diff options
Diffstat (limited to 'sound/core/oss/linear.c')
| -rw-r--r-- | sound/core/oss/linear.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/sound/core/oss/linear.c b/sound/core/oss/linear.c new file mode 100644 index 000000000000..12ed27a57b27 --- /dev/null +++ b/sound/core/oss/linear.c @@ -0,0 +1,158 @@ +/* + * Linear conversion Plug-In + * Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>, + * Abramo Bagnara <abramo@alsa-project.org> + * + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Library General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#include <sound/driver.h> +#include <linux/time.h> +#include <sound/core.h> +#include <sound/pcm.h> +#include "pcm_plugin.h" + +/* + * Basic linear conversion plugin + */ + +typedef struct linear_private_data { + int conv; +} linear_t; + +static void convert(snd_pcm_plugin_t *plugin, + const snd_pcm_plugin_channel_t *src_channels, + snd_pcm_plugin_channel_t *dst_channels, + snd_pcm_uframes_t frames) +{ +#define CONV_LABELS +#include "plugin_ops.h" +#undef CONV_LABELS + linear_t *data = (linear_t *)plugin->extra_data; + void *conv = conv_labels[data->conv]; + int channel; + int nchannels = plugin->src_format.channels; + for (channel = 0; channel < nchannels; ++channel) { + char *src; + char *dst; + int src_step, dst_step; + snd_pcm_uframes_t frames1; + if (!src_channels[channel].enabled) { + if (dst_channels[channel].wanted) + snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format); + dst_channels[channel].enabled = 0; + continue; + } + dst_channels[channel].enabled = 1; + src = src_channels[channel].area.addr + src_channels[channel].area.first / 8; + dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8; + src_step = src_channels[channel].area.step / 8; + dst_step = dst_channels[channel].area.step / 8; + frames1 = frames; + while (frames1-- > 0) { + goto *conv; +#define CONV_END after +#include "plugin_ops.h" +#undef CONV_END + after: + src += src_step; + dst += dst_step; + } + } +} + +static snd_pcm_sframes_t linear_transfer(snd_pcm_plugin_t *plugin, + const snd_pcm_plugin_channel_t *src_channels, + snd_pcm_plugin_channel_t *dst_channels, + snd_pcm_uframes_t frames) +{ + linear_t *data; + + snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO); + data = (linear_t *)plugin->extra_data; + if (frames == 0) + return 0; +#ifdef CONFIG_SND_DEBUG + { + unsigned int channel; + for (channel = 0; channel < plugin->src_format.channels; channel++) { + snd_assert(src_channels[channel].area.first % 8 == 0 && + src_channels[channel].area.step % 8 == 0, + return -ENXIO); + snd_assert(dst_channels[channel].area.first % 8 == 0 && + dst_channels[channel].area.step % 8 == 0, + return -ENXIO); + } + } +#endif + convert(plugin, src_channels, dst_channels, frames); + return frames; +} + +int conv_index(int src_format, int dst_format) +{ + int src_endian, dst_endian, sign, src_width, dst_width; + + sign = (snd_pcm_format_signed(src_format) != + snd_pcm_format_signed(dst_format)); +#ifdef SNDRV_LITTLE_ENDIAN + src_endian = snd_pcm_format_big_endian(src_format); + dst_endian = snd_pcm_format_big_endian(dst_format); +#else + src_endian = snd_pcm_format_little_endian(src_format); + dst_endian = snd_pcm_format_little_endian(dst_format); +#endif + + if (src_endian < 0) + src_endian = 0; + if (dst_endian < 0) + dst_endian = 0; + + src_width = snd_pcm_format_width(src_format) / 8 - 1; + dst_width = snd_pcm_format_width(dst_format) / 8 - 1; + + return src_width * 32 + src_endian * 16 + sign * 8 + dst_width * 2 + dst_endian; +} + +int snd_pcm_plugin_build_linear(snd_pcm_plug_t *plug, + snd_pcm_plugin_format_t *src_format, + snd_pcm_plugin_format_t *dst_format, + snd_pcm_plugin_t **r_plugin) +{ + int err; + struct linear_private_data *data; + snd_pcm_plugin_t *plugin; + + snd_assert(r_plugin != NULL, return -ENXIO); + *r_plugin = NULL; + + snd_assert(src_format->rate == dst_format->rate, return -ENXIO); + snd_assert(src_format->channels == dst_format->channels, return -ENXIO); + snd_assert(snd_pcm_format_linear(src_format->format) && + snd_pcm_format_linear(dst_format->format), return -ENXIO); + + err = snd_pcm_plugin_build(plug, "linear format conversion", + src_format, dst_format, + sizeof(linear_t), &plugin); + if (err < 0) + return err; + data = (linear_t *)plugin->extra_data; + data->conv = conv_index(src_format->format, dst_format->format); + plugin->transfer = linear_transfer; + *r_plugin = plugin; + return 0; +} |