libs/ardour/pcm_utils.cc

   1 /*
   2     Copyright (C) 2006 Paul Davis , portions Erik de Castro Lopo
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include "ardour/pcm_utils.h"
  21
  22 #include <cmath>
  23
  24 using namespace std;
  25
  26 // TODO: check CPU_CLIPS_POSITIVE and CPU_CLIPS_NEGATIVE with scons
  27 #define CPU_CLIPS_NEGATIVE 0
  28 #define CPU_CLIPS_POSITIVE 0
  29
  30 /* these routines deal with 24 bit int handling (tribytes)
  31  *   originally from libsndfile, but modified.  XXX - Copyright Erik de Castro Lopo
  32  */
  33
  34 void
  35 pcm_let2f_array (tribyte *src, int count, float *dest)
  36 {
  37         /* Special normfactor because tribyte value is read into an int. */
  38         static const float normfact = 1.0 / ((float) 0x80000000);
  39
  40         unsigned char   *ucptr ;
  41         int                             value ;
  42
  43         ucptr = ((unsigned char*) src) + 3 * count ;
  44         while (--count >= 0)
  45         {       ucptr -= 3 ;
  46                 value = LET2H_INT_PTR (ucptr) ;
  47                 dest [count] = ((float) value) * normfact ;
  48                 } ;
  49 } /* let2f_array */
  50
  51 void
  52 pcm_bet2f_array (tribyte *src, int count, float *dest)
  53 {
  54         /* Special normfactor because tribyte value is read into an int. */
  55         static const float normfact = 1.0 / ((float) 0x80000000);
  56
  57         unsigned char   *ucptr ;
  58         int                             value ;
  59
  60
  61         ucptr = ((unsigned char*) src) + 3 * count ;
  62         while (--count >= 0)
  63         {       ucptr -= 3 ;
  64                 value = BET2H_INT_PTR (ucptr) ;
  65                 dest [count] = ((float) value) * normfact ;
  66                         } ;
  67 } /* bet2f_array */
  68
  69 void
  70 pcm_f2let_array (float *src, tribyte *dest, int count)
  71 {
  72         static const float normfact = (1.0 * 0x7FFFFF);
  73
  74         unsigned char   *ucptr ;
  75         int                             value ;
  76
  77         ucptr = ((unsigned char*) dest) + 3 * count ;
  78
  79         while (count)
  80         {       count -- ;
  81                 ucptr -= 3 ;
  82                 value = lrintf (src [count] * normfact) ;
  83                 ucptr [0] = value ;
  84                 ucptr [1] = value >> 8 ;
  85                 ucptr [2] = value >> 16 ;
  86                 } ;
  87 } /* f2let_array */
  88
  89 void
  90 pcm_f2let_clip_array (float *src, tribyte *dest, int count)
  91 {
  92         static const float normfact = (8.0 * 0x10000000);
  93
  94         unsigned char   *ucptr ;
  95         float                   scaled_value ;
  96         int                             value ;
  97
  98         ucptr = ((unsigned char*) dest) + 3 * count ;
  99
 100         while (count)
 101         {       count -- ;
 102                 ucptr -= 3 ;
 103                 scaled_value = src [count] * normfact ;
 104                 if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
 105                 {       ucptr [0] = 0xFF ;
 106                         ucptr [1] = 0xFF ;
 107                         ucptr [2] = 0x7F ;
 108                         continue ;
 109                         } ;
 110                 if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
 111                 {       ucptr [0] = 0x00 ;
 112                         ucptr [1] = 0x00 ;
 113                         ucptr [2] = 0x80 ;
 114                         continue ;
 115                         } ;
 116
 117                 value = lrintf (scaled_value) ;
 118                 ucptr [0] = value >> 8 ;
 119                 ucptr [1] = value >> 16 ;
 120                 ucptr [2] = value >> 24 ;
 121                 } ;
 122 } /* f2let_clip_array */
 123
 124 void
 125 pcm_f2bet_array (const float *src, tribyte *dest, int count)
 126 {
 127         static const float normfact = (1.0 * 0x7FFFFF);
 128
 129         unsigned char   *ucptr ;
 130         int                             value ;
 131
 132         ucptr = ((unsigned char*) dest) + 3 * count ;
 133
 134         while (--count >= 0)
 135         {       ucptr -= 3 ;
 136                 value = lrintf (src [count] * normfact) ;
 137                 ucptr [0] = value >> 16 ;
 138                 ucptr [1] = value >> 8 ;
 139                 ucptr [2] = value ;
 140                 } ;
 141 } /* f2bet_array */
 142
 143 void
 144 pcm_f2bet_clip_array (const float *src, tribyte *dest, int count)
 145 {
 146         static const float normfact = (8.0 * 0x10000000);
 147
 148         unsigned char   *ucptr ;
 149         float                   scaled_value ;
 150         int                             value ;
 151
 152         ucptr = ((unsigned char*) dest) + 3 * count ;
 153
 154         while (--count >= 0)
 155         {       ucptr -= 3 ;
 156                 scaled_value = src [count] * normfact ;
 157                 if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
 158                 {       ucptr [0] = 0x7F ;
 159                         ucptr [1] = 0xFF ;
 160                         ucptr [2] = 0xFF ;
 161                         continue ;
 162                         } ;
 163                 if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
 164                 {       ucptr [0] = 0x80 ;
 165                         ucptr [1] = 0x00 ;
 166                         ucptr [2] = 0x00 ;
 167                         continue ;
 168                 } ;
 169
 170                 value = lrint (scaled_value) ;
 171                 ucptr [0] = value >> 24 ;
 172                 ucptr [1] = value >> 16 ;
 173                 ucptr [2] = value >> 8 ;
 174                 } ;
 175 } /* f2bet_clip_array */
 176
 177 //@@@@@@@