apps/codecs/libpcm/ieee_float.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2009 Yoshihisa Uchida
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include "codeclib.h"
  22 #include "pcm_common.h"
  23 #include "support_formats.h"
  24
  25 /*
  26  * IEEE float
  27  */
  28
  29 static struct pcm_format *fmt;
  30
  31 static bool set_format(struct pcm_format *format)
  32 {
  33     fmt = format;
  34
  35     if (fmt->channels == 0)
  36     {
  37         DEBUGF("CODEC_ERROR: channels is 0\n");
  38         return false;
  39     }
  40
  41     if (fmt->bitspersample != 32 && fmt->bitspersample != 64)
  42     {
  43         DEBUGF("CODEC_ERROR: ieee float must be 32 or 64 bitspersample: %d\n",
  44                              fmt->bitspersample);
  45         return false;
  46     }
  47
  48     fmt->bytespersample = fmt->bitspersample >> 3;
  49
  50     if (fmt->blockalign == 0)
  51         fmt->blockalign = fmt->bytespersample * fmt->channels;
  52
  53     fmt->samplesperblock = fmt->blockalign / (fmt->bytespersample * fmt->channels);
  54
  55     /* chunksize = about 1/50[sec] data */
  56     fmt->chunksize = (ci->id3->frequency / (50 * fmt->samplesperblock))
  57                                          * fmt->blockalign;
  58
  59     return true;
  60 }
  61
  62 static struct pcm_pos *get_seek_pos(long seek_time,
  63                                     uint8_t *(*read_buffer)(size_t *realsize))
  64 {
  65     static struct pcm_pos newpos;
  66     uint32_t newblock = ((uint64_t)seek_time * ci->id3->frequency)
  67                                              / (1000LL * fmt->samplesperblock);
  68
  69     (void)read_buffer;
  70     newpos.pos     = newblock * fmt->blockalign;
  71     newpos.samples = newblock * fmt->samplesperblock;
  72     return &newpos;
  73 }
  74
  75 static int decode(const uint8_t *inbuf, size_t inbufsize,
  76                   int32_t *outbuf, int *outbufsize)
  77 {
  78     uint32_t i;
  79     int32_t pcm;
  80     int16_t exp;
  81     int sgn;
  82
  83     if (fmt->bitspersample == 32)
  84     {
  85         for (i = 0; i < inbufsize; i += 4)
  86         {
  87             if (fmt->is_little_endian)
  88             {
  89                 pcm = (inbuf[0]<<5)|(inbuf[1]<<13)|((inbuf[2]|0x80)<<21);
  90                 exp = ((inbuf[2]>>7)|((inbuf[3]&0x7f)<<1)) - 127;
  91                 sgn = inbuf[3] & 0x80;
  92             }
  93             else
  94             {
  95                 pcm = (inbuf[3]<<5)|(inbuf[2]<<13)|((inbuf[1]|0x80)<<21);
  96                 exp = ((inbuf[1]>>7)|((inbuf[0]&0x7f)<<1)) - 127;
  97                 sgn = inbuf[0] & 0x80;
  98             }
  99             if (exp > -29 && exp < 0)
 100             {
 101                 pcm >>= -exp;
 102                 if (sgn)
 103                     pcm = -pcm;
 104             }
 105             else if (exp < -28)
 106                 pcm = 0;
 107             else
 108                 pcm = (sgn)?-(1<<28):(1<<28)-1;
 109
 110             outbuf[i/4] = pcm;
 111             inbuf += 4;
 112         }
 113         *outbufsize = inbufsize >> 2;
 114     }
 115     else
 116     {
 117         for (i = 0; i < inbufsize; i += 8)
 118         {
 119             if (fmt->is_little_endian)
 120             {
 121                 pcm = inbuf[3]|(inbuf[4]<<8)|(inbuf[5]<<16)|(((inbuf[6]&0x0f)|0x10)<<24);
 122                 exp = (((inbuf[6]&0xf0)>>4)|((inbuf[7]&0x7f)<<4)) - 1023;
 123                 sgn = inbuf[7] & 0x80;
 124             }
 125             else
 126             {
 127                 pcm = inbuf[4]|(inbuf[3]<<8)|(inbuf[2]<<16)|(((inbuf[1]&0x0f)|0x10)<<24);
 128                 exp = (((inbuf[1]&0xf0)>>4)|((inbuf[0]&0x7f)<<4)) - 1023;
 129                 sgn = inbuf[0] & 0x80;
 130             }
 131             if (exp > -29 && exp < 0)
 132             {
 133                 pcm >>= -exp;
 134                 if (sgn)
 135                     pcm = -pcm;
 136             }
 137             else if (exp < -28)
 138                 pcm = 0;
 139             else
 140                 pcm = (sgn)?-(1<<28):(1<<28)-1;
 141
 142             outbuf[i/8] = pcm;
 143             inbuf += 8;
 144         }
 145         *outbufsize = inbufsize >> 3;
 146     }
 147
 148     if (fmt->channels == 2)
 149         *outbufsize >>= 1;
 150
 151     return CODEC_OK;
 152 }
 153
 154 static const struct pcm_codec codec = {
 155                                           set_format,
 156                                           get_seek_pos,
 157                                           decode,
 158                                       };
 159
 160 const struct pcm_codec *get_ieee_float_codec(void)
 161 {
 162     return &codec;
 163 }