build: Convert alsa detection to new macros.
[paraslash.git] / imdct.c
1 /*
2 * FFT/IFFT transforms.
3 *
4 * Extracted 2009 from mplayer 2009-02-10 libavcodec/fft.c and libavcodec/mdct.c
5 *
6 * Copyright (c) 2008 Loren Merritt
7 * Copyright (c) 2002 Fabrice Bellard
8 * Partly based on libdjbfft by D. J. Bernstein
9 *
10 * Licensed under the GNU Lesser General Public License.
11 * For licencing details see COPYING.LIB.
12 */
13
14 /**
15 * \file imdct.c Inverse modified discrete cosine transform.
16 */
17
18 #include <math.h>
19 #include <regex.h>
20
21 #include "para.h"
22 #include "error.h"
23 #include "string.h"
24 #include "imdct.h"
25 #include "wma.h"
26
27 typedef float fftsample_t;
28
29 /** Canonical representation of a complex number. */
30 struct fft_complex {
31 /** Real part. */
32 fftsample_t re;
33 /** Imaginary part. */
34 fftsample_t im;
35 };
36
37 /** FFT Lookup table. */
38 struct fft_context {
39 /** Number of bits of this instance of the FFT. */
40 int nbits;
41 /** The lookup table for cosine values. */
42 uint16_t *revtab;
43 };
44
45 struct mdct_context {
46 /** Size of MDCT (number of input data * 2). */
47 int n;
48 /** n = 2^n bits. */
49 int nbits;
50 /** Cosine table for pre/post rotation. */
51 fftsample_t *tcos;
52 /** Sine table for pre/post rotation. */
53 fftsample_t *tsin;
54 /** The context for the underlying fast Fourier transform. */
55 struct fft_context fft;
56 };
57
58 /** \cond cosine_tabs */
59
60 /* cos(2 * pi * x / n) for 0 <= x <= n / 4, followed by its reverse */
61 #define COSINE_TAB(n) static fftsample_t cos_ ## n[n / 2] __a_aligned(16)
62
63 COSINE_TAB(16);
64 COSINE_TAB(32);
65 COSINE_TAB(64);
66 COSINE_TAB(128);
67 COSINE_TAB(256);
68 COSINE_TAB(512);
69 COSINE_TAB(1024);
70 COSINE_TAB(2048);
71 COSINE_TAB(4096);
72 COSINE_TAB(8192);
73 COSINE_TAB(16384);
74 COSINE_TAB(32768);
75 COSINE_TAB(65536);
76
77 static fftsample_t *cos_tabs[] = {
78 cos_16, cos_32, cos_64, cos_128, cos_256, cos_512, cos_1024, cos_2048,
79 cos_4096, cos_8192, cos_16384, cos_32768, cos_65536,
80 };
81 /** \endcond cosine_tabs */
82
83 __a_const static int split_radix_permutation(int i, int n)
84 {
85 int m;
86 if (n <= 2)
87 return i & 1;
88 m = n >> 1;
89 if ((i & m) == 0)
90 return split_radix_permutation(i, m) * 2;
91 m >>= 1;
92 if ((i & m) == 0)
93 return split_radix_permutation(i, m) * 4 + 1;
94 else
95 return split_radix_permutation(i, m) * 4 - 1;
96 }
97
98 #define BF(x, y, a, b) {\
99 x = a - b;\
100 y = a + b;\
101 }
102
103 #define BUTTERFLIES(a0, a1, a2, a3) {\
104 BF(t3, t5, t5, t1);\
105 BF(a2.re, a0.re, a0.re, t5);\
106 BF(a3.im, a1.im, a1.im, t3);\
107 BF(t4, t6, t2, t6);\
108 BF(a3.re, a1.re, a1.re, t4);\
109 BF(a2.im, a0.im, a0.im, t6);\
110 }
111
112 /*
113 * Force loading all the inputs before storing any. This is slightly slower for
114 * small data, but avoids store->load aliasing for addresses separated by large
115 * powers of 2.
116 */
117 #define BUTTERFLIES_BIG(a0, a1, a2, a3) {\
118 fftsample_t r0 = a0.re, i0 = a0.im, r1 = a1.re, i1 = a1.im;\
119 BF(t3, t5, t5, t1);\
120 BF(a2.re, a0.re, r0, t5);\
121 BF(a3.im, a1.im, i1, t3);\
122 BF(t4, t6, t2, t6);\
123 BF(a3.re, a1.re, r1, t4);\
124 BF(a2.im, a0.im, i0, t6);\
125 }
126
127 #define TRANSFORM(a0, a1, a2, a3, wre,wim) {\
128 t1 = a2.re * wre + a2.im * wim;\
129 t2 = a2.im * wre - a2.re * wim;\
130 t5 = a3.re * wre - a3.im * wim;\
131 t6 = a3.im * wre + a3.re * wim;\
132 BUTTERFLIES(a0, a1, a2, a3)\
133 }
134
135 #define TRANSFORM_ZERO(a0, a1, a2, a3) {\
136 t1 = a2.re;\
137 t2 = a2.im;\
138 t5 = a3.re;\
139 t6 = a3.im;\
140 BUTTERFLIES(a0, a1, a2, a3)\
141 }
142
143 /* z[0...8n - 1], w[1...2n - 1] */
144 #define PASS(name)\
145 static void name(struct fft_complex *z, const fftsample_t *wre, unsigned int n)\
146 {\
147 fftsample_t t1, t2, t3, t4, t5, t6;\
148 int o1 = 2 * n;\
149 int o2 = 4 * n;\
150 int o3 = 6 * n;\
151 const fftsample_t *wim = wre + o1;\
152 n--;\
153 \
154 TRANSFORM_ZERO(z[0], z[o1], z[o2], z[o3]);\
155 TRANSFORM(z[1], z[o1 + 1], z[o2 + 1], z[o3 + 1], wre[1], wim[-1]);\
156 do {\
157 z += 2;\
158 wre += 2;\
159 wim -= 2;\
160 TRANSFORM(z[0], z[o1], z[o2], z[o3], wre[0], wim[0]);\
161 TRANSFORM(z[1], z[o1 + 1], z[o2 + 1], z[o3 + 1], wre[1], wim[-1]);\
162 } while (--n);\
163 }
164
165 PASS(pass)
166 #undef BUTTERFLIES
167 #define BUTTERFLIES BUTTERFLIES_BIG
168
169 #define DECL_FFT(n, n2, n4)\
170 static void fft##n(struct fft_complex *z)\
171 {\
172 fft ## n2(z);\
173 fft ## n4(z + n4 * 2);\
174 fft ## n4(z + n4 * 3);\
175 pass(z, cos_ ## n, n4 / 2);\
176 }
177
178 static void fft4(struct fft_complex *z)
179 {
180 fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
181
182 BF(t3, t1, z[0].re, z[1].re);
183 BF(t8, t6, z[3].re, z[2].re);
184 BF(z[2].re, z[0].re, t1, t6);
185 BF(t4, t2, z[0].im, z[1].im);
186 BF(t7, t5, z[2].im, z[3].im);
187 BF(z[3].im, z[1].im, t4, t8);
188 BF(z[3].re, z[1].re, t3, t7);
189 BF(z[2].im, z[0].im, t2, t5);
190 }
191
192 static void fft8(struct fft_complex *z)
193 {
194 fftsample_t t1, t2, t3, t4, t5, t6, t7, t8;
195
196 fft4(z);
197
198 BF(t1, z[5].re, z[4].re, -z[5].re);
199 BF(t2, z[5].im, z[4].im, -z[5].im);
200 BF(t3, z[7].re, z[6].re, -z[7].re);
201 BF(t4, z[7].im, z[6].im, -z[7].im);
202 BF(t8, t1, t3, t1);
203 BF(t7, t2, t2, t4);
204 BF(z[4].re, z[0].re, z[0].re, t1);
205 BF(z[4].im, z[0].im, z[0].im, t2);
206 BF(z[6].re, z[2].re, z[2].re, t7);
207 BF(z[6].im, z[2].im, z[2].im, t8);
208
209 TRANSFORM(z[1], z[3], z[5], z[7], M_SQRT1_2, M_SQRT1_2);
210 }
211
212 static void fft16(struct fft_complex *z)
213 {
214 fftsample_t t1, t2, t3, t4, t5, t6;
215
216 fft8(z);
217 fft4(z + 8);
218 fft4(z + 12);
219
220 TRANSFORM_ZERO(z[0], z[4], z[8], z[12]);
221 TRANSFORM(z[2], z[6], z[10], z[14], M_SQRT1_2, M_SQRT1_2);
222 TRANSFORM(z[1], z[5], z[9], z[13], cos_16[1], cos_16[3]);
223 TRANSFORM(z[3], z[7], z[11], z[15], cos_16[3], cos_16[1]);
224 }
225
226 DECL_FFT(32, 16, 8)
227 DECL_FFT(64, 32, 16)
228 DECL_FFT(128, 64, 32)
229 DECL_FFT(256, 128, 64)
230 DECL_FFT(512, 256, 128)
231
232 DECL_FFT(1024, 512, 256)
233 DECL_FFT(2048, 1024, 512)
234 DECL_FFT(4096, 2048, 1024)
235 DECL_FFT(8192, 4096, 2048)
236 DECL_FFT(16384, 8192, 4096)
237 DECL_FFT(32768, 16384, 8192)
238 DECL_FFT(65536, 32768, 16384)
239
240 static void (*fft_dispatch[]) (struct fft_complex *) = {
241 fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
242 fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
243 };
244
245 static void fft(struct fft_context *s, struct fft_complex *z)
246 {
247 fft_dispatch[s->nbits - 2] (z);
248 }
249
250 /* complex multiplication: p = a * b */
251 #define CMUL(pre, pim, are, aim, bre, bim) \
252 {\
253 fftsample_t _are = (are);\
254 fftsample_t _aim = (aim);\
255 fftsample_t _bre = (bre);\
256 fftsample_t _bim = (bim);\
257 (pre) = _are * _bre - _aim * _bim;\
258 (pim) = _are * _bim + _aim * _bre;\
259 }
260
261 /**
262 * Compute the middle half of the inverse MDCT of size N = 2^nbits
263 *
264 * Thus excluding the parts that can be derived by symmetry.
265 *
266 * \param output N/2 samples.
267 * \param input N/2 samples.
268 */
269 static void imdct_half(struct mdct_context *s, fftsample_t *output,
270 const fftsample_t *input)
271 {
272 int k, n8, n4, n2, n, j;
273 const uint16_t *revtab = s->fft.revtab;
274 const fftsample_t *tcos = s->tcos;
275 const fftsample_t *tsin = s->tsin;
276 const fftsample_t *in1, *in2;
277 struct fft_complex *z = (struct fft_complex *)output;
278
279 n = 1 << s->nbits;
280 n2 = n >> 1;
281 n4 = n >> 2;
282 n8 = n >> 3;
283
284 /* pre rotation */
285 in1 = input;
286 in2 = input + n2 - 1;
287 for (k = 0; k < n4; k++) {
288 j = revtab[k];
289 CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
290 in1 += 2;
291 in2 -= 2;
292 }
293 fft(&s->fft, z);
294
295 /* post rotation + reordering */
296 for (k = 0; k < n8; k++) {
297 fftsample_t r0, i0, r1, i1;
298 CMUL(r0, i1, z[n8 - k - 1].im, z[n8 - k - 1].re,
299 tsin[n8 - k - 1], tcos[n8 - k - 1]);
300 CMUL(r1, i0, z[n8 + k].im, z[n8 + k].re, tsin[n8 + k],
301 tcos[n8 + k]);
302 z[n8 - k - 1].re = r0;
303 z[n8 - k - 1].im = i0;
304 z[n8 + k].re = r1;
305 z[n8 + k].im = i1;
306 }
307 }
308
309 /**
310 * Compute the inverse MDCT.
311 *
312 * \param ctx The initialized context structure.
313 * \param output N samples.
314 * \param input N/2 samples.
315 *
316 * \sa \ref imdct_init().
317 */
318 void imdct(struct mdct_context *ctx, float *output, const float *input)
319 {
320 int k;
321 int n = 1 << ctx->nbits;
322 int n2 = n >> 1;
323 int n4 = n >> 2;
324
325 imdct_half(ctx, output + n4, input);
326
327 for (k = 0; k < n4; k++) {
328 output[k] = -output[n2 - k - 1];
329 output[n - k - 1] = output[n2 + k];
330 }
331 }
332
333 static int fft_init(struct fft_context *s, int nbits)
334 {
335 int i, j, n;
336
337 if (nbits < 2 || nbits > 16)
338 return -E_FFT_BAD_PARAMS;
339 s->nbits = nbits;
340 n = 1 << nbits;
341
342 s->revtab = para_malloc(n * sizeof(uint16_t));
343 for (j = 4; j <= nbits; j++) {
344 int k = 1 << j;
345 double freq = 2 * M_PI / k;
346 fftsample_t *tab = cos_tabs[j - 4];
347 for (i = 0; i <= k / 4; i++)
348 tab[i] = cos(i * freq);
349 for (i = 1; i < k / 4; i++)
350 tab[k / 2 - i] = tab[i];
351 }
352 for (i = 0; i < n; i++)
353 s->revtab[-split_radix_permutation(i, n) & (n - 1)] = i;
354 return 0;
355 }
356
357 /**
358 * Initialize the inverse modified cosine transform.
359 *
360 * \param nbits The number of bits to use (4 <= \a nbits <= 18).
361 *
362 * \param result Opaque structure that must be passed to \ref imdct().
363 *
364 * \return Standard.
365 */
366 int imdct_init(int nbits, struct mdct_context **result)
367 {
368 int ret, n, n4, i;
369 double alpha;
370 struct mdct_context *s;
371
372 s = para_calloc(sizeof(*s));
373 n = 1 << nbits;
374 s->nbits = nbits;
375 s->n = n;
376 n4 = n >> 2;
377 s->tcos = para_malloc(n4 * sizeof(fftsample_t));
378 s->tsin = para_malloc(n4 * sizeof(fftsample_t));
379
380 for (i = 0; i < n4; i++) {
381 alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;
382 s->tcos[i] = -cos(alpha);
383 s->tsin[i] = -sin(alpha);
384 }
385 ret = fft_init(&s->fft, s->nbits - 2);
386 if (ret < 0)
387 goto fail;
388 *result = s;
389 return 0;
390 fail:
391 freep(&s->tcos);
392 freep(&s->tsin);
393 free(s);
394 return ret;
395 }
396
397 /**
398 * Deallocate imdct resources.
399 *
400 * \param ctx The pointer obtained by imdct_init().
401 */
402 void imdct_end(struct mdct_context *ctx)
403 {
404 free(ctx->tcos);
405 free(ctx->tsin);
406 free(ctx->fft.revtab);
407 free(ctx);
408 }