/
iolayer.c
1192 lines (871 loc) · 26.7 KB
/
iolayer.c
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
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#include "imager.h"
#include "iolayer.h"
#include "imerror.h"
#include "log.h"
#include <stdlib.h>
#include <stdio.h>
#ifdef _MSC_VER
#include <io.h>
#endif
#include <string.h>
#include <errno.h>
#define IOL_DEB(x)
char *io_type_names[] = { "FDSEEK", "FDNOSEEK", "BUFFER", "CBSEEK", "CBNOSEEK", "BUFCHAIN" };
typedef struct io_blink {
char buf[BBSIZ];
/* size_t cnt; */
size_t len; /* How large is this buffer = BBZIS for now */
struct io_blink *next;
struct io_blink *prev;
} io_blink;
/* Structures that describe callback interfaces */
typedef struct {
off_t offset;
off_t cpos;
} io_ex_rseek;
typedef struct {
off_t offset;
off_t cpos;
io_blink *head;
io_blink *tail;
io_blink *cp;
} io_ex_fseek;
typedef struct {
off_t offset; /* Offset of the source - not used */
off_t length; /* Total length of chain in bytes */
io_blink *head; /* Start of chain */
io_blink *tail; /* End of chain */
off_t tfill; /* End of stream in last link */
io_blink *cp; /* Current element of list */
off_t cpos; /* Offset within the current */
off_t gpos; /* Global position in stream */
} io_ex_bchain;
typedef struct {
off_t offset; /* Offset of the source - not used */
off_t cpos; /* Offset within the current */
} io_ex_buffer;
static void io_obj_setp_buffer(io_obj *io, char *p, size_t len, i_io_closebufp_t closecb, void *closedata);
static void io_obj_setp_cb2 (io_obj *io, void *p, i_io_readl_t readcb, i_io_writel_t writecb, i_io_seekl_t seekcb, i_io_closel_t closecb, i_io_destroyl_t destroycb);
/* turn current offset, file length, whence and offset into a new offset */
#define calc_seek_offset(curr_off, length, offset, whence) \
(((whence) == SEEK_SET) ? (offset) : \
((whence) == SEEK_CUR) ? (curr_off) + (offset) : \
((whence) == SEEK_END) ? (length) + (offset) : -1)
/*
=head1 NAME
iolayer.c - encapsulates different source of data into a single framework.
=head1 SYNOPSIS
io_glue *ig = io_new_fd( fileno(stdin) );
method = io_reqmeth( IOL_NOSEEK | IOL_MMAP ); // not implemented yet
io_glue_commit_types(ig); // always assume IOL_SEEK for now
switch (method) {
case IOL_NOSEEK:
code that uses ig->readcb()
to read data goes here.
break;
case IOL_MMAP:
code that uses ig->readcb()
to read data goes here.
break;
}
io_glue_destroy(ig);
// and much more
=head1 DESCRIPTION
iolayer.c implements the basic functions to create and destroy io_glue
objects for Imager. The typical usage pattern for data sources is:
1. Create the source (io_new_fd)
2. Define how you want to get data from it (io_reqmeth)
3. read from it using the interface requested (ig->readdb, ig->mmapcb)
4. Close the source, which
shouldn't really close the underlying source. (io_glue DESTROY)
=head1 FUNCTION REFERENCE
Some of these functions are internal.
=over
=cut
*/
static ssize_t fd_read(io_glue *ig, void *buf, size_t count);
static ssize_t fd_write(io_glue *ig, const void *buf, size_t count);
static off_t fd_seek(io_glue *ig, off_t offset, int whence);
static int fd_close(io_glue *ig);
static ssize_t fd_size(io_glue *ig);
static const char *my_strerror(int err);
/*
* Callbacks for sources that cannot seek
*/
/* fakeseek_read: read method for when emulating a seekable source
static
ssize_t
fakeseek_read(io_glue *ig, void *buf, size_t count) {
io_ex_fseek *exdata = ig->exdata;
return 0;
}
*/
/*
* Callbacks for sources that can seek
*/
/*
=item realseek_read(ig, buf, count)
Does the reading from a source that can be seeked on
ig - io_glue object
buf - buffer to return data in
count - number of bytes to read into buffer max
=cut
*/
static
ssize_t
realseek_read(io_glue *ig, void *buf, size_t count) {
io_ex_rseek *ier = ig->exdata;
void *p = ig->source.cb.p;
ssize_t rc = 0;
size_t bc = 0;
char *cbuf = buf;
IOL_DEB( printf("realseek_read: buf = %p, count = %d\n",
buf, count) );
/* Is this a good idea? Would it be better to handle differently?
skip handling? */
while( count!=bc && (rc = ig->source.cb.readcb(p,cbuf+bc,count-bc))>0 ) {
bc+=rc;
}
ier->cpos += bc;
IOL_DEB( printf("realseek_read: rc = %d, bc = %d\n", rc, bc) );
return rc < 0 ? rc : bc;
}
/*
=item realseek_write(ig, buf, count)
Does the writing to a 'source' that can be seeked on
ig - io_glue object
buf - buffer that contains data
count - number of bytes to write
=cut
*/
static
ssize_t
realseek_write(io_glue *ig, const void *buf, size_t count) {
io_ex_rseek *ier = ig->exdata;
void *p = ig->source.cb.p;
ssize_t rc = 0;
size_t bc = 0;
char *cbuf = (char*)buf;
IOL_DEB( printf("realseek_write: ig = %p, ier->cpos = %ld, buf = %p, "
"count = %d\n", ig, (long) ier->cpos, buf, count) );
/* Is this a good idea? Would it be better to handle differently?
skip handling? */
while( count!=bc && (rc = ig->source.cb.writecb(p,cbuf+bc,count-bc))>0 ) {
bc+=rc;
}
ier->cpos += bc;
IOL_DEB( printf("realseek_write: rc = %d, bc = %d\n", rc, bc) );
return rc < 0 ? rc : bc;
}
/*
=item realseek_close(ig)
Closes a source that can be seeked on. Not sure if this should be an
actual close or not. Does nothing for now. Should be fixed.
ig - data source
=cut */
static
int
realseek_close(io_glue *ig) {
mm_log((1, "realseek_close(ig %p)\n", ig));
if (ig->source.cb.closecb)
return ig->source.cb.closecb(ig->source.cb.p);
else
return 0;
}
/* realseek_seek(ig, offset, whence)
Implements seeking for a source that is seekable, the purpose of having this is to be able to
have an offset into a file that is different from what the underlying library thinks.
ig - data source
offset - offset into stream
whence - whence argument a la lseek
=cut
*/
static
off_t
realseek_seek(io_glue *ig, off_t offset, int whence) {
/* io_ex_rseek *ier = ig->exdata; Needed later */
void *p = ig->source.cb.p;
int rc;
IOL_DEB( printf("realseek_seek(ig %p, offset %ld, whence %d)\n", ig, (long) offset, whence) );
rc = ig->source.cb.seekcb(p, offset, whence);
IOL_DEB( printf("realseek_seek: rc %ld\n", (long) rc) );
return rc;
/* FIXME: How about implementing this offset handling stuff? */
}
static
void
realseek_destroy(io_glue *ig) {
io_ex_rseek *ier = ig->exdata;
if (ig->source.cb.destroycb)
ig->source.cb.destroycb(ig->source.cb.p);
myfree(ier);
}
/*
* Callbacks for sources that are a fixed size buffer
*/
/*
=item buffer_read(ig, buf, count)
Does the reading from a buffer source
ig - io_glue object
buf - buffer to return data in
count - number of bytes to read into buffer max
=cut
*/
static
ssize_t
buffer_read(io_glue *ig, void *buf, size_t count) {
io_ex_buffer *ieb = ig->exdata;
IOL_DEB( printf("buffer_read: ieb->cpos = %ld, buf = %p, count = %d\n", (long) ieb->cpos, buf, count) );
if ( ieb->cpos+count > ig->source.buffer.len ) {
mm_log((1,"buffer_read: short read: cpos=%d, len=%d, count=%d\n", ieb->cpos, ig->source.buffer.len));
count = ig->source.buffer.len - ieb->cpos;
}
memcpy(buf, ig->source.buffer.data+ieb->cpos, count);
ieb->cpos += count;
IOL_DEB( printf("buffer_read: count = %d\n", count) );
return count;
}
/*
=item buffer_write(ig, buf, count)
Does nothing, returns -1
ig - io_glue object
buf - buffer that contains data
count - number of bytes to write
=cut
*/
static
ssize_t
buffer_write(io_glue *ig, const void *buf, size_t count) {
mm_log((1, "buffer_write called, this method should never be called.\n"));
return -1;
}
/*
=item buffer_close(ig)
Closes a source that can be seeked on. Not sure if this should be an actual close
or not. Does nothing for now. Should be fixed.
ig - data source
=cut
*/
static
int
buffer_close(io_glue *ig) {
mm_log((1, "buffer_close(ig %p)\n", ig));
return 0;
}
/* buffer_seek(ig, offset, whence)
Implements seeking for a buffer source.
ig - data source
offset - offset into stream
whence - whence argument a la lseek
=cut
*/
static
off_t
buffer_seek(io_glue *ig, off_t offset, int whence) {
io_ex_buffer *ieb = ig->exdata;
off_t reqpos =
calc_seek_offset(ieb->cpos, ig->source.buffer.len, offset, whence);
if (reqpos > ig->source.buffer.len) {
mm_log((1, "seeking out of readable range\n"));
return (off_t)-1;
}
if (reqpos < 0) {
i_push_error(0, "seek before beginning of file");
return (off_t)-1;
}
ieb->cpos = reqpos;
IOL_DEB( printf("buffer_seek(ig %p, offset %ld, whence %d)\n", ig, (long) offset, whence) );
return reqpos;
/* FIXME: How about implementing this offset handling stuff? */
}
static
void
buffer_destroy(io_glue *ig) {
io_ex_buffer *ieb = ig->exdata;
if (ig->source.buffer.closecb) {
mm_log((1,"calling close callback %p for io_buffer\n",
ig->source.buffer.closecb));
ig->source.buffer.closecb(ig->source.buffer.closedata);
}
myfree(ieb);
}
/*
* Callbacks for sources that are a chain of variable sized buffers
*/
/* Helper functions for buffer chains */
static
io_blink*
io_blink_new(void) {
io_blink *ib;
mm_log((1, "io_blink_new()\n"));
ib = mymalloc(sizeof(io_blink));
ib->next = NULL;
ib->prev = NULL;
ib->len = BBSIZ;
memset(&ib->buf, 0, ib->len);
return ib;
}
/*
=item io_bchain_advance(ieb)
Advances the buffer chain to the next link - extending if
necessary. Also adjusts the cpos and tfill counters as needed.
ieb - buffer chain object
=cut
*/
static
void
io_bchain_advance(io_ex_bchain *ieb) {
if (ieb->cp->next == NULL) {
ieb->tail = io_blink_new();
ieb->tail->prev = ieb->cp;
ieb->cp->next = ieb->tail;
ieb->tfill = 0; /* Only set this if we added a new slice */
}
ieb->cp = ieb->cp->next;
ieb->cpos = 0;
}
/*
=item io_bchain_destroy()
frees all resources used by a buffer chain.
=cut
*/
void
io_destroy_bufchain(io_ex_bchain *ieb) {
io_blink *cp;
mm_log((1, "io_destroy_bufchain(ieb %p)\n", ieb));
cp = ieb->head;
while(cp) {
io_blink *t = cp->next;
myfree(cp);
cp = t;
}
}
/*
static
void
bufchain_dump(io_ex_bchain *ieb) {
mm_log((1, " buf_chain_dump(ieb %p)\n"));
mm_log((1, " buf_chain_dump: ieb->offset = %d\n", ieb->offset));
mm_log((1, " buf_chain_dump: ieb->length = %d\n", ieb->length));
mm_log((1, " buf_chain_dump: ieb->head = %p\n", ieb->head ));
mm_log((1, " buf_chain_dump: ieb->tail = %p\n", ieb->tail ));
mm_log((1, " buf_chain_dump: ieb->tfill = %d\n", ieb->tfill ));
mm_log((1, " buf_chain_dump: ieb->cp = %p\n", ieb->cp ));
mm_log((1, " buf_chain_dump: ieb->cpos = %d\n", ieb->cpos ));
mm_log((1, " buf_chain_dump: ieb->gpos = %d\n", ieb->gpos ));
}
*/
/*
* TRUE if lengths are NOT equal
*/
/*
static
void
chainlencert( io_glue *ig ) {
int clen;
int cfl = 0;
size_t csize = 0;
size_t cpos = 0;
io_ex_bchain *ieb = ig->exdata;
io_blink *cp = ieb->head;
if (ieb->gpos > ieb->length) mm_log((1, "BBAR : ieb->gpos = %d, ieb->length = %d\n", ieb->gpos, ieb->length));
while(cp) {
clen = (cp == ieb->tail) ? ieb->tfill : cp->len;
if (ieb->head == cp && cp->prev) mm_log((1, "Head of chain has a non null prev\n"));
if (ieb->tail == cp && cp->next) mm_log((1, "Tail of chain has a non null next\n"));
if (ieb->head != cp && !cp->prev) mm_log((1, "Middle of chain has a null prev\n"));
if (ieb->tail != cp && !cp->next) mm_log((1, "Middle of chain has a null next\n"));
if (cp->prev && cp->prev->next != cp) mm_log((1, "%p = cp->prev->next != cp\n", cp->prev->next));
if (cp->next && cp->next->prev != cp) mm_log((1, "%p cp->next->prev != cp\n", cp->next->prev));
if (cp == ieb->cp) {
cfl = 1;
cpos += ieb->cpos;
}
if (!cfl) cpos += clen;
csize += clen;
cp = cp->next;
}
if (( csize != ieb->length )) mm_log((1, "BAR : csize = %d, ieb->length = %d\n", csize, ieb->length));
if (( cpos != ieb->gpos )) mm_log((1, "BAR : cpos = %d, ieb->gpos = %d\n", cpos, ieb->gpos ));
}
static
void
chaincert( io_glue *ig) {
size_t csize = 0;
io_ex_bchain *ieb = ig->exdata;
io_blink *cp = ieb->head;
mm_log((1, "Chain verification.\n"));
mm_log((1, " buf_chain_dump: ieb->offset = %d\n", ieb->offset));
mm_log((1, " buf_chain_dump: ieb->length = %d\n", ieb->length));
mm_log((1, " buf_chain_dump: ieb->head = %p\n", ieb->head ));
mm_log((1, " buf_chain_dump: ieb->tail = %p\n", ieb->tail ));
mm_log((1, " buf_chain_dump: ieb->tfill = %d\n", ieb->tfill ));
mm_log((1, " buf_chain_dump: ieb->cp = %p\n", ieb->cp ));
mm_log((1, " buf_chain_dump: ieb->cpos = %d\n", ieb->cpos ));
mm_log((1, " buf_chain_dump: ieb->gpos = %d\n", ieb->gpos ));
while(cp) {
int clen = cp == ieb->tail ? ieb->tfill : cp->len;
mm_log((1, "link: %p <- %p -> %p\n", cp->prev, cp, cp->next));
if (ieb->head == cp && cp->prev) mm_log((1, "Head of chain has a non null prev\n"));
if (ieb->tail == cp && cp->next) mm_log((1, "Tail of chain has a non null next\n"));
if (ieb->head != cp && !cp->prev) mm_log((1, "Middle of chain has a null prev\n"));
if (ieb->tail != cp && !cp->next) mm_log((1, "Middle of chain has a null next\n"));
if (cp->prev && cp->prev->next != cp) mm_log((1, "%p = cp->prev->next != cp\n", cp->prev->next));
if (cp->next && cp->next->prev != cp) mm_log((1, "%p cp->next->prev != cp\n", cp->next->prev));
csize += clen;
cp = cp->next;
}
mm_log((1, "csize = %d %s ieb->length = %d\n", csize, csize == ieb->length ? "==" : "!=", ieb->length));
}
*/
/*
=item bufchain_read(ig, buf, count)
Does the reading from a source that can be seeked on
ig - io_glue object
buf - buffer to return data in
count - number of bytes to read into buffer max
=cut
*/
static
ssize_t
bufchain_read(io_glue *ig, void *buf, size_t count) {
io_ex_bchain *ieb = ig->exdata;
size_t scount = count;
char *cbuf = buf;
size_t sk;
mm_log((1, "bufchain_read(ig %p, buf %p, count %ld)\n", ig, buf, count));
while( scount ) {
int clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
if (clen == ieb->cpos) {
if (ieb->cp == ieb->tail) break; /* EOF */
ieb->cp = ieb->cp->next;
ieb->cpos = 0;
clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
}
sk = clen - ieb->cpos;
sk = sk > scount ? scount : sk;
memcpy(&cbuf[count-scount], &ieb->cp->buf[ieb->cpos], sk);
scount -= sk;
ieb->cpos += sk;
ieb->gpos += sk;
}
mm_log((1, "bufchain_read: returning %d\n", count-scount));
return count-scount;
}
/*
=item bufchain_write(ig, buf, count)
Does the writing to a 'source' that can be seeked on
ig - io_glue object
buf - buffer that contains data
count - number of bytes to write
=cut
*/
static
ssize_t
bufchain_write(io_glue *ig, const void *buf, size_t count) {
char *cbuf = (char *)buf;
io_ex_bchain *ieb = ig->exdata;
size_t ocount = count;
size_t sk;
mm_log((1, "bufchain_write: ig = %p, buf = %p, count = %d\n", ig, buf, count));
IOL_DEB( printf("bufchain_write: ig = %p, ieb->cpos = %ld, buf = %p, count = %d\n", ig, (long) ieb->cpos, buf, count) );
while(count) {
mm_log((2, "bufchain_write: - looping - count = %d\n", count));
if (ieb->cp->len == ieb->cpos) {
mm_log((1, "bufchain_write: cp->len == ieb->cpos = %d - advancing chain\n", (long) ieb->cpos));
io_bchain_advance(ieb);
}
sk = ieb->cp->len - ieb->cpos;
sk = sk > count ? count : sk;
memcpy(&ieb->cp->buf[ieb->cpos], &cbuf[ocount-count], sk);
if (ieb->cp == ieb->tail) {
int extend = ieb->cpos + sk - ieb->tfill;
mm_log((2, "bufchain_write: extending tail by %d\n", extend));
if (extend > 0) {
ieb->length += extend;
ieb->tfill += extend;
}
}
ieb->cpos += sk;
ieb->gpos += sk;
count -= sk;
}
return ocount;
}
/*
=item bufchain_close(ig)
Closes a source that can be seeked on. Not sure if this should be an actual close
or not. Does nothing for now. Should be fixed.
ig - data source
=cut
*/
static
int
bufchain_close(io_glue *ig) {
mm_log((1, "bufchain_close(ig %p)\n",ig));
IOL_DEB( printf("bufchain_close(ig %p)\n", ig) );
return 0;
}
/* bufchain_seek(ig, offset, whence)
Implements seeking for a source that is seekable, the purpose of having this is to be able to
have an offset into a file that is different from what the underlying library thinks.
ig - data source
offset - offset into stream
whence - whence argument a la lseek
=cut
*/
static
off_t
bufchain_seek(io_glue *ig, off_t offset, int whence) {
io_ex_bchain *ieb = ig->exdata;
int wrlen;
off_t scount = calc_seek_offset(ieb->gpos, ieb->length, offset, whence);
off_t sk;
mm_log((1, "bufchain_seek(ig %p, offset %ld, whence %d)\n", ig, offset, whence));
if (scount < 0) {
i_push_error(0, "invalid whence supplied or seek before start of file");
return (off_t)-1;
}
ieb->cp = ieb->head;
ieb->cpos = 0;
ieb->gpos = 0;
while( scount ) {
int clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
if (clen == ieb->cpos) {
if (ieb->cp == ieb->tail) break; /* EOF */
ieb->cp = ieb->cp->next;
ieb->cpos = 0;
clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
}
sk = clen - ieb->cpos;
sk = sk > scount ? scount : sk;
scount -= sk;
ieb->cpos += sk;
ieb->gpos += sk;
}
wrlen = scount;
if (wrlen > 0) {
/*
* extending file - get ieb into consistent state and then
* call write which will get it to the correct position
*/
char TB[BBSIZ];
memset(TB, 0, BBSIZ);
ieb->gpos = ieb->length;
ieb->cpos = ieb->tfill;
while(wrlen > 0) {
ssize_t rc, wl = i_min(wrlen, BBSIZ);
mm_log((1, "bufchain_seek: wrlen = %d, wl = %d\n", wrlen, wl));
rc = bufchain_write( ig, TB, wl );
if (rc != wl) i_fatal(0, "bufchain_seek: Unable to extend file\n");
wrlen -= rc;
}
}
mm_log((2, "bufchain_seek: returning ieb->gpos = %d\n", ieb->gpos));
return ieb->gpos;
}
static
void
bufchain_destroy(io_glue *ig) {
io_ex_bchain *ieb = ig->exdata;
io_destroy_bufchain(ieb);
myfree(ieb);
}
/*
* Methods for setting up data source
*/
/*
=item io_obj_setp_buffer(io, p, len)
Sets an io_object for reading from a buffer source
io - io object that describes a source
p - pointer to buffer
len - length of buffer
=cut
*/
static void
io_obj_setp_buffer(io_obj *io, char *p, size_t len, i_io_closebufp_t closecb,
void *closedata) {
io->buffer.type = BUFFER;
io->buffer.data = p;
io->buffer.len = len;
io->buffer.closecb = closecb;
io->buffer.closedata = closedata;
}
/*
=item io_obj_setp_cb2(io, p, readcb, writecb, seekcb, closecb, destroycb)
Sets an io_object for reading from a source that uses callbacks
io - io object that describes a source
p - pointer to data for callbacks
readcb - read callback to read from source
writecb - write callback to write to source
seekcb - seek callback to seek on source
closecb - flush any pending data
destroycb - release any extra resources
=cut
*/
static void
io_obj_setp_cb2(io_obj *io, void *p, i_io_readl_t readcb, i_io_writel_t writecb, i_io_seekl_t seekcb, i_io_closel_t closecb, i_io_destroyl_t destroycb) {
io->cb.type = CBSEEK;
io->cb.p = p;
io->cb.readcb = readcb;
io->cb.writecb = writecb;
io->cb.seekcb = seekcb;
io->cb.closecb = closecb;
io->cb.destroycb = destroycb;
}
/*
=item io_glue_commit_types(ig)
This is now effectively a no-op.
=cut
*/
void
io_glue_commit_types(io_glue *ig) {
io_type inn = ig->source.type;
mm_log((1, "io_glue_commit_types(ig %p)\n", ig));
mm_log((1, "io_glue_commit_types: source type %d (%s)\n", inn, io_type_names[inn]));
if (ig->flags & 0x01) {
mm_log((1, "io_glue_commit_types: type already set up\n"));
return;
}
ig->flags |= 0x01; /* indicate source has been setup already */
}
/*
=item io_glue_gettypes(ig, reqmeth)
Returns a set of compatible interfaces to read data with.
ig - io_glue object
reqmeth - request mask
The request mask is a bit mask (of something that hasn't been implemented yet)
of interfaces that it would like to read data from the source which the ig
describes.
=cut
*/
void
io_glue_gettypes(io_glue *ig, int reqmeth) {
ig = NULL;
reqmeth = 0;
/* FIXME: Implement this function! */
/* if (ig->source.type =
if (reqmeth & IO_BUFF) */
}
/*
=item io_new_bufchain()
returns a new io_glue object that has the 'empty' source and but can
be written to and read from later (like a pseudo file).
=cut
*/
io_glue *
io_new_bufchain() {
io_glue *ig;
io_ex_bchain *ieb = mymalloc(sizeof(io_ex_bchain));
mm_log((1, "io_new_bufchain()\n"));
ig = mymalloc(sizeof(io_glue));
memset(ig, 0, sizeof(*ig));
ig->source.type = BUFCHAIN;
ieb->offset = 0;
ieb->length = 0;
ieb->cpos = 0;
ieb->gpos = 0;
ieb->tfill = 0;
ieb->head = io_blink_new();
ieb->cp = ieb->head;
ieb->tail = ieb->head;
ig->exdata = ieb;
ig->readcb = bufchain_read;
ig->writecb = bufchain_write;
ig->seekcb = bufchain_seek;
ig->closecb = bufchain_close;
ig->destroycb = bufchain_destroy;
return ig;
}
/*
=item io_new_buffer(data, len)
Returns a new io_glue object that has the source defined as reading
from specified buffer. Note that the buffer is not copied.
data - buffer to read from
len - length of buffer
=cut
*/
io_glue *
io_new_buffer(char *data, size_t len, i_io_closebufp_t closecb, void *closedata) {
io_glue *ig;
io_ex_buffer *ieb = mymalloc(sizeof(io_ex_buffer));
mm_log((1, "io_new_buffer(data %p, len %d, closecb %p, closedata %p)\n", data, len, closecb, closedata));
ig = mymalloc(sizeof(io_glue));
memset(ig, 0, sizeof(*ig));
io_obj_setp_buffer(&ig->source, data, len, closecb, closedata);
ig->flags = 0;
ieb->offset = 0;
ieb->cpos = 0;
ig->exdata = ieb;
ig->readcb = buffer_read;
ig->writecb = buffer_write;
ig->seekcb = buffer_seek;
ig->closecb = buffer_close;
ig->destroycb = buffer_destroy;
return ig;
}
/*
=item io_new_fd(fd)
returns a new io_glue object that has the source defined as reading
from specified filedescriptor. Note that the the interface to recieving
data from the io_glue callbacks hasn't been done yet.
fd - file descriptor to read/write from
=cut
*/
io_glue *
io_new_fd(int fd) {
io_glue *ig;
mm_log((1, "io_new_fd(fd %d)\n", fd));
ig = mymalloc(sizeof(io_glue));
memset(ig, 0, sizeof(*ig));
ig->source.type = FDSEEK;
ig->source.fdseek.fd = fd;
ig->flags = 0;
ig->exdata = NULL;
ig->readcb = fd_read;
ig->writecb = fd_write;
ig->seekcb = fd_seek;
ig->closecb = fd_close;
ig->sizecb = fd_size;
ig->destroycb = NULL;
mm_log((1, "(%p) <- io_new_fd\n", ig));
return ig;