1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2004-2009 Josh Coalson
3 * Copyright (C) 2011-2016 Xiph.Org Foundation
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 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * - Neither the name of the Xiph.org Foundation nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #ifdef HAVE_CONFIG_H
34 # include <config.h>
35 #endif
36
37 #include "FLAC/assert.h"
38 #include "share/compat.h"
39 #include "private/float.h"
40
41 #ifdef FLAC__INTEGER_ONLY_LIBRARY
42
43 const FLAC__fixedpoint FLAC__FP_ZERO = 0;
44 const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
45 const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
46 const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
47 const FLAC__fixedpoint FLAC__FP_E = 178145;
48
49 /* Lookup tables for Knuth's logarithm algorithm */
50 #define LOG2_LOOKUP_PRECISION 16
51 static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
52 {
53 /*
54 * 0 fraction bits
55 */
56 /* undefined */ 0x00000000,
57 /* lg(2/1) = */ 0x00000001,
58 /* lg(4/3) = */ 0x00000000,
59 /* lg(8/7) = */ 0x00000000,
60 /* lg(16/15) = */ 0x00000000,
61 /* lg(32/31) = */ 0x00000000,
62 /* lg(64/63) = */ 0x00000000,
63 /* lg(128/127) = */ 0x00000000,
64 /* lg(256/255) = */ 0x00000000,
65 /* lg(512/511) = */ 0x00000000,
66 /* lg(1024/1023) = */ 0x00000000,
67 /* lg(2048/2047) = */ 0x00000000,
68 /* lg(4096/4095) = */ 0x00000000,
69 /* lg(8192/8191) = */ 0x00000000,
70 /* lg(16384/16383) = */ 0x00000000,
71 /* lg(32768/32767) = */ 0x00000000
72 },
73 {
74 /*
75 * 4 fraction bits
76 */
77 /* undefined */ 0x00000000,
78 /* lg(2/1) = */ 0x00000010,
79 /* lg(4/3) = */ 0x00000007,
80 /* lg(8/7) = */ 0x00000003,
81 /* lg(16/15) = */ 0x00000001,
82 /* lg(32/31) = */ 0x00000001,
83 /* lg(64/63) = */ 0x00000000,
84 /* lg(128/127) = */ 0x00000000,
85 /* lg(256/255) = */ 0x00000000,
86 /* lg(512/511) = */ 0x00000000,
87 /* lg(1024/1023) = */ 0x00000000,
88 /* lg(2048/2047) = */ 0x00000000,
89 /* lg(4096/4095) = */ 0x00000000,
90 /* lg(8192/8191) = */ 0x00000000,
91 /* lg(16384/16383) = */ 0x00000000,
92 /* lg(32768/32767) = */ 0x00000000
93 },
94 {
95 /*
96 * 8 fraction bits
97 */
98 /* undefined */ 0x00000000,
99 /* lg(2/1) = */ 0x00000100,
100 /* lg(4/3) = */ 0x0000006a,
101 /* lg(8/7) = */ 0x00000031,
102 /* lg(16/15) = */ 0x00000018,
103 /* lg(32/31) = */ 0x0000000c,
104 /* lg(64/63) = */ 0x00000006,
105 /* lg(128/127) = */ 0x00000003,
106 /* lg(256/255) = */ 0x00000001,
107 /* lg(512/511) = */ 0x00000001,
108 /* lg(1024/1023) = */ 0x00000000,
109 /* lg(2048/2047) = */ 0x00000000,
110 /* lg(4096/4095) = */ 0x00000000,
111 /* lg(8192/8191) = */ 0x00000000,
112 /* lg(16384/16383) = */ 0x00000000,
113 /* lg(32768/32767) = */ 0x00000000
114 },
115 {
116 /*
117 * 12 fraction bits
118 */
119 /* undefined */ 0x00000000,
120 /* lg(2/1) = */ 0x00001000,
121 /* lg(4/3) = */ 0x000006a4,
122 /* lg(8/7) = */ 0x00000315,
123 /* lg(16/15) = */ 0x0000017d,
124 /* lg(32/31) = */ 0x000000bc,
125 /* lg(64/63) = */ 0x0000005d,
126 /* lg(128/127) = */ 0x0000002e,
127 /* lg(256/255) = */ 0x00000017,
128 /* lg(512/511) = */ 0x0000000c,
129 /* lg(1024/1023) = */ 0x00000006,
130 /* lg(2048/2047) = */ 0x00000003,
131 /* lg(4096/4095) = */ 0x00000001,
132 /* lg(8192/8191) = */ 0x00000001,
133 /* lg(16384/16383) = */ 0x00000000,
134 /* lg(32768/32767) = */ 0x00000000
135 },
136 {
137 /*
138 * 16 fraction bits
139 */
140 /* undefined */ 0x00000000,
141 /* lg(2/1) = */ 0x00010000,
142 /* lg(4/3) = */ 0x00006a40,
143 /* lg(8/7) = */ 0x00003151,
144 /* lg(16/15) = */ 0x000017d6,
145 /* lg(32/31) = */ 0x00000bba,
146 /* lg(64/63) = */ 0x000005d1,
147 /* lg(128/127) = */ 0x000002e6,
148 /* lg(256/255) = */ 0x00000172,
149 /* lg(512/511) = */ 0x000000b9,
150 /* lg(1024/1023) = */ 0x0000005c,
151 /* lg(2048/2047) = */ 0x0000002e,
152 /* lg(4096/4095) = */ 0x00000017,
153 /* lg(8192/8191) = */ 0x0000000c,
154 /* lg(16384/16383) = */ 0x00000006,
155 /* lg(32768/32767) = */ 0x00000003
156 },
157 {
158 /*
159 * 20 fraction bits
160 */
161 /* undefined */ 0x00000000,
162 /* lg(2/1) = */ 0x00100000,
163 /* lg(4/3) = */ 0x0006a3fe,
164 /* lg(8/7) = */ 0x00031513,
165 /* lg(16/15) = */ 0x00017d60,
166 /* lg(32/31) = */ 0x0000bb9d,
167 /* lg(64/63) = */ 0x00005d10,
168 /* lg(128/127) = */ 0x00002e59,
169 /* lg(256/255) = */ 0x00001721,
170 /* lg(512/511) = */ 0x00000b8e,
171 /* lg(1024/1023) = */ 0x000005c6,
172 /* lg(2048/2047) = */ 0x000002e3,
173 /* lg(4096/4095) = */ 0x00000171,
174 /* lg(8192/8191) = */ 0x000000b9,
175 /* lg(16384/16383) = */ 0x0000005c,
176 /* lg(32768/32767) = */ 0x0000002e
177 },
178 {
179 /*
180 * 24 fraction bits
181 */
182 /* undefined */ 0x00000000,
183 /* lg(2/1) = */ 0x01000000,
184 /* lg(4/3) = */ 0x006a3fe6,
185 /* lg(8/7) = */ 0x00315130,
186 /* lg(16/15) = */ 0x0017d605,
187 /* lg(32/31) = */ 0x000bb9ca,
188 /* lg(64/63) = */ 0x0005d0fc,
189 /* lg(128/127) = */ 0x0002e58f,
190 /* lg(256/255) = */ 0x0001720e,
191 /* lg(512/511) = */ 0x0000b8d8,
192 /* lg(1024/1023) = */ 0x00005c61,
193 /* lg(2048/2047) = */ 0x00002e2d,
194 /* lg(4096/4095) = */ 0x00001716,
195 /* lg(8192/8191) = */ 0x00000b8b,
196 /* lg(16384/16383) = */ 0x000005c5,
197 /* lg(32768/32767) = */ 0x000002e3
198 },
199 {
200 /*
201 * 28 fraction bits
202 */
203 /* undefined */ 0x00000000,
204 /* lg(2/1) = */ 0x10000000,
205 /* lg(4/3) = */ 0x06a3fe5c,
206 /* lg(8/7) = */ 0x03151301,
207 /* lg(16/15) = */ 0x017d6049,
208 /* lg(32/31) = */ 0x00bb9ca6,
209 /* lg(64/63) = */ 0x005d0fba,
210 /* lg(128/127) = */ 0x002e58f7,
211 /* lg(256/255) = */ 0x001720da,
212 /* lg(512/511) = */ 0x000b8d87,
213 /* lg(1024/1023) = */ 0x0005c60b,
214 /* lg(2048/2047) = */ 0x0002e2d7,
215 /* lg(4096/4095) = */ 0x00017160,
216 /* lg(8192/8191) = */ 0x0000b8ad,
217 /* lg(16384/16383) = */ 0x00005c56,
218 /* lg(32768/32767) = */ 0x00002e2b
219 }
220 };
221
222 #if 0
223 static const FLAC__uint64 log2_lookup_wide[] = {
224 {
225 /*
226 * 32 fraction bits
227 */
228 /* undefined */ 0x00000000,
229 /* lg(2/1) = */ FLAC__U64L(0x100000000),
230 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
231 /* lg(8/7) = */ FLAC__U64L(0x31513015),
232 /* lg(16/15) = */ FLAC__U64L(0x17d60497),
233 /* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
234 /* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
235 /* lg(128/127) = */ FLAC__U64L(0x02e58f74),
236 /* lg(256/255) = */ FLAC__U64L(0x01720d9c),
237 /* lg(512/511) = */ FLAC__U64L(0x00b8d875),
238 /* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
239 /* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
240 /* lg(4096/4095) = */ FLAC__U64L(0x00171600),
241 /* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
242 /* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
243 /* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
244 },
245 {
246 /*
247 * 48 fraction bits
248 */
249 /* undefined */ 0x00000000,
250 /* lg(2/1) = */ FLAC__U64L(0x1000000000000),
251 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
252 /* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
253 /* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
254 /* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
255 /* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
256 /* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
257 /* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
258 /* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
259 /* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
260 /* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
261 /* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
262 /* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
263 /* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
264 /* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
265 }
266 };
267 #endif
268
FLAC__fixedpoint_log2(FLAC__uint32 x,uint32_t fracbits,uint32_t precision)269 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, uint32_t fracbits, uint32_t precision)
270 {
271 const FLAC__uint32 ONE = (1u << fracbits);
272 const FLAC__uint32 *table = log2_lookup[fracbits >> 2];
273
274 FLAC__ASSERT(fracbits < 32);
275 FLAC__ASSERT((fracbits & 0x3) == 0);
276
277 if(x < ONE)
278 return 0;
279
280 if(precision > LOG2_LOOKUP_PRECISION)
281 precision = LOG2_LOOKUP_PRECISION;
282
283 /* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
284 {
285 FLAC__uint32 y = 0;
286 FLAC__uint32 z = x >> 1, k = 1;
287 while (x > ONE && k < precision) {
288 if (x - z >= ONE) {
289 x -= z;
290 z = x >> k;
291 y += table[k];
292 }
293 else {
294 z >>= 1;
295 k++;
296 }
297 }
298 return y;
299 }
300 }
301
302 #endif /* defined FLAC__INTEGER_ONLY_LIBRARY */
303