1 /*-
2  * Copyright (c) 2014 Michihiro NAKAJIMA
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 #include "archive_platform.h"
27 
28 __FBSDID("$FreeBSD$");
29 
30 #ifdef HAVE_ERRNO_H
31 #include <errno.h>
32 #endif
33 #include <stdio.h>
34 #ifdef HAVE_STDLIB_H
35 #include <stdlib.h>
36 #endif
37 #ifdef HAVE_STRING_H
38 #include <string.h>
39 #endif
40 #ifdef HAVE_LZ4_H
41 #include <lz4.h>
42 #endif
43 #ifdef HAVE_LZ4HC_H
44 #include <lz4hc.h>
45 #endif
46 
47 #include "archive.h"
48 #include "archive_endian.h"
49 #include "archive_private.h"
50 #include "archive_write_private.h"
51 #include "archive_xxhash.h"
52 
53 #define LZ4_MAGICNUMBER	0x184d2204
54 
55 struct private_data {
56 	int		 compression_level;
57 	unsigned	 header_written:1;
58 	unsigned	 version_number:1;
59 	unsigned	 block_independence:1;
60 	unsigned	 block_checksum:1;
61 	unsigned	 stream_size:1;
62 	unsigned	 stream_checksum:1;
63 	unsigned	 preset_dictionary:1;
64 	unsigned	 block_maximum_size:3;
65 #if defined(HAVE_LIBLZ4) && LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 2
66 	int64_t		 total_in;
67 	char		*out;
68 	char		*out_buffer;
69 	size_t		 out_buffer_size;
70 	size_t		 out_block_size;
71 	char		*in;
72 	char		*in_buffer_allocated;
73 	char		*in_buffer;
74 	size_t		 in_buffer_size;
75 	size_t		 block_size;
76 
77 	void		*xxh32_state;
78 	void		*lz4_stream;
79 #else
80 	struct archive_write_program_data *pdata;
81 #endif
82 };
83 
84 static int archive_filter_lz4_close(struct archive_write_filter *);
85 static int archive_filter_lz4_free(struct archive_write_filter *);
86 static int archive_filter_lz4_open(struct archive_write_filter *);
87 static int archive_filter_lz4_options(struct archive_write_filter *,
88 		    const char *, const char *);
89 static int archive_filter_lz4_write(struct archive_write_filter *,
90 		    const void *, size_t);
91 
92 /*
93  * Add a lz4 compression filter to this write handle.
94  */
95 int
96 archive_write_add_filter_lz4(struct archive *_a)
97 {
98 	struct archive_write *a = (struct archive_write *)_a;
99 	struct archive_write_filter *f = __archive_write_allocate_filter(_a);
100 	struct private_data *data;
101 
102 	archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
103 	    ARCHIVE_STATE_NEW, "archive_write_add_filter_lz4");
104 
105 	data = calloc(1, sizeof(*data));
106 	if (data == NULL) {
107 		archive_set_error(&a->archive, ENOMEM, "Out of memory");
108 		return (ARCHIVE_FATAL);
109 	}
110 
111 	/*
112 	 * Setup default settings.
113 	 */
114 	data->compression_level = 1;
115 	data->version_number = 0x01;
116 	data->block_independence = 1;
117 	data->block_checksum = 0;
118 	data->stream_size = 0;
119 	data->stream_checksum = 1;
120 	data->preset_dictionary = 0;
121 	data->block_maximum_size = 7;
122 
123 	/*
124 	 * Setup a filter setting.
125 	 */
126 	f->data = data;
127 	f->options = &archive_filter_lz4_options;
128 	f->close = &archive_filter_lz4_close;
129 	f->free = &archive_filter_lz4_free;
130 	f->open = &archive_filter_lz4_open;
131 	f->code = ARCHIVE_FILTER_LZ4;
132 	f->name = "lz4";
133 #if defined(HAVE_LIBLZ4) && LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 2
134 	return (ARCHIVE_OK);
135 #else
136 	/*
137 	 * We don't have lz4 library, and execute external lz4 program
138 	 * instead.
139 	 */
140 	data->pdata = __archive_write_program_allocate("lz4");
141 	if (data->pdata == NULL) {
142 		free(data);
143 		archive_set_error(&a->archive, ENOMEM, "Out of memory");
144 		return (ARCHIVE_FATAL);
145 	}
146 	data->compression_level = 0;
147 	archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
148 	    "Using external lz4 program");
149 	return (ARCHIVE_WARN);
150 #endif
151 }
152 
153 /*
154  * Set write options.
155  */
156 static int
157 archive_filter_lz4_options(struct archive_write_filter *f,
158     const char *key, const char *value)
159 {
160 	struct private_data *data = (struct private_data *)f->data;
161 
162 	if (strcmp(key, "compression-level") == 0) {
163 		int val;
164 		if (value == NULL || !((val = value[0] - '0') >= 1 && val <= 9) ||
165 		    value[1] != '\0')
166 			return (ARCHIVE_WARN);
167 
168 #ifndef HAVE_LZ4HC_H
169 		if(val >= 3)
170 		{
171 			archive_set_error(f->archive, ARCHIVE_ERRNO_PROGRAMMER,
172 				"High compression not included in this build");
173 			return (ARCHIVE_FATAL);
174 		}
175 #endif
176 		data->compression_level = val;
177 		return (ARCHIVE_OK);
178 	}
179 	if (strcmp(key, "stream-checksum") == 0) {
180 		data->stream_checksum = value != NULL;
181 		return (ARCHIVE_OK);
182 	}
183 	if (strcmp(key, "block-checksum") == 0) {
184 		data->block_checksum = value != NULL;
185 		return (ARCHIVE_OK);
186 	}
187 	if (strcmp(key, "block-size") == 0) {
188 		if (value == NULL || !(value[0] >= '4' && value[0] <= '7') ||
189 		    value[1] != '\0')
190 			return (ARCHIVE_WARN);
191 		data->block_maximum_size = value[0] - '0';
192 		return (ARCHIVE_OK);
193 	}
194 	if (strcmp(key, "block-dependence") == 0) {
195 		data->block_independence = value == NULL;
196 		return (ARCHIVE_OK);
197 	}
198 
199 	/* Note: The "warn" return is just to inform the options
200 	 * supervisor that we didn't handle it.  It will generate
201 	 * a suitable error if no one used this option. */
202 	return (ARCHIVE_WARN);
203 }
204 
205 #if defined(HAVE_LIBLZ4) && LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 2
206 /* Don't compile this if we don't have liblz4. */
207 
208 static int drive_compressor(struct archive_write_filter *, const char *,
209     size_t);
210 static int drive_compressor_independence(struct archive_write_filter *,
211     const char *, size_t);
212 static int drive_compressor_dependence(struct archive_write_filter *,
213     const char *, size_t);
214 static int lz4_write_stream_descriptor(struct archive_write_filter *);
215 static ssize_t lz4_write_one_block(struct archive_write_filter *, const char *,
216     size_t);
217 
218 
219 /*
220  * Setup callback.
221  */
222 static int
223 archive_filter_lz4_open(struct archive_write_filter *f)
224 {
225 	struct private_data *data = (struct private_data *)f->data;
226 	int ret;
227 	size_t required_size;
228 	static size_t bkmap[] = { 64 * 1024, 256 * 1024, 1 * 1024 * 1024,
229 			   4 * 1024 * 1024 };
230 	size_t pre_block_size;
231 
232 	ret = __archive_write_open_filter(f->next_filter);
233 	if (ret != 0)
234 		return (ret);
235 
236 	if (data->block_maximum_size < 4)
237 		data->block_size = bkmap[0];
238 	else
239 		data->block_size = bkmap[data->block_maximum_size - 4];
240 
241 	required_size = 4 + 15 + 4 + data->block_size + 4 + 4;
242 	if (data->out_buffer_size < required_size) {
243 		size_t bs = required_size, bpb;
244 		free(data->out_buffer);
245 		if (f->archive->magic == ARCHIVE_WRITE_MAGIC) {
246 			/* Buffer size should be a multiple number of
247 			 * the of bytes per block for performance. */
248 			bpb = archive_write_get_bytes_per_block(f->archive);
249 			if (bpb > bs)
250 				bs = bpb;
251 			else if (bpb != 0) {
252 				bs += bpb;
253 				bs -= bs % bpb;
254 			}
255 		}
256 		data->out_block_size = bs;
257 		bs += required_size;
258 		data->out_buffer = malloc(bs);
259 		data->out = data->out_buffer;
260 		data->out_buffer_size = bs;
261 	}
262 
263 	pre_block_size = (data->block_independence)? 0: 64 * 1024;
264 	if (data->in_buffer_size < data->block_size + pre_block_size) {
265 		free(data->in_buffer_allocated);
266 		data->in_buffer_size = data->block_size;
267 		data->in_buffer_allocated =
268 		    malloc(data->in_buffer_size + pre_block_size);
269 		data->in_buffer = data->in_buffer_allocated + pre_block_size;
270 		if (!data->block_independence && data->compression_level >= 3)
271 		    data->in_buffer = data->in_buffer_allocated;
272 		data->in = data->in_buffer;
273 		data->in_buffer_size = data->block_size;
274 	}
275 
276 	if (data->out_buffer == NULL || data->in_buffer_allocated == NULL) {
277 		archive_set_error(f->archive, ENOMEM,
278 		    "Can't allocate data for compression buffer");
279 		return (ARCHIVE_FATAL);
280 	}
281 
282 	f->write = archive_filter_lz4_write;
283 
284 	return (ARCHIVE_OK);
285 }
286 
287 /*
288  * Write data to the out stream.
289  *
290  * Returns ARCHIVE_OK if all data written, error otherwise.
291  */
292 static int
293 archive_filter_lz4_write(struct archive_write_filter *f,
294     const void *buff, size_t length)
295 {
296 	struct private_data *data = (struct private_data *)f->data;
297 	int ret = ARCHIVE_OK;
298 	const char *p;
299 	size_t remaining;
300 	ssize_t size;
301 
302 	/* If we haven't written a stream descriptor, we have to do it first. */
303 	if (!data->header_written) {
304 		ret = lz4_write_stream_descriptor(f);
305 		if (ret != ARCHIVE_OK)
306 			return (ret);
307 		data->header_written = 1;
308 	}
309 
310 	/* Update statistics */
311 	data->total_in += length;
312 
313 	p = (const char *)buff;
314 	remaining = length;
315 	while (remaining) {
316 		size_t l;
317 		/* Compress input data to output buffer */
318 		size = lz4_write_one_block(f, p, remaining);
319 		if (size < ARCHIVE_OK)
320 			return (ARCHIVE_FATAL);
321 		l = data->out - data->out_buffer;
322 		if (l >= data->out_block_size) {
323 			ret = __archive_write_filter(f->next_filter,
324 			    data->out_buffer, data->out_block_size);
325 			l -= data->out_block_size;
326 			memcpy(data->out_buffer,
327 			    data->out_buffer + data->out_block_size, l);
328 			data->out = data->out_buffer + l;
329 			if (ret < ARCHIVE_WARN)
330 				break;
331 		}
332 		p += size;
333 		remaining -= size;
334 	}
335 
336 	return (ret);
337 }
338 
339 /*
340  * Finish the compression.
341  */
342 static int
343 archive_filter_lz4_close(struct archive_write_filter *f)
344 {
345 	struct private_data *data = (struct private_data *)f->data;
346 	int ret, r1;
347 
348 	/* Finish compression cycle. */
349 	ret = (int)lz4_write_one_block(f, NULL, 0);
350 	if (ret >= 0) {
351 		/*
352 		 * Write the last block and the end of the stream data.
353 		 */
354 
355 		/* Write End Of Stream. */
356 		memset(data->out, 0, 4); data->out += 4;
357 		/* Write Stream checksum if needed. */
358 		if (data->stream_checksum) {
359 			unsigned int checksum;
360 			checksum = __archive_xxhash.XXH32_digest(
361 					data->xxh32_state);
362 			data->xxh32_state = NULL;
363 			archive_le32enc(data->out, checksum);
364 			data->out += 4;
365 		}
366 		ret = __archive_write_filter(f->next_filter,
367 			    data->out_buffer, data->out - data->out_buffer);
368 	}
369 
370 	r1 = __archive_write_close_filter(f->next_filter);
371 	return (r1 < ret ? r1 : ret);
372 }
373 
374 static int
375 archive_filter_lz4_free(struct archive_write_filter *f)
376 {
377 	struct private_data *data = (struct private_data *)f->data;
378 
379 	if (data->lz4_stream != NULL) {
380 #ifdef HAVE_LZ4HC_H
381 		if (data->compression_level >= 3)
382 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
383 			LZ4_freeStreamHC(data->lz4_stream);
384 #else
385 			LZ4_freeHC(data->lz4_stream);
386 #endif
387 		else
388 #endif
389 #if LZ4_VERSION_MINOR >= 3
390 			LZ4_freeStream(data->lz4_stream);
391 #else
392 			LZ4_free(data->lz4_stream);
393 #endif
394 	}
395 	free(data->out_buffer);
396 	free(data->in_buffer_allocated);
397 	free(data->xxh32_state);
398 	free(data);
399 	f->data = NULL;
400 	return (ARCHIVE_OK);
401 }
402 
403 static int
404 lz4_write_stream_descriptor(struct archive_write_filter *f)
405 {
406 	struct private_data *data = (struct private_data *)f->data;
407 	uint8_t *sd;
408 
409 	sd = (uint8_t *)data->out;
410 	/* Write Magic Number. */
411 	archive_le32enc(&sd[0], LZ4_MAGICNUMBER);
412 	/* FLG */
413 	sd[4] = (data->version_number << 6)
414 	      | (data->block_independence << 5)
415 	      | (data->block_checksum << 4)
416 	      | (data->stream_size << 3)
417 	      | (data->stream_checksum << 2)
418 	      | (data->preset_dictionary << 0);
419 	/* BD */
420 	sd[5] = (data->block_maximum_size << 4);
421 	sd[6] = (__archive_xxhash.XXH32(&sd[4], 2, 0) >> 8) & 0xff;
422 	data->out += 7;
423 	if (data->stream_checksum)
424 		data->xxh32_state = __archive_xxhash.XXH32_init(0);
425 	else
426 		data->xxh32_state = NULL;
427 	return (ARCHIVE_OK);
428 }
429 
430 static ssize_t
431 lz4_write_one_block(struct archive_write_filter *f, const char *p,
432     size_t length)
433 {
434 	struct private_data *data = (struct private_data *)f->data;
435 	ssize_t r;
436 
437 	if (p == NULL) {
438 		/* Compress remaining uncompressed data. */
439 		if (data->in_buffer == data->in)
440 			return 0;
441 		else {
442 			size_t l = data->in - data->in_buffer;
443 			r = drive_compressor(f, data->in_buffer, l);
444 			if (r == ARCHIVE_OK)
445 				r = (ssize_t)l;
446 		}
447 	} else if ((data->block_independence || data->compression_level < 3) &&
448 	    data->in_buffer == data->in && length >= data->block_size) {
449 		r = drive_compressor(f, p, data->block_size);
450 		if (r == ARCHIVE_OK)
451 			r = (ssize_t)data->block_size;
452 	} else {
453 		size_t remaining_size = data->in_buffer_size -
454 			(data->in - data->in_buffer);
455 		size_t l = (remaining_size > length)? length: remaining_size;
456 		memcpy(data->in, p, l);
457 		data->in += l;
458 		if (l == remaining_size) {
459 			r = drive_compressor(f, data->in_buffer,
460 			    data->block_size);
461 			if (r == ARCHIVE_OK)
462 				r = (ssize_t)l;
463 			data->in = data->in_buffer;
464 		} else
465 			r = (ssize_t)l;
466 	}
467 
468 	return (r);
469 }
470 
471 
472 /*
473  * Utility function to push input data through compressor, writing
474  * full output blocks as necessary.
475  *
476  * Note that this handles both the regular write case (finishing ==
477  * false) and the end-of-archive case (finishing == true).
478  */
479 static int
480 drive_compressor(struct archive_write_filter *f, const char *p, size_t length)
481 {
482 	struct private_data *data = (struct private_data *)f->data;
483 
484 	if (data->stream_checksum)
485 		__archive_xxhash.XXH32_update(data->xxh32_state,
486 			p, (int)length);
487 	if (data->block_independence)
488 		return drive_compressor_independence(f, p, length);
489 	else
490 		return drive_compressor_dependence(f, p, length);
491 }
492 
493 static int
494 drive_compressor_independence(struct archive_write_filter *f, const char *p,
495     size_t length)
496 {
497 	struct private_data *data = (struct private_data *)f->data;
498 	unsigned int outsize;
499 
500 #ifdef HAVE_LZ4HC_H
501 	if (data->compression_level >= 3)
502 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
503 		outsize = LZ4_compress_HC(p, data->out + 4,
504 		     (int)length, (int)data->block_size,
505 		    data->compression_level);
506 #else
507 		outsize = LZ4_compressHC2_limitedOutput(p, data->out + 4,
508 		    (int)length, (int)data->block_size,
509 		    data->compression_level);
510 #endif
511 	else
512 #endif
513 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
514 		outsize = LZ4_compress_default(p, data->out + 4,
515 		    (int)length, (int)data->block_size);
516 #else
517 		outsize = LZ4_compress_limitedOutput(p, data->out + 4,
518 		    (int)length, (int)data->block_size);
519 #endif
520 
521 	if (outsize) {
522 		/* The buffer is compressed. */
523 		archive_le32enc(data->out, outsize);
524 		data->out += 4;
525 	} else {
526 		/* The buffer is not compressed. The commpressed size was
527 		 * bigger than its uncompressed size. */
528 		archive_le32enc(data->out, length | 0x80000000);
529 		data->out += 4;
530 		memcpy(data->out, p, length);
531 		outsize = length;
532 	}
533 	data->out += outsize;
534 	if (data->block_checksum) {
535 		unsigned int checksum =
536 		    __archive_xxhash.XXH32(data->out - outsize, outsize, 0);
537 		archive_le32enc(data->out, checksum);
538 		data->out += 4;
539 	}
540 	return (ARCHIVE_OK);
541 }
542 
543 static int
544 drive_compressor_dependence(struct archive_write_filter *f, const char *p,
545     size_t length)
546 {
547 	struct private_data *data = (struct private_data *)f->data;
548 	int outsize;
549 
550 #define DICT_SIZE	(64 * 1024)
551 #ifdef HAVE_LZ4HC_H
552 	if (data->compression_level >= 3) {
553 		if (data->lz4_stream == NULL) {
554 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
555 			data->lz4_stream = LZ4_createStreamHC();
556 			LZ4_resetStreamHC(data->lz4_stream, data->compression_level);
557 #else
558 			data->lz4_stream =
559 			    LZ4_createHC(data->in_buffer_allocated);
560 #endif
561 			if (data->lz4_stream == NULL) {
562 				archive_set_error(f->archive, ENOMEM,
563 				    "Can't allocate data for compression"
564 				    " buffer");
565 				return (ARCHIVE_FATAL);
566 			}
567 		}
568 		else
569 			LZ4_loadDictHC(data->lz4_stream, data->in_buffer_allocated, DICT_SIZE);
570 
571 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
572 		outsize = LZ4_compress_HC_continue(
573 		    data->lz4_stream, p, data->out + 4, (int)length,
574 		    (int)data->block_size);
575 #else
576 		outsize = LZ4_compressHC2_limitedOutput_continue(
577 		    data->lz4_stream, p, data->out + 4, (int)length,
578 		    (int)data->block_size, data->compression_level);
579 #endif
580 	} else
581 #endif
582 	{
583 		if (data->lz4_stream == NULL) {
584 			data->lz4_stream = LZ4_createStream();
585 			if (data->lz4_stream == NULL) {
586 				archive_set_error(f->archive, ENOMEM,
587 				    "Can't allocate data for compression"
588 				    " buffer");
589 				return (ARCHIVE_FATAL);
590 			}
591 		}
592 		else
593 			LZ4_loadDict(data->lz4_stream, data->in_buffer_allocated, DICT_SIZE);
594 
595 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
596 		outsize = LZ4_compress_fast_continue(
597 		    data->lz4_stream, p, data->out + 4, (int)length,
598 		    (int)data->block_size, 1);
599 #else
600 		outsize = LZ4_compress_limitedOutput_continue(
601 		    data->lz4_stream, p, data->out + 4, (int)length,
602 		    (int)data->block_size);
603 #endif
604 	}
605 
606 	if (outsize) {
607 		/* The buffer is compressed. */
608 		archive_le32enc(data->out, outsize);
609 		data->out += 4;
610 	} else {
611 		/* The buffer is not compressed. The commpressed size was
612 		 * bigger than its uncompressed size. */
613 		archive_le32enc(data->out, length | 0x80000000);
614 		data->out += 4;
615 		memcpy(data->out, p, length);
616 		outsize = length;
617 	}
618 	data->out += outsize;
619 	if (data->block_checksum) {
620 		unsigned int checksum =
621 		    __archive_xxhash.XXH32(data->out - outsize, outsize, 0);
622 		archive_le32enc(data->out, checksum);
623 		data->out += 4;
624 	}
625 
626 	if (length == data->block_size) {
627 #ifdef HAVE_LZ4HC_H
628 		if (data->compression_level >= 3) {
629 #if LZ4_VERSION_MAJOR >= 1 && LZ4_VERSION_MINOR >= 7
630 			LZ4_saveDictHC(data->lz4_stream, data->in_buffer_allocated, DICT_SIZE);
631 #else
632 			LZ4_slideInputBufferHC(data->lz4_stream);
633 #endif
634 			data->in_buffer = data->in_buffer_allocated + DICT_SIZE;
635 		}
636 		else
637 #endif
638 			LZ4_saveDict(data->lz4_stream,
639 			    data->in_buffer_allocated, DICT_SIZE);
640 #undef DICT_SIZE
641 	}
642 	return (ARCHIVE_OK);
643 }
644 
645 #else /* HAVE_LIBLZ4 */
646 
647 static int
648 archive_filter_lz4_open(struct archive_write_filter *f)
649 {
650 	struct private_data *data = (struct private_data *)f->data;
651 	struct archive_string as;
652 	int r;
653 
654 	archive_string_init(&as);
655 	archive_strcpy(&as, "lz4 -z -q -q");
656 
657 	/* Specify a compression level. */
658 	if (data->compression_level > 0) {
659 		archive_strcat(&as, " -");
660 		archive_strappend_char(&as, '0' + data->compression_level);
661 	}
662 	/* Specify a block size. */
663 	archive_strcat(&as, " -B");
664 	archive_strappend_char(&as, '0' + data->block_maximum_size);
665 
666 	if (data->block_checksum)
667 		archive_strcat(&as, " -BX");
668 	if (data->stream_checksum == 0)
669 		archive_strcat(&as, " --no-frame-crc");
670 	if (data->block_independence == 0)
671 		archive_strcat(&as, " -BD");
672 
673 	f->write = archive_filter_lz4_write;
674 
675 	r = __archive_write_program_open(f, data->pdata, as.s);
676 	archive_string_free(&as);
677 	return (r);
678 }
679 
680 static int
681 archive_filter_lz4_write(struct archive_write_filter *f, const void *buff,
682     size_t length)
683 {
684 	struct private_data *data = (struct private_data *)f->data;
685 
686 	return __archive_write_program_write(f, data->pdata, buff, length);
687 }
688 
689 static int
690 archive_filter_lz4_close(struct archive_write_filter *f)
691 {
692 	struct private_data *data = (struct private_data *)f->data;
693 
694 	return __archive_write_program_close(f, data->pdata);
695 }
696 
697 static int
698 archive_filter_lz4_free(struct archive_write_filter *f)
699 {
700 	struct private_data *data = (struct private_data *)f->data;
701 
702 	__archive_write_program_free(data->pdata);
703 	free(data);
704 	return (ARCHIVE_OK);
705 }
706 
707 #endif /* HAVE_LIBLZ4 */
708