blob: 3ba52a336554f1190beb6eadcc705bd890502d1f [file] [log] [blame]
Mike Frysinger64b15022010-01-08 02:48:03 -05001/* getline.c -- Replacement for GNU C library function getline
2
3Copyright (C) 1993, 1996, 2001, 2002 Free Software Foundation, Inc.
4
5This program is free software; you can redistribute it and/or
6modify it under the terms of the GNU General Public License as
7published by the Free Software Foundation; either version 2 of the
8License, or (at your option) any later version.
9
10This program is distributed in the hope that it will be useful, but
11WITHOUT ANY WARRANTY; without even the implied warranty of
12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13General Public License for more details.
14
15You should have received a copy of the GNU General Public License
16along with this program; if not, write to the Free Software
17Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
18
19/* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
20
21#include <assert.h>
22#include <stdio.h>
23
24/* Always add at least this many bytes when extending the buffer. */
25#define MIN_CHUNK 64
26
27/* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
28 + OFFSET (and null-terminate it). *LINEPTR is a pointer returned from
29 malloc (or NULL), pointing to *N characters of space. It is realloc'd
30 as necessary. Return the number of characters read (not including the
31 null terminator), or -1 on error or EOF.
32 NOTE: There is another getstr() function declared in <curses.h>. */
33static int getstr(char **lineptr, size_t *n, FILE *stream,
34 char terminator, size_t offset)
35{
36 int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
37 char *read_pos; /* Where we're reading into *LINEPTR. */
38 int ret;
39
40 if (!lineptr || !n || !stream)
41 return -1;
42
43 if (!*lineptr) {
44 *n = MIN_CHUNK;
45 *lineptr = malloc(*n);
46 if (!*lineptr)
47 return -1;
48 }
49
50 nchars_avail = *n - offset;
51 read_pos = *lineptr + offset;
52
53 for (;;) {
54 register int c = getc(stream);
55
56 /* We always want at least one char left in the buffer, since we
57 always (unless we get an error while reading the first char)
58 NUL-terminate the line buffer. */
59
60 assert(*n - nchars_avail == read_pos - *lineptr);
61 if (nchars_avail < 2) {
62 if (*n > MIN_CHUNK)
63 *n *= 2;
64 else
65 *n += MIN_CHUNK;
66
67 nchars_avail = *n + *lineptr - read_pos;
68 *lineptr = realloc(*lineptr, *n);
69 if (!*lineptr)
70 return -1;
71 read_pos = *n - nchars_avail + *lineptr;
72 assert(*n - nchars_avail == read_pos - *lineptr);
73 }
74
75 if (c == EOF || ferror (stream)) {
76 /* Return partial line, if any. */
77 if (read_pos == *lineptr)
78 return -1;
79 else
80 break;
81 }
82
83 *read_pos++ = c;
84 nchars_avail--;
85
86 if (c == terminator)
87 /* Return the line. */
88 break;
89 }
90
91 /* Done - NUL terminate and return the number of chars read. */
92 *read_pos = '\0';
93
94 ret = read_pos - (*lineptr + offset);
95 return ret;
96}
97
98int getline (char **lineptr, size_t *n, FILE *stream)
99{
100 return getstr(lineptr, n, stream, '\n', 0);
101}