1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
40#endif
41static const char rcsid[] =
| 1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)fseek.c 8.3 (Berkeley) 1/2/94";
40#endif
41static const char rcsid[] =
|
42 "$FreeBSD: head/lib/libc/stdio/fseek.c 71579 2001-01-24 13:01:12Z deischen $";
| 42 "$FreeBSD: head/lib/libc/stdio/fseek.c 72529 2001-02-16 06:11:22Z imp $";
|
43#endif /* LIBC_SCCS and not lint */
44
45#include "namespace.h"
46#include <sys/types.h>
47#include <sys/stat.h>
48#include <fcntl.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <errno.h>
52#include "un-namespace.h"
53#include "local.h"
54#include "libc_private.h"
55
56#define POS_ERR (-(fpos_t)1)
57
58int
59fseek(fp, offset, whence)
60 register FILE *fp;
61 long offset;
62 int whence;
63{
64 return (fseeko(fp, offset, whence));
65}
66
67int
68fseeko(fp, offset, whence)
69 FILE *fp;
70 off_t offset;
71 int whence;
72{
73 int ret;
74
75 /* make sure stdio is set up */
76 if (!__sdidinit)
77 __sinit();
78
79 FLOCKFILE(fp);
80 ret = _fseeko(fp, offset, whence);
81 FUNLOCKFILE(fp);
82 return (ret);
83}
84
85/*
86 * Seek the given file to the given offset.
87 * `Whence' must be one of the three SEEK_* macros.
88 */
89int
90_fseeko(fp, offset, whence)
91 FILE *fp;
92 off_t offset;
93 int whence;
94{
95 register fpos_t (*seekfn) __P((void *, fpos_t, int));
96 fpos_t target, curoff;
97 size_t n;
98 struct stat st;
99 int havepos;
100
101 /*
102 * Have to be able to seek.
103 */
104 if ((seekfn = fp->_seek) == NULL) {
105 errno = ESPIPE; /* historic practice */
106 return (EOF);
107 }
108
109 /*
110 * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
111 * After this, whence is either SEEK_SET or SEEK_END.
112 */
113 switch (whence) {
114
115 case SEEK_CUR:
116 /*
117 * In order to seek relative to the current stream offset,
118 * we have to first find the current stream offset a la
119 * ftell (see ftell for details).
120 */
121 if (fp->_flags & __SOFF)
122 curoff = fp->_offset;
123 else {
124 curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
125 if (curoff == -1)
126 return (EOF);
127 }
128 if (fp->_flags & __SRD) {
129 curoff -= fp->_r;
130 if (HASUB(fp))
131 curoff -= fp->_ur;
132 } else if (fp->_flags & __SWR && fp->_p != NULL)
133 curoff += fp->_p - fp->_bf._base;
134
135 offset += curoff;
136 whence = SEEK_SET;
137 havepos = 1;
138 break;
139
140 case SEEK_SET:
141 case SEEK_END:
142 curoff = 0; /* XXX just to keep gcc quiet */
143 havepos = 0;
144 break;
145
146 default:
147 errno = EINVAL;
148 return (EOF);
149 }
150
151 /*
152 * Can only optimise if:
153 * reading (and not reading-and-writing);
154 * not unbuffered; and
155 * this is a `regular' Unix file (and hence seekfn==__sseek).
156 * We must check __NBF first, because it is possible to have __NBF
157 * and __SOPT both set.
158 */
159 if (fp->_bf._base == NULL)
160 __smakebuf(fp);
161 if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
162 goto dumb;
163 if ((fp->_flags & __SOPT) == 0) {
164 if (seekfn != __sseek ||
165 fp->_file < 0 || _fstat(fp->_file, &st) ||
166 (st.st_mode & S_IFMT) != S_IFREG) {
167 fp->_flags |= __SNPT;
168 goto dumb;
169 }
170 fp->_blksize = st.st_blksize;
171 fp->_flags |= __SOPT;
172 }
173
174 /*
175 * We are reading; we can try to optimise.
176 * Figure out where we are going and where we are now.
177 */
178 if (whence == SEEK_SET)
179 target = offset;
180 else {
181 if (_fstat(fp->_file, &st))
182 goto dumb;
183 target = st.st_size + offset;
184 }
185
186 if (!havepos) {
187 if (fp->_flags & __SOFF)
188 curoff = fp->_offset;
189 else {
190 curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
191 if (curoff == POS_ERR)
192 goto dumb;
193 }
194 curoff -= fp->_r;
195 if (HASUB(fp))
196 curoff -= fp->_ur;
197 }
198
199 /*
200 * Compute the number of bytes in the input buffer (pretending
201 * that any ungetc() input has been discarded). Adjust current
202 * offset backwards by this count so that it represents the
203 * file offset for the first byte in the current input buffer.
204 */
205 if (HASUB(fp)) {
206 curoff += fp->_r; /* kill off ungetc */
| 43#endif /* LIBC_SCCS and not lint */
44
45#include "namespace.h"
46#include <sys/types.h>
47#include <sys/stat.h>
48#include <fcntl.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <errno.h>
52#include "un-namespace.h"
53#include "local.h"
54#include "libc_private.h"
55
56#define POS_ERR (-(fpos_t)1)
57
58int
59fseek(fp, offset, whence)
60 register FILE *fp;
61 long offset;
62 int whence;
63{
64 return (fseeko(fp, offset, whence));
65}
66
67int
68fseeko(fp, offset, whence)
69 FILE *fp;
70 off_t offset;
71 int whence;
72{
73 int ret;
74
75 /* make sure stdio is set up */
76 if (!__sdidinit)
77 __sinit();
78
79 FLOCKFILE(fp);
80 ret = _fseeko(fp, offset, whence);
81 FUNLOCKFILE(fp);
82 return (ret);
83}
84
85/*
86 * Seek the given file to the given offset.
87 * `Whence' must be one of the three SEEK_* macros.
88 */
89int
90_fseeko(fp, offset, whence)
91 FILE *fp;
92 off_t offset;
93 int whence;
94{
95 register fpos_t (*seekfn) __P((void *, fpos_t, int));
96 fpos_t target, curoff;
97 size_t n;
98 struct stat st;
99 int havepos;
100
101 /*
102 * Have to be able to seek.
103 */
104 if ((seekfn = fp->_seek) == NULL) {
105 errno = ESPIPE; /* historic practice */
106 return (EOF);
107 }
108
109 /*
110 * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
111 * After this, whence is either SEEK_SET or SEEK_END.
112 */
113 switch (whence) {
114
115 case SEEK_CUR:
116 /*
117 * In order to seek relative to the current stream offset,
118 * we have to first find the current stream offset a la
119 * ftell (see ftell for details).
120 */
121 if (fp->_flags & __SOFF)
122 curoff = fp->_offset;
123 else {
124 curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
125 if (curoff == -1)
126 return (EOF);
127 }
128 if (fp->_flags & __SRD) {
129 curoff -= fp->_r;
130 if (HASUB(fp))
131 curoff -= fp->_ur;
132 } else if (fp->_flags & __SWR && fp->_p != NULL)
133 curoff += fp->_p - fp->_bf._base;
134
135 offset += curoff;
136 whence = SEEK_SET;
137 havepos = 1;
138 break;
139
140 case SEEK_SET:
141 case SEEK_END:
142 curoff = 0; /* XXX just to keep gcc quiet */
143 havepos = 0;
144 break;
145
146 default:
147 errno = EINVAL;
148 return (EOF);
149 }
150
151 /*
152 * Can only optimise if:
153 * reading (and not reading-and-writing);
154 * not unbuffered; and
155 * this is a `regular' Unix file (and hence seekfn==__sseek).
156 * We must check __NBF first, because it is possible to have __NBF
157 * and __SOPT both set.
158 */
159 if (fp->_bf._base == NULL)
160 __smakebuf(fp);
161 if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
162 goto dumb;
163 if ((fp->_flags & __SOPT) == 0) {
164 if (seekfn != __sseek ||
165 fp->_file < 0 || _fstat(fp->_file, &st) ||
166 (st.st_mode & S_IFMT) != S_IFREG) {
167 fp->_flags |= __SNPT;
168 goto dumb;
169 }
170 fp->_blksize = st.st_blksize;
171 fp->_flags |= __SOPT;
172 }
173
174 /*
175 * We are reading; we can try to optimise.
176 * Figure out where we are going and where we are now.
177 */
178 if (whence == SEEK_SET)
179 target = offset;
180 else {
181 if (_fstat(fp->_file, &st))
182 goto dumb;
183 target = st.st_size + offset;
184 }
185
186 if (!havepos) {
187 if (fp->_flags & __SOFF)
188 curoff = fp->_offset;
189 else {
190 curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
191 if (curoff == POS_ERR)
192 goto dumb;
193 }
194 curoff -= fp->_r;
195 if (HASUB(fp))
196 curoff -= fp->_ur;
197 }
198
199 /*
200 * Compute the number of bytes in the input buffer (pretending
201 * that any ungetc() input has been discarded). Adjust current
202 * offset backwards by this count so that it represents the
203 * file offset for the first byte in the current input buffer.
204 */
205 if (HASUB(fp)) {
206 curoff += fp->_r; /* kill off ungetc */
|
207 n = fp->_up - fp->_bf._base;
| 207 n = fp->_extra->_up - fp->_bf._base;
|
208 curoff -= n;
209 n += fp->_ur;
210 } else {
211 n = fp->_p - fp->_bf._base;
212 curoff -= n;
213 n += fp->_r;
214 }
215
216 /*
217 * If the target offset is within the current buffer,
218 * simply adjust the pointers, clear EOF, undo ungetc(),
219 * and return. (If the buffer was modified, we have to
220 * skip this; see fgetln.c.)
221 */
222 if ((fp->_flags & __SMOD) == 0 &&
223 target >= curoff && target < curoff + n) {
224 register int o = target - curoff;
225
226 fp->_p = fp->_bf._base + o;
227 fp->_r = n - o;
228 if (HASUB(fp))
229 FREEUB(fp);
230 fp->_flags &= ~__SEOF;
231 return (0);
232 }
233
234 /*
235 * The place we want to get to is not within the current buffer,
236 * but we can still be kind to the kernel copyout mechanism.
237 * By aligning the file offset to a block boundary, we can let
238 * the kernel use the VM hardware to map pages instead of
239 * copying bytes laboriously. Using a block boundary also
240 * ensures that we only read one block, rather than two.
241 */
242 curoff = target & ~(fp->_blksize - 1);
243 if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
244 goto dumb;
245 fp->_r = 0;
246 fp->_p = fp->_bf._base;
247 if (HASUB(fp))
248 FREEUB(fp);
249 fp->_flags &= ~__SEOF;
250 n = target - curoff;
251 if (n) {
252 if (__srefill(fp) || fp->_r < n)
253 goto dumb;
254 fp->_p += n;
255 fp->_r -= n;
256 }
257 return (0);
258
259 /*
260 * We get here if we cannot optimise the seek ... just
261 * do it. Allow the seek function to change fp->_bf._base.
262 */
263dumb:
264 if (__sflush(fp) ||
265 (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR)
266 return (EOF);
267 /* success: clear EOF indicator and discard ungetc() data */
268 if (HASUB(fp))
269 FREEUB(fp);
270 fp->_p = fp->_bf._base;
271 fp->_r = 0;
272 /* fp->_w = 0; */ /* unnecessary (I think...) */
273 fp->_flags &= ~__SEOF;
274 return (0);
275}
| 208 curoff -= n;
209 n += fp->_ur;
210 } else {
211 n = fp->_p - fp->_bf._base;
212 curoff -= n;
213 n += fp->_r;
214 }
215
216 /*
217 * If the target offset is within the current buffer,
218 * simply adjust the pointers, clear EOF, undo ungetc(),
219 * and return. (If the buffer was modified, we have to
220 * skip this; see fgetln.c.)
221 */
222 if ((fp->_flags & __SMOD) == 0 &&
223 target >= curoff && target < curoff + n) {
224 register int o = target - curoff;
225
226 fp->_p = fp->_bf._base + o;
227 fp->_r = n - o;
228 if (HASUB(fp))
229 FREEUB(fp);
230 fp->_flags &= ~__SEOF;
231 return (0);
232 }
233
234 /*
235 * The place we want to get to is not within the current buffer,
236 * but we can still be kind to the kernel copyout mechanism.
237 * By aligning the file offset to a block boundary, we can let
238 * the kernel use the VM hardware to map pages instead of
239 * copying bytes laboriously. Using a block boundary also
240 * ensures that we only read one block, rather than two.
241 */
242 curoff = target & ~(fp->_blksize - 1);
243 if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
244 goto dumb;
245 fp->_r = 0;
246 fp->_p = fp->_bf._base;
247 if (HASUB(fp))
248 FREEUB(fp);
249 fp->_flags &= ~__SEOF;
250 n = target - curoff;
251 if (n) {
252 if (__srefill(fp) || fp->_r < n)
253 goto dumb;
254 fp->_p += n;
255 fp->_r -= n;
256 }
257 return (0);
258
259 /*
260 * We get here if we cannot optimise the seek ... just
261 * do it. Allow the seek function to change fp->_bf._base.
262 */
263dumb:
264 if (__sflush(fp) ||
265 (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR)
266 return (EOF);
267 /* success: clear EOF indicator and discard ungetc() data */
268 if (HASUB(fp))
269 FREEUB(fp);
270 fp->_p = fp->_bf._base;
271 fp->_r = 0;
272 /* fp->_w = 0; */ /* unnecessary (I think...) */
273 fp->_flags &= ~__SEOF;
274 return (0);
275}
|