Merge branch 'singlecompression' into single
[kai/samba-autobuild/.git] / compression / lzxpress.c
1 /*
2  * Copyright (C) Matthieu Suiche 2008
3  *
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the author nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  */
34
35 #include "replace.h"
36 #include "lzxpress.h"
37
38
39 #define __BUF_POS_CONST(buf,ofs)(((const uint8_t *)buf)+(ofs))
40 #define __PULL_BYTE(buf,ofs) \
41         ((uint8_t)((*__BUF_POS_CONST(buf,ofs)) & 0xFF))
42
43 #ifndef PULL_LE_UINT16
44 #define PULL_LE_UINT16(buf,ofs) ((uint16_t)( \
45         ((uint16_t)(((uint16_t)(__PULL_BYTE(buf,(ofs)+0))) << 0)) | \
46         ((uint16_t)(((uint16_t)(__PULL_BYTE(buf,(ofs)+1))) << 8)) \
47 ))
48 #endif
49
50 #ifndef PULL_LE_UINT32
51 #define PULL_LE_UINT32(buf,ofs) ((uint32_t)( \
52         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+0))) <<  0)) | \
53         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+1))) <<  8)) | \
54         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+2))) << 16)) | \
55         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+3))) << 24)) \
56 ))
57 #endif
58
59 ssize_t lzxpress_compress(const uint8_t *uncompressed,
60                           uint32_t uncompressed_size,
61                           uint8_t *compressed,
62                           uint32_t max_compressed_size)
63 {
64         uint32_t uncompressed_pos, compressed_pos, byte_left;
65         uint32_t max_offset, best_offset;
66         int32_t offset;
67         uint32_t max_len, len, best_len;
68         const uint8_t *str1, *str2;
69         uint32_t indic;
70         uint8_t *indic_pos;
71         uint32_t indic_bit, nibble_index;
72
73         uint32_t metadata_size;
74         uint16_t metadata;
75         uint16_t *dest;
76
77         if (!uncompressed_size) {
78                 return 0;
79         }
80
81         uncompressed_pos = 0;
82         indic = 0;
83         compressed_pos = sizeof(uint32_t);
84         indic_pos = &compressed[0];
85
86         byte_left = uncompressed_size;
87         indic_bit = 0;
88         nibble_index = 0;
89
90         if (uncompressed_pos > XPRESS_BLOCK_SIZE)
91                 return 0;
92
93         do {
94                 bool found = false;
95
96                 max_offset = uncompressed_pos;
97
98                 str1 = &uncompressed[uncompressed_pos];
99
100                 best_len = 2;
101                 best_offset = 0;
102
103                 max_offset = MIN(0x1FFF, max_offset);
104
105                 /* search for the longest match in the window for the lookahead buffer */
106                 for (offset = 1; (uint32_t)offset <= max_offset; offset++) {
107                         str2 = &str1[-offset];
108
109                         /* maximum len we can encode into metadata */
110                         max_len = MIN((255 + 15 + 7 + 3), byte_left);
111
112                         for (len = 0; (len < max_len) && (str1[len] == str2[len]); len++);
113
114                         /*
115                          * We check if len is better than the value found before, including the
116                          * sequence of identical bytes
117                          */
118                         if (len > best_len) {
119                                 found = true;
120                                 best_len = len;
121                                 best_offset = offset;
122                         }
123                 }
124
125                 if (found) {
126                         metadata_size = 0;
127                         dest = (uint16_t *)&compressed[compressed_pos];
128
129                         if (best_len < 10) {
130                                 /* Classical meta-data */
131                                 metadata = (uint16_t)(((best_offset - 1) << 3) | (best_len - 3));
132                                 dest[metadata_size / sizeof(uint16_t)] = metadata;
133                                 metadata_size += sizeof(uint16_t);
134                         } else {
135                                 metadata = (uint16_t)(((best_offset - 1) << 3) | 7);
136                                 dest[metadata_size / sizeof(uint16_t)] = metadata;
137                                 metadata_size = sizeof(uint16_t);
138
139                                 if (best_len < (15 + 7 + 3)) {
140                                         /* Shared byte */
141                                         if (!nibble_index) {
142                                                 compressed[compressed_pos + metadata_size] = (best_len - (3 + 7)) & 0xF;
143                                                 metadata_size += sizeof(uint8_t);
144                                         } else {
145                                                 compressed[nibble_index] &= 0xF;
146                                                 compressed[nibble_index] |= (best_len - (3 + 7)) * 16;
147                                         }
148                                 } else if (best_len < (3 + 7 + 15 + 255)) {
149                                         /* Shared byte */
150                                         if (!nibble_index) {
151                                                 compressed[compressed_pos + metadata_size] = 15;
152                                                 metadata_size += sizeof(uint8_t);
153                                         } else {
154                                                 compressed[nibble_index] &= 0xF;
155                                                 compressed[nibble_index] |= (15 * 16);
156                                         }
157
158                                         /* Additionnal best_len */
159                                         compressed[compressed_pos + metadata_size] = (best_len - (3 + 7 + 15)) & 0xFF;
160                                         metadata_size += sizeof(uint8_t);
161                                 } else {
162                                         /* Shared byte */
163                                         if (!nibble_index) {
164                                                 compressed[compressed_pos + metadata_size] |= 15;
165                                                 metadata_size += sizeof(uint8_t);
166                                         } else {
167                                                 compressed[nibble_index] |= 15 << 4;
168                                         }
169
170                                         /* Additionnal best_len */
171                                         compressed[compressed_pos + metadata_size] = 255;
172
173                                         metadata_size += sizeof(uint8_t);
174
175                                         compressed[compressed_pos + metadata_size] = (best_len - 3) & 0xFF;
176                                         compressed[compressed_pos + metadata_size + 1] = ((best_len - 3) >> 8) & 0xFF;
177                                         metadata_size += sizeof(uint16_t);
178                                 }
179                         }
180
181                         indic |= 1 << (32 - ((indic_bit % 32) + 1));
182
183                         if (best_len > 9) {
184                                 if (nibble_index == 0) {
185                                         nibble_index = compressed_pos + sizeof(uint16_t);
186                                 } else {
187                                         nibble_index = 0;
188                                 }
189                         }
190
191                         compressed_pos += metadata_size;
192                         uncompressed_pos += best_len;
193                         byte_left -= best_len;
194                 } else {
195                         compressed[compressed_pos++] = uncompressed[uncompressed_pos++];
196                         byte_left--;
197                 }
198                 indic_bit++;
199
200                 if ((indic_bit - 1) % 32 > (indic_bit % 32)) {
201                         *(uint32_t *)indic_pos = indic;
202                         indic = 0;
203                         indic_pos = &compressed[compressed_pos];
204                         compressed_pos += sizeof(uint32_t);
205                 }
206         } while (byte_left > 3);
207
208         do {
209                 compressed[compressed_pos] = uncompressed[uncompressed_pos];
210                 indic_bit++;
211
212                 uncompressed_pos++;
213                 compressed_pos++;
214                 if (((indic_bit - 1) % 32) > (indic_bit % 32)){
215                         *(uint32_t *)indic_pos = indic;
216                         indic = 0;
217                         indic_pos = &compressed[compressed_pos];
218                         compressed_pos += sizeof(uint32_t);
219                 }
220         } while (uncompressed_pos < uncompressed_size);
221
222         if ((indic_bit % 32) > 0) {
223                 for (; (indic_bit % 32) != 0; indic_bit++)
224                         indic |= 0 << (32 - ((indic_bit % 32) + 1));
225
226                 *(uint32_t *)indic_pos = indic;
227                 compressed_pos += sizeof(uint32_t);
228         }
229
230         return compressed_pos;
231 }
232
233 ssize_t lzxpress_decompress(const uint8_t *input,
234                             uint32_t input_size,
235                             uint8_t *output,
236                             uint32_t max_output_size)
237 {
238         uint32_t output_index, input_index;
239         uint32_t indicator, indicator_bit;
240         uint32_t length;
241         uint32_t offset;
242         uint32_t nibble_index;
243
244         output_index = 0;
245         input_index = 0;
246         indicator = 0;
247         indicator_bit = 0;
248         length = 0;
249         offset = 0;
250         nibble_index = 0;
251
252         do {
253                 if (indicator_bit == 0) {
254                         indicator = PULL_LE_UINT32(input, input_index);
255                         input_index += sizeof(uint32_t);
256                         indicator_bit = 32;
257                 }
258                 indicator_bit--;
259
260                 /*
261                  * check whether the bit specified by indicator_bit is set or not
262                  * set in indicator. For example, if indicator_bit has value 4
263                  * check whether the 4th bit of the value in indicator is set
264                  */
265                 if (((indicator >> indicator_bit) & 1) == 0) {
266                         output[output_index] = input[input_index];
267                         input_index += sizeof(uint8_t);
268                         output_index += sizeof(uint8_t);
269                 } else {
270                         length = PULL_LE_UINT16(input, input_index);
271                         input_index += sizeof(uint16_t);
272                         offset = length / 8;
273                         length = length % 8;
274
275                         if (length == 7) {
276                                 if (nibble_index == 0) {
277                                         nibble_index = input_index;
278                                         length = input[input_index] % 16;
279                                         input_index += sizeof(uint8_t);
280                                 } else {
281                                         length = input[nibble_index] / 16;
282                                         nibble_index = 0;
283                                 }
284
285                                 if (length == 15) {
286                                         length = input[input_index];
287                                         input_index += sizeof(uint8_t);
288                                         if (length == 255) {
289                                                 length = PULL_LE_UINT16(input, input_index);
290                                                 input_index += sizeof(uint16_t);
291                                                 length -= (15 + 7);
292                                         }
293                                         length += 15;
294                                 }
295                                 length += 7;
296                         }
297
298                         length += 3;
299
300                         do {
301                                 if ((output_index >= max_output_size) || ((offset + 1) > output_index)) break;
302
303                                 output[output_index] = output[output_index - offset - 1];
304
305                                 output_index += sizeof(uint8_t);
306                                 length -= sizeof(uint8_t);
307                         } while (length != 0);
308                 }
309         } while ((output_index < max_output_size) && (input_index < (input_size)));
310
311         return output_index;
312 }