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