) +{ + char *cp; + size_t error, readlen; + + while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { + error = fwrite(cp, sizeof(char), readlen, stdout); + if (error != readlen) + err(1, "stdout"); + cnt--; + } + + fflush(fp); +} + +static void +head_bytes(FILE *fp, off_t cnt) +{ + char buf[4096]; + size_t readlen; + + while (cnt) { + if ((uintmax_t)cnt < sizeof(buf)) + readlen = cnt; + else + readlen = sizeof(buf); + readlen = fread(buf, sizeof(char), readlen, fp); + if (readlen == 0) + break; + if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) + err(1, "stdout"); + cnt -= readlen; + } +} + +static void +obsolete(char *argv[]) +{ + char *ap; + + while ((ap = *++argv)) { + /* Return if "--" or not "-[0-9]*". */ + if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) + return; + if ((ap = malloc(strlen(*argv) + 2)) == NULL) + err(1, NULL); + ap[0] = '-'; + ap[1] = 'n'; + (void)strcpy(ap + 2, *argv + 1); + *argv = ap; + } +} + +static void +usage(void) +{ + + (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); + exit(1); +} |