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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgfortran/] [io/] [file_pos.c] - Blame information for rev 801

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1 733 jeremybenn
/* Copyright (C) 2002-2003, 2005, 2006, 2007, 2009, 2010
2
   Free Software Foundation, Inc.
3
   Contributed by Andy Vaught and Janne Blomqvist
4
 
5
This file is part of the GNU Fortran runtime library (libgfortran).
6
 
7
Libgfortran is free software; you can redistribute it and/or modify
8
it under the terms of the GNU General Public License as published by
9
the Free Software Foundation; either version 3, or (at your option)
10
any later version.
11
 
12
Libgfortran is distributed in the hope that it will be useful,
13
but WITHOUT ANY WARRANTY; without even the implied warranty of
14
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15
GNU General Public License for more details.
16
 
17
Under Section 7 of GPL version 3, you are granted additional
18
permissions described in the GCC Runtime Library Exception, version
19
3.1, as published by the Free Software Foundation.
20
 
21
You should have received a copy of the GNU General Public License and
22
a copy of the GCC Runtime Library Exception along with this program;
23
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24
<http://www.gnu.org/licenses/>.  */
25
 
26
#include "io.h"
27
#include "fbuf.h"
28
#include "unix.h"
29
#include <string.h>
30
 
31
/* file_pos.c-- Implement the file positioning statements, i.e. BACKSPACE,
32
   ENDFILE, and REWIND as well as the FLUSH statement.  */
33
 
34
 
35
/* formatted_backspace(fpp, u)-- Move the file back one line.  The
36
   current position is after the newline that terminates the previous
37
   record, and we have to sift backwards to find the newline before
38
   that or the start of the file, whichever comes first.  */
39
 
40
static const int READ_CHUNK = 4096;
41
 
42
static void
43
formatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
44
{
45
  gfc_offset base;
46
  char p[READ_CHUNK];
47
  ssize_t n;
48
 
49
  base = stell (u->s) - 1;
50
 
51
  do
52
    {
53
      n = (base < READ_CHUNK) ? base : READ_CHUNK;
54
      base -= n;
55
      if (sseek (u->s, base, SEEK_SET) < 0)
56
        goto io_error;
57
      if (sread (u->s, p, n) != n)
58
        goto io_error;
59
 
60
      /* We have moved backwards from the current position, it should
61
         not be possible to get a short read.  Because it is not
62
         clear what to do about such thing, we ignore the possibility.  */
63
 
64
      /* There is no memrchr() in the C library, so we have to do it
65
         ourselves.  */
66
 
67
      while (n > 0)
68
        {
69
          n--;
70
          if (p[n] == '\n')
71
            {
72
              base += n + 1;
73
              goto done;
74
            }
75
        }
76
 
77
    }
78
  while (base != 0);
79
 
80
  /* base is the new pointer.  Seek to it exactly.  */
81
 done:
82
  if (sseek (u->s, base, SEEK_SET) < 0)
83
    goto io_error;
84
  u->last_record--;
85
  u->endfile = NO_ENDFILE;
86
 
87
  return;
88
 
89
 io_error:
90
  generate_error (&fpp->common, LIBERROR_OS, NULL);
91
}
92
 
93
 
94
/* unformatted_backspace(fpp) -- Move the file backwards for an unformatted
95
   sequential file.  We are guaranteed to be between records on entry and
96
   we have to shift to the previous record.  Loop over subrecords.  */
97
 
98
static void
99
unformatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
100
{
101
  gfc_offset m, slen;
102
  GFC_INTEGER_4 m4;
103
  GFC_INTEGER_8 m8;
104
  ssize_t length;
105
  int continued;
106
  char p[sizeof (GFC_INTEGER_8)];
107
 
108
  if (compile_options.record_marker == 0)
109
    length = sizeof (GFC_INTEGER_4);
110
  else
111
    length = compile_options.record_marker;
112
 
113
  do
114
    {
115
      slen = - (gfc_offset) length;
116
      if (sseek (u->s, slen, SEEK_CUR) < 0)
117
        goto io_error;
118
      if (sread (u->s, p, length) != length)
119
        goto io_error;
120
 
121
      /* Only GFC_CONVERT_NATIVE and GFC_CONVERT_SWAP are valid here.  */
122
      if (likely (u->flags.convert == GFC_CONVERT_NATIVE))
123
        {
124
          switch (length)
125
            {
126
            case sizeof(GFC_INTEGER_4):
127
              memcpy (&m4, p, sizeof (m4));
128
              m = m4;
129
              break;
130
 
131
            case sizeof(GFC_INTEGER_8):
132
              memcpy (&m8, p, sizeof (m8));
133
              m = m8;
134
              break;
135
 
136
            default:
137
              runtime_error ("Illegal value for record marker");
138
              break;
139
            }
140
        }
141
      else
142
        {
143
          switch (length)
144
            {
145
            case sizeof(GFC_INTEGER_4):
146
              reverse_memcpy (&m4, p, sizeof (m4));
147
              m = m4;
148
              break;
149
 
150
            case sizeof(GFC_INTEGER_8):
151
              reverse_memcpy (&m8, p, sizeof (m8));
152
              m = m8;
153
              break;
154
 
155
            default:
156
              runtime_error ("Illegal value for record marker");
157
              break;
158
            }
159
 
160
        }
161
 
162
      continued = m < 0;
163
      if (continued)
164
        m = -m;
165
 
166
      if (sseek (u->s, -m -2 * length, SEEK_CUR) < 0)
167
        goto io_error;
168
    } while (continued);
169
 
170
  u->last_record--;
171
  return;
172
 
173
 io_error:
174
  generate_error (&fpp->common, LIBERROR_OS, NULL);
175
}
176
 
177
 
178
extern void st_backspace (st_parameter_filepos *);
179
export_proto(st_backspace);
180
 
181
void
182
st_backspace (st_parameter_filepos *fpp)
183
{
184
  gfc_unit *u;
185
 
186
  library_start (&fpp->common);
187
 
188
  u = find_unit (fpp->common.unit);
189
  if (u == NULL)
190
    {
191
      generate_error (&fpp->common, LIBERROR_BAD_UNIT, NULL);
192
      goto done;
193
    }
194
 
195
  /* Direct access is prohibited, and so is unformatted stream access.  */
196
 
197
 
198
  if (u->flags.access == ACCESS_DIRECT)
199
    {
200
      generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
201
                      "Cannot BACKSPACE a file opened for DIRECT access");
202
      goto done;
203
    }
204
 
205
  if (u->flags.access == ACCESS_STREAM && u->flags.form == FORM_UNFORMATTED)
206
    {
207
      generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
208
                      "Cannot BACKSPACE an unformatted stream file");
209
      goto done;
210
    }
211
 
212
  /* Make sure format buffer is flushed and reset.  */
213
  if (u->flags.form == FORM_FORMATTED)
214
    {
215
      int pos = fbuf_reset (u);
216
      if (pos != 0)
217
        sseek (u->s, pos, SEEK_CUR);
218
    }
219
 
220
 
221
  /* Check for special cases involving the ENDFILE record first.  */
222
 
223
  if (u->endfile == AFTER_ENDFILE)
224
    {
225
      u->endfile = AT_ENDFILE;
226
      u->flags.position = POSITION_APPEND;
227
      sflush (u->s);
228
    }
229
  else
230
    {
231
      if (stell (u->s) == 0)
232
        {
233
          u->flags.position = POSITION_REWIND;
234
          goto done;            /* Common special case */
235
        }
236
 
237
      if (u->mode == WRITING)
238
        {
239
          /* If there are previously written bytes from a write with
240
             ADVANCE="no", add a record marker before performing the
241
             BACKSPACE.  */
242
 
243
          if (u->previous_nonadvancing_write)
244
            finish_last_advance_record (u);
245
 
246
          u->previous_nonadvancing_write = 0;
247
 
248
          unit_truncate (u, stell (u->s), &fpp->common);
249
          u->mode = READING;
250
        }
251
 
252
      if (u->flags.form == FORM_FORMATTED)
253
        formatted_backspace (fpp, u);
254
      else
255
        unformatted_backspace (fpp, u);
256
 
257
      u->flags.position = POSITION_UNSPECIFIED;
258
      u->endfile = NO_ENDFILE;
259
      u->current_record = 0;
260
      u->bytes_left = 0;
261
    }
262
 
263
 done:
264
  if (u != NULL)
265
    unlock_unit (u);
266
 
267
  library_end ();
268
}
269
 
270
 
271
extern void st_endfile (st_parameter_filepos *);
272
export_proto(st_endfile);
273
 
274
void
275
st_endfile (st_parameter_filepos *fpp)
276
{
277
  gfc_unit *u;
278
 
279
  library_start (&fpp->common);
280
 
281
  u = find_unit (fpp->common.unit);
282
  if (u != NULL)
283
    {
284
      if (u->flags.access == ACCESS_DIRECT)
285
        {
286
          generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
287
                          "Cannot perform ENDFILE on a file opened "
288
                          "for DIRECT access");
289
          goto done;
290
        }
291
 
292
      if (u->flags.access == ACCESS_SEQUENTIAL
293
          && u->endfile == AFTER_ENDFILE)
294
        {
295
          generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
296
                          "Cannot perform ENDFILE on a file already "
297
                          "positioned after the EOF marker");
298
          goto done;
299
        }
300
 
301
      /* If there are previously written bytes from a write with ADVANCE="no",
302
         add a record marker before performing the ENDFILE.  */
303
 
304
      if (u->previous_nonadvancing_write)
305
        finish_last_advance_record (u);
306
 
307
      u->previous_nonadvancing_write = 0;
308
 
309
      if (u->current_record)
310
        {
311
          st_parameter_dt dtp;
312
          dtp.common = fpp->common;
313
          memset (&dtp.u.p, 0, sizeof (dtp.u.p));
314
          dtp.u.p.current_unit = u;
315
          next_record (&dtp, 1);
316
        }
317
 
318
      unit_truncate (u, stell (u->s), &fpp->common);
319
      u->endfile = AFTER_ENDFILE;
320
      if (0 == stell (u->s))
321
        u->flags.position = POSITION_REWIND;
322
    }
323
  else
324
    {
325
      if (fpp->common.unit < 0)
326
        {
327
          generate_error (&fpp->common, LIBERROR_BAD_OPTION,
328
                          "Bad unit number in statement");
329
          return;
330
        }
331
 
332
      u = find_or_create_unit (fpp->common.unit);
333
      if (u->s == NULL)
334
        {
335
          /* Open the unit with some default flags.  */
336
          st_parameter_open opp;
337
          unit_flags u_flags;
338
 
339
          memset (&u_flags, '\0', sizeof (u_flags));
340
          u_flags.access = ACCESS_SEQUENTIAL;
341
          u_flags.action = ACTION_READWRITE;
342
 
343
          /* Is it unformatted?  */
344
          if (!(fpp->common.flags & (IOPARM_DT_HAS_FORMAT | IOPARM_DT_LIST_FORMAT
345
                                     | IOPARM_DT_IONML_SET)))
346
            u_flags.form = FORM_UNFORMATTED;
347
          else
348
            u_flags.form = FORM_UNSPECIFIED;
349
 
350
          u_flags.delim = DELIM_UNSPECIFIED;
351
          u_flags.blank = BLANK_UNSPECIFIED;
352
          u_flags.pad = PAD_UNSPECIFIED;
353
          u_flags.decimal = DECIMAL_UNSPECIFIED;
354
          u_flags.encoding = ENCODING_UNSPECIFIED;
355
          u_flags.async = ASYNC_UNSPECIFIED;
356
          u_flags.round = ROUND_UNSPECIFIED;
357
          u_flags.sign = SIGN_UNSPECIFIED;
358
          u_flags.status = STATUS_UNKNOWN;
359
          u_flags.convert = GFC_CONVERT_NATIVE;
360
 
361
          opp.common = fpp->common;
362
          opp.common.flags &= IOPARM_COMMON_MASK;
363
          u = new_unit (&opp, u, &u_flags);
364
          if (u == NULL)
365
            return;
366
          u->endfile = AFTER_ENDFILE;
367
        }
368
    }
369
 
370
  done:
371
    unlock_unit (u);
372
 
373
  library_end ();
374
}
375
 
376
 
377
extern void st_rewind (st_parameter_filepos *);
378
export_proto(st_rewind);
379
 
380
void
381
st_rewind (st_parameter_filepos *fpp)
382
{
383
  gfc_unit *u;
384
 
385
  library_start (&fpp->common);
386
 
387
  u = find_unit (fpp->common.unit);
388
  if (u != NULL)
389
    {
390
      if (u->flags.access == ACCESS_DIRECT)
391
        generate_error (&fpp->common, LIBERROR_BAD_OPTION,
392
                        "Cannot REWIND a file opened for DIRECT access");
393
      else
394
        {
395
          /* If there are previously written bytes from a write with ADVANCE="no",
396
             add a record marker before performing the ENDFILE.  */
397
 
398
          if (u->previous_nonadvancing_write)
399
            finish_last_advance_record (u);
400
 
401
          u->previous_nonadvancing_write = 0;
402
 
403
          fbuf_reset (u);
404
 
405
          u->last_record = 0;
406
 
407
          if (sseek (u->s, 0, SEEK_SET) < 0)
408
            generate_error (&fpp->common, LIBERROR_OS, NULL);
409
 
410
          /* Set this for compatibilty with g77 for /dev/null.  */
411
          if (ssize (u->s) == 0)
412
            u->endfile = AT_ENDFILE;
413
          else
414
            {
415
              /* We are rewinding so we are not at the end.  */
416
              u->endfile = NO_ENDFILE;
417
            }
418
 
419
          u->current_record = 0;
420
          u->strm_pos = 1;
421
          u->read_bad = 0;
422
        }
423
      /* Update position for INQUIRE.  */
424
      u->flags.position = POSITION_REWIND;
425
      unlock_unit (u);
426
    }
427
 
428
  library_end ();
429
}
430
 
431
 
432
extern void st_flush (st_parameter_filepos *);
433
export_proto(st_flush);
434
 
435
void
436
st_flush (st_parameter_filepos *fpp)
437
{
438
  gfc_unit *u;
439
 
440
  library_start (&fpp->common);
441
 
442
  u = find_unit (fpp->common.unit);
443
  if (u != NULL)
444
    {
445
      /* Make sure format buffer is flushed.  */
446
      if (u->flags.form == FORM_FORMATTED)
447
        fbuf_flush (u, u->mode);
448
 
449
      sflush (u->s);
450
      unlock_unit (u);
451
    }
452
  else
453
    /* FLUSH on unconnected unit is illegal: F95 std., 9.3.5. */
454
    generate_error (&fpp->common, LIBERROR_BAD_OPTION,
455
                        "Specified UNIT in FLUSH is not connected");
456
 
457
  library_end ();
458
}

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