Initial revision
[imager.git] / iolayer.c
CommitLineData
02d1d628
AMH
1#include "io.h"
2#include "iolayer.h"
3#include "log.h"
4#include <stdlib.h>
5#include <stdio.h>
6#ifdef _MSC_VER
7#include <io.h>
8#endif
9
10#define IOL_DEB(x)
11
12
13char *io_type_names[] = { "FDSEEK", "FDNOSEEK", "BUFFER", "CBSEEK", "CBNOSEEK", "BUFCHAIN" };
14
15
16/*
17=head1 NAME
18
19iolayer.c - encapsulates different source of data into a single framework.
20
21=head1 SYNOPSIS
22
23 io_glue *ig = io_new_fd( fileno(stdin) );
24 method = io_reqmeth( IOL_NOSEEK | IOL_MMAP ); // not implemented yet
25 io_glue_commit_types(ig); // always assume IOL_SEEK for now
26 switch (method) {
27 case IOL_NOSEEK:
28 code that uses ig->readcb()
29 to read data goes here.
30 break;
31 case IOL_MMAP:
32 code that uses ig->readcb()
33 to read data goes here.
34 break;
35 }
36
37 io_glue_DESTROY(ig);
38 // and much more
39
40=head1 DESCRIPTION
41
42iolayer.c implements the basic functions to create and destroy io_glue
43objects for Imager. The typical usage pattern for data sources is:
44
45 1. Create the source (io_new_fd)
46 2. Define how you want to get data from it (io_reqmeth)
47 3. read from it using the interface requested (ig->readdb, ig->mmapcb)
48 4. Close the source, which
49 shouldn't really close the underlying source. (io_glue DESTROY)
50
51=head1 FUNCTION REFERENCE
52
53Some of these functions are internal.
54
55=over 4
56
57=cut
58*/
59
60
61
62
63/*
64 * Callbacks for sources that cannot seek
65 */
66
67/* fakeseek_read: read method for when emulating a seekable source
68static
69ssize_t
70fakeseek_read(io_glue *ig, void *buf, size_t count) {
71 io_ex_fseek *exdata = ig->exdata;
72 return 0;
73}
74*/
75
76
77
78/*
79 * Callbacks for sources that can seek
80 */
81
82/*
83=item realseek_read(ig, buf, count)
84
85Does the reading from a source that can be seeked on
86
87 ig - io_glue object
88 buf - buffer to return data in
89 count - number of bytes to read into buffer max
90
91=cut
92*/
93
94static
95ssize_t
96realseek_read(io_glue *ig, void *buf, size_t count) {
97 io_ex_rseek *ier = ig->exdata;
98 int fd = (int)ig->source.cb.p;
99 ssize_t rc = 0;
100 size_t bc = 0;
101 char *cbuf = buf;
102
103 IOL_DEB( printf("realseek_read: fd = %d, ier->cpos = %ld, buf = 0x%p, count = %d\n", fd, (long) ier->cpos, buf, count) );
104 /* Is this a good idea? Would it be better to handle differently? skip handling? */
105 while( count!=bc && (rc = ig->source.cb.readcb(fd,cbuf+bc,count-bc))>0 ) bc+=rc;
106
107 ier->cpos += bc;
108 IOL_DEB( printf("realseek_read: rc = %d, bc = %d\n", rc, bc) );
109 return bc;
110}
111
112
113/*
114=item realseek_write(ig, buf, count)
115
116Does the writing to a 'source' that can be seeked on
117
118 ig - io_glue object
119 buf - buffer that contains data
120 count - number of bytes to write
121
122=cut
123*/
124
125static
126ssize_t
127realseek_write(io_glue *ig, const void *buf, size_t count) {
128 io_ex_rseek *ier = ig->exdata;
129 int fd = (int)ig->source.cb.p;
130 ssize_t rc = 0;
131 size_t bc = 0;
132 char *cbuf = (char*)buf;
133
134 IOL_DEB( printf("realseek_write: fd = %d, ier->cpos = %ld, buf = 0x%p, count = %d\n", fd, (long) ier->cpos, buf, count) );
135 /* Is this a good idea? Would it be better to handle differently? skip handling? */
136
137 while( count!=bc && (rc = ig->source.cb.writecb(fd,cbuf+bc,count-bc))>0 ) bc+=rc;
138
139 ier->cpos += bc;
140 IOL_DEB( printf("realseek_write: rc = %d, bc = %d\n", rc, bc) );
141 return bc;
142}
143
144
145/*
146=item realseek_close(ig)
147
148Closes a source that can be seeked on. Not sure if this should be an actual close
149or not. Does nothing for now. Should be fixed.
150
151 ig - data source
152
153=cut
154*/
155
156static
157void
158realseek_close(io_glue *ig) {
159 mm_log((1, "realseek_close(ig %p)\n", ig));
160 /* FIXME: Do stuff here */
161}
162
163
164/* realseek_seek(ig, offset, whence)
165
166Implements seeking for a source that is seekable, the purpose of having this is to be able to
167have an offset into a file that is different from what the underlying library thinks.
168
169 ig - data source
170 offset - offset into stream
171 whence - whence argument a la lseek
172
173=cut
174*/
175
176static
177off_t
178realseek_seek(io_glue *ig, off_t offset, int whence) {
179 /* io_ex_rseek *ier = ig->exdata; Needed later */
180 int fd = (int)ig->source.cb.p;
181 int rc;
182 IOL_DEB( printf("realseek_seek(ig 0x%p, offset %ld, whence %d)\n", ig, (long) offset, whence) );
183 rc = lseek(fd, offset, whence);
184
185 IOL_DEB( printf("realseek_seek: rc %ld\n", (long) rc) );
186 return rc;
187 /* FIXME: How about implementing this offset handling stuff? */
188}
189
190
191
192
193
194
195
196/*
197 * Callbacks for sources that are a chain of variable sized buffers
198 */
199
200
201
202/* Helper functions for buffer chains */
203
204static
205io_blink*
206io_blink_new() {
207 io_blink *ib;
208
209 mm_log((1, "io_blink_new()\n"));
210
211 ib = mymalloc(sizeof(io_blink));
212
213 ib->next = NULL;
214 ib->prev = NULL;
215 ib->len = BBSIZ;
216
217 memset(&ib->buf, 0, ib->len);
218 return ib;
219}
220
221
222
223/*
224=item io_bchain_advance(ieb)
225
226Advances the buffer chain to the next link - extending if
227necessary. Also adjusts the cpos and tfill counters as needed.
228
229 ieb - buffer chain object
230
231=cut
232*/
233
234static
235void
236io_bchain_advance(io_ex_bchain *ieb) {
237 if (ieb->cp->next == NULL) {
238 ieb->tail = io_blink_new();
239 ieb->tail->prev = ieb->cp;
240 ieb->cp->next = ieb->tail;
241
242 ieb->tfill = 0; /* Only set this if we added a new slice */
243 }
244 ieb->cp = ieb->cp->next;
245 ieb->cpos = 0;
246}
247
248
249/*
250
251static
252void
253bufchain_dump(io_ex_bchain *ieb) {
254 mm_log((1, " buf_chain_dump(ieb %p)\n"));
255 mm_log((1, " buf_chain_dump: ieb->offset = %d\n", ieb->offset));
256 mm_log((1, " buf_chain_dump: ieb->length = %d\n", ieb->length));
257 mm_log((1, " buf_chain_dump: ieb->head = %p\n", ieb->head ));
258 mm_log((1, " buf_chain_dump: ieb->tail = %p\n", ieb->tail ));
259 mm_log((1, " buf_chain_dump: ieb->tfill = %d\n", ieb->tfill ));
260 mm_log((1, " buf_chain_dump: ieb->cp = %p\n", ieb->cp ));
261 mm_log((1, " buf_chain_dump: ieb->cpos = %d\n", ieb->cpos ));
262 mm_log((1, " buf_chain_dump: ieb->gpos = %d\n", ieb->gpos ));
263}
264*/
265
266/*
267 * TRUE if lengths are NOT equal
268 */
269
270/*
271static
272void
273chainlencert( io_glue *ig ) {
274 int clen;
275 int cfl = 0;
276 size_t csize = 0;
277 size_t cpos = 0;
278 io_ex_bchain *ieb = ig->exdata;
279 io_blink *cp = ieb->head;
280
281
282 if (ieb->gpos > ieb->length) mm_log((1, "BBAR : ieb->gpos = %d, ieb->length = %d\n", ieb->gpos, ieb->length));
283
284 while(cp) {
285 clen = (cp == ieb->tail) ? ieb->tfill : cp->len;
286 if (ieb->head == cp && cp->prev) mm_log((1, "Head of chain has a non null prev\n"));
287 if (ieb->tail == cp && cp->next) mm_log((1, "Tail of chain has a non null next\n"));
288
289 if (ieb->head != cp && !cp->prev) mm_log((1, "Middle of chain has a null prev\n"));
290 if (ieb->tail != cp && !cp->next) mm_log((1, "Middle of chain has a null next\n"));
291
292 if (cp->prev && cp->prev->next != cp) mm_log((1, "%p = cp->prev->next != cp\n", cp->prev->next));
293 if (cp->next && cp->next->prev != cp) mm_log((1, "%p cp->next->prev != cp\n", cp->next->prev));
294
295 if (cp == ieb->cp) {
296 cfl = 1;
297 cpos += ieb->cpos;
298 }
299
300 if (!cfl) cpos += clen;
301
302 csize += clen;
303 cp = cp->next;
304 }
305 if (( csize != ieb->length )) mm_log((1, "BAR : csize = %d, ieb->length = %d\n", csize, ieb->length));
306 if (( cpos != ieb->gpos )) mm_log((1, "BAR : cpos = %d, ieb->gpos = %d\n", cpos, ieb->gpos ));
307}
308
309
310static
311void
312chaincert( io_glue *ig) {
313 size_t csize = 0;
314 io_ex_bchain *ieb = ig->exdata;
315 io_blink *cp = ieb->head;
316
317 mm_log((1, "Chain verification.\n"));
318
319 mm_log((1, " buf_chain_dump: ieb->offset = %d\n", ieb->offset));
320 mm_log((1, " buf_chain_dump: ieb->length = %d\n", ieb->length));
321 mm_log((1, " buf_chain_dump: ieb->head = %p\n", ieb->head ));
322 mm_log((1, " buf_chain_dump: ieb->tail = %p\n", ieb->tail ));
323 mm_log((1, " buf_chain_dump: ieb->tfill = %d\n", ieb->tfill ));
324 mm_log((1, " buf_chain_dump: ieb->cp = %p\n", ieb->cp ));
325 mm_log((1, " buf_chain_dump: ieb->cpos = %d\n", ieb->cpos ));
326 mm_log((1, " buf_chain_dump: ieb->gpos = %d\n", ieb->gpos ));
327
328 while(cp) {
329 int clen = cp == ieb->tail ? ieb->tfill : cp->len;
330 mm_log((1, "link: %p <- %p -> %p\n", cp->prev, cp, cp->next));
331 if (ieb->head == cp && cp->prev) mm_log((1, "Head of chain has a non null prev\n"));
332 if (ieb->tail == cp && cp->next) mm_log((1, "Tail of chain has a non null next\n"));
333
334 if (ieb->head != cp && !cp->prev) mm_log((1, "Middle of chain has a null prev\n"));
335 if (ieb->tail != cp && !cp->next) mm_log((1, "Middle of chain has a null next\n"));
336
337 if (cp->prev && cp->prev->next != cp) mm_log((1, "%p = cp->prev->next != cp\n", cp->prev->next));
338 if (cp->next && cp->next->prev != cp) mm_log((1, "%p cp->next->prev != cp\n", cp->next->prev));
339
340 csize += clen;
341 cp = cp->next;
342 }
343
344 mm_log((1, "csize = %d %s ieb->length = %d\n", csize, csize == ieb->length ? "==" : "!=", ieb->length));
345}
346*/
347
348
349
350
351
352
353
354
355
356
357
358/*
359=item bufchain_read(ig, buf, count)
360
361Does the reading from a source that can be seeked on
362
363 ig - io_glue object
364 buf - buffer to return data in
365 count - number of bytes to read into buffer max
366
367=cut
368*/
369
370static
371ssize_t
372bufchain_read(io_glue *ig, void *buf, size_t count) {
373 io_ex_bchain *ieb = ig->exdata;
374 size_t scount = count;
375 char *cbuf = buf;
376 size_t sk;
377
378 mm_log((1, "bufchain_read(ig %p, buf %p, count %ld)\n", ig, buf, count));
379 IOL_DEB( printf("bufchain_read: fd = %d, ier->cpos = %ld, buf = 0x%p, count = %d\n", fd, (long) ier->cpos, buf, count) );
380
381 while( scount ) {
382 int clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
383 if (clen == ieb->cpos) {
384 if (ieb->cp == ieb->tail) break; /* EOF */
385 ieb->cp = ieb->cp->next;
386 ieb->cpos = 0;
387 clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
388 }
389
390 sk = clen - ieb->cpos;
391 sk = sk > scount ? scount : sk;
392
393 memcpy(&cbuf[count-scount], &ieb->cp->buf[ieb->cpos], sk);
394 scount -= sk;
395 ieb->cpos += sk;
396 ieb->gpos += sk;
397 }
398
399 mm_log((1, "bufchain_read: returning %d\n", count-scount));
400 return count-scount;
401}
402
403
404
405
406
407/*
408=item bufchain_write(ig, buf, count)
409
410Does the writing to a 'source' that can be seeked on
411
412 ig - io_glue object
413 buf - buffer that contains data
414 count - number of bytes to write
415
416=cut
417*/
418
419static
420ssize_t
421bufchain_write(io_glue *ig, const void *buf, size_t count) {
422 char *cbuf = (char *)buf;
423 io_ex_bchain *ieb = ig->exdata;
424 size_t ocount = count;
425 size_t sk;
426
427 mm_log((1, "bufchain_write: ig = %p, buf = 0x%p, count = %d\n", ig, buf, count));
428
429 IOL_DEB( printf("bufchain_write: ig = %p, ieb->cpos = %ld, buf = 0x%p, count = %d\n", ig, (long) ieb->cpos, buf, count) );
430
431 while(count) {
432 mm_log((2, "bufchain_write: - looping - count = %d\n", count));
433 if (ieb->cp->len == ieb->cpos) {
434 mm_log((1, "bufchain_write: cp->len == ieb->cpos = %d - advancing chain\n", (long) ieb->cpos));
435 io_bchain_advance(ieb);
436 }
437
438 sk = ieb->cp->len - ieb->cpos;
439 sk = sk > count ? count : sk;
440 memcpy(&ieb->cp->buf[ieb->cpos], &cbuf[ocount-count], sk);
441
442 if (ieb->cp == ieb->tail) {
443 int extend = ieb->cpos + sk - ieb->tfill;
444 mm_log((2, "bufchain_write: extending tail by %d\n", extend));
445 if (extend > 0) {
446 ieb->length += extend;
447 ieb->tfill += extend;
448 }
449 }
450
451 ieb->cpos += sk;
452 ieb->gpos += sk;
453 count -= sk;
454 }
455 return ocount;
456}
457
458/*
459=item bufchain_close(ig)
460
461Closes a source that can be seeked on. Not sure if this should be an actual close
462or not. Does nothing for now. Should be fixed.
463
464 ig - data source
465
466=cut
467*/
468
469static
470void
471bufchain_close(io_glue *ig) {
472 mm_log((1, "bufchain_close(ig %p)\n",ig));
473 IOL_DEB( printf("bufchain_close(ig 0x%p)\n", ig) );
474 /* FIXME: Commit a seek point here */
475
476}
477
478
479/* bufchain_seek(ig, offset, whence)
480
481Implements seeking for a source that is seekable, the purpose of having this is to be able to
482have an offset into a file that is different from what the underlying library thinks.
483
484 ig - data source
485 offset - offset into stream
486 whence - whence argument a la lseek
487
488=cut
489*/
490
491static
492off_t
493bufchain_seek(io_glue *ig, off_t offset, int whence) {
494 io_ex_bchain *ieb = ig->exdata;
495 io_blink *ib = NULL;
496 int wrlen;
497
498 off_t cof = 0;
499 off_t scount = offset;
500 off_t sk;
501
502 mm_log((1, "bufchain_seek(ig %p, offset %ld, whence %d)\n", ig, offset, whence));
503
504 switch (whence) {
505 case SEEK_SET: /* SEEK_SET = 0, From the top */
506 ieb->cp = ieb->head;
507 ieb->cpos = 0;
508 ieb->gpos = 0;
509
510 while( scount ) {
511 int clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
512 if (clen == ieb->cpos) {
513 if (ieb->cp == ieb->tail) break; /* EOF */
514 ieb->cp = ieb->cp->next;
515 ieb->cpos = 0;
516 clen = (ieb->cp == ieb->tail) ? ieb->tfill : ieb->cp->len;
517 }
518
519 sk = clen - ieb->cpos;
520 sk = sk > scount ? scount : sk;
521
522 scount -= sk;
523 ieb->cpos += sk;
524 ieb->gpos += sk;
525 }
526
527 wrlen = scount;
528
529 if (wrlen > 0) {
530 /*
531 * extending file - get ieb into consistent state and then
532 * call write which will get it to the correct position
533 */
534 char TB[BBSIZ];
535 memset(TB, 0, BBSIZ);
536 ieb->gpos = ieb->length;
537 ieb->cpos = ieb->tfill;
538
539 while(wrlen > 0) {
540 ssize_t rc, wl = min(wrlen, BBSIZ);
541 mm_log((1, "bufchain_seek: wrlen = %d, wl = %d\n", wrlen, wl));
542 rc = bufchain_write( ig, TB, wl );
543 if (rc != wl) m_fatal(0, "bufchain_seek: Unable to extend file\n");
544 wrlen -= rc;
545 }
546 }
547
548 break;
549
550 case SEEK_CUR:
551 m_fatal(123, "SEEK_CUR IS NOT IMPLEMENTED\n");
552
553 /*
554 case SEEK_CUR:
555 ib = ieb->cp;
556 if (cof < 0) {
557 cof += ib->cpos;
558 cpos = 0;
559 while(cof < 0 && ib->prev) {
560 ib = ib->prev;
561 cof += ib->len;
562 }
563 */
564
565 case SEEK_END: /* SEEK_END = 2 */
566 if (cof>0) m_fatal(0, "bufchain_seek: SEEK_END + %d : Extending files via seek not supported!\n", cof);
567
568 ieb->cp = ieb->tail;
569 ieb->cpos = ieb->tfill;
570
571 if (cof<0) {
572 cof += ieb->cpos;
573 ieb->cpos = 0;
574
575 while(cof<0 && ib->prev) {
576 ib = ib->prev;
577 cof += ib->len;
578 }
579
580 if (cof<0) m_fatal(0, "bufchain_seek: Tried to seek before start of file\n");
581 ieb->gpos = ieb->length+offset;
582 ieb->cpos = cof;
583 }
584 break;
585 default:
586 m_fatal(0, "bufchain_seek: Unhandled seek request: whence = %d\n", whence );
587 }
588
589 mm_log((2, "bufchain_seek: returning ieb->gpos = %d\n", ieb->gpos));
590 return ieb->gpos;
591}
592
593
594
595
596
597
598/*
599 * Methods for setting up data source
600 */
601
602/*
603=item io_obj_setp_buffer(io, p, len)
604
605Sets an io_object for reading from a buffer source
606
607 io - io object that describes a source
608 p - pointer to buffer
609 len - length of buffer
610
611=cut
612*/
613
614void
615io_obj_setp_buffer(io_obj *io, void *p, size_t len) {
616 io->buffer.type = BUFFER;
617 io->buffer.c = (char*) p;
618 io->buffer.len = len;
619}
620
621
622/*
623=item io_obj_setp_cbuf(io, p)
624
625Sets an io_object for reading/writing from a buffer source
626
627 io - io object that describes a source
628 p - pointer to buffer
629 len - length of buffer
630
631=cut
632*/
633
634void
635io_obj_setp_bufchain(io_obj *io) {
636 io->type = BUFCHAIN;
637}
638
639
640/*
641=item io_obj_setp_cb(io, p, readcb, writecb, seekcb)
642
643Sets an io_object for reading from a source that uses callbacks
644
645 io - io object that describes a source
646 p - pointer to data for callbacks
647 readcb - read callback to read from source
648 writecb - write callback to write to source
649 seekcb - seek callback to seek on source
650
651=cut
652*/
653
654void
655io_obj_setp_cb(io_obj *io, void *p, readl readcb, writel writecb, seekl seekcb) {
656 io->cb.type = CBSEEK;
657 io->cb.p = p;
658 io->cb.readcb = readcb;
659 io->cb.writecb = writecb;
660 io->cb.seekcb = seekcb;
661}
662
663/*
664=item io_glue_commit_types(ig)
665
666Creates buffers and initializes structures to read with the chosen interface.
667
668 ig - io_glue object
669
670=cut
671*/
672
673void
674io_glue_commit_types(io_glue *ig) {
675 io_type inn = ig->source.type;
676
677 mm_log((1, "io_glue_commit_types(ig 0x%p)\n", ig));
678 mm_log((1, "io_glue_commit_types: source type %d (%s)\n", inn, io_type_names[inn]));
679
680 switch (inn) {
681 case BUFCHAIN:
682 {
683 io_ex_bchain *ieb = mymalloc(sizeof(io_ex_bchain));
684
685 ieb->offset = 0;
686 ieb->length = 0;
687 ieb->cpos = 0;
688 ieb->gpos = 0;
689 ieb->tfill = 0;
690
691 ieb->head = io_blink_new();
692 ieb->cp = ieb->head;
693 ieb->tail = ieb->head;
694
695 ig->exdata = ieb;
696 ig->readcb = bufchain_read;
697 ig->writecb = bufchain_write;
698 ig->seekcb = bufchain_seek;
699 ig->closecb = bufchain_close;
700 }
701 break;
702 case CBSEEK:
703 default:
704 {
705 io_ex_rseek *ier = mymalloc(sizeof(io_ex_rseek));
706
707 ier->offset = 0;
708 ier->cpos = 0;
709
710 ig->exdata = ier;
711 ig->readcb = realseek_read;
712 ig->writecb = realseek_write;
713 ig->seekcb = realseek_seek;
714 ig->closecb = realseek_close;
715 }
716 }
717}
718
719/*
720=item io_glue_gettypes(ig, reqmeth)
721
722Returns a set of compatible interfaces to read data with.
723
724 ig - io_glue object
725 reqmeth - request mask
726
727The request mask is a bit mask (of something that hasn't been implemented yet)
728of interfaces that it would like to read data from the source which the ig
729describes.
730
731=cut
732*/
733
734void
735io_glue_gettypes(io_glue *ig, int reqmeth) {
736
737 ig = NULL;
738 reqmeth = 0;
739
740 /* FIXME: Implement this function! */
741 /* if (ig->source.type =
742 if (reqmeth & IO_BUFF) */
743
744}
745
746
747/*
748=item io_new_bufchain()
749
750returns a new io_glue object that has the 'empty' source and but can
751be written to and read from later (like a pseudo file).
752
753=cut
754*/
755
756io_glue *
757io_new_bufchain() {
758 io_glue *ig = mymalloc(sizeof(io_glue));
759 io_obj_setp_bufchain(&ig->source);
760 return ig;
761}
762
763
764/*
765=item io_new_fd(fd)
766
767returns a new io_glue object that has the source defined as reading
768from specified filedescriptor. Note that the the interface to recieving
769data from the io_glue callbacks hasn't been done yet.
770
771 fd - file descriptor to read/write from
772
773=cut
774*/
775
776io_glue *
777io_new_fd(int fd) {
778 io_glue *ig = mymalloc(sizeof(io_glue));
779#ifdef _MSC_VER
780 io_obj_setp_cb(&ig->source, (void*)fd, _read, _write, _lseek);
781#else
782 io_obj_setp_cb(&ig->source, (void*)fd, read, write, lseek);
783#endif
784 return ig;
785}
786
787
788
789/*
790=item io_slurp(ig)
791
792Takes the source that the io_glue is bound to and allocates space
793for a return buffer and returns the entire content in a single buffer.
794Note: This only works for io_glue objects that contain a bufchain. It
795is usefull for saving to scalars and such.
796
797 ig - io_glue object
798 c - pointer to a pointer to where data should be copied to
799
800=cut
801*/
802
803size_t
804io_slurp(io_glue *ig, unsigned char **c) {
805 ssize_t rc;
806 off_t orgoff;
807 io_ex_bchain *ieb;
808 unsigned char *cc;
809 io_type inn = ig->source.type;
810
811 if ( inn != BUFCHAIN ) {
812 m_fatal(0, "io_slurp: called on a source that is not from a bufchain\n");
813 }
814
815 ieb = ig->exdata;
816 cc = *c = mymalloc( ieb->length );
817
818 orgoff = ieb->gpos;
819
820 bufchain_seek(ig, 0, SEEK_SET);
821
822 rc = bufchain_read(ig, cc, ieb->length);
823
824 if (rc != ieb->length)
825 m_fatal(1, "io_slurp: bufchain_read returned an incomplete read: rc = %d, request was %d\n", rc, ieb->length);
826
827 return rc;
828}
829
830
831/*
832=item io_glue_DESTROY(ig)
833
834A destructor method for io_glue objects. Should clean up all related buffers.
835Might leave us with a dangling pointer issue on some buffers.
836
837 ig - io_glue object to destroy.
838
839=cut
840*/
841
842void
843io_glue_DESTROY(io_glue *ig) {
844 free(ig);
845 /* FIXME: Handle extradata and such */
846}