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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
|
/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
Contributed by Andy Vaught and Janne Blomqvist
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
Libgfortran 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 General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "io.h"
#include "fbuf.h"
#include "unix.h"
#include <string.h>
/* file_pos.c-- Implement the file positioning statements, i.e. BACKSPACE,
ENDFILE, and REWIND as well as the FLUSH statement. */
/* formatted_backspace(fpp, u)-- Move the file back one line. The
current position is after the newline that terminates the previous
record, and we have to sift backwards to find the newline before
that or the start of the file, whichever comes first. */
#define READ_CHUNK 4096
static void
formatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
{
gfc_offset base;
char p[READ_CHUNK];
ssize_t n;
base = stell (u->s) - 1;
do
{
n = (base < READ_CHUNK) ? base : READ_CHUNK;
base -= n;
if (sseek (u->s, base, SEEK_SET) < 0)
goto io_error;
if (sread (u->s, p, n) != n)
goto io_error;
/* We have moved backwards from the current position, it should
not be possible to get a short read. Because it is not
clear what to do about such thing, we ignore the possibility. */
/* There is no memrchr() in the C library, so we have to do it
ourselves. */
while (n > 0)
{
n--;
if (p[n] == '\n')
{
base += n + 1;
goto done;
}
}
}
while (base != 0);
/* base is the new pointer. Seek to it exactly. */
done:
if (sseek (u->s, base, SEEK_SET) < 0)
goto io_error;
u->last_record--;
u->endfile = NO_ENDFILE;
return;
io_error:
generate_error (&fpp->common, LIBERROR_OS, NULL);
}
/* unformatted_backspace(fpp) -- Move the file backwards for an unformatted
sequential file. We are guaranteed to be between records on entry and
we have to shift to the previous record. Loop over subrecords. */
static void
unformatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
{
gfc_offset m, slen;
GFC_INTEGER_4 m4;
GFC_INTEGER_8 m8;
ssize_t length;
int continued;
char p[sizeof (GFC_INTEGER_8)];
if (compile_options.record_marker == 0)
length = sizeof (GFC_INTEGER_4);
else
length = compile_options.record_marker;
do
{
slen = - (gfc_offset) length;
if (sseek (u->s, slen, SEEK_CUR) < 0)
goto io_error;
if (sread (u->s, p, length) != length)
goto io_error;
/* Only GFC_CONVERT_NATIVE and GFC_CONVERT_SWAP are valid here. */
if (likely (u->flags.convert == GFC_CONVERT_NATIVE))
{
switch (length)
{
case sizeof(GFC_INTEGER_4):
memcpy (&m4, p, sizeof (m4));
m = m4;
break;
case sizeof(GFC_INTEGER_8):
memcpy (&m8, p, sizeof (m8));
m = m8;
break;
default:
runtime_error ("Illegal value for record marker");
break;
}
}
else
{
uint32_t u32;
uint64_t u64;
switch (length)
{
case sizeof(GFC_INTEGER_4):
memcpy (&u32, p, sizeof (u32));
u32 = __builtin_bswap32 (u32);
memcpy (&m4, &u32, sizeof (m4));
m = m4;
break;
case sizeof(GFC_INTEGER_8):
memcpy (&u64, p, sizeof (u64));
u64 = __builtin_bswap64 (u64);
memcpy (&m8, &u64, sizeof (m8));
m = m8;
break;
default:
runtime_error ("Illegal value for record marker");
break;
}
}
continued = m < 0;
if (continued)
m = -m;
if (sseek (u->s, -m -2 * length, SEEK_CUR) < 0)
goto io_error;
} while (continued);
u->last_record--;
return;
io_error:
generate_error (&fpp->common, LIBERROR_OS, NULL);
}
extern void st_backspace (st_parameter_filepos *);
export_proto(st_backspace);
void
st_backspace (st_parameter_filepos *fpp)
{
gfc_unit *u;
library_start (&fpp->common);
u = find_unit (fpp->common.unit);
if (u == NULL)
{
generate_error (&fpp->common, LIBERROR_BAD_UNIT, NULL);
goto done;
}
/* Direct access is prohibited, and so is unformatted stream access. */
if (u->flags.access == ACCESS_DIRECT)
{
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
"Cannot BACKSPACE a file opened for DIRECT access");
goto done;
}
if (u->flags.access == ACCESS_STREAM && u->flags.form == FORM_UNFORMATTED)
{
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
"Cannot BACKSPACE an unformatted stream file");
goto done;
}
/* Make sure format buffer is flushed and reset. */
if (u->flags.form == FORM_FORMATTED)
{
int pos = fbuf_reset (u);
if (pos != 0)
sseek (u->s, pos, SEEK_CUR);
}
/* Check for special cases involving the ENDFILE record first. */
if (u->endfile == AFTER_ENDFILE)
{
u->endfile = AT_ENDFILE;
u->flags.position = POSITION_APPEND;
sflush (u->s);
}
else
{
if (stell (u->s) == 0)
{
u->flags.position = POSITION_REWIND;
goto done; /* Common special case */
}
if (u->mode == WRITING)
{
/* If there are previously written bytes from a write with
ADVANCE="no", add a record marker before performing the
BACKSPACE. */
if (u->previous_nonadvancing_write)
finish_last_advance_record (u);
u->previous_nonadvancing_write = 0;
unit_truncate (u, stell (u->s), &fpp->common);
u->mode = READING;
}
if (u->flags.form == FORM_FORMATTED)
formatted_backspace (fpp, u);
else
unformatted_backspace (fpp, u);
u->flags.position = POSITION_UNSPECIFIED;
u->endfile = NO_ENDFILE;
u->current_record = 0;
u->bytes_left = 0;
}
done:
if (u != NULL)
unlock_unit (u);
library_end ();
}
extern void st_endfile (st_parameter_filepos *);
export_proto(st_endfile);
void
st_endfile (st_parameter_filepos *fpp)
{
gfc_unit *u;
library_start (&fpp->common);
u = find_unit (fpp->common.unit);
if (u != NULL)
{
if (u->flags.access == ACCESS_DIRECT)
{
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
"Cannot perform ENDFILE on a file opened "
"for DIRECT access");
goto done;
}
if (u->flags.access == ACCESS_SEQUENTIAL
&& u->endfile == AFTER_ENDFILE)
{
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
"Cannot perform ENDFILE on a file already "
"positioned after the EOF marker");
goto done;
}
/* If there are previously written bytes from a write with ADVANCE="no",
add a record marker before performing the ENDFILE. */
if (u->previous_nonadvancing_write)
finish_last_advance_record (u);
u->previous_nonadvancing_write = 0;
if (u->current_record)
{
st_parameter_dt dtp;
dtp.common = fpp->common;
memset (&dtp.u.p, 0, sizeof (dtp.u.p));
dtp.u.p.current_unit = u;
next_record (&dtp, 1);
}
unit_truncate (u, stell (u->s), &fpp->common);
u->endfile = AFTER_ENDFILE;
if (0 == stell (u->s))
u->flags.position = POSITION_REWIND;
}
else
{
if (fpp->common.unit < 0)
{
generate_error (&fpp->common, LIBERROR_BAD_OPTION,
"Bad unit number in statement");
return;
}
u = find_or_create_unit (fpp->common.unit);
if (u->s == NULL)
{
/* Open the unit with some default flags. */
st_parameter_open opp;
unit_flags u_flags;
memset (&u_flags, '\0', sizeof (u_flags));
u_flags.access = ACCESS_SEQUENTIAL;
u_flags.action = ACTION_READWRITE;
/* Is it unformatted? */
if (!(fpp->common.flags & (IOPARM_DT_HAS_FORMAT | IOPARM_DT_LIST_FORMAT
| IOPARM_DT_IONML_SET)))
u_flags.form = FORM_UNFORMATTED;
else
u_flags.form = FORM_UNSPECIFIED;
u_flags.delim = DELIM_UNSPECIFIED;
u_flags.blank = BLANK_UNSPECIFIED;
u_flags.pad = PAD_UNSPECIFIED;
u_flags.decimal = DECIMAL_UNSPECIFIED;
u_flags.encoding = ENCODING_UNSPECIFIED;
u_flags.async = ASYNC_UNSPECIFIED;
u_flags.round = ROUND_UNSPECIFIED;
u_flags.sign = SIGN_UNSPECIFIED;
u_flags.status = STATUS_UNKNOWN;
u_flags.convert = GFC_CONVERT_NATIVE;
opp.common = fpp->common;
opp.common.flags &= IOPARM_COMMON_MASK;
u = new_unit (&opp, u, &u_flags);
if (u == NULL)
return;
u->endfile = AFTER_ENDFILE;
}
}
done:
unlock_unit (u);
library_end ();
}
extern void st_rewind (st_parameter_filepos *);
export_proto(st_rewind);
void
st_rewind (st_parameter_filepos *fpp)
{
gfc_unit *u;
library_start (&fpp->common);
u = find_unit (fpp->common.unit);
if (u != NULL)
{
if (u->flags.access == ACCESS_DIRECT)
generate_error (&fpp->common, LIBERROR_BAD_OPTION,
"Cannot REWIND a file opened for DIRECT access");
else
{
/* If there are previously written bytes from a write with ADVANCE="no",
add a record marker before performing the ENDFILE. */
if (u->previous_nonadvancing_write)
finish_last_advance_record (u);
u->previous_nonadvancing_write = 0;
fbuf_reset (u);
u->last_record = 0;
if (sseek (u->s, 0, SEEK_SET) < 0)
{
generate_error (&fpp->common, LIBERROR_OS, NULL);
library_end ();
return;
}
/* Set this for compatibilty with g77 for /dev/null. */
if (ssize (u->s) == 0)
u->endfile = AT_ENDFILE;
else
{
/* We are rewinding so we are not at the end. */
u->endfile = NO_ENDFILE;
}
u->current_record = 0;
u->strm_pos = 1;
u->read_bad = 0;
}
/* Update position for INQUIRE. */
u->flags.position = POSITION_REWIND;
unlock_unit (u);
}
library_end ();
}
extern void st_flush (st_parameter_filepos *);
export_proto(st_flush);
void
st_flush (st_parameter_filepos *fpp)
{
gfc_unit *u;
library_start (&fpp->common);
u = find_unit (fpp->common.unit);
if (u != NULL)
{
/* Make sure format buffer is flushed. */
if (u->flags.form == FORM_FORMATTED)
fbuf_flush (u, u->mode);
sflush (u->s);
unlock_unit (u);
}
else
/* FLUSH on unconnected unit is illegal: F95 std., 9.3.5. */
generate_error (&fpp->common, LIBERROR_BAD_OPTION,
"Specified UNIT in FLUSH is not connected");
library_end ();
}
|