diff options
Diffstat (limited to 'ANDROID_3.4.5/sound/core/oss/mulaw.c')
| -rw-r--r-- | ANDROID_3.4.5/sound/core/oss/mulaw.c | 344 |
1 files changed, 0 insertions, 344 deletions
diff --git a/ANDROID_3.4.5/sound/core/oss/mulaw.c b/ANDROID_3.4.5/sound/core/oss/mulaw.c deleted file mode 100644 index 7915564b..00000000 --- a/ANDROID_3.4.5/sound/core/oss/mulaw.c +++ /dev/null @@ -1,344 +0,0 @@ -/* - * Mu-Law conversion Plug-In Interface - * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz> - * Uros Bizjak <uros@kss-loka.si> - * - * Based on reference implementation by Sun Microsystems, Inc. - * - * 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 <linux/time.h> -#include <sound/core.h> -#include <sound/pcm.h> -#include "pcm_plugin.h" - -#define SIGN_BIT (0x80) /* Sign bit for a u-law byte. */ -#define QUANT_MASK (0xf) /* Quantization field mask. */ -#define NSEGS (8) /* Number of u-law segments. */ -#define SEG_SHIFT (4) /* Left shift for segment number. */ -#define SEG_MASK (0x70) /* Segment field mask. */ - -static inline int val_seg(int val) -{ - int r = 0; - val >>= 7; - if (val & 0xf0) { - val >>= 4; - r += 4; - } - if (val & 0x0c) { - val >>= 2; - r += 2; - } - if (val & 0x02) - r += 1; - return r; -} - -#define BIAS (0x84) /* Bias for linear code. */ - -/* - * linear2ulaw() - Convert a linear PCM value to u-law - * - * In order to simplify the encoding process, the original linear magnitude - * is biased by adding 33 which shifts the encoding range from (0 - 8158) to - * (33 - 8191). The result can be seen in the following encoding table: - * - * Biased Linear Input Code Compressed Code - * ------------------------ --------------- - * 00000001wxyza 000wxyz - * 0000001wxyzab 001wxyz - * 000001wxyzabc 010wxyz - * 00001wxyzabcd 011wxyz - * 0001wxyzabcde 100wxyz - * 001wxyzabcdef 101wxyz - * 01wxyzabcdefg 110wxyz - * 1wxyzabcdefgh 111wxyz - * - * Each biased linear code has a leading 1 which identifies the segment - * number. The value of the segment number is equal to 7 minus the number - * of leading 0's. The quantization interval is directly available as the - * four bits wxyz. * The trailing bits (a - h) are ignored. - * - * Ordinarily the complement of the resulting code word is used for - * transmission, and so the code word is complemented before it is returned. - * - * For further information see John C. Bellamy's Digital Telephony, 1982, - * John Wiley & Sons, pps 98-111 and 472-476. - */ -static unsigned char linear2ulaw(int pcm_val) /* 2's complement (16-bit range) */ -{ - int mask; - int seg; - unsigned char uval; - - /* Get the sign and the magnitude of the value. */ - if (pcm_val < 0) { - pcm_val = BIAS - pcm_val; - mask = 0x7F; - } else { - pcm_val += BIAS; - mask = 0xFF; - } - if (pcm_val > 0x7FFF) - pcm_val = 0x7FFF; - - /* Convert the scaled magnitude to segment number. */ - seg = val_seg(pcm_val); - - /* - * Combine the sign, segment, quantization bits; - * and complement the code word. - */ - uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF); - return uval ^ mask; -} - -/* - * ulaw2linear() - Convert a u-law value to 16-bit linear PCM - * - * First, a biased linear code is derived from the code word. An unbiased - * output can then be obtained by subtracting 33 from the biased code. - * - * Note that this function expects to be passed the complement of the - * original code word. This is in keeping with ISDN conventions. - */ -static int ulaw2linear(unsigned char u_val) -{ - int t; - - /* Complement to obtain normal u-law value. */ - u_val = ~u_val; - - /* - * Extract and bias the quantization bits. Then - * shift up by the segment number and subtract out the bias. - */ - t = ((u_val & QUANT_MASK) << 3) + BIAS; - t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT; - - return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS)); -} - -/* - * Basic Mu-Law plugin - */ - -typedef void (*mulaw_f)(struct snd_pcm_plugin *plugin, - const struct snd_pcm_plugin_channel *src_channels, - struct snd_pcm_plugin_channel *dst_channels, - snd_pcm_uframes_t frames); - -struct mulaw_priv { - mulaw_f func; - int cvt_endian; /* need endian conversion? */ - unsigned int native_ofs; /* byte offset in native format */ - unsigned int copy_ofs; /* byte offset in s16 format */ - unsigned int native_bytes; /* byte size of the native format */ - unsigned int copy_bytes; /* bytes to copy per conversion */ - u16 flip; /* MSB flip for signedness, done after endian conversion */ -}; - -static inline void cvt_s16_to_native(struct mulaw_priv *data, - unsigned char *dst, u16 sample) -{ - sample ^= data->flip; - if (data->cvt_endian) - sample = swab16(sample); - if (data->native_bytes > data->copy_bytes) - memset(dst, 0, data->native_bytes); - memcpy(dst + data->native_ofs, (char *)&sample + data->copy_ofs, - data->copy_bytes); -} - -static void mulaw_decode(struct snd_pcm_plugin *plugin, - const struct snd_pcm_plugin_channel *src_channels, - struct snd_pcm_plugin_channel *dst_channels, - snd_pcm_uframes_t frames) -{ - struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data; - 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) { - signed short sample = ulaw2linear(*src); - cvt_s16_to_native(data, dst, sample); - src += src_step; - dst += dst_step; - } - } -} - -static inline signed short cvt_native_to_s16(struct mulaw_priv *data, - unsigned char *src) -{ - u16 sample = 0; - memcpy((char *)&sample + data->copy_ofs, src + data->native_ofs, - data->copy_bytes); - if (data->cvt_endian) - sample = swab16(sample); - sample ^= data->flip; - return (signed short)sample; -} - -static void mulaw_encode(struct snd_pcm_plugin *plugin, - const struct snd_pcm_plugin_channel *src_channels, - struct snd_pcm_plugin_channel *dst_channels, - snd_pcm_uframes_t frames) -{ - struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data; - 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) { - signed short sample = cvt_native_to_s16(data, src); - *dst = linear2ulaw(sample); - src += src_step; - dst += dst_step; - } - } -} - -static snd_pcm_sframes_t mulaw_transfer(struct snd_pcm_plugin *plugin, - const struct snd_pcm_plugin_channel *src_channels, - struct snd_pcm_plugin_channel *dst_channels, - snd_pcm_uframes_t frames) -{ - struct mulaw_priv *data; - - if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) - return -ENXIO; - if (frames == 0) - return 0; -#ifdef CONFIG_SND_DEBUG - { - unsigned int channel; - for (channel = 0; channel < plugin->src_format.channels; channel++) { - if (snd_BUG_ON(src_channels[channel].area.first % 8 || - src_channels[channel].area.step % 8)) - return -ENXIO; - if (snd_BUG_ON(dst_channels[channel].area.first % 8 || - dst_channels[channel].area.step % 8)) - return -ENXIO; - } - } -#endif - data = (struct mulaw_priv *)plugin->extra_data; - data->func(plugin, src_channels, dst_channels, frames); - return frames; -} - -static void init_data(struct mulaw_priv *data, snd_pcm_format_t format) -{ -#ifdef SNDRV_LITTLE_ENDIAN - data->cvt_endian = snd_pcm_format_big_endian(format) > 0; -#else - data->cvt_endian = snd_pcm_format_little_endian(format) > 0; -#endif - if (!snd_pcm_format_signed(format)) - data->flip = 0x8000; - data->native_bytes = snd_pcm_format_physical_width(format) / 8; - data->copy_bytes = data->native_bytes < 2 ? 1 : 2; - if (snd_pcm_format_little_endian(format)) { - data->native_ofs = data->native_bytes - data->copy_bytes; - data->copy_ofs = 2 - data->copy_bytes; - } else { - /* S24 in 4bytes need an 1 byte offset */ - data->native_ofs = data->native_bytes - - snd_pcm_format_width(format) / 8; - } -} - -int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *plug, - struct snd_pcm_plugin_format *src_format, - struct snd_pcm_plugin_format *dst_format, - struct snd_pcm_plugin **r_plugin) -{ - int err; - struct mulaw_priv *data; - struct snd_pcm_plugin *plugin; - struct snd_pcm_plugin_format *format; - mulaw_f func; - - if (snd_BUG_ON(!r_plugin)) - return -ENXIO; - *r_plugin = NULL; - - if (snd_BUG_ON(src_format->rate != dst_format->rate)) - return -ENXIO; - if (snd_BUG_ON(src_format->channels != dst_format->channels)) - return -ENXIO; - - if (dst_format->format == SNDRV_PCM_FORMAT_MU_LAW) { - format = src_format; - func = mulaw_encode; - } - else if (src_format->format == SNDRV_PCM_FORMAT_MU_LAW) { - format = dst_format; - func = mulaw_decode; - } - else { - snd_BUG(); - return -EINVAL; - } - if (snd_BUG_ON(!snd_pcm_format_linear(format->format))) - return -ENXIO; - - err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion", - src_format, dst_format, - sizeof(struct mulaw_priv), &plugin); - if (err < 0) - return err; - data = (struct mulaw_priv *)plugin->extra_data; - data->func = func; - init_data(data, format->format); - plugin->transfer = mulaw_transfer; - *r_plugin = plugin; - return 0; -} |