pcm_plugin.c

是关于linux2.5.1的完全源码

			snd_pcm_plugin_free(plugin);
			return err;
		}      					    
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		srcformat = tmpformat;
		src_access = dst_access;
	}

	/* format change */
	if (srcformat.format != dstformat.format) {
		tmpformat.format = dstformat.format;
		if (tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
			err = snd_pcm_plugin_build_mulaw(plug,
							 &srcformat, &tmpformat,
							 &plugin);
		}
		else if (snd_pcm_format_linear(srcformat.format) &&
			 snd_pcm_format_linear(tmpformat.format)) {
			err = snd_pcm_plugin_build_linear(plug,
							  &srcformat, &tmpformat,
							  &plugin);
		}
		else
			return -EINVAL;
		pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
		if (err < 0)
			return err;
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		srcformat = tmpformat;
		src_access = dst_access;
	}

	/* de-interleave */
	if (src_access != dst_access) {
		err = snd_pcm_plugin_build_copy(plug,
						&srcformat,
						&tmpformat,
						&plugin);
		pdprintf("interleave change (copy: returns %i)\n", err);
		if (err < 0)
			return err;
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
	}

	return 0;
}

snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(snd_pcm_plug_t *plug,
					 char *buf,
					 snd_pcm_uframes_t count,
					 snd_pcm_plugin_channel_t **channels)
{
	snd_pcm_plugin_t *plugin;
	snd_pcm_plugin_channel_t *v;
	snd_pcm_plugin_format_t *format;
	int width, nchannels, channel;
	int stream = snd_pcm_plug_stream(plug);

	snd_assert(buf != NULL, return -ENXIO);
	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
		plugin = snd_pcm_plug_first(plug);
		format = &plugin->src_format;
	} else {
		plugin = snd_pcm_plug_last(plug);
		format = &plugin->dst_format;
	}
	v = plugin->buf_channels;
	*channels = v;
	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
		return width;
	nchannels = format->channels;
	snd_assert(plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED || format->channels <= 1, return -ENXIO);
	for (channel = 0; channel < nchannels; channel++, v++) {
		v->enabled = 1;
		v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
		v->area.addr = buf;
		v->area.first = channel * width;
		v->area.step = nchannels * width;
	}
	return count;
}

int snd_pcm_plug_playback_channels_mask(snd_pcm_plug_t *plug,
					bitset_t *client_vmask)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_last(plug);
	if (plugin == NULL) {
		return 0;
	} else {
		int schannels = plugin->dst_format.channels;
		bitset_t bs[bitset_size(schannels)];
		bitset_t *srcmask;
		bitset_t *dstmask = bs;
		int err;
		bitset_one(dstmask, schannels);
		if (plugin == NULL) {
			bitset_and(client_vmask, dstmask, schannels);
			return 0;
		}
		while (1) {
			err = plugin->src_channels_mask(plugin, dstmask, &srcmask);
			if (err < 0)
				return err;
			dstmask = srcmask;
			if (plugin->prev == NULL)
				break;
			plugin = plugin->prev;
		}
		bitset_and(client_vmask, dstmask, plugin->src_format.channels);
		return 0;
	}
}

int snd_pcm_plug_capture_channels_mask(snd_pcm_plug_t *plug,
				       bitset_t *client_vmask)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_first(plug);
	if (plugin == NULL) {
		return 0;
	} else {
		int schannels = plugin->src_format.channels;
		bitset_t bs[bitset_size(schannels)];
		bitset_t *srcmask = bs;
		bitset_t *dstmask;
		int err;
		bitset_one(srcmask, schannels);
		while (1) {
			err = plugin->dst_channels_mask(plugin, srcmask, &dstmask);
			if (err < 0)
				return err;
			srcmask = dstmask;
			if (plugin->next == NULL)
				break;
			plugin = plugin->next;
		}
		bitset_and(client_vmask, srcmask, plugin->dst_format.channels);
		return 0;
	}
}

static int snd_pcm_plug_playback_disable_useless_channels(snd_pcm_plug_t *plug,
							  snd_pcm_plugin_channel_t *src_channels)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_first(plug);
	unsigned int nchannels = plugin->src_format.channels;
	bitset_t bs[bitset_size(nchannels)];
	bitset_t *srcmask = bs;
	int err;
	unsigned int channel;
	for (channel = 0; channel < nchannels; channel++) {
		if (src_channels[channel].enabled)
			bitset_set(srcmask, channel);
		else
			bitset_reset(srcmask, channel);
	}
	err = snd_pcm_plug_playback_channels_mask(plug, srcmask);
	if (err < 0)
		return err;
	for (channel = 0; channel < nchannels; channel++) {
		if (!bitset_get(srcmask, channel))
			src_channels[channel].enabled = 0;
	}
	return 0;
}

static int snd_pcm_plug_capture_disable_useless_channels(snd_pcm_plug_t *plug,
							 snd_pcm_plugin_channel_t *src_channels,
							 snd_pcm_plugin_channel_t *client_channels)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_last(plug);
	unsigned int nchannels = plugin->dst_format.channels;
	bitset_t bs[bitset_size(nchannels)];
	bitset_t *dstmask = bs;
	bitset_t *srcmask;
	int err;
	unsigned int channel;
	for (channel = 0; channel < nchannels; channel++) {
		if (client_channels[channel].enabled)
			bitset_set(dstmask, channel);
		else
			bitset_reset(dstmask, channel);
	}
	while (plugin) {
		err = plugin->src_channels_mask(plugin, dstmask, &srcmask);
		if (err < 0)
			return err;
		dstmask = srcmask;
		plugin = plugin->prev;
	}
	plugin = snd_pcm_plug_first(plug);
	nchannels = plugin->src_format.channels;
	for (channel = 0; channel < nchannels; channel++) {
		if (!bitset_get(dstmask, channel))
			src_channels[channel].enabled = 0;
	}
	return 0;
}

snd_pcm_sframes_t snd_pcm_plug_write_transfer(snd_pcm_plug_t *plug, snd_pcm_plugin_channel_t *src_channels, snd_pcm_uframes_t size)
{
	snd_pcm_plugin_t *plugin, *next;
	snd_pcm_plugin_channel_t *dst_channels;
	int err;
	snd_pcm_sframes_t frames = size;

	if ((err = snd_pcm_plug_playback_disable_useless_channels(plug, src_channels)) < 0)
		return err;
	
	plugin = snd_pcm_plug_first(plug);
	while (plugin && frames > 0) {
		if ((next = plugin->next) != NULL) {
			snd_pcm_sframes_t frames1 = frames;
			if (plugin->dst_frames)
				frames1 = plugin->dst_frames(plugin, frames);
			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
				return err;
			}
			if (err != frames1) {
				frames = err;
				if (plugin->src_frames)
					frames = plugin->src_frames(plugin, frames1);
			}
		} else
			dst_channels = 0;
		pdprintf("write plugin: %s, %li\n", plugin->name, frames);
		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
			return frames;
		src_channels = dst_channels;
		plugin = next;
	}
	return snd_pcm_plug_client_size(plug, frames);
}

snd_pcm_sframes_t snd_pcm_plug_read_transfer(snd_pcm_plug_t *plug, snd_pcm_plugin_channel_t *dst_channels_final, snd_pcm_uframes_t size)
{
	snd_pcm_plugin_t *plugin, *next;
	snd_pcm_plugin_channel_t *src_channels, *dst_channels;
	snd_pcm_sframes_t frames = size;
	int err;

	frames = snd_pcm_plug_slave_size(plug, frames);
	if (frames < 0)
		return frames;

	src_channels = 0;
	plugin = snd_pcm_plug_first(plug);
	while (plugin && frames > 0) {
		if ((next = plugin->next) != NULL) {
			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
				return err;
			}
			frames = err;
			if (!plugin->prev) {
				if ((err = snd_pcm_plug_capture_disable_useless_channels(plug, dst_channels, dst_channels_final) < 0))
					return err;
			}
		} else {
			dst_channels = dst_channels_final;
		}
		pdprintf("read plugin: %s, %li\n", plugin->name, frames);
		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
			return frames;
		plugin = next;
		src_channels = dst_channels;
	}
	return frames;
}

int snd_pcm_area_silence(const snd_pcm_channel_area_t *dst_area, size_t dst_offset,
			 size_t samples, int format)
{
	/* FIXME: sub byte resolution and odd dst_offset */
	char *dst;
	unsigned int dst_step;
	int width;
	u_int64_t silence;
	if (!dst_area->addr)
		return 0;
	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
	width = snd_pcm_format_physical_width(format);
	silence = snd_pcm_format_silence_64(format);
	if (dst_area->step == (unsigned int) width) {
		size_t dwords = samples * width / 64;
		samples -= dwords * 64 / width;
		while (dwords-- > 0)
			*((u_int64_t*)dst)++ = silence;
		if (samples == 0)
			return 0;
	}
	dst_step = dst_area->step / 8;
	switch (width) {
	case 4: {
		u_int8_t s0 = silence & 0xf0;
		u_int8_t s1 = silence & 0x0f;
		int dstbit = dst_area->first % 8;
		int dstbit_step = dst_area->step % 8;
		while (samples-- > 0) {
			if (dstbit) {
				*dst &= 0xf0;
				*dst |= s1;
			} else {
				*dst &= 0x0f;
				*dst |= s0;
			}
			dst += dst_step;
			dstbit += dstbit_step;
			if (dstbit == 8) {
				dst++;
				dstbit = 0;
			}
		}
		break;
	}
	case 8: {
		u_int8_t sil = silence;
		while (samples-- > 0) {
			*dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 16: {
		u_int16_t sil = silence;
		while (samples-- > 0) {
			*(u_int16_t*)dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 32: {
		u_int32_t sil = silence;
		while (samples-- > 0) {
			*(u_int32_t*)dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 64: {
		while (samples-- > 0) {
			*(u_int64_t*)dst = silence;
			dst += dst_step;
		}
		break;
	}
	default:
		snd_BUG();
	}
	return 0;
}

int snd_pcm_areas_silence(const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset,
			  unsigned int channels, snd_pcm_uframes_t frames, int format)
{
	int width = snd_pcm_format_physical_width(format);
	while (channels > 0) {
		void *addr = dst_areas->addr;
		unsigned int step = dst_areas->step;
		const snd_pcm_channel_area_t *begin = dst_areas;
		int vc = channels;
		unsigned int v = 0;
		int err;
		while (1) {
			vc--;
			v++;
			dst_areas++;
			if (vc == 0 ||
			    dst_areas->addr != addr ||
			    dst_areas->step != step ||
			    dst_areas->first != dst_areas[-1].first + width)
				break;
		}
		if (v > 1 && v * width == step) {
			/* Collapse the areas */
			snd_pcm_channel_area_t d;
			d.addr = begin->addr;
			d.first = begin->first;
			d.step = width;
			err = snd_pcm_area_silence(&d, dst_offset * v, frames * v, format);
			channels -= v;
		} else {
			err = snd_pcm_area_silence(begin, dst_offset, frames, format);
			dst_areas = begin + 1;
			channels--;
		}
		if (err < 0)
			return err;
	}
	return 0;
}


int snd_pcm_area_copy(const snd_pcm_channel_area_t *src_area, size_t src_offset,
		      const snd_pcm_channel_area_t *dst_area, size_t dst_offset,
		      size_t samples, int format)
{
	/* FIXME: sub byte resolution and odd dst_offset */
	char *src, *dst;
	int width;
	int src_step, dst_step;
	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
	if (!src_area->addr)
		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
	if (!dst_area->addr)
		return 0;
	width = snd_pcm_format_physical_width(format);
	if (src_area->step == (unsigned int) width &&
	    dst_area->step == (unsigned int) width) {
		size_t bytes = samples * width / 8;
		samples -= bytes * 8 / width;
		memcpy(dst, src, bytes);
		if (samples == 0)
			return 0;
	}
	src_step = src_area->step / 8;
	dst_step = dst_area->step / 8;
	switch (width) {
	case 4: {
		int srcbit = src_area->first % 8;
		int srcbit_step = src_area->step % 8;
		int dstbit = dst_area->first % 8;
		int dstbit_step = dst_area->step % 8;
		while (samples-- > 0) {
			unsigned char srcval;
			if (srcbit)
				srcval = *src & 0x0f;
			else
				srcval = *src & 0xf0;
			if (dstbit)
				*dst &= 0xf0;
			else
				*dst &= 0x0f;
			*dst |= srcval;
			src += src_step;
			srcbit += srcbit_step;
			if (srcbit == 8) {
				src++;
				srcbit = 0;
			}
			dst += dst_step;
			dstbit += dstbit_step;
			if (dstbit == 8) {
				dst++;
				dstbit = 0;
			}
		}
		break;
	}
	case 8: {
		while (samples-- > 0) {
			*dst = *src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 16: {
		while (samples-- > 0) {
			*(u_int16_t*)dst = *(u_int16_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 32: {
		while (samples-- > 0) {
			*(u_int32_t*)dst = *(u_int32_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 64: {
		while (samples-- > 0) {
			*(u_int64_t*)dst = *(u_int64_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	default:
		snd_BUG();
	}
	return 0;
}

int snd_pcm_areas_copy(const snd_pcm_channel_area_t *src_areas, snd_pcm_uframes_t src_offset,
		       const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset,
		       unsigned int channels, snd_pcm_uframes_t frames, int format)
{
	int width = snd_pcm_format_physical_width(format);
	while (channels > 0) {
		unsigned int step = src_areas->step;
		void *src_addr = src_areas->addr;
		const snd_pcm_channel_area_t *src_start = src_areas;
		void *dst_addr = dst_areas->addr;
		const snd_pcm_channel_area_t *dst_start = dst_areas;
		int vc = channels;
		unsigned int v = 0;
		while (dst_areas->step == step) {
			vc--;
			v++;
			src_areas++;
			dst_areas++;
			if (vc == 0 ||
			    src_areas->step != step ||
			    src_areas->addr != src_addr ||
			    dst_areas->addr != dst_addr ||
			    src_areas->first != src_areas[-1].first + width ||
			    dst_areas->first != dst_areas[-1].first + width)
				break;
		}
		if (v > 1 && v * width == step) {
			/* Collapse the areas */
			snd_pcm_channel_area_t s, d;
			s.addr = src_start->addr;
			s.first = src_start->first;
			s.step = width;
			d.addr = dst_start->addr;
			d.first = dst_start->first;
			d.step = width;
			snd_pcm_area_copy(&s, src_offset * v, &d, dst_offset * v, frames * v, format);
			channels -= v;
		} else {
			snd_pcm_area_copy(src_start, src_offset, dst_start, dst_offset, frames, format);
			src_areas = src_start + 1;
			dst_areas = dst_start + 1;
			channels--;
		}
	}
	return 0;
}