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c4029823 | 1 | /* Copyright (C) 1991, 92, 94, 95, 96 Free Software Foundation, Inc. |
28f540f4 RM |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Library General Public License as | |
6 | published by the Free Software Foundation; either version 2 of the | |
7 | License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Library General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Library General Public | |
15 | License along with the GNU C Library; see the file COPYING.LIB. If | |
16 | not, write to the Free Software Foundation, Inc., 675 Mass Ave, | |
17 | Cambridge, MA 02139, USA. */ | |
18 | ||
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19 | #include <stdio.h> |
20 | #include <stdlib.h> | |
21 | #include <string.h> | |
60092701 | 22 | #include <errno.h> |
28f540f4 RM |
23 | |
24 | struct memstream_info | |
25 | { | |
26 | char **buffer; | |
27 | size_t *bufsize; | |
28 | }; | |
29 | ||
30 | /* Enlarge STREAM's buffer. */ | |
31 | static void | |
ebe3b3eb | 32 | enlarge_buffer (register FILE *stream, int c) |
28f540f4 RM |
33 | { |
34 | struct memstream_info *info = (struct memstream_info *) stream->__cookie; | |
35 | size_t need; | |
36 | ||
37 | if (stream->__put_limit != stream->__buffer) | |
38 | /* Record how much has actually been written into the buffer. */ | |
39 | *info->bufsize = stream->__bufp - stream->__buffer; | |
40 | ||
41 | if (stream->__target != -1 | |
42 | && stream->__target > *info->bufsize) | |
43 | /* Our target (where the buffer maps to) is always zero except when | |
44 | the user just did a SEEK_END fseek. If he sought within the | |
45 | buffer, we need do nothing and will zero the target below. If he | |
46 | sought past the end of the object, grow and zero-fill the buffer | |
47 | up to the target address. */ | |
48 | need = stream->__target; | |
49 | else | |
50 | need = *info->bufsize; | |
51 | ||
52 | /* We always need an extra character in the buffer. Either we are | |
53 | writing C, or we are flushing and need to write a NUL terminator. */ | |
54 | ++need; | |
55 | ||
56 | if (stream->__bufsize < need) | |
57 | { | |
58 | /* Enlarge the buffer. */ | |
59 | char *newbuf; | |
60 | size_t newsize; | |
61 | if (stream->__bufsize * 2 < need) | |
62 | newsize = need; | |
63 | else | |
64 | newsize = stream->__bufsize * 2; | |
c4029823 | 65 | newbuf = (char *) realloc ((void *) stream->__buffer, newsize); |
28f540f4 RM |
66 | if (newbuf == NULL) |
67 | { | |
68 | stream->__error = 1; | |
69 | return; | |
70 | } | |
71 | *info->buffer = stream->__buffer = newbuf; | |
72 | stream->__bufsize = newsize; | |
73 | } | |
74 | ||
75 | stream->__target = stream->__offset = 0; | |
76 | stream->__get_limit = stream->__bufp = stream->__buffer + *info->bufsize; | |
77 | stream->__put_limit = stream->__buffer + stream->__bufsize; | |
78 | ||
79 | need -= stream->__bufp - stream->__buffer + 1; | |
80 | if (need > 0) | |
81 | { | |
82 | /* We are extending the buffer after an fseek; zero-fill new space. */ | |
c4029823 | 83 | memset (stream->__bufp, '\0', need); |
28f540f4 RM |
84 | stream->__bufp += need; |
85 | } | |
86 | ||
87 | if (c != EOF) | |
88 | *stream->__bufp++ = (unsigned char) c; | |
89 | else | |
90 | *stream->__bufp = '\0'; | |
91 | } | |
92 | ||
93 | /* Seek function for memstreams. | |
94 | There is no external state to munge. */ | |
95 | ||
96 | static int | |
ebe3b3eb | 97 | seek (void *cookie, fpos_t *pos, int whence) |
28f540f4 RM |
98 | { |
99 | switch (whence) | |
100 | { | |
101 | case SEEK_SET: | |
102 | case SEEK_CUR: | |
103 | return 0; | |
104 | ||
105 | case SEEK_END: | |
106 | /* Return the position relative to the end of the object. | |
107 | fseek has just flushed us, so the info is consistent. */ | |
108 | *pos += *((struct memstream_info *) cookie)->bufsize; | |
109 | return 0; | |
110 | ||
111 | default: | |
112 | __libc_fatal ("memstream::seek called with bogus WHENCE\n"); | |
113 | return -1; | |
114 | } | |
115 | } | |
116 | ||
117 | static int | |
ebe3b3eb | 118 | free_info (void *cookie) |
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119 | { |
120 | #if 0 | |
121 | struct memstream_info *info = (struct memstream_info *) cookie; | |
122 | char *buf; | |
123 | ||
124 | buf = (char *) realloc ((PTR) *info->buffer, *info->bufsize); | |
125 | if (buf != NULL) | |
126 | *info->buffer = buf; | |
127 | #endif | |
128 | ||
129 | free (cookie); | |
130 | ||
131 | return 0; | |
132 | } | |
133 | \f | |
134 | /* Open a stream that writes into a malloc'd buffer that is expanded as | |
135 | necessary. *BUFLOC and *SIZELOC are updated with the buffer's location | |
136 | and the number of characters written on fflush or fclose. */ | |
137 | FILE * | |
c4029823 UD |
138 | open_memstream (bufloc, sizeloc) |
139 | char **bufloc; | |
140 | size_t *sizeloc; | |
28f540f4 RM |
141 | { |
142 | FILE *stream; | |
143 | struct memstream_info *info; | |
144 | ||
145 | if (bufloc == NULL || sizeloc == NULL) | |
146 | { | |
c4029823 | 147 | __set_errno (EINVAL); |
28f540f4 RM |
148 | return NULL; |
149 | } | |
150 | ||
151 | stream = fmemopen ((char *) NULL, BUFSIZ, "w+"); | |
152 | if (stream == NULL) | |
153 | return NULL; | |
154 | ||
155 | info = (struct memstream_info *) malloc (sizeof (struct memstream_info)); | |
156 | if (info == NULL) | |
157 | { | |
158 | int save = errno; | |
159 | (void) fclose (stream); | |
c4029823 | 160 | __set_errno (save); |
28f540f4 RM |
161 | return NULL; |
162 | } | |
163 | ||
164 | stream->__room_funcs.__output = enlarge_buffer; | |
165 | stream->__io_funcs.__seek = seek; | |
166 | stream->__io_funcs.__close = free_info; | |
c4029823 | 167 | stream->__cookie = (void *) info; |
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168 | stream->__userbuf = 1; |
169 | ||
170 | info->buffer = bufloc; | |
171 | info->bufsize = sizeloc; | |
172 | ||
173 | *bufloc = stream->__buffer; | |
174 | ||
175 | return stream; | |
176 | } |