1 /*
2 * Copyright (c) 1990, 2007 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
6 * provided that the above copyright notice and this paragraph are
7 * duplicated in all such forms and that any documentation,
8 * and/or other materials related to such
9 * distribution and use acknowledge that the software was developed
10 * by the University of California, Berkeley. The name of the
11 * University may not be used to endorse or promote products derived
12 * from this software without specific prior written permission.
13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16 */
17
18 /*
19 FUNCTION
20 <<fread>>, <<fread_unlocked>>---read array elements from a file
21
22 INDEX
23 fread
24 INDEX
25 fread_unlocked
26 INDEX
27 _fread_r
28 INDEX
29 _fread_unlocked_r
30
31 SYNOPSIS
32 #include <stdio.h>
33 size_t fread(void *restrict <[buf]>, size_t <[size]>, size_t <[count]>,
34 FILE *restrict <[fp]>);
35
36 #define _BSD_SOURCE
37 #include <stdio.h>
38 size_t fread_unlocked(void *restrict <[buf]>, size_t <[size]>, size_t <[count]>,
39 FILE *restrict <[fp]>);
40
41 #include <stdio.h>
42 size_t fread( void *restrict <[buf]>,
43 size_t <[size]>, size_t <[count]>, FILE *restrict <[fp]>);
44
45 #include <stdio.h>
46 size_t fread_unlocked( void *restrict <[buf]>,
47 size_t <[size]>, size_t <[count]>, FILE *restrict <[fp]>);
48
49 DESCRIPTION
50 <<fread>> attempts to copy, from the file or stream identified by
51 <[fp]>, <[count]> elements (each of size <[size]>) into memory,
52 starting at <[buf]>. <<fread>> may copy fewer elements than
53 <[count]> if an error, or end of file, intervenes.
54
55 <<fread>> also advances the file position indicator (if any) for
56 <[fp]> by the number of @emph{characters} actually read.
57
58 <<fread_unlocked>> is a non-thread-safe version of <<fread>>.
59 <<fread_unlocked>> may only safely be used within a scope
60 protected by flockfile() (or ftrylockfile()) and funlockfile(). This
61 function may safely be used in a multi-threaded program if and only
62 if they are called while the invoking thread owns the (FILE *)
63 object, as is the case after a successful call to the flockfile() or
64 ftrylockfile() functions. If threads are disabled, then
65 <<fread_unlocked>> is equivalent to <<fread>>.
66
67 <<_fread_r>> and <<_fread_unlocked_r>> are simply reentrant versions of the
68 above that take an additional reentrant structure pointer argument: <[ptr]>.
69
70 RETURNS
71 The result of <<fread>> is the number of elements it succeeded in
72 reading.
73
74 PORTABILITY
75 ANSI C requires <<fread>>.
76
77 <<fread_unlocked>> is a BSD extension also provided by GNU libc.
78
79 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
80 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
81 */
82
83 #define _DEFAULT_SOURCE
84 #include <_ansi.h>
85 #include <stdio.h>
86 #include <string.h>
87 #include <malloc.h>
88 #include "local.h"
89
90 #ifdef __IMPL_UNLOCKED__
91 #define _fread_r _fread_unlocked_r
92 #define fread fread_unlocked
93 #endif
94
95 #ifdef __SCLE
96 static size_t
crlf_r(struct _reent * ptr,FILE * fp,char * buf,size_t count,int eof)97 crlf_r (struct _reent * ptr,
98 FILE * fp,
99 char * buf,
100 size_t count,
101 int eof)
102 {
103 int r;
104 char *s, *d, *e;
105
106 if (count == 0)
107 return 0;
108
109 e = buf + count;
110 for (s=d=buf; s<e-1; s++)
111 {
112 if (*s == '\r' && s[1] == '\n')
113 s++;
114 *d++ = *s;
115 }
116 if (s < e)
117 {
118 if (*s == '\r')
119 {
120 int c = _sgetc_raw ( fp);
121 if (c == '\n')
122 *s = '\n';
123 else
124 ungetc (c, fp);
125 }
126 *d++ = *s++;
127 }
128
129
130 while (d < e)
131 {
132 r = getc ( fp);
133 if (r == EOF)
134 return count - (e-d);
135 *d++ = r;
136 }
137
138 return count;
139
140 }
141
142 #endif
143
144 size_t
fread(void * __restrict buf,size_t size,size_t count,FILE * __restrict fp)145 fread (
146 void *__restrict buf,
147 size_t size,
148 size_t count,
149 FILE * __restrict fp)
150 {
151 register size_t resid;
152 register char *p;
153 register int r;
154 size_t total;
155
156 if ((resid = count * size) == 0)
157 return 0;
158
159 CHECK_INIT(ptr, fp);
160
161 _newlib_flockfile_start (fp);
162 if (ORIENT (fp, -1) != -1)
163 {
164 count = 0;
165 goto ret;
166 }
167 if (fp->_r < 0)
168 fp->_r = 0;
169 total = resid;
170 p = buf;
171
172 #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
173
174 /* Optimize unbuffered I/O. */
175 if (fp->_flags & __SNBF)
176 {
177 /* First copy any available characters from ungetc buffer. */
178 int copy_size = resid > (size_t) fp->_r ? fp->_r : (int) resid;
179 (void) memcpy ((void *) p, (void *) fp->_p, (size_t) copy_size);
180 fp->_p += copy_size;
181 fp->_r -= copy_size;
182 p += copy_size;
183 resid -= copy_size;
184
185 /* If still more data needed, free any allocated ungetc buffer. */
186 if (HASUB (fp) && resid > 0)
187 FREEUB (ptr, fp);
188
189 /* Finally read directly into user's buffer if needed. */
190 while (resid > 0)
191 {
192 int rc = 0;
193 /* save fp buffering state */
194 void *old_base = fp->_bf._base;
195 void * old_p = fp->_p;
196 int old_size = fp->_bf._size;
197 /* allow __refill to use user's buffer */
198 fp->_bf._base = (unsigned char *) p;
199 fp->_bf._size = resid;
200 fp->_p = (unsigned char *) p;
201 rc = _srefill ( fp);
202 /* restore fp buffering back to original state */
203 fp->_bf._base = old_base;
204 fp->_bf._size = old_size;
205 fp->_p = old_p;
206 resid -= fp->_r;
207 p += fp->_r;
208 fp->_r = 0;
209 if (rc)
210 {
211 #ifdef __SCLE
212 if (fp->_flags & __SCLE)
213 {
214 _newlib_flockfile_exit (fp);
215 return crlf_r (ptr, fp, buf, total-resid, 1) / size;
216 }
217 #endif
218 _newlib_flockfile_exit (fp);
219 return (total - resid) / size;
220 }
221 }
222 }
223 else
224 #endif /* !PREFER_SIZE_OVER_SPEED && !__OPTIMIZE_SIZE__ */
225 {
226 while (resid > (size_t) (r = fp->_r))
227 {
228 (void) memcpy ((void *) p, (void *) fp->_p, (size_t) r);
229 fp->_p += r;
230 /* fp->_r = 0 ... done in __srefill */
231 p += r;
232 resid -= r;
233 if (_srefill ( fp))
234 {
235 /* no more input: return partial result */
236 #ifdef __SCLE
237 if (fp->_flags & __SCLE)
238 {
239 _newlib_flockfile_exit (fp);
240 return crlf_r (ptr, fp, buf, total-resid, 1) / size;
241 }
242 #endif
243 _newlib_flockfile_exit (fp);
244 return (total - resid) / size;
245 }
246 }
247 (void) memcpy ((void *) p, (void *) fp->_p, resid);
248 fp->_r -= resid;
249 fp->_p += resid;
250 }
251
252 /* Perform any CR/LF clean-up if necessary. */
253 #ifdef __SCLE
254 if (fp->_flags & __SCLE)
255 {
256 _newlib_flockfile_exit (fp);
257 return crlf_r(ptr, fp, buf, total, 0) / size;
258 }
259 #endif
260 ret:
261 _newlib_flockfile_end (fp);
262 return count;
263 }
264
