bump version number to 1.1.3
[flac.git] / src / libFLAC / float.c
1 /* libFLAC - Free Lossless Audio Codec library
2  * Copyright (C) 2004,2005,2006  Josh Coalson
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * - Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *
11  * - 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.
14  *
15  * - Neither the name of the Xiph.org Foundation nor the names of its
16  * contributors may be used to endorse or promote products derived from
17  * this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31
32 #if HAVE_CONFIG_H
33 #  include <config.h>
34 #endif
35
36 #include "FLAC/assert.h"
37
38 #include "private/float.h"
39
40 #ifdef FLAC__INTEGER_ONLY_LIBRARY
41
42 /* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
43 #ifdef _MSC_VER
44 #define FLAC__U64L(x) x
45 #else
46 #define FLAC__U64L(x) x##LLU
47 #endif
48
49 const FLAC__fixedpoint FLAC__FP_ZERO = 0;
50 const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
51 const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
52 const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
53 const FLAC__fixedpoint FLAC__FP_E = 178145;
54
55 /* Lookup tables for Knuth's logarithm algorithm */
56 #define LOG2_LOOKUP_PRECISION 16
57 static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
58         {
59                 /*
60                  * 0 fraction bits
61                  */
62                 /* undefined */ 0x00000000,
63                 /* lg(2/1) = */ 0x00000001,
64                 /* lg(4/3) = */ 0x00000000,
65                 /* lg(8/7) = */ 0x00000000,
66                 /* lg(16/15) = */ 0x00000000,
67                 /* lg(32/31) = */ 0x00000000,
68                 /* lg(64/63) = */ 0x00000000,
69                 /* lg(128/127) = */ 0x00000000,
70                 /* lg(256/255) = */ 0x00000000,
71                 /* lg(512/511) = */ 0x00000000,
72                 /* lg(1024/1023) = */ 0x00000000,
73                 /* lg(2048/2047) = */ 0x00000000,
74                 /* lg(4096/4095) = */ 0x00000000,
75                 /* lg(8192/8191) = */ 0x00000000,
76                 /* lg(16384/16383) = */ 0x00000000,
77                 /* lg(32768/32767) = */ 0x00000000
78         },
79         {
80                 /*
81                  * 4 fraction bits
82                  */
83                 /* undefined */ 0x00000000,
84                 /* lg(2/1) = */ 0x00000010,
85                 /* lg(4/3) = */ 0x00000007,
86                 /* lg(8/7) = */ 0x00000003,
87                 /* lg(16/15) = */ 0x00000001,
88                 /* lg(32/31) = */ 0x00000001,
89                 /* lg(64/63) = */ 0x00000000,
90                 /* lg(128/127) = */ 0x00000000,
91                 /* lg(256/255) = */ 0x00000000,
92                 /* lg(512/511) = */ 0x00000000,
93                 /* lg(1024/1023) = */ 0x00000000,
94                 /* lg(2048/2047) = */ 0x00000000,
95                 /* lg(4096/4095) = */ 0x00000000,
96                 /* lg(8192/8191) = */ 0x00000000,
97                 /* lg(16384/16383) = */ 0x00000000,
98                 /* lg(32768/32767) = */ 0x00000000
99         },
100         {
101                 /*
102                  * 8 fraction bits
103                  */
104                 /* undefined */ 0x00000000,
105                 /* lg(2/1) = */ 0x00000100,
106                 /* lg(4/3) = */ 0x0000006a,
107                 /* lg(8/7) = */ 0x00000031,
108                 /* lg(16/15) = */ 0x00000018,
109                 /* lg(32/31) = */ 0x0000000c,
110                 /* lg(64/63) = */ 0x00000006,
111                 /* lg(128/127) = */ 0x00000003,
112                 /* lg(256/255) = */ 0x00000001,
113                 /* lg(512/511) = */ 0x00000001,
114                 /* lg(1024/1023) = */ 0x00000000,
115                 /* lg(2048/2047) = */ 0x00000000,
116                 /* lg(4096/4095) = */ 0x00000000,
117                 /* lg(8192/8191) = */ 0x00000000,
118                 /* lg(16384/16383) = */ 0x00000000,
119                 /* lg(32768/32767) = */ 0x00000000
120         },
121         {
122                 /*
123                  * 12 fraction bits
124                  */
125                 /* undefined */ 0x00000000,
126                 /* lg(2/1) = */ 0x00001000,
127                 /* lg(4/3) = */ 0x000006a4,
128                 /* lg(8/7) = */ 0x00000315,
129                 /* lg(16/15) = */ 0x0000017d,
130                 /* lg(32/31) = */ 0x000000bc,
131                 /* lg(64/63) = */ 0x0000005d,
132                 /* lg(128/127) = */ 0x0000002e,
133                 /* lg(256/255) = */ 0x00000017,
134                 /* lg(512/511) = */ 0x0000000c,
135                 /* lg(1024/1023) = */ 0x00000006,
136                 /* lg(2048/2047) = */ 0x00000003,
137                 /* lg(4096/4095) = */ 0x00000001,
138                 /* lg(8192/8191) = */ 0x00000001,
139                 /* lg(16384/16383) = */ 0x00000000,
140                 /* lg(32768/32767) = */ 0x00000000
141         },
142         {
143                 /*
144                  * 16 fraction bits
145                  */
146                 /* undefined */ 0x00000000,
147                 /* lg(2/1) = */ 0x00010000,
148                 /* lg(4/3) = */ 0x00006a40,
149                 /* lg(8/7) = */ 0x00003151,
150                 /* lg(16/15) = */ 0x000017d6,
151                 /* lg(32/31) = */ 0x00000bba,
152                 /* lg(64/63) = */ 0x000005d1,
153                 /* lg(128/127) = */ 0x000002e6,
154                 /* lg(256/255) = */ 0x00000172,
155                 /* lg(512/511) = */ 0x000000b9,
156                 /* lg(1024/1023) = */ 0x0000005c,
157                 /* lg(2048/2047) = */ 0x0000002e,
158                 /* lg(4096/4095) = */ 0x00000017,
159                 /* lg(8192/8191) = */ 0x0000000c,
160                 /* lg(16384/16383) = */ 0x00000006,
161                 /* lg(32768/32767) = */ 0x00000003
162         },
163         {
164                 /*
165                  * 20 fraction bits
166                  */
167                 /* undefined */ 0x00000000,
168                 /* lg(2/1) = */ 0x00100000,
169                 /* lg(4/3) = */ 0x0006a3fe,
170                 /* lg(8/7) = */ 0x00031513,
171                 /* lg(16/15) = */ 0x00017d60,
172                 /* lg(32/31) = */ 0x0000bb9d,
173                 /* lg(64/63) = */ 0x00005d10,
174                 /* lg(128/127) = */ 0x00002e59,
175                 /* lg(256/255) = */ 0x00001721,
176                 /* lg(512/511) = */ 0x00000b8e,
177                 /* lg(1024/1023) = */ 0x000005c6,
178                 /* lg(2048/2047) = */ 0x000002e3,
179                 /* lg(4096/4095) = */ 0x00000171,
180                 /* lg(8192/8191) = */ 0x000000b9,
181                 /* lg(16384/16383) = */ 0x0000005c,
182                 /* lg(32768/32767) = */ 0x0000002e
183         },
184         {
185                 /*
186                  * 24 fraction bits
187                  */
188                 /* undefined */ 0x00000000,
189                 /* lg(2/1) = */ 0x01000000,
190                 /* lg(4/3) = */ 0x006a3fe6,
191                 /* lg(8/7) = */ 0x00315130,
192                 /* lg(16/15) = */ 0x0017d605,
193                 /* lg(32/31) = */ 0x000bb9ca,
194                 /* lg(64/63) = */ 0x0005d0fc,
195                 /* lg(128/127) = */ 0x0002e58f,
196                 /* lg(256/255) = */ 0x0001720e,
197                 /* lg(512/511) = */ 0x0000b8d8,
198                 /* lg(1024/1023) = */ 0x00005c61,
199                 /* lg(2048/2047) = */ 0x00002e2d,
200                 /* lg(4096/4095) = */ 0x00001716,
201                 /* lg(8192/8191) = */ 0x00000b8b,
202                 /* lg(16384/16383) = */ 0x000005c5,
203                 /* lg(32768/32767) = */ 0x000002e3
204         },
205         {
206                 /*
207                  * 28 fraction bits
208                  */
209                 /* undefined */ 0x00000000,
210                 /* lg(2/1) = */ 0x10000000,
211                 /* lg(4/3) = */ 0x06a3fe5c,
212                 /* lg(8/7) = */ 0x03151301,
213                 /* lg(16/15) = */ 0x017d6049,
214                 /* lg(32/31) = */ 0x00bb9ca6,
215                 /* lg(64/63) = */ 0x005d0fba,
216                 /* lg(128/127) = */ 0x002e58f7,
217                 /* lg(256/255) = */ 0x001720da,
218                 /* lg(512/511) = */ 0x000b8d87,
219                 /* lg(1024/1023) = */ 0x0005c60b,
220                 /* lg(2048/2047) = */ 0x0002e2d7,
221                 /* lg(4096/4095) = */ 0x00017160,
222                 /* lg(8192/8191) = */ 0x0000b8ad,
223                 /* lg(16384/16383) = */ 0x00005c56,
224                 /* lg(32768/32767) = */ 0x00002e2b
225         }
226 };
227
228 #if 0
229 static const FLAC__uint64 log2_lookup_wide[] = {
230         {
231                 /*
232                  * 32 fraction bits
233                  */
234                 /* undefined */ 0x00000000,
235                 /* lg(2/1) = */ FLAC__U64L(0x100000000),
236                 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
237                 /* lg(8/7) = */ FLAC__U64L(0x31513015),
238                 /* lg(16/15) = */ FLAC__U64L(0x17d60497),
239                 /* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
240                 /* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
241                 /* lg(128/127) = */ FLAC__U64L(0x02e58f74),
242                 /* lg(256/255) = */ FLAC__U64L(0x01720d9c),
243                 /* lg(512/511) = */ FLAC__U64L(0x00b8d875),
244                 /* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
245                 /* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
246                 /* lg(4096/4095) = */ FLAC__U64L(0x00171600),
247                 /* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
248                 /* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
249                 /* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
250         },
251         {
252                 /*
253                  * 48 fraction bits
254                  */
255                 /* undefined */ 0x00000000,
256                 /* lg(2/1) = */ FLAC__U64L(0x1000000000000),
257                 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
258                 /* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
259                 /* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
260                 /* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
261                 /* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
262                 /* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
263                 /* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
264                 /* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
265                 /* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
266                 /* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
267                 /* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
268                 /* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
269                 /* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
270                 /* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
271         }
272 };
273 #endif
274
275 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision)
276 {
277         const FLAC__uint32 ONE = (1u << fracbits);
278         const FLAC__uint32 *table = log2_lookup[fracbits >> 2];
279
280         FLAC__ASSERT(fracbits < 32);
281         FLAC__ASSERT((fracbits & 0x3) == 0);
282
283         if(x < ONE)
284                 return 0;
285         
286         if(precision > LOG2_LOOKUP_PRECISION)
287                 precision = LOG2_LOOKUP_PRECISION;
288
289         /* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
290         {
291                 FLAC__uint32 y = 0;
292                 FLAC__uint32 z = x >> 1, k = 1;
293                 while (x > ONE && k < precision) {
294                         if (x - z >= ONE) {
295                                 x -= z;
296                                 z = x >> k;
297                                 y += table[k];
298                         }
299                         else {
300                                 z >>= 1;
301                                 k++;
302                         }
303                 }
304                 return y;
305         }
306 }
307
308 #endif /* defined FLAC__INTEGER_ONLY_LIBRARY */