1 /* Copyright (c) 2002, Joerg Wunsch
2 All rights reserved.
3
4 Redistribution and use in source and binary forms, with or without
5 modification, are permitted provided that the following conditions are met:
6
7 * Redistributions of source code must retain the above copyright
8 notice, this list of conditions and the following disclaimer.
9 * Redistributions in binary form must reproduce the above copyright
10 notice, this list of conditions and the following disclaimer in
11 the documentation and/or other materials provided with the
12 distribution.
13 * Neither the name of the copyright holders nor the names of
14 contributors may be used to endorse or promote products derived
15 from this software without specific prior written permission.
16
17 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /* $Id: fread.c 1944 2009-04-01 23:12:20Z arcanum $ */
31
32 #include "stdio_private.h"
33
34 #ifdef _WANT_FAST_BUFIO
35 #include "../stdlib/mul_overflow.h"
36 #endif
37
38 extern FILE *const stdin _ATTRIBUTE((__weak__));
39 extern FILE *const stdout _ATTRIBUTE((__weak__));
40
41 size_t
fread(void * ptr,size_t size,size_t nmemb,FILE * stream)42 fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
43 {
44 size_t i, j;
45 uint8_t *cp = (uint8_t *) ptr;
46 int c;
47
48 if ((stream->flags & __SRD) == 0 || size == 0)
49 return 0;
50
51 #ifdef _WANT_FAST_BUFIO
52 size_t bytes;
53 if ((stream->flags & __SBUF) != 0 &&
54 !mul_overflow(size, nmemb, &bytes) && bytes > 0)
55 {
56 struct __file_bufio *bf = (struct __file_bufio *) stream;
57 __ungetc_t unget;
58 bool flushed = false;
59
60 again:
61 __bufio_lock(stream);
62 __bufio_setdir_locked(stream, __SRD);
63
64 /* Deal with any pending unget */
65 if ((unget = __atomic_exchange_ungetc(&stream->unget, 0)) != 0) {
66 *cp++ = (unget - 1);
67 bytes--;
68 }
69
70 while (bytes) {
71 int this_time = bf->len - bf->off;
72
73 if (this_time) {
74 /* Drain any buffered data */
75 if (bytes < (size_t) this_time)
76 this_time = bytes;
77 memcpy(cp, bf->buf + bf->off, this_time);
78 bf->off += this_time;
79 cp += this_time;
80 bytes -= this_time;
81 } else {
82 /* Flush stdout if reading from stdin */
83 if (!flushed) {
84 flushed = true;
85 if (stream == stdin && stdout != NULL) {
86 __bufio_unlock(stream);
87 fflush(stdout);
88 goto again;
89 }
90 }
91 if (bytes < (size_t) bf->size) {
92 /* Small reads go through the buffer */
93 int ret = __bufio_fill_locked(stream);
94 if (ret) {
95 stream->flags |= (ret == _FDEV_ERR)? __SERR: __SEOF;
96 break;
97 }
98 } else {
99 /* Flush any buffered data */
100 bf->len = 0;
101 bf->off = 0;
102
103 /* Large reads go directly to the destination */
104 ssize_t len = (bf->read)(bf->fd, cp, bytes);
105 if (len <= 0) {
106 stream->flags |= (len < 0) ? __SERR : __SEOF;
107 break;
108 }
109 cp += len;
110 bytes -= len;
111 bf->pos += len;
112 }
113 }
114 }
115 __bufio_unlock(stream);
116 return (cp - (uint8_t *) ptr) / size;
117 }
118 #endif
119 for (i = 0; i < nmemb; i++)
120 for (j = 0; j < size; j++) {
121 c = getc(stream);
122 if (c == EOF)
123 return i;
124 *cp++ = (uint8_t)c;
125 }
126
127 return i;
128 }
129
