1 /* getstr.c -- core function for GNU C library getline replacement function
2
3 Copyright (C) 1993, 1996-2000 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 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
18
19 /* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
20
21 #if HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24
25 #include <stdio.h>
26 #include <sys/types.h>
27
28 #include <assert.h>
29
30 #if STDC_HEADERS
31 # include <stdlib.h>
32 #else
33 char *malloc (), *realloc ();
34 #endif
35
36 /* Always add at least this many bytes when extending the buffer. */
37 #define MIN_CHUNK 64
38
39 /* Read up to (and including) a delimiter DELIM1 from STREAM into *LINEPTR
40 + OFFSET (and NUL-terminate it). If DELIM2 is non-zero, then read up
41 and including the first occurrence of DELIM1 or DELIM2. *LINEPTR is
42 a pointer returned from malloc (or NULL), pointing to *N characters of
43 space. It is realloc'd as necessary. Return the number of characters
44 read (not including the NUL terminator), or -1 on error or EOF. */
45
46 int
getstr(char ** lineptr,size_t * n,FILE * stream,int delim1,int delim2,size_t offset)47 getstr (char **lineptr, size_t *n, FILE *stream, int delim1, int delim2,
48 size_t offset)
49 {
50 int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
51 char *read_pos; /* Where we're reading into *LINEPTR. */
52 int ret;
53
54 if (!lineptr || !n || !stream)
55 return -1;
56
57 if (!*lineptr)
58 {
59 *n = MIN_CHUNK;
60 *lineptr = malloc (*n);
61 if (!*lineptr)
62 return -1;
63 }
64
65 nchars_avail = *n - offset;
66 read_pos = *lineptr + offset;
67
68 for (;;)
69 {
70 register int c = getc (stream);
71
72 /* We always want at least one char left in the buffer, since we
73 always (unless we get an error while reading the first char)
74 NUL-terminate the line buffer. */
75
76 assert(*n - nchars_avail == read_pos - *lineptr);
77 if (nchars_avail < 2)
78 {
79 if (*n > MIN_CHUNK)
80 *n *= 2;
81 else
82 *n += MIN_CHUNK;
83
84 nchars_avail = *n + *lineptr - read_pos;
85 *lineptr = realloc (*lineptr, *n);
86 if (!*lineptr)
87 return -1;
88 read_pos = *n - nchars_avail + *lineptr;
89 assert(*n - nchars_avail == read_pos - *lineptr);
90 }
91
92 if (c == EOF || ferror (stream))
93 {
94 /* Return partial line, if any. */
95 if (read_pos == *lineptr)
96 return -1;
97 else
98 break;
99 }
100
101 *read_pos++ = c;
102 nchars_avail--;
103
104 if (c == delim1 || (delim2 && c == delim2))
105 /* Return the line. */
106 break;
107 }
108
109 /* Done - NUL terminate and return the number of chars read. */
110 *read_pos = '\0';
111
112 ret = read_pos - (*lineptr + offset);
113 return ret;
114 }
115