2 * Copyright (c) 2003-2004 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 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include "archive_platform.h"
28 __FBSDID("$FreeBSD: src/lib/libarchive/archive_read_support_compression_none.c,v 1.8 2006/08/29 04:59:25 kientzle Exp $");
37 #include "archive_private.h"
39 struct archive_decompress_none
{
42 char *next
; /* Current read location. */
43 size_t avail
; /* Bytes in my buffer. */
44 const char *client_buff
; /* Client buffer information. */
46 const char *client_next
;
53 * Size of internal buffer used for combining short reads. This is
54 * also an upper limit on the size of a read request. Recall,
55 * however, that we can (and will!) return blocks of data larger than
56 * this. The read semantics are: you ask for a minimum, I give you a
57 * pointer to my best-effort match and tell you how much data is
58 * there. It could be less than you asked for, it could be much more.
59 * For example, a client might use mmap() to "read" the entire file as
60 * a single block. In that case, I will return that entire block to
63 #define BUFFER_SIZE 65536
65 #define minimum(a, b) (a < b ? a : b)
67 static int archive_decompressor_none_bid(const void *, size_t);
68 static int archive_decompressor_none_finish(struct archive
*);
69 static int archive_decompressor_none_init(struct archive
*,
70 const void *, size_t);
71 static ssize_t
archive_decompressor_none_read_ahead(struct archive
*,
72 const void **, size_t);
73 static ssize_t
archive_decompressor_none_read_consume(struct archive
*,
75 static ssize_t
archive_decompressor_none_skip(struct archive
*, size_t);
78 archive_read_support_compression_none(struct archive
*a
)
80 return (__archive_read_register_compression(a
,
81 archive_decompressor_none_bid
,
82 archive_decompressor_none_init
));
86 * Try to detect an "uncompressed" archive.
89 archive_decompressor_none_bid(const void *buff
, size_t len
)
94 return (1); /* Default: We'll take it if noone else does. */
98 archive_decompressor_none_init(struct archive
*a
, const void *buff
, size_t n
)
100 struct archive_decompress_none
*state
;
102 a
->compression_code
= ARCHIVE_COMPRESSION_NONE
;
103 a
->compression_name
= "none";
105 state
= (struct archive_decompress_none
*)malloc(sizeof(*state
));
107 archive_set_error(a
, ENOMEM
, "Can't allocate input data");
108 return (ARCHIVE_FATAL
);
110 memset(state
, 0, sizeof(*state
));
112 state
->buffer_size
= BUFFER_SIZE
;
113 state
->buffer
= malloc(state
->buffer_size
);
114 state
->next
= state
->buffer
;
115 if (state
->buffer
== NULL
) {
117 archive_set_error(a
, ENOMEM
, "Can't allocate input buffer");
118 return (ARCHIVE_FATAL
);
121 /* Save reference to first block of data. */
122 state
->client_buff
= buff
;
123 state
->client_total
= n
;
124 state
->client_next
= state
->client_buff
;
125 state
->client_avail
= state
->client_total
;
127 a
->compression_data
= state
;
128 a
->compression_read_ahead
= archive_decompressor_none_read_ahead
;
129 a
->compression_read_consume
= archive_decompressor_none_read_consume
;
130 a
->compression_skip
= archive_decompressor_none_skip
;
131 a
->compression_finish
= archive_decompressor_none_finish
;
137 * We just pass through pointers to the client buffer if we can.
138 * If the client buffer is short, then we copy stuff to our internal
139 * buffer to combine reads.
142 archive_decompressor_none_read_ahead(struct archive
*a
, const void **buff
,
145 struct archive_decompress_none
*state
;
148 state
= a
->compression_data
;
153 * Don't make special efforts to handle requests larger than
156 if (min
> state
->buffer_size
)
157 min
= state
->buffer_size
;
160 * Try to satisfy the request directly from the client
161 * buffer. We can do this if all of the data in the copy
162 * buffer was copied from the current client buffer. This
163 * also covers the case where the copy buffer is empty and
164 * the client buffer has all the data we need.
166 if (state
->client_total
>= state
->client_avail
+ state
->avail
167 && state
->client_avail
+ state
->avail
>= min
) {
168 state
->client_avail
+= state
->avail
;
169 state
->client_next
-= state
->avail
;
171 state
->next
= state
->buffer
;
172 *buff
= state
->client_next
;
173 return (state
->client_avail
);
177 * If we can't use client buffer, we'll have to use copy buffer.
180 /* Move data forward in copy buffer if necessary. */
181 if (state
->next
> state
->buffer
&&
182 state
->next
+ min
> state
->buffer
+ state
->buffer_size
) {
183 if (state
->avail
> 0)
184 memmove(state
->buffer
, state
->next
, state
->avail
);
185 state
->next
= state
->buffer
;
188 /* Collect data in copy buffer to fulfill request. */
189 while (state
->avail
< min
) {
190 /* Copy data from client buffer to our copy buffer. */
191 if (state
->client_avail
> 0) {
192 /* First estimate: copy to fill rest of buffer. */
193 size_t tocopy
= (state
->buffer
+ state
->buffer_size
)
194 - (state
->next
+ state
->avail
);
195 /* Don't copy more than is available. */
196 if (tocopy
> state
->client_avail
)
197 tocopy
= state
->client_avail
;
198 memcpy(state
->next
+ state
->avail
, state
->client_next
,
200 state
->client_next
+= tocopy
;
201 state
->client_avail
-= tocopy
;
202 state
->avail
+= tocopy
;
204 /* There is no more client data: fetch more. */
206 * It seems to me that const void ** and const
207 * char ** should be compatible, but they
208 * aren't, hence the cast.
210 bytes_read
= (a
->client_reader
)(a
, a
->client_data
,
211 (const void **)&state
->client_buff
);
212 if (bytes_read
< 0) { /* Read error. */
213 state
->client_total
= state
->client_avail
= 0;
214 state
->client_next
= state
->client_buff
= NULL
;
218 if (bytes_read
== 0) { /* End-of-file. */
219 state
->client_total
= state
->client_avail
= 0;
220 state
->client_next
= state
->client_buff
= NULL
;
221 state
->end_of_file
= 1;
224 a
->raw_position
+= bytes_read
;
225 state
->client_total
= bytes_read
;
226 state
->client_avail
= state
->client_total
;
227 state
->client_next
= state
->client_buff
;
232 return (state
->avail
);
236 * Mark the appropriate data as used. Note that the request here will
237 * often be much smaller than the size of the previous read_ahead
241 archive_decompressor_none_read_consume(struct archive
*a
, size_t request
)
243 struct archive_decompress_none
*state
;
245 state
= a
->compression_data
;
246 if (state
->avail
> 0) {
247 /* Read came from copy buffer. */
248 state
->next
+= request
;
249 state
->avail
-= request
;
251 /* Read came from client buffer. */
252 state
->client_next
+= request
;
253 state
->client_avail
-= request
;
255 a
->file_position
+= request
;
260 * Skip at most request bytes. Skipped data is marked as consumed.
263 archive_decompressor_none_skip(struct archive
*a
, size_t request
)
265 struct archive_decompress_none
*state
;
266 ssize_t bytes_skipped
, total_bytes_skipped
= 0;
269 state
= a
->compression_data
;
273 * If there is data in the buffers already, use that first.
275 if (state
->avail
> 0) {
276 min
= minimum(request
, state
->avail
);
277 bytes_skipped
= archive_decompressor_none_read_consume(a
, min
);
278 request
-= bytes_skipped
;
279 total_bytes_skipped
+= bytes_skipped
;
281 if (state
->client_avail
> 0) {
282 min
= minimum(request
, state
->client_avail
);
283 bytes_skipped
= archive_decompressor_none_read_consume(a
, min
);
284 request
-= bytes_skipped
;
285 total_bytes_skipped
+= bytes_skipped
;
288 return (total_bytes_skipped
);
290 * If no client_skipper is provided, just read the old way. It is very
291 * likely that after skipping, the request has not yet been fully
292 * satisfied (and is still > 0). In that case, read as well.
294 if (a
->client_skipper
!= NULL
) {
295 bytes_skipped
= (a
->client_skipper
)(a
, a
->client_data
,
297 if (bytes_skipped
< 0) { /* error */
298 state
->client_total
= state
->client_avail
= 0;
299 state
->client_next
= state
->client_buff
= NULL
;
301 return (bytes_skipped
);
303 total_bytes_skipped
+= bytes_skipped
;
304 a
->file_position
+= bytes_skipped
;
305 request
-= bytes_skipped
;
306 state
->client_next
= state
->client_buff
;
307 a
->raw_position
+= bytes_skipped
;
308 state
->client_avail
= state
->client_total
= 0;
310 while (request
> 0) {
311 const void* dummy_buffer
;
313 bytes_read
= archive_decompressor_none_read_ahead(a
,
314 &dummy_buffer
, request
);
317 assert(bytes_read
>= 0); /* precondition for cast below */
318 min
= minimum((size_t)bytes_read
, request
);
319 bytes_read
= archive_decompressor_none_read_consume(a
, min
);
320 total_bytes_skipped
+= bytes_read
;
321 request
-= bytes_read
;
323 assert(request
== 0);
324 return (total_bytes_skipped
);
328 archive_decompressor_none_finish(struct archive
*a
)
330 struct archive_decompress_none
*state
;
332 state
= a
->compression_data
;
335 a
->compression_data
= NULL
;
336 if (a
->client_closer
!= NULL
)
337 return ((a
->client_closer
)(a
, a
->client_data
));