1 /* 2 * Route Plug-In 3 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org> 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 <sound/driver.h> 23 24 #ifdef CONFIG_SND_PCM_OSS_PLUGINS 25 26 #include <linux/slab.h> 27 #include <linux/time.h> 28 #include <sound/core.h> 29 #include <sound/pcm.h> 30 #include "pcm_plugin.h" 31 32 static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts, 33 snd_pcm_uframes_t frames, int format) 34 { 35 int dst = 0; 36 for (; dst < ndsts; ++dst) { 37 if (dvp->wanted) 38 snd_pcm_area_silence(&dvp->area, 0, frames, format); 39 dvp->enabled = 0; 40 dvp++; 41 } 42 } 43 44 static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel, 45 struct snd_pcm_plugin_channel *dst_channel, 46 snd_pcm_uframes_t frames, int format) 47 { 48 dst_channel->enabled = 1; 49 snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format); 50 } 51 52 static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin, 53 const struct snd_pcm_plugin_channel *src_channels, 54 struct snd_pcm_plugin_channel *dst_channels, 55 snd_pcm_uframes_t frames) 56 { 57 int nsrcs, ndsts, dst; 58 struct snd_pcm_plugin_channel *dvp; 59 int format; 60 61 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO); 62 if (frames == 0) 63 return 0; 64 65 nsrcs = plugin->src_format.channels; 66 ndsts = plugin->dst_format.channels; 67 68 format = plugin->dst_format.format; 69 dvp = dst_channels; 70 if (nsrcs <= 1) { 71 /* expand to all channels */ 72 for (dst = 0; dst < ndsts; ++dst) { 73 copy_area(src_channels, dvp, frames, format); 74 dvp++; 75 } 76 return frames; 77 } 78 79 for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) { 80 copy_area(src_channels, dvp, frames, format); 81 dvp++; 82 src_channels++; 83 } 84 if (dst < ndsts) 85 zero_areas(dvp, ndsts - dst, frames, format); 86 return frames; 87 } 88 89 int snd_pcm_plugin_build_route(struct snd_pcm_substream *plug, 90 struct snd_pcm_plugin_format *src_format, 91 struct snd_pcm_plugin_format *dst_format, 92 struct snd_pcm_plugin **r_plugin) 93 { 94 struct snd_pcm_plugin *plugin; 95 int err; 96 97 snd_assert(r_plugin != NULL, return -ENXIO); 98 *r_plugin = NULL; 99 snd_assert(src_format->rate == dst_format->rate, return -ENXIO); 100 snd_assert(src_format->format == dst_format->format, return -ENXIO); 101 102 err = snd_pcm_plugin_build(plug, "route conversion", 103 src_format, dst_format, 0, &plugin); 104 if (err < 0) 105 return err; 106 107 plugin->transfer = route_transfer; 108 *r_plugin = plugin; 109 return 0; 110 } 111 112 #endif 113