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180 lines
5.7 KiB
180 lines
5.7 KiB
/* |
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* Linear conversion Plug-In |
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* Copyright (c) 1999 by Jaroslav Kysela <[email protected]>, |
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* Abramo Bagnara <[email protected]> |
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* |
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* |
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* This library is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU Library General Public License as |
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* published by the Free Software Foundation; either version 2 of |
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* the License, or (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Library General Public License for more details. |
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* |
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* You should have received a copy of the GNU Library General Public |
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* License along with this library; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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* |
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*/ |
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#include <linux/time.h> |
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#include <sound/core.h> |
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#include <sound/pcm.h> |
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#include "pcm_plugin.h" |
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/* |
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* Basic linear conversion plugin |
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*/ |
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struct linear_priv { |
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int cvt_endian; /* need endian conversion? */ |
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unsigned int src_ofs; /* byte offset in source format */ |
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unsigned int dst_ofs; /* byte soffset in destination format */ |
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unsigned int copy_ofs; /* byte offset in temporary u32 data */ |
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unsigned int dst_bytes; /* byte size of destination format */ |
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unsigned int copy_bytes; /* bytes to copy per conversion */ |
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unsigned int flip; /* MSB flip for signeness, done after endian conv */ |
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}; |
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static inline void do_convert(struct linear_priv *data, |
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unsigned char *dst, unsigned char *src) |
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{ |
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unsigned int tmp = 0; |
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unsigned char *p = (unsigned char *)&tmp; |
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memcpy(p + data->copy_ofs, src + data->src_ofs, data->copy_bytes); |
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if (data->cvt_endian) |
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tmp = swab32(tmp); |
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tmp ^= data->flip; |
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memcpy(dst, p + data->dst_ofs, data->dst_bytes); |
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} |
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static void convert(struct snd_pcm_plugin *plugin, |
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const struct snd_pcm_plugin_channel *src_channels, |
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struct snd_pcm_plugin_channel *dst_channels, |
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snd_pcm_uframes_t frames) |
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{ |
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struct linear_priv *data = (struct linear_priv *)plugin->extra_data; |
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int channel; |
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int nchannels = plugin->src_format.channels; |
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for (channel = 0; channel < nchannels; ++channel) { |
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char *src; |
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char *dst; |
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int src_step, dst_step; |
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snd_pcm_uframes_t frames1; |
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if (!src_channels[channel].enabled) { |
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if (dst_channels[channel].wanted) |
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snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format); |
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dst_channels[channel].enabled = 0; |
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continue; |
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} |
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dst_channels[channel].enabled = 1; |
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src = src_channels[channel].area.addr + src_channels[channel].area.first / 8; |
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dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8; |
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src_step = src_channels[channel].area.step / 8; |
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dst_step = dst_channels[channel].area.step / 8; |
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frames1 = frames; |
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while (frames1-- > 0) { |
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do_convert(data, dst, src); |
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src += src_step; |
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dst += dst_step; |
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} |
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} |
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} |
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static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin, |
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const struct snd_pcm_plugin_channel *src_channels, |
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struct snd_pcm_plugin_channel *dst_channels, |
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snd_pcm_uframes_t frames) |
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{ |
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if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) |
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return -ENXIO; |
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if (frames == 0) |
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return 0; |
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#ifdef CONFIG_SND_DEBUG |
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{ |
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unsigned int channel; |
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for (channel = 0; channel < plugin->src_format.channels; channel++) { |
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if (snd_BUG_ON(src_channels[channel].area.first % 8 || |
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src_channels[channel].area.step % 8)) |
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return -ENXIO; |
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if (snd_BUG_ON(dst_channels[channel].area.first % 8 || |
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dst_channels[channel].area.step % 8)) |
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return -ENXIO; |
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} |
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} |
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#endif |
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if (frames > dst_channels[0].frames) |
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frames = dst_channels[0].frames; |
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convert(plugin, src_channels, dst_channels, frames); |
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return frames; |
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} |
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static void init_data(struct linear_priv *data, |
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snd_pcm_format_t src_format, snd_pcm_format_t dst_format) |
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{ |
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int src_le, dst_le, src_bytes, dst_bytes; |
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src_bytes = snd_pcm_format_width(src_format) / 8; |
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dst_bytes = snd_pcm_format_width(dst_format) / 8; |
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src_le = snd_pcm_format_little_endian(src_format) > 0; |
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dst_le = snd_pcm_format_little_endian(dst_format) > 0; |
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data->dst_bytes = dst_bytes; |
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data->cvt_endian = src_le != dst_le; |
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data->copy_bytes = src_bytes < dst_bytes ? src_bytes : dst_bytes; |
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if (src_le) { |
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data->copy_ofs = 4 - data->copy_bytes; |
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data->src_ofs = src_bytes - data->copy_bytes; |
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} else |
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data->src_ofs = snd_pcm_format_physical_width(src_format) / 8 - |
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src_bytes; |
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if (dst_le) |
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data->dst_ofs = 4 - data->dst_bytes; |
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else |
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data->dst_ofs = snd_pcm_format_physical_width(dst_format) / 8 - |
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dst_bytes; |
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if (snd_pcm_format_signed(src_format) != |
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snd_pcm_format_signed(dst_format)) { |
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if (dst_le) |
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data->flip = (__force u32)cpu_to_le32(0x80000000); |
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else |
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data->flip = (__force u32)cpu_to_be32(0x80000000); |
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} |
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} |
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int snd_pcm_plugin_build_linear(struct snd_pcm_substream *plug, |
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struct snd_pcm_plugin_format *src_format, |
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struct snd_pcm_plugin_format *dst_format, |
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struct snd_pcm_plugin **r_plugin) |
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{ |
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int err; |
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struct linear_priv *data; |
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struct snd_pcm_plugin *plugin; |
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if (snd_BUG_ON(!r_plugin)) |
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return -ENXIO; |
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*r_plugin = NULL; |
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if (snd_BUG_ON(src_format->rate != dst_format->rate)) |
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return -ENXIO; |
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if (snd_BUG_ON(src_format->channels != dst_format->channels)) |
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return -ENXIO; |
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if (snd_BUG_ON(!snd_pcm_format_linear(src_format->format) || |
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!snd_pcm_format_linear(dst_format->format))) |
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return -ENXIO; |
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err = snd_pcm_plugin_build(plug, "linear format conversion", |
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src_format, dst_format, |
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sizeof(struct linear_priv), &plugin); |
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if (err < 0) |
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return err; |
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data = (struct linear_priv *)plugin->extra_data; |
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init_data(data, src_format->format, dst_format->format); |
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plugin->transfer = linear_transfer; |
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*r_plugin = plugin; |
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return 0; |
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}
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