1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* fmemopen implementation.
Copyright (C) 2015-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* fmemopen() from 2.22 and forward works as defined by POSIX. It also
provides an older symbol, version 2.2.5, that behaves different regarding
SEEK_END (libio/oldfmemopen.c). */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/types.h>
#include "libioP.h"
typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
struct fmemopen_cookie_struct
{
char *buffer; /* memory buffer. */
int mybuffer; /* allocated my buffer? */
int append; /* buffer open for append? */
size_t size; /* buffer length in bytes. */
off64_t pos; /* current position at the buffer. */
size_t maxpos; /* max position in buffer. */
};
static ssize_t
fmemopen_read (void *cookie, char *b, size_t s)
{
fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
if (c->pos + s > c->maxpos)
{
s = c->maxpos - c->pos;
if ((size_t) c->pos > c->maxpos)
s = 0;
}
memcpy (b, &(c->buffer[c->pos]), s);
c->pos += s;
return s;
}
static ssize_t
fmemopen_write (void *cookie, const char *b, size_t s)
{
fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;;
off64_t pos = c->append ? c->maxpos : c->pos;
int addnullc = (s == 0 || b[s - 1] != '\0');
if (pos + s > c->size)
{
if ((size_t) (c->pos + addnullc) >= c->size)
{
__set_errno (ENOSPC);
return 0;
}
s = c->size - pos;
}
memcpy (&(c->buffer[pos]), b, s);
c->pos = pos + s;
if ((size_t) c->pos > c->maxpos)
{
c->maxpos = c->pos;
if (c->maxpos < c->size && addnullc)
c->buffer[c->maxpos] = '\0';
/* A null byte is written in a stream open for update iff it fits. */
else if (c->append == 0 && addnullc != 0)
c->buffer[c->size-1] = '\0';
}
return s;
}
static int
fmemopen_seek (void *cookie, off64_t *p, int w)
{
off64_t np;
fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
switch (w)
{
case SEEK_SET:
np = *p;
break;
case SEEK_CUR:
np = c->pos + *p;
break;
case SEEK_END:
np = c->maxpos + *p;
break;
default:
return -1;
}
if (np < 0 || (size_t) np > c->size)
{
__set_errno (EINVAL);
return -1;
}
*p = c->pos = np;
return 0;
}
static int
fmemopen_close (void *cookie)
{
fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
if (c->mybuffer)
free (c->buffer);
free (c);
return 0;
}
FILE *
__fmemopen (void *buf, size_t len, const char *mode)
{
cookie_io_functions_t iof;
fmemopen_cookie_t *c;
FILE *result;
c = (fmemopen_cookie_t *) calloc (sizeof (fmemopen_cookie_t), 1);
if (c == NULL)
return NULL;
c->mybuffer = (buf == NULL);
if (c->mybuffer)
{
c->buffer = (char *) malloc (len);
if (c->buffer == NULL)
{
free (c);
return NULL;
}
c->buffer[0] = '\0';
}
else
{
if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
{
free (c);
__set_errno (EINVAL);
return NULL;
}
c->buffer = buf;
/* POSIX states that w+ mode should truncate the buffer. */
if (mode[0] == 'w' && mode[1] == '+')
c->buffer[0] = '\0';
if (mode[0] == 'a')
c->maxpos = strnlen (c->buffer, len);
}
/* Mode | starting position (cookie::pos) | size (cookie::size)
------ |----------------------------------|-----------------------------
read | beginning of the buffer | size argument
write | beginning of the buffer | zero
append | first null or size buffer + 1 | first null or size argument
*/
c->size = len;
if (mode[0] == 'r')
c->maxpos = len;
c->append = mode[0] == 'a';
if (c->append)
c->pos = c->maxpos;
else
c->pos = 0;
iof.read = fmemopen_read;
iof.write = fmemopen_write;
iof.seek = fmemopen_seek;
iof.close = fmemopen_close;
result = _IO_fopencookie (c, mode, iof);
if (__glibc_unlikely (result == NULL))
{
if (c->mybuffer)
free (c->buffer);
free (c);
}
return result;
}
libc_hidden_def (__fmemopen)
versioned_symbol (libc, __fmemopen, fmemopen, GLIBC_2_22);
|
