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 <sound/driver.h> 23 24 #ifdef CONFIG_SND_PCM_OSS_PLUGINS 25 26 #include <linux/time.h> 27 #include <sound/core.h> 28 #include <sound/pcm.h> 29 #include "pcm_plugin.h" 30 31 static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin, 32 const struct snd_pcm_plugin_channel *src_channels, 33 struct snd_pcm_plugin_channel *dst_channels, 34 snd_pcm_uframes_t frames) 35 { 36 unsigned int channel; 37 unsigned int nchannels; 38 39 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO); 40 if (frames == 0) 41 return 0; 42 nchannels = plugin->src_format.channels; 43 for (channel = 0; channel < nchannels; channel++) { 44 snd_assert(src_channels->area.first % 8 == 0 && 45 src_channels->area.step % 8 == 0, 46 return -ENXIO); 47 snd_assert(dst_channels->area.first % 8 == 0 && 48 dst_channels->area.step % 8 == 0, 49 return -ENXIO); 50 if (!src_channels->enabled) { 51 if (dst_channels->wanted) 52 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format); 53 dst_channels->enabled = 0; 54 continue; 55 } 56 dst_channels->enabled = 1; 57 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format); 58 src_channels++; 59 dst_channels++; 60 } 61 return frames; 62 } 63 64 int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug, 65 struct snd_pcm_plugin_format *src_format, 66 struct snd_pcm_plugin_format *dst_format, 67 struct snd_pcm_plugin **r_plugin) 68 { 69 int err; 70 struct snd_pcm_plugin *plugin; 71 int width; 72 73 snd_assert(r_plugin != NULL, return -ENXIO); 74 *r_plugin = NULL; 75 76 snd_assert(src_format->format == dst_format->format, return -ENXIO); 77 snd_assert(src_format->rate == dst_format->rate, return -ENXIO); 78 snd_assert(src_format->channels == dst_format->channels, return -ENXIO); 79 80 width = snd_pcm_format_physical_width(src_format->format); 81 snd_assert(width > 0, return -ENXIO); 82 83 err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format, 84 0, &plugin); 85 if (err < 0) 86 return err; 87 plugin->transfer = copy_transfer; 88 *r_plugin = plugin; 89 return 0; 90 } 91 92 #endif 93