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