1 /* 2 * Linear conversion 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 snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin, 28 const struct snd_pcm_plugin_channel *src_channels, 29 struct snd_pcm_plugin_channel *dst_channels, 30 snd_pcm_uframes_t frames) 31 { 32 unsigned int channel; 33 unsigned int nchannels; 34 35 if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) 36 return -ENXIO; 37 if (frames == 0) 38 return 0; 39 nchannels = plugin->src_format.channels; 40 for (channel = 0; channel < nchannels; channel++) { 41 if (snd_BUG_ON(src_channels->area.first % 8 || 42 src_channels->area.step % 8)) 43 return -ENXIO; 44 if (snd_BUG_ON(dst_channels->area.first % 8 || 45 dst_channels->area.step % 8)) 46 return -ENXIO; 47 if (!src_channels->enabled) { 48 if (dst_channels->wanted) 49 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format); 50 dst_channels->enabled = 0; 51 continue; 52 } 53 dst_channels->enabled = 1; 54 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format); 55 src_channels++; 56 dst_channels++; 57 } 58 return frames; 59 } 60 61 int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug, 62 struct snd_pcm_plugin_format *src_format, 63 struct snd_pcm_plugin_format *dst_format, 64 struct snd_pcm_plugin **r_plugin) 65 { 66 int err; 67 struct snd_pcm_plugin *plugin; 68 int width; 69 70 if (snd_BUG_ON(!r_plugin)) 71 return -ENXIO; 72 *r_plugin = NULL; 73 74 if (snd_BUG_ON(src_format->format != dst_format->format)) 75 return -ENXIO; 76 if (snd_BUG_ON(src_format->rate != dst_format->rate)) 77 return -ENXIO; 78 if (snd_BUG_ON(src_format->channels != dst_format->channels)) 79 return -ENXIO; 80 81 width = snd_pcm_format_physical_width(src_format->format); 82 if (snd_BUG_ON(width <= 0)) 83 return -ENXIO; 84 85 err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format, 86 0, &plugin); 87 if (err < 0) 88 return err; 89 plugin->transfer = copy_transfer; 90 *r_plugin = plugin; 91 return 0; 92 } 93