2 * Copyright (c) 2003-2007 Tim Kientzle
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 * This file contains the "essential" portions of the read API, that
28 * is, stuff that will probably always be used by any client that
29 * actually needs to read an archive. Optional pieces have been, as
30 * far as possible, separated out into separate files to avoid
31 * needlessly bloating statically-linked clients.
34 #include "archive_platform.h"
35 __FBSDID("$FreeBSD: src/lib/libarchive/archive_read.c,v 1.39 2008/12/06 06:45:15 kientzle Exp $");
52 #include "archive_entry.h"
53 #include "archive_private.h"
54 #include "archive_read_private.h"
56 #define minimum(a, b) (a < b ? a : b)
58 static int build_stream(struct archive_read *);
59 static int choose_format(struct archive_read *);
60 static struct archive_vtable *archive_read_vtable(void);
61 static int _archive_read_close(struct archive *);
62 static int _archive_read_finish(struct archive *);
64 static struct archive_vtable *
65 archive_read_vtable(void)
67 static struct archive_vtable av;
68 static int inited = 0;
71 av.archive_finish = _archive_read_finish;
72 av.archive_close = _archive_read_close;
78 * Allocate, initialize and return a struct archive object.
81 archive_read_new(void)
83 struct archive_read *a;
85 a = (struct archive_read *)malloc(sizeof(*a));
88 memset(a, 0, sizeof(*a));
89 a->archive.magic = ARCHIVE_READ_MAGIC;
91 a->archive.state = ARCHIVE_STATE_NEW;
92 a->entry = archive_entry_new();
93 a->archive.vtable = archive_read_vtable();
99 * Record the do-not-extract-to file. This belongs in archive_read_extract.c.
102 archive_read_extract_set_skip_file(struct archive *_a, dev_t d, ino_t i)
104 struct archive_read *a = (struct archive_read *)_a;
105 __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY,
106 "archive_read_extract_set_skip_file");
107 a->skip_file_dev = d;
108 a->skip_file_ino = i;
112 * Set read options for the format.
115 archive_read_set_format_options(struct archive *_a, const char *s)
117 struct archive_read *a;
118 struct archive_format_descriptor *format;
119 char key[64], val[64];
124 if (s == NULL || *s == '\0')
126 a = (struct archive_read *)_a;
127 __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
128 ARCHIVE_STATE_NEW, "archive_read_set_format_options");
130 for (i = 0; i < sizeof(a->formats)/sizeof(a->formats[0]); i++) {
131 format = &a->formats[i];
132 if (format == NULL || format->options == NULL ||
133 format->name == NULL)
134 /* This format does not support option. */
137 while ((len = __archive_parse_options(s, format->name,
138 sizeof(key), key, sizeof(val), val)) > 0) {
139 valp = val[0] == '\0' ? NULL : val;
141 r = format->options(a, key, valp);
143 if (r == ARCHIVE_FATAL)
149 archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
150 "Illegal format options.");
151 return (ARCHIVE_WARN);
157 * Set read options for the filter.
160 archive_read_set_filter_options(struct archive *_a, const char *s)
162 struct archive_read *a;
163 struct archive_read_filter *filter;
164 struct archive_read_filter_bidder *bidder;
165 char key[64], val[64];
168 if (s == NULL || *s == '\0')
170 a = (struct archive_read *)_a;
171 __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
172 ARCHIVE_STATE_NEW, "archive_read_set_filter_options");
175 for (filter = a->filter; filter != NULL; filter = filter->upstream) {
176 bidder = filter->bidder;
179 if (bidder->options == NULL)
180 /* This bidder does not support option */
182 while ((len = __archive_parse_options(s, filter->name,
183 sizeof(key), key, sizeof(val), val)) > 0) {
185 r = bidder->options(bidder, key, NULL);
187 r = bidder->options(bidder, key, val);
188 if (r == ARCHIVE_FATAL)
194 archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
195 "Illegal format options.");
196 return (ARCHIVE_WARN);
202 * Set read options for the format and the filter.
205 archive_read_set_options(struct archive *_a, const char *s)
209 r = archive_read_set_format_options(_a, s);
212 r = archive_read_set_filter_options(_a, s);
222 archive_read_open(struct archive *a, void *client_data,
223 archive_open_callback *client_opener, archive_read_callback *client_reader,
224 archive_close_callback *client_closer)
226 /* Old archive_read_open() is just a thin shell around
227 * archive_read_open2. */
228 return archive_read_open2(a, client_data, client_opener,
229 client_reader, NULL, client_closer);
233 client_read_proxy(struct archive_read_filter *self, const void **buff)
236 r = (self->archive->client.reader)(&self->archive->archive,
238 self->archive->archive.raw_position += r;
243 client_skip_proxy(struct archive_read_filter *self, int64_t request)
245 int64_t ask, get, total;
246 /* Limit our maximum seek request to 1GB on platforms
247 * with 32-bit off_t (such as Windows). */
248 int64_t skip_limit = ((int64_t)1) << (sizeof(off_t) * 8 - 2);
250 if (self->archive->client.skipper == NULL)
255 if (ask > skip_limit)
257 get = (self->archive->client.skipper)(&self->archive->archive,
262 self->archive->archive.raw_position += get;
268 client_close_proxy(struct archive_read_filter *self)
272 if (self->archive->client.closer != NULL)
273 r = (self->archive->client.closer)((struct archive *)self->archive,
281 archive_read_open2(struct archive *_a, void *client_data,
282 archive_open_callback *client_opener,
283 archive_read_callback *client_reader,
284 archive_skip_callback *client_skipper,
285 archive_close_callback *client_closer)
287 struct archive_read *a = (struct archive_read *)_a;
288 struct archive_read_filter *filter;
291 __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
292 "archive_read_open");
294 if (client_reader == NULL)
296 "No reader function provided to archive_read_open");
298 /* Open data source. */
299 if (client_opener != NULL) {
300 e =(client_opener)(&a->archive, client_data);
302 /* If the open failed, call the closer to clean up. */
304 (client_closer)(&a->archive, client_data);
309 /* Save the client functions and mock up the initial source. */
310 a->client.reader = client_reader;
311 a->client.skipper = client_skipper;
312 a->client.closer = client_closer;
314 filter = calloc(1, sizeof(*filter));
316 return (ARCHIVE_FATAL);
317 filter->bidder = NULL;
318 filter->upstream = NULL;
320 filter->data = client_data;
321 filter->read = client_read_proxy;
322 filter->skip = client_skip_proxy;
323 filter->close = client_close_proxy;
324 filter->name = "none";
325 filter->code = ARCHIVE_COMPRESSION_NONE;
328 /* Build out the input pipeline. */
331 a->archive.state = ARCHIVE_STATE_HEADER;
337 * Allow each registered stream transform to bid on whether
338 * it wants to handle this stream. Repeat until we've finished
339 * building the pipeline.
342 build_stream(struct archive_read *a)
344 int number_bidders, i, bid, best_bid;
345 struct archive_read_filter_bidder *bidder, *best_bidder;
346 struct archive_read_filter *filter;
350 number_bidders = sizeof(a->bidders) / sizeof(a->bidders[0]);
356 for (i = 0; i < number_bidders; i++, bidder++) {
357 if (bidder->bid != NULL) {
358 bid = (bidder->bid)(bidder, a->filter);
359 if (bid > best_bid) {
361 best_bidder = bidder;
366 /* If no bidder, we're done. */
367 if (best_bidder == NULL) {
368 a->archive.compression_name = a->filter->name;
369 a->archive.compression_code = a->filter->code;
374 = (struct archive_read_filter *)calloc(1, sizeof(*filter));
376 return (ARCHIVE_FATAL);
377 filter->bidder = best_bidder;
379 filter->upstream = a->filter;
380 r = (best_bidder->init)(filter);
381 if (r != ARCHIVE_OK) {
390 * Read header of next entry.
393 archive_read_next_header2(struct archive *_a, struct archive_entry *entry)
395 struct archive_read *a = (struct archive_read *)_a;
398 __archive_check_magic(_a, ARCHIVE_READ_MAGIC,
399 ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
400 "archive_read_next_header");
402 archive_entry_clear(entry);
403 archive_clear_error(&a->archive);
406 * If no format has yet been chosen, choose one.
408 if (a->format == NULL) {
409 slot = choose_format(a);
411 a->archive.state = ARCHIVE_STATE_FATAL;
412 return (ARCHIVE_FATAL);
414 a->format = &(a->formats[slot]);
418 * If client didn't consume entire data, skip any remainder
419 * (This is especially important for GNU incremental directories.)
421 if (a->archive.state == ARCHIVE_STATE_DATA) {
422 ret = archive_read_data_skip(&a->archive);
423 if (ret == ARCHIVE_EOF) {
424 archive_set_error(&a->archive, EIO, "Premature end-of-file.");
425 a->archive.state = ARCHIVE_STATE_FATAL;
426 return (ARCHIVE_FATAL);
428 if (ret != ARCHIVE_OK)
432 /* Record start-of-header. */
433 a->header_position = a->archive.file_position;
435 ret = (a->format->read_header)(a, entry);
438 * EOF and FATAL are persistent at this layer. By
439 * modifying the state, we guarantee that future calls to
440 * read a header or read data will fail.
444 a->archive.state = ARCHIVE_STATE_EOF;
447 a->archive.state = ARCHIVE_STATE_DATA;
450 a->archive.state = ARCHIVE_STATE_DATA;
455 a->archive.state = ARCHIVE_STATE_FATAL;
459 a->read_data_output_offset = 0;
460 a->read_data_remaining = 0;
465 archive_read_next_header(struct archive *_a, struct archive_entry **entryp)
468 struct archive_read *a = (struct archive_read *)_a;
470 ret = archive_read_next_header2(_a, a->entry);
476 * Allow each registered format to bid on whether it wants to handle
477 * the next entry. Return index of winning bidder.
480 choose_format(struct archive_read *a)
487 slots = sizeof(a->formats) / sizeof(a->formats[0]);
491 /* Set up a->format and a->pformat_data for convenience of bidders. */
492 a->format = &(a->formats[0]);
493 for (i = 0; i < slots; i++, a->format++) {
494 if (a->format->bid) {
495 bid = (a->format->bid)(a);
496 if (bid == ARCHIVE_FATAL)
497 return (ARCHIVE_FATAL);
498 if ((bid > best_bid) || (best_bid_slot < 0)) {
506 * There were no bidders; this is a serious programmer error
507 * and demands a quick and definitive abort.
509 if (best_bid_slot < 0)
510 __archive_errx(1, "No formats were registered; you must "
511 "invoke at least one archive_read_support_format_XXX "
512 "function in order to successfully read an archive.");
515 * There were bidders, but no non-zero bids; this means we
516 * can't support this stream.
519 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
520 "Unrecognized archive format");
521 return (ARCHIVE_FATAL);
524 return (best_bid_slot);
528 * Return the file offset (within the uncompressed data stream) where
529 * the last header started.
532 archive_read_header_position(struct archive *_a)
534 struct archive_read *a = (struct archive_read *)_a;
535 __archive_check_magic(_a, ARCHIVE_READ_MAGIC,
536 ARCHIVE_STATE_ANY, "archive_read_header_position");
537 return (a->header_position);
541 * Read data from an archive entry, using a read(2)-style interface.
542 * This is a convenience routine that just calls
543 * archive_read_data_block and copies the results into the client
544 * buffer, filling any gaps with zero bytes. Clients using this
545 * API can be completely ignorant of sparse-file issues; sparse files
546 * will simply be padded with nulls.
548 * DO NOT intermingle calls to this function and archive_read_data_block
549 * to read a single entry body.
552 archive_read_data(struct archive *_a, void *buff, size_t s)
554 struct archive_read *a = (struct archive_read *)_a;
556 const void *read_buf;
565 if (a->read_data_remaining == 0) {
566 read_buf = a->read_data_block;
567 r = archive_read_data_block(&a->archive, &read_buf,
568 &a->read_data_remaining, &a->read_data_offset);
569 a->read_data_block = read_buf;
570 if (r == ARCHIVE_EOF)
573 * Error codes are all negative, so the status
574 * return here cannot be confused with a valid
575 * byte count. (ARCHIVE_OK is zero.)
581 if (a->read_data_offset < a->read_data_output_offset) {
582 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
583 "Encountered out-of-order sparse blocks");
584 return (ARCHIVE_RETRY);
587 /* Compute the amount of zero padding needed. */
588 if (a->read_data_output_offset + (off_t)s <
589 a->read_data_offset) {
591 } else if (a->read_data_output_offset <
592 a->read_data_offset) {
593 len = a->read_data_offset -
594 a->read_data_output_offset;
599 memset(dest, 0, len);
601 a->read_data_output_offset += len;
605 /* Copy data if there is any space left. */
607 len = a->read_data_remaining;
610 memcpy(dest, a->read_data_block, len);
612 a->read_data_block += len;
613 a->read_data_remaining -= len;
614 a->read_data_output_offset += len;
615 a->read_data_offset += len;
623 #if ARCHIVE_API_VERSION < 3
625 * Obsolete function provided for compatibility only. Note that the API
626 * of this function doesn't allow the caller to detect if the remaining
627 * data from the archive entry is shorter than the buffer provided, or
628 * even if an error occurred while reading data.
631 archive_read_data_into_buffer(struct archive *a, void *d, ssize_t len)
634 archive_read_data(a, d, len);
640 * Skip over all remaining data in this entry.
643 archive_read_data_skip(struct archive *_a)
645 struct archive_read *a = (struct archive_read *)_a;
651 __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
652 "archive_read_data_skip");
654 if (a->format->read_data_skip != NULL)
655 r = (a->format->read_data_skip)(a);
657 while ((r = archive_read_data_block(&a->archive,
658 &buff, &size, &offset))
663 if (r == ARCHIVE_EOF)
666 a->archive.state = ARCHIVE_STATE_HEADER;
671 * Read the next block of entry data from the archive.
672 * This is a zero-copy interface; the client receives a pointer,
673 * size, and file offset of the next available block of data.
675 * Returns ARCHIVE_OK if the operation is successful, ARCHIVE_EOF if
676 * the end of entry is encountered.
679 archive_read_data_block(struct archive *_a,
680 const void **buff, size_t *size, off_t *offset)
682 struct archive_read *a = (struct archive_read *)_a;
683 __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
684 "archive_read_data_block");
686 if (a->format->read_data == NULL) {
687 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
689 "No format_read_data_block function registered");
690 return (ARCHIVE_FATAL);
693 return (a->format->read_data)(a, buff, size, offset);
697 * Close the file and release most resources.
699 * Be careful: client might just call read_new and then read_finish.
700 * Don't assume we actually read anything or performed any non-trivial
704 _archive_read_close(struct archive *_a)
706 struct archive_read *a = (struct archive_read *)_a;
707 int r = ARCHIVE_OK, r1 = ARCHIVE_OK;
710 __archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
711 ARCHIVE_STATE_ANY, "archive_read_close");
712 archive_clear_error(&a->archive);
713 a->archive.state = ARCHIVE_STATE_CLOSED;
716 /* Call cleanup functions registered by optional components. */
717 if (a->cleanup_archive_extract != NULL)
718 r = (a->cleanup_archive_extract)(a);
720 /* TODO: Clean up the formatters. */
722 /* Clean up the filter pipeline. */
723 while (a->filter != NULL) {
724 struct archive_read_filter *t = a->filter->upstream;
725 if (a->filter->close != NULL) {
726 r1 = (a->filter->close)(a->filter);
730 free(a->filter->buffer);
735 /* Release the bidder objects. */
736 n = sizeof(a->bidders)/sizeof(a->bidders[0]);
737 for (i = 0; i < n; i++) {
738 if (a->bidders[i].free != NULL) {
739 r1 = (a->bidders[i].free)(&a->bidders[i]);
749 * Release memory and other resources.
752 _archive_read_finish(struct archive *_a)
754 struct archive_read *a = (struct archive_read *)_a;
759 __archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_ANY,
760 "archive_read_finish");
761 if (a->archive.state != ARCHIVE_STATE_CLOSED)
762 r = archive_read_close(&a->archive);
764 /* Cleanup format-specific data. */
765 slots = sizeof(a->formats) / sizeof(a->formats[0]);
766 for (i = 0; i < slots; i++) {
767 a->format = &(a->formats[i]);
768 if (a->formats[i].cleanup)
769 (a->formats[i].cleanup)(a);
772 archive_string_free(&a->archive.error_string);
774 archive_entry_free(a->entry);
775 a->archive.magic = 0;
777 #if ARCHIVE_API_VERSION > 1
783 * Used internally by read format handlers to register their bid and
784 * initialization functions.
787 __archive_read_register_format(struct archive_read *a,
790 int (*bid)(struct archive_read *),
791 int (*options)(struct archive_read *, const char *, const char *),
792 int (*read_header)(struct archive_read *, struct archive_entry *),
793 int (*read_data)(struct archive_read *, const void **, size_t *, off_t *),
794 int (*read_data_skip)(struct archive_read *),
795 int (*cleanup)(struct archive_read *))
799 __archive_check_magic(&a->archive,
800 ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
801 "__archive_read_register_format");
803 number_slots = sizeof(a->formats) / sizeof(a->formats[0]);
805 for (i = 0; i < number_slots; i++) {
806 if (a->formats[i].bid == bid)
807 return (ARCHIVE_WARN); /* We've already installed */
808 if (a->formats[i].bid == NULL) {
809 a->formats[i].bid = bid;
810 a->formats[i].options = options;
811 a->formats[i].read_header = read_header;
812 a->formats[i].read_data = read_data;
813 a->formats[i].read_data_skip = read_data_skip;
814 a->formats[i].cleanup = cleanup;
815 a->formats[i].data = format_data;
816 a->formats[i].name = name;
821 __archive_errx(1, "Not enough slots for format registration");
822 return (ARCHIVE_FATAL); /* Never actually called. */
826 * Used internally by decompression routines to register their bid and
827 * initialization functions.
829 struct archive_read_filter_bidder *
830 __archive_read_get_bidder(struct archive_read *a)
834 __archive_check_magic(&a->archive,
835 ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
836 "__archive_read_get_bidder");
838 number_slots = sizeof(a->bidders) / sizeof(a->bidders[0]);
840 for (i = 0; i < number_slots; i++) {
841 if (a->bidders[i].bid == NULL) {
842 memset(a->bidders + i, 0, sizeof(a->bidders[0]));
843 return (a->bidders + i);
847 __archive_errx(1, "Not enough slots for compression registration");
848 return (NULL); /* Never actually executed. */
852 * The next three functions comprise the peek/consume internal I/O
853 * system used by archive format readers. This system allows fairly
854 * flexible read-ahead and allows the I/O code to operate in a
855 * zero-copy manner most of the time.
857 * In the ideal case, filters generate blocks of data
858 * and __archive_read_ahead() just returns pointers directly into
859 * those blocks. Then __archive_read_consume() just bumps those
860 * pointers. Only if your request would span blocks does the I/O
861 * layer use a copy buffer to provide you with a contiguous block of
862 * data. The __archive_read_skip() is an optimization; it scans ahead
863 * very quickly (it usually translates into a seek() operation if
864 * you're reading uncompressed disk files).
866 * A couple of useful idioms:
867 * * "I just want some data." Ask for 1 byte and pay attention to
868 * the "number of bytes available" from __archive_read_ahead().
869 * You can consume more than you asked for; you just can't consume
870 * more than is available. If you consume everything that's
871 * immediately available, the next read_ahead() call will pull
873 * * "I want to output a large block of data." As above, ask for 1 byte,
874 * emit all that's available (up to whatever limit you have), then
875 * repeat until you're done.
876 * * "I want to peek ahead by a large amount." Ask for 4k or so, then
877 * double and repeat until you get an error or have enough. Note
878 * that the I/O layer will likely end up expanding its copy buffer
879 * to fit your request, so use this technique cautiously. This
880 * technique is used, for example, by some of the format tasting
881 * code that has uncertain look-ahead needs.
883 * TODO: Someday, provide a more generic __archive_read_seek() for
884 * those cases where it's useful. This is tricky because there are lots
885 * of cases where seek() is not available (reading gzip data from a
886 * network socket, for instance), so there needs to be a good way to
887 * communicate whether seek() is available and users of that interface
888 * need to use non-seeking strategies whenever seek() is not available.
892 * Looks ahead in the input stream:
893 * * If 'avail' pointer is provided, that returns number of bytes available
894 * in the current buffer, which may be much larger than requested.
895 * * If end-of-file, *avail gets set to zero.
896 * * If error, *avail gets error code.
897 * * If request can be met, returns pointer to data, returns NULL
898 * if request is not met.
900 * Note: If you just want "some data", ask for 1 byte and pay attention
901 * to *avail, which will have the actual amount available. If you
902 * know exactly how many bytes you need, just ask for that and treat
903 * a NULL return as an error.
905 * Important: This does NOT move the file pointer. See
906 * __archive_read_consume() below.
910 * This is tricky. We need to provide our clients with pointers to
911 * contiguous blocks of memory but we want to avoid copying whenever
914 * Mostly, this code returns pointers directly into the block of data
915 * provided by the client_read routine. It can do this unless the
916 * request would split across blocks. In that case, we have to copy
917 * into an internal buffer to combine reads.
920 __archive_read_ahead(struct archive_read *a, size_t min, ssize_t *avail)
922 return (__archive_read_filter_ahead(a->filter, min, avail));
926 __archive_read_filter_ahead(struct archive_read_filter *filter,
927 size_t min, ssize_t *avail)
934 *avail = ARCHIVE_FATAL;
939 * Keep pulling more data until we can satisfy the request.
944 * If we can satisfy from the copy buffer, we're done.
946 if (filter->avail >= min) {
948 *avail = filter->avail;
949 return (filter->next);
953 * We can satisfy directly from client buffer if everything
954 * currently in the copy buffer is still in the client buffer.
956 if (filter->client_total >= filter->client_avail + filter->avail
957 && filter->client_avail + filter->avail >= min) {
958 /* "Roll back" to client buffer. */
959 filter->client_avail += filter->avail;
960 filter->client_next -= filter->avail;
961 /* Copy buffer is now empty. */
963 filter->next = filter->buffer;
964 /* Return data from client buffer. */
966 *avail = filter->client_avail;
967 return (filter->client_next);
970 /* Move data forward in copy buffer if necessary. */
971 if (filter->next > filter->buffer &&
972 filter->next + min > filter->buffer + filter->buffer_size) {
973 if (filter->avail > 0)
974 memmove(filter->buffer, filter->next, filter->avail);
975 filter->next = filter->buffer;
978 /* If we've used up the client data, get more. */
979 if (filter->client_avail <= 0) {
980 if (filter->end_of_file) {
985 bytes_read = (filter->read)(filter,
986 &filter->client_buff);
987 if (bytes_read < 0) { /* Read error. */
988 filter->client_total = filter->client_avail = 0;
989 filter->client_next = filter->client_buff = NULL;
992 *avail = ARCHIVE_FATAL;
995 if (bytes_read == 0) { /* Premature end-of-file. */
996 filter->client_total = filter->client_avail = 0;
997 filter->client_next = filter->client_buff = NULL;
998 filter->end_of_file = 1;
999 /* Return whatever we do have. */
1001 *avail = filter->avail;
1004 filter->position += bytes_read;
1005 filter->client_total = bytes_read;
1006 filter->client_avail = filter->client_total;
1007 filter->client_next = filter->client_buff;
1012 * We can't satisfy the request from the copy
1013 * buffer or the existing client data, so we
1014 * need to copy more client data over to the
1018 /* Ensure the buffer is big enough. */
1019 if (min > filter->buffer_size) {
1023 /* Double the buffer; watch for overflow. */
1024 s = t = filter->buffer_size;
1029 if (t <= s) { /* Integer overflow! */
1031 &filter->archive->archive,
1033 "Unable to allocate copy buffer");
1036 *avail = ARCHIVE_FATAL;
1041 /* Now s >= min, so allocate a new buffer. */
1042 p = (char *)malloc(s);
1045 &filter->archive->archive,
1047 "Unable to allocate copy buffer");
1050 *avail = ARCHIVE_FATAL;
1053 /* Move data into newly-enlarged buffer. */
1054 if (filter->avail > 0)
1055 memmove(p, filter->next, filter->avail);
1056 free(filter->buffer);
1057 filter->next = filter->buffer = p;
1058 filter->buffer_size = s;
1061 /* We can add client data to copy buffer. */
1062 /* First estimate: copy to fill rest of buffer. */
1063 tocopy = (filter->buffer + filter->buffer_size)
1064 - (filter->next + filter->avail);
1065 /* Don't waste time buffering more than we need to. */
1066 if (tocopy + filter->avail > min)
1067 tocopy = min - filter->avail;
1068 /* Don't copy more than is available. */
1069 if (tocopy > filter->client_avail)
1070 tocopy = filter->client_avail;
1072 memcpy(filter->next + filter->avail, filter->client_next,
1074 /* Remove this data from client buffer. */
1075 filter->client_next += tocopy;
1076 filter->client_avail -= tocopy;
1077 /* add it to copy buffer. */
1078 filter->avail += tocopy;
1084 * Move the file pointer forward. This should be called after
1085 * __archive_read_ahead() returns data to you. Don't try to move
1086 * ahead by more than the amount of data available according to
1087 * __archive_read_ahead().
1090 * Mark the appropriate data as used. Note that the request here will
1091 * often be much smaller than the size of the previous read_ahead
1095 __archive_read_consume(struct archive_read *a, size_t request)
1098 r = __archive_read_filter_consume(a->filter, request);
1099 a->archive.file_position += r;
1104 __archive_read_filter_consume(struct archive_read_filter * filter,
1107 if (filter->avail > 0) {
1108 /* Read came from copy buffer. */
1109 filter->next += request;
1110 filter->avail -= request;
1112 /* Read came from client buffer. */
1113 filter->client_next += request;
1114 filter->client_avail -= request;
1120 * Move the file pointer ahead by an arbitrary amount. If you're
1121 * reading uncompressed data from a disk file, this will actually
1122 * translate into a seek() operation. Even in cases where seek()
1123 * isn't feasible, this at least pushes the read-and-discard loop
1124 * down closer to the data source.
1127 __archive_read_skip(struct archive_read *a, int64_t request)
1129 return (__archive_read_filter_skip(a->filter, request));
1133 __archive_read_filter_skip(struct archive_read_filter *filter, int64_t request)
1135 int64_t bytes_skipped, total_bytes_skipped = 0;
1141 * If there is data in the buffers already, use that first.
1143 if (filter->avail > 0) {
1144 min = minimum(request, (off_t)filter->avail);
1145 bytes_skipped = __archive_read_consume(filter->archive, min);
1146 request -= bytes_skipped;
1147 total_bytes_skipped += bytes_skipped;
1149 if (filter->client_avail > 0) {
1150 min = minimum(request, (int64_t)filter->client_avail);
1151 bytes_skipped = __archive_read_consume(filter->archive, min);
1152 request -= bytes_skipped;
1153 total_bytes_skipped += bytes_skipped;
1156 return (total_bytes_skipped);
1158 * If a client_skipper was provided, try that first.
1160 #if ARCHIVE_API_VERSION < 2
1161 if ((filter->skip != NULL) && (request < SSIZE_MAX)) {
1163 if (filter->skip != NULL) {
1165 bytes_skipped = (filter->skip)(filter, request);
1166 if (bytes_skipped < 0) { /* error */
1167 filter->client_total = filter->client_avail = 0;
1168 filter->client_next = filter->client_buff = NULL;
1170 return (bytes_skipped);
1172 filter->archive->archive.file_position += bytes_skipped;
1173 total_bytes_skipped += bytes_skipped;
1174 request -= bytes_skipped;
1175 filter->client_next = filter->client_buff;
1176 filter->client_avail = filter->client_total = 0;
1179 * Note that client_skipper will usually not satisfy the
1180 * full request (due to low-level blocking concerns),
1181 * so even if client_skipper is provided, we may still
1182 * have to use ordinary reads to finish out the request.
1184 while (request > 0) {
1185 const void* dummy_buffer;
1187 dummy_buffer = __archive_read_ahead(filter->archive,
1190 return (bytes_read);
1191 if (bytes_read == 0) {
1192 /* We hit EOF before we satisfied the skip request. */
1193 archive_set_error(&filter->archive->archive,
1195 "Truncated input file (need to skip %jd bytes)",
1197 return (ARCHIVE_FATAL);
1199 min = (size_t)(minimum(bytes_read, request));
1200 bytes_read = __archive_read_consume(filter->archive, min);
1201 total_bytes_skipped += bytes_read;
1202 request -= bytes_read;
1204 return (total_bytes_skipped);