1 /* getline.c -- Replacement for GNU C library function getline
2
3 Copyright (C) 1993 Free Software Foundation, Inc.
4
5 This program is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details. */
14
15 /* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
16
17 #ifdef HAVE_CONFIG_H
18 #include <config.h>
19 #endif
20
21 #include <sys/types.h>
22 #include <stdio.h>
23 #include <assert.h>
24 #include <errno.h>
25 #include "getline.h"
26
27 #if STDC_HEADERS
28 #include <stdlib.h>
29 #else
30 char *malloc (), *realloc ();
31 #endif
32
33 /* Always add at least this many bytes when extending the buffer. */
34 #define MIN_CHUNK 64
35
36 /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
37 + OFFSET (and null-terminate it). If LIMIT is non-negative, then
38 read no more than LIMIT chars.
39
40 *LINEPTR is a pointer returned from malloc (or NULL), pointing to
41 *N characters of space. It is realloc'd as necessary.
42
43 Return the number of characters read (not including the null
44 terminator), or -1 on error or EOF. On a -1 return, the caller
45 should check feof(), if not then errno has been set to indicate the
46 error. */
47
48 int
getstr(char ** lineptr,size_t * n,FILE * stream,char terminator,int offset,int limit)49 getstr (char **lineptr, size_t *n, FILE *stream, char terminator, int offset,
50 int limit)
51 {
52 int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
53 char *read_pos; /* Where we're reading into *LINEPTR. */
54 int ret;
55
56 if (!lineptr || !n || !stream)
57 {
58 errno = EINVAL;
59 return -1;
60 }
61
62 if (!*lineptr)
63 {
64 *n = MIN_CHUNK;
65 *lineptr = malloc (*n);
66 if (!*lineptr)
67 {
68 errno = ENOMEM;
69 return -1;
70 }
71 }
72
73 nchars_avail = *n - offset;
74 read_pos = *lineptr + offset;
75
76 for (;;)
77 {
78 int save_errno;
79 register int c;
80
81 if (limit == 0)
82 break;
83 else
84 {
85 c = getc (stream);
86
87 /* If limit is negative, then we shouldn't pay attention to
88 it, so decrement only if positive. */
89 if (limit > 0)
90 limit--;
91 }
92
93 save_errno = errno;
94
95 /* We always want at least one char left in the buffer, since we
96 always (unless we get an error while reading the first char)
97 NUL-terminate the line buffer. */
98
99 assert((*lineptr + *n) == (read_pos + nchars_avail));
100 if (nchars_avail < 2)
101 {
102 if (*n > MIN_CHUNK)
103 *n *= 2;
104 else
105 *n += MIN_CHUNK;
106
107 nchars_avail = *n + *lineptr - read_pos;
108 *lineptr = realloc (*lineptr, *n);
109 if (!*lineptr)
110 {
111 errno = ENOMEM;
112 return -1;
113 }
114 read_pos = *n - nchars_avail + *lineptr;
115 assert((*lineptr + *n) == (read_pos + nchars_avail));
116 }
117
118 if (ferror (stream))
119 {
120 /* Might like to return partial line, but there is no
121 place for us to store errno. And we don't want to just
122 lose errno. */
123 errno = save_errno;
124 return -1;
125 }
126
127 if (c == EOF)
128 {
129 /* Return partial line, if any. */
130 if (read_pos == *lineptr)
131 return -1;
132 else
133 break;
134 }
135
136 *read_pos++ = c;
137 nchars_avail--;
138
139 if (c == terminator)
140 /* Return the line. */
141 break;
142 }
143
144 /* Done - NUL terminate and return the number of chars read. */
145 *read_pos = '\0';
146
147 ret = read_pos - (*lineptr + offset);
148 return ret;
149 }
150
151 int
get_line(char ** lineptr,size_t * n,FILE * stream)152 get_line (char **lineptr, size_t *n, FILE *stream)
153 {
154 return getstr (lineptr, n, stream, '\n', 0, GETLINE_NO_LIMIT);
155 }
156
157 int
getline_safe(char ** lineptr,size_t * n,FILE * stream,int limit)158 getline_safe (char **lineptr, size_t *n, FILE *stream, int limit)
159 {
160 return getstr (lineptr, n, stream, '\n', 0, limit);
161 }
162