xref: /freebsd/contrib/mandoc/compat_getline.c (revision 1323ec57)
1 /* $Id: compat_getline.c,v 1.2 2020/06/15 01:37:14 schwarze Exp $ */
2 /*
3  * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 #include "config.h"
18 
19 #include <sys/types.h>
20 #include <errno.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 
24 ssize_t
25 getline(char **buf, size_t *bufsz, FILE *fp)
26 {
27 	char	*nbuf;
28 	size_t	 nbufsz, pos;
29 	int	 c;
30 
31 	if (buf == NULL || bufsz == NULL) {
32 		errno = EINVAL;
33 		return -1;
34 	}
35 
36 	if (*buf == NULL)
37 		*bufsz = 0;
38 	else
39 		**buf = '\0';
40 
41 	pos = 0;
42 	for (;;) {
43 		if (pos + 1 >= *bufsz) {
44 			nbufsz = *bufsz ? *bufsz * 2 : BUFSIZ;
45 			if ((nbuf = realloc(*buf, nbufsz)) == NULL)
46 				return -1;
47 			*buf = nbuf;
48 			*bufsz = nbufsz;
49 		}
50 		if ((c = fgetc(fp)) == EOF) {
51 			(*buf)[pos] = '\0';
52 			return pos > 0 && feof(fp) ? (ssize_t)pos : -1;
53 		}
54 		(*buf)[pos++] = c;
55 		(*buf)[pos] = '\0';
56 		if (c == '\n')
57 			return pos;
58 	}
59 }
60