1/*-
2 * Copyright (c) 2008 Joerg Sonnenberger
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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.
24 */
25
26/*-
27 * Copyright (c) 1985, 1986, 1992, 1993
28 *	The Regents of the University of California.  All rights reserved.
29 *
30 * This code is derived from software contributed to Berkeley by
31 * Diomidis Spinellis and James A. Woods, derived from original
32 * work by Spencer Thomas and Joseph Orost.
33 *
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
36 * are met:
37 * 1. Redistributions of source code must retain the above copyright
38 *    notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 *    notice, this list of conditions and the following disclaimer in the
41 *    documentation and/or other materials provided with the distribution.
42 * 3. Neither the name of the University nor the names of its contributors
43 *    may be used to endorse or promote products derived from this software
44 *    without specific prior written permission.
45 *
46 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
47 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
48 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
49 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
50 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
51 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
52 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
53 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
54 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
55 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
56 * SUCH DAMAGE.
57 */
58
59#include "archive_platform.h"
60
61__FBSDID("$FreeBSD: head/lib/libarchive/archive_write_set_compression_compress.c 201111 2009-12-28 03:33:05Z kientzle $");
62
63#ifdef HAVE_ERRNO_H
64#include <errno.h>
65#endif
66#ifdef HAVE_STDLIB_H
67#include <stdlib.h>
68#endif
69#ifdef HAVE_STRING_H
70#include <string.h>
71#endif
72
73#include "archive.h"
74#include "archive_private.h"
75#include "archive_write_private.h"
76
77#define	HSIZE		69001	/* 95% occupancy */
78#define	HSHIFT		8	/* 8 - trunc(log2(HSIZE / 65536)) */
79#define	CHECK_GAP 10000		/* Ratio check interval. */
80
81#define	MAXCODE(bits)	((1 << (bits)) - 1)
82
83/*
84 * the next two codes should not be changed lightly, as they must not
85 * lie within the contiguous general code space.
86 */
87#define	FIRST	257		/* First free entry. */
88#define	CLEAR	256		/* Table clear output code. */
89
90struct private_data {
91	int64_t in_count, out_count, checkpoint;
92
93	int code_len;			/* Number of bits/code. */
94	int cur_maxcode;		/* Maximum code, given n_bits. */
95	int max_maxcode;		/* Should NEVER generate this code. */
96	int hashtab [HSIZE];
97	unsigned short codetab [HSIZE];
98	int first_free;		/* First unused entry. */
99	int compress_ratio;
100
101	int cur_code, cur_fcode;
102
103	int bit_offset;
104	unsigned char bit_buf;
105
106	unsigned char	*compressed;
107	size_t		 compressed_buffer_size;
108	size_t		 compressed_offset;
109};
110
111static int archive_compressor_compress_open(struct archive_write_filter *);
112static int archive_compressor_compress_write(struct archive_write_filter *,
113		    const void *, size_t);
114static int archive_compressor_compress_close(struct archive_write_filter *);
115static int archive_compressor_compress_free(struct archive_write_filter *);
116
117#if ARCHIVE_VERSION_NUMBER < 4000000
118int
119archive_write_set_compression_compress(struct archive *a)
120{
121	__archive_write_filters_free(a);
122	return (archive_write_add_filter_compress(a));
123}
124#endif
125
126/*
127 * Add a compress filter to this write handle.
128 */
129int
130archive_write_add_filter_compress(struct archive *_a)
131{
132	struct archive_write *a = (struct archive_write *)_a;
133	struct archive_write_filter *f = __archive_write_allocate_filter(_a);
134
135	archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
136	    ARCHIVE_STATE_NEW, "archive_write_add_filter_compress");
137	f->open = &archive_compressor_compress_open;
138	f->code = ARCHIVE_FILTER_COMPRESS;
139	f->name = "compress";
140	return (ARCHIVE_OK);
141}
142
143/*
144 * Setup callback.
145 */
146static int
147archive_compressor_compress_open(struct archive_write_filter *f)
148{
149	struct private_data *state;
150	size_t bs = 65536, bpb;
151
152	f->code = ARCHIVE_FILTER_COMPRESS;
153	f->name = "compress";
154
155	state = (struct private_data *)calloc(1, sizeof(*state));
156	if (state == NULL) {
157		archive_set_error(f->archive, ENOMEM,
158		    "Can't allocate data for compression");
159		return (ARCHIVE_FATAL);
160	}
161
162	if (f->archive->magic == ARCHIVE_WRITE_MAGIC) {
163		/* Buffer size should be a multiple number of the of bytes
164		 * per block for performance. */
165		bpb = archive_write_get_bytes_per_block(f->archive);
166		if (bpb > bs)
167			bs = bpb;
168		else if (bpb != 0)
169			bs -= bs % bpb;
170	}
171	state->compressed_buffer_size = bs;
172	state->compressed = malloc(state->compressed_buffer_size);
173
174	if (state->compressed == NULL) {
175		archive_set_error(f->archive, ENOMEM,
176		    "Can't allocate data for compression buffer");
177		free(state);
178		return (ARCHIVE_FATAL);
179	}
180
181	f->write = archive_compressor_compress_write;
182	f->close = archive_compressor_compress_close;
183	f->free = archive_compressor_compress_free;
184
185	state->max_maxcode = 0x10000;	/* Should NEVER generate this code. */
186	state->in_count = 0;		/* Length of input. */
187	state->bit_buf = 0;
188	state->bit_offset = 0;
189	state->out_count = 3;		/* Includes 3-byte header mojo. */
190	state->compress_ratio = 0;
191	state->checkpoint = CHECK_GAP;
192	state->code_len = 9;
193	state->cur_maxcode = MAXCODE(state->code_len);
194	state->first_free = FIRST;
195
196	memset(state->hashtab, 0xff, sizeof(state->hashtab));
197
198	/* Prime output buffer with a gzip header. */
199	state->compressed[0] = 0x1f; /* Compress */
200	state->compressed[1] = 0x9d;
201	state->compressed[2] = 0x90; /* Block mode, 16bit max */
202	state->compressed_offset = 3;
203
204	f->data = state;
205	return (0);
206}
207
208/*-
209 * Output the given code.
210 * Inputs:
211 * 	code:	A n_bits-bit integer.  If == -1, then EOF.  This assumes
212 *		that n_bits <= (long)wordsize - 1.
213 * Outputs:
214 * 	Outputs code to the file.
215 * Assumptions:
216 *	Chars are 8 bits long.
217 * Algorithm:
218 * 	Maintain a BITS character long buffer (so that 8 codes will
219 * fit in it exactly).  Use the VAX insv instruction to insert each
220 * code in turn.  When the buffer fills up empty it and start over.
221 */
222
223static const unsigned char rmask[9] =
224	{0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
225
226static int
227output_byte(struct archive_write_filter *f, unsigned char c)
228{
229	struct private_data *state = f->data;
230
231	state->compressed[state->compressed_offset++] = c;
232	++state->out_count;
233
234	if (state->compressed_buffer_size == state->compressed_offset) {
235		int ret = __archive_write_filter(f->next_filter,
236		    state->compressed, state->compressed_buffer_size);
237		if (ret != ARCHIVE_OK)
238			return ARCHIVE_FATAL;
239		state->compressed_offset = 0;
240	}
241
242	return ARCHIVE_OK;
243}
244
245static int
246output_code(struct archive_write_filter *f, int ocode)
247{
248	struct private_data *state = f->data;
249	int bits, ret, clear_flg, bit_offset;
250
251	clear_flg = ocode == CLEAR;
252
253	/*
254	 * Since ocode is always >= 8 bits, only need to mask the first
255	 * hunk on the left.
256	 */
257	bit_offset = state->bit_offset % 8;
258	state->bit_buf |= (ocode << bit_offset) & 0xff;
259	output_byte(f, state->bit_buf);
260
261	bits = state->code_len - (8 - bit_offset);
262	ocode >>= 8 - bit_offset;
263	/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
264	if (bits >= 8) {
265		output_byte(f, ocode & 0xff);
266		ocode >>= 8;
267		bits -= 8;
268	}
269	/* Last bits. */
270	state->bit_offset += state->code_len;
271	state->bit_buf = ocode & rmask[bits];
272	if (state->bit_offset == state->code_len * 8)
273		state->bit_offset = 0;
274
275	/*
276	 * If the next entry is going to be too big for the ocode size,
277	 * then increase it, if possible.
278	 */
279	if (clear_flg || state->first_free > state->cur_maxcode) {
280	       /*
281		* Write the whole buffer, because the input side won't
282		* discover the size increase until after it has read it.
283		*/
284		if (state->bit_offset > 0) {
285			while (state->bit_offset < state->code_len * 8) {
286				ret = output_byte(f, state->bit_buf);
287				if (ret != ARCHIVE_OK)
288					return ret;
289				state->bit_offset += 8;
290				state->bit_buf = 0;
291			}
292		}
293		state->bit_buf = 0;
294		state->bit_offset = 0;
295
296		if (clear_flg) {
297			state->code_len = 9;
298			state->cur_maxcode = MAXCODE(state->code_len);
299		} else {
300			state->code_len++;
301			if (state->code_len == 16)
302				state->cur_maxcode = state->max_maxcode;
303			else
304				state->cur_maxcode = MAXCODE(state->code_len);
305		}
306	}
307
308	return (ARCHIVE_OK);
309}
310
311static int
312output_flush(struct archive_write_filter *f)
313{
314	struct private_data *state = f->data;
315	int ret;
316
317	/* At EOF, write the rest of the buffer. */
318	if (state->bit_offset % 8) {
319		state->code_len = (state->bit_offset % 8 + 7) / 8;
320		ret = output_byte(f, state->bit_buf);
321		if (ret != ARCHIVE_OK)
322			return ret;
323	}
324
325	return (ARCHIVE_OK);
326}
327
328/*
329 * Write data to the compressed stream.
330 */
331static int
332archive_compressor_compress_write(struct archive_write_filter *f,
333    const void *buff, size_t length)
334{
335	struct private_data *state = (struct private_data *)f->data;
336	int i;
337	int ratio;
338	int c, disp, ret;
339	const unsigned char *bp;
340
341	if (length == 0)
342		return ARCHIVE_OK;
343
344	bp = buff;
345
346	if (state->in_count == 0) {
347		state->cur_code = *bp++;
348		++state->in_count;
349		--length;
350	}
351
352	while (length--) {
353		c = *bp++;
354		state->in_count++;
355		state->cur_fcode = (c << 16) + state->cur_code;
356		i = ((c << HSHIFT) ^ state->cur_code);	/* Xor hashing. */
357
358		if (state->hashtab[i] == state->cur_fcode) {
359			state->cur_code = state->codetab[i];
360			continue;
361		}
362		if (state->hashtab[i] < 0)	/* Empty slot. */
363			goto nomatch;
364		/* Secondary hash (after G. Knott). */
365		if (i == 0)
366			disp = 1;
367		else
368			disp = HSIZE - i;
369 probe:
370		if ((i -= disp) < 0)
371			i += HSIZE;
372
373		if (state->hashtab[i] == state->cur_fcode) {
374			state->cur_code = state->codetab[i];
375			continue;
376		}
377		if (state->hashtab[i] >= 0)
378			goto probe;
379 nomatch:
380		ret = output_code(f, state->cur_code);
381		if (ret != ARCHIVE_OK)
382			return ret;
383		state->cur_code = c;
384		if (state->first_free < state->max_maxcode) {
385			state->codetab[i] = state->first_free++;	/* code -> hashtable */
386			state->hashtab[i] = state->cur_fcode;
387			continue;
388		}
389		if (state->in_count < state->checkpoint)
390			continue;
391
392		state->checkpoint = state->in_count + CHECK_GAP;
393
394		if (state->in_count <= 0x007fffff && state->out_count != 0)
395			ratio = (int)(state->in_count * 256 / state->out_count);
396		else if ((ratio = (int)(state->out_count / 256)) == 0)
397			ratio = 0x7fffffff;
398		else
399			ratio = (int)(state->in_count / ratio);
400
401		if (ratio > state->compress_ratio)
402			state->compress_ratio = ratio;
403		else {
404			state->compress_ratio = 0;
405			memset(state->hashtab, 0xff, sizeof(state->hashtab));
406			state->first_free = FIRST;
407			ret = output_code(f, CLEAR);
408			if (ret != ARCHIVE_OK)
409				return ret;
410		}
411	}
412
413	return (ARCHIVE_OK);
414}
415
416
417/*
418 * Finish the compression...
419 */
420static int
421archive_compressor_compress_close(struct archive_write_filter *f)
422{
423	struct private_data *state = (struct private_data *)f->data;
424	int ret;
425
426	ret = output_code(f, state->cur_code);
427	if (ret != ARCHIVE_OK)
428		return ret;
429	ret = output_flush(f);
430	if (ret != ARCHIVE_OK)
431		return ret;
432
433	/* Write the last block */
434	ret = __archive_write_filter(f->next_filter,
435	    state->compressed, state->compressed_offset);
436	return (ret);
437}
438
439static int
440archive_compressor_compress_free(struct archive_write_filter *f)
441{
442	struct private_data *state = (struct private_data *)f->data;
443
444	free(state->compressed);
445	free(state);
446	return (ARCHIVE_OK);
447}
448