Merge branch 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy...
[linux-2.6] / sound / core / oss / rate.c
1 /*
2  *  Rate conversion Plug-In
3  *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This library is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU Library General Public License as
8  *   published by the Free Software Foundation; either version 2 of
9  *   the License, or (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU Library General Public License for more details.
15  *
16  *   You should have received a copy of the GNU Library General Public
17  *   License along with this library; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21   
22 #include <linux/time.h>
23 #include <sound/core.h>
24 #include <sound/pcm.h>
25 #include "pcm_plugin.h"
26
27 #define SHIFT   11
28 #define BITS    (1<<SHIFT)
29 #define R_MASK  (BITS-1)
30
31 /*
32  *  Basic rate conversion plugin
33  */
34
35 struct rate_channel {
36         signed short last_S1;
37         signed short last_S2;
38 };
39  
40 typedef void (*rate_f)(struct snd_pcm_plugin *plugin,
41                        const struct snd_pcm_plugin_channel *src_channels,
42                        struct snd_pcm_plugin_channel *dst_channels,
43                        int src_frames, int dst_frames);
44
45 struct rate_priv {
46         unsigned int pitch;
47         unsigned int pos;
48         rate_f func;
49         snd_pcm_sframes_t old_src_frames, old_dst_frames;
50         struct rate_channel channels[0];
51 };
52
53 static void rate_init(struct snd_pcm_plugin *plugin)
54 {
55         unsigned int channel;
56         struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
57         data->pos = 0;
58         for (channel = 0; channel < plugin->src_format.channels; channel++) {
59                 data->channels[channel].last_S1 = 0;
60                 data->channels[channel].last_S2 = 0;
61         }
62 }
63
64 static void resample_expand(struct snd_pcm_plugin *plugin,
65                             const struct snd_pcm_plugin_channel *src_channels,
66                             struct snd_pcm_plugin_channel *dst_channels,
67                             int src_frames, int dst_frames)
68 {
69         unsigned int pos = 0;
70         signed int val;
71         signed short S1, S2;
72         signed short *src, *dst;
73         unsigned int channel;
74         int src_step, dst_step;
75         int src_frames1, dst_frames1;
76         struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
77         struct rate_channel *rchannels = data->channels;
78         
79         for (channel = 0; channel < plugin->src_format.channels; channel++) {
80                 pos = data->pos;
81                 S1 = rchannels->last_S1;
82                 S2 = rchannels->last_S2;
83                 if (!src_channels[channel].enabled) {
84                         if (dst_channels[channel].wanted)
85                                 snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
86                         dst_channels[channel].enabled = 0;
87                         continue;
88                 }
89                 dst_channels[channel].enabled = 1;
90                 src = (signed short *)src_channels[channel].area.addr +
91                         src_channels[channel].area.first / 8 / 2;
92                 dst = (signed short *)dst_channels[channel].area.addr +
93                         dst_channels[channel].area.first / 8 / 2;
94                 src_step = src_channels[channel].area.step / 8 / 2;
95                 dst_step = dst_channels[channel].area.step / 8 / 2;
96                 src_frames1 = src_frames;
97                 dst_frames1 = dst_frames;
98                 while (dst_frames1-- > 0) {
99                         if (pos & ~R_MASK) {
100                                 pos &= R_MASK;
101                                 S1 = S2;
102                                 if (src_frames1-- > 0) {
103                                         S2 = *src;
104                                         src += src_step;
105                                 }
106                         }
107                         val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
108                         if (val < -32768)
109                                 val = -32768;
110                         else if (val > 32767)
111                                 val = 32767;
112                         *dst = val;
113                         dst += dst_step;
114                         pos += data->pitch;
115                 }
116                 rchannels->last_S1 = S1;
117                 rchannels->last_S2 = S2;
118                 rchannels++;
119         }
120         data->pos = pos;
121 }
122
123 static void resample_shrink(struct snd_pcm_plugin *plugin,
124                             const struct snd_pcm_plugin_channel *src_channels,
125                             struct snd_pcm_plugin_channel *dst_channels,
126                             int src_frames, int dst_frames)
127 {
128         unsigned int pos = 0;
129         signed int val;
130         signed short S1, S2;
131         signed short *src, *dst;
132         unsigned int channel;
133         int src_step, dst_step;
134         int src_frames1, dst_frames1;
135         struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
136         struct rate_channel *rchannels = data->channels;
137
138         for (channel = 0; channel < plugin->src_format.channels; ++channel) {
139                 pos = data->pos;
140                 S1 = rchannels->last_S1;
141                 S2 = rchannels->last_S2;
142                 if (!src_channels[channel].enabled) {
143                         if (dst_channels[channel].wanted)
144                                 snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
145                         dst_channels[channel].enabled = 0;
146                         continue;
147                 }
148                 dst_channels[channel].enabled = 1;
149                 src = (signed short *)src_channels[channel].area.addr +
150                         src_channels[channel].area.first / 8 / 2;
151                 dst = (signed short *)dst_channels[channel].area.addr +
152                         dst_channels[channel].area.first / 8 / 2;
153                 src_step = src_channels[channel].area.step / 8 / 2;
154                 dst_step = dst_channels[channel].area.step / 8 / 2;
155                 src_frames1 = src_frames;
156                 dst_frames1 = dst_frames;
157                 while (dst_frames1 > 0) {
158                         S1 = S2;
159                         if (src_frames1-- > 0) {
160                                 S1 = *src;
161                                 src += src_step;
162                         }
163                         if (pos & ~R_MASK) {
164                                 pos &= R_MASK;
165                                 val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
166                                 if (val < -32768)
167                                         val = -32768;
168                                 else if (val > 32767)
169                                         val = 32767;
170                                 *dst = val;
171                                 dst += dst_step;
172                                 dst_frames1--;
173                         }
174                         pos += data->pitch;
175                 }
176                 rchannels->last_S1 = S1;
177                 rchannels->last_S2 = S2;
178                 rchannels++;
179         }
180         data->pos = pos;
181 }
182
183 static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
184 {
185         struct rate_priv *data;
186         snd_pcm_sframes_t res;
187
188         snd_assert(plugin != NULL, return -ENXIO);
189         if (frames == 0)
190                 return 0;
191         data = (struct rate_priv *)plugin->extra_data;
192         if (plugin->src_format.rate < plugin->dst_format.rate) {
193                 res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
194         } else {
195                 res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);          
196         }
197         if (data->old_src_frames > 0) {
198                 snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
199                 while (data->old_src_frames < frames1) {
200                         frames1 >>= 1;
201                         res1 <<= 1;
202                 }
203                 while (data->old_src_frames > frames1) {
204                         frames1 <<= 1;
205                         res1 >>= 1;
206                 }
207                 if (data->old_src_frames == frames1)
208                         return res1;
209         }
210         data->old_src_frames = frames;
211         data->old_dst_frames = res;
212         return res;
213 }
214
215 static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
216 {
217         struct rate_priv *data;
218         snd_pcm_sframes_t res;
219
220         snd_assert(plugin != NULL, return -ENXIO);
221         if (frames == 0)
222                 return 0;
223         data = (struct rate_priv *)plugin->extra_data;
224         if (plugin->src_format.rate < plugin->dst_format.rate) {
225                 res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
226         } else {
227                 res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
228         }
229         if (data->old_dst_frames > 0) {
230                 snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;
231                 while (data->old_dst_frames < frames1) {
232                         frames1 >>= 1;
233                         res1 <<= 1;
234                 }
235                 while (data->old_dst_frames > frames1) {
236                         frames1 <<= 1;
237                         res1 >>= 1;
238                 }
239                 if (data->old_dst_frames == frames1)
240                         return res1;
241         }
242         data->old_dst_frames = frames;
243         data->old_src_frames = res;
244         return res;
245 }
246
247 static snd_pcm_sframes_t rate_transfer(struct snd_pcm_plugin *plugin,
248                              const struct snd_pcm_plugin_channel *src_channels,
249                              struct snd_pcm_plugin_channel *dst_channels,
250                              snd_pcm_uframes_t frames)
251 {
252         snd_pcm_uframes_t dst_frames;
253         struct rate_priv *data;
254
255         snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
256         if (frames == 0)
257                 return 0;
258 #ifdef CONFIG_SND_DEBUG
259         {
260                 unsigned int channel;
261                 for (channel = 0; channel < plugin->src_format.channels; channel++) {
262                         snd_assert(src_channels[channel].area.first % 8 == 0 &&
263                                    src_channels[channel].area.step % 8 == 0,
264                                    return -ENXIO);
265                         snd_assert(dst_channels[channel].area.first % 8 == 0 &&
266                                    dst_channels[channel].area.step % 8 == 0,
267                                    return -ENXIO);
268                 }
269         }
270 #endif
271
272         dst_frames = rate_dst_frames(plugin, frames);
273         if (dst_frames > dst_channels[0].frames)
274                 dst_frames = dst_channels[0].frames;
275         data = (struct rate_priv *)plugin->extra_data;
276         data->func(plugin, src_channels, dst_channels, frames, dst_frames);
277         return dst_frames;
278 }
279
280 static int rate_action(struct snd_pcm_plugin *plugin,
281                        enum snd_pcm_plugin_action action,
282                        unsigned long udata)
283 {
284         snd_assert(plugin != NULL, return -ENXIO);
285         switch (action) {
286         case INIT:
287         case PREPARE:
288                 rate_init(plugin);
289                 break;
290         default:
291                 break;
292         }
293         return 0;       /* silenty ignore other actions */
294 }
295
296 int snd_pcm_plugin_build_rate(struct snd_pcm_substream *plug,
297                               struct snd_pcm_plugin_format *src_format,
298                               struct snd_pcm_plugin_format *dst_format,
299                               struct snd_pcm_plugin **r_plugin)
300 {
301         int err;
302         struct rate_priv *data;
303         struct snd_pcm_plugin *plugin;
304
305         snd_assert(r_plugin != NULL, return -ENXIO);
306         *r_plugin = NULL;
307
308         snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
309         snd_assert(src_format->channels > 0, return -ENXIO);
310         snd_assert(src_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
311         snd_assert(dst_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
312         snd_assert(src_format->rate != dst_format->rate, return -ENXIO);
313
314         err = snd_pcm_plugin_build(plug, "rate conversion",
315                                    src_format, dst_format,
316                                    sizeof(struct rate_priv) +
317                                    src_format->channels * sizeof(struct rate_channel),
318                                    &plugin);
319         if (err < 0)
320                 return err;
321         data = (struct rate_priv *)plugin->extra_data;
322         if (src_format->rate < dst_format->rate) {
323                 data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;
324                 data->func = resample_expand;
325         } else {
326                 data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;
327                 data->func = resample_shrink;
328         }
329         data->pos = 0;
330         rate_init(plugin);
331         data->old_src_frames = data->old_dst_frames = 0;
332         plugin->transfer = rate_transfer;
333         plugin->src_frames = rate_src_frames;
334         plugin->dst_frames = rate_dst_frames;
335         plugin->action = rate_action;
336         *r_plugin = plugin;
337         return 0;
338 }