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 <linux/slab.h> 23 #include <linux/time.h> 24 #include <sound/core.h> 25 #include <sound/pcm.h> 26 #include "pcm_plugin.h" 27 28 static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts, 29 snd_pcm_uframes_t frames, int format) 30 { 31 int dst = 0; 32 for (; dst < ndsts; ++dst) { 33 if (dvp->wanted) 34 snd_pcm_area_silence(&dvp->area, 0, frames, format); 35 dvp->enabled = 0; 36 dvp++; 37 } 38 } 39 40 static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel, 41 struct snd_pcm_plugin_channel *dst_channel, 42 snd_pcm_uframes_t frames, int format) 43 { 44 dst_channel->enabled = 1; 45 snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format); 46 } 47 48 static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin, 49 const struct snd_pcm_plugin_channel *src_channels, 50 struct snd_pcm_plugin_channel *dst_channels, 51 snd_pcm_uframes_t frames) 52 { 53 int nsrcs, ndsts, dst; 54 struct snd_pcm_plugin_channel *dvp; 55 int format; 56 57 if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) 58 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 if (snd_BUG_ON(!r_plugin)) 95 return -ENXIO; 96 *r_plugin = NULL; 97 if (snd_BUG_ON(src_format->rate != dst_format->rate)) 98 return -ENXIO; 99 if (snd_BUG_ON(src_format->format != dst_format->format)) 100 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