reactos/lib/3rdparty/libsamplerate/src_linear.c

   1 /*
   2 ** Copyright (C) 2002-2008 Erik de Castro Lopo <erikd@mega-nerd.com>
   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  17 */
  18
  19 /*
  20 ** This code is part of Secret Rabibt Code aka libsamplerate. A commercial
  21 ** use license for this code is available, please see:
  22 **              http://www.mega-nerd.com/SRC/procedure.html
  23 */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28
  29 #include "config.h"
  30 #include "float_cast.h"
  31 #include "common.h"
  32
  33 static int linear_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
  34 static void linear_reset (SRC_PRIVATE *psrc) ;
  35
  36 /*========================================================================================
  37 */
  38
  39 #define LINEAR_MAGIC_MARKER     MAKE_MAGIC ('l', 'i', 'n', 'e', 'a', 'r')
  40
  41 #define SRC_DEBUG       0
  42
  43 typedef struct
  44 {       int             linear_magic_marker ;
  45         int             channels ;
  46         int             reset ;
  47         long    in_count, in_used ;
  48         long    out_count, out_gen ;
  49         float   last_value [1] ;
  50 } LINEAR_DATA ;
  51
  52 /*----------------------------------------------------------------------------------------
  53 */
  54
  55 static int
  56 linear_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
  57 {       LINEAR_DATA *priv ;
  58         double          src_ratio, input_index, rem ;
  59         int                     ch ;
  60
  61         if (psrc->private_data == NULL)
  62                 return SRC_ERR_NO_PRIVATE ;
  63
  64         priv = (LINEAR_DATA*) psrc->private_data ;
  65
  66         if (priv->reset)
  67         {       /* If we have just been reset, set the last_value data. */
  68                 for (ch = 0 ; ch < priv->channels ; ch++)
  69                         priv->last_value [ch] = data->data_in [ch] ;
  70                 priv->reset = 0 ;
  71                 } ;
  72
  73         priv->in_count = data->input_frames * priv->channels ;
  74         priv->out_count = data->output_frames * priv->channels ;
  75         priv->in_used = priv->out_gen = 0 ;
  76
  77         src_ratio = psrc->last_ratio ;
  78         input_index = psrc->last_position ;
  79
  80         /* Calculate samples before first sample in input array. */
  81         while (input_index < 1.0 && priv->out_gen < priv->out_count)
  82         {
  83                 if (priv->in_used + priv->channels * (1.0 + input_index) >= priv->in_count)
  84                         break ;
  85
  86                 if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
  87                         src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ;
  88
  89                 for (ch = 0 ; ch < priv->channels ; ch++)
  90                 {       data->data_out [priv->out_gen] = (float) (priv->last_value [ch] + input_index *
  91                                                                                 (data->data_in [ch] - priv->last_value [ch])) ;
  92                         priv->out_gen ++ ;
  93                         } ;
  94
  95                 /* Figure out the next index. */
  96                 input_index += 1.0 / src_ratio ;
  97                 } ;
  98
  99         rem = fmod_one (input_index) ;
 100         priv->in_used += priv->channels * lrint (input_index - rem) ;
 101         input_index = rem ;
 102
 103         /* Main processing loop. */
 104         while (priv->out_gen < priv->out_count && priv->in_used + priv->channels * input_index < priv->in_count)
 105         {
 106                 if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
 107                         src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ;
 108
 109                 if (SRC_DEBUG && priv->in_used < priv->channels && input_index < 1.0)
 110                 {       printf ("Whoops!!!!   in_used : %ld     channels : %d     input_index : %f\n", priv->in_used, priv->channels, input_index) ;
 111                         exit (1) ;
 112                         } ;
 113
 114                 for (ch = 0 ; ch < priv->channels ; ch++)
 115                 {       data->data_out [priv->out_gen] = (float) (data->data_in [priv->in_used - priv->channels + ch] + input_index *
 116                                                 (data->data_in [priv->in_used + ch] - data->data_in [priv->in_used - priv->channels + ch])) ;
 117                         priv->out_gen ++ ;
 118                         } ;
 119
 120                 /* Figure out the next index. */
 121                 input_index += 1.0 / src_ratio ;
 122                 rem = fmod_one (input_index) ;
 123
 124                 priv->in_used += priv->channels * lrint (input_index - rem) ;
 125                 input_index = rem ;
 126                 } ;
 127
 128         if (priv->in_used > priv->in_count)
 129         {       input_index += (priv->in_used - priv->in_count) / priv->channels ;
 130                 priv->in_used = priv->in_count ;
 131                 } ;
 132
 133         psrc->last_position = input_index ;
 134
 135         if (priv->in_used > 0)
 136                 for (ch = 0 ; ch < priv->channels ; ch++)
 137                         priv->last_value [ch] = data->data_in [priv->in_used - priv->channels + ch] ;
 138
 139         /* Save current ratio rather then target ratio. */
 140         psrc->last_ratio = src_ratio ;
 141
 142         data->input_frames_used = priv->in_used / priv->channels ;
 143         data->output_frames_gen = priv->out_gen / priv->channels ;
 144
 145         return SRC_ERR_NO_ERROR ;
 146 } /* linear_vari_process */
 147
 148 /*------------------------------------------------------------------------------
 149 */
 150
 151 const char*
 152 linear_get_name (int src_enum)
 153 {
 154         if (src_enum == SRC_LINEAR)
 155                 return "Linear Interpolator" ;
 156
 157         return NULL ;
 158 } /* linear_get_name */
 159
 160 const char*
 161 linear_get_description (int src_enum)
 162 {
 163         if (src_enum == SRC_LINEAR)
 164                 return "Linear interpolator, very fast, poor quality." ;
 165
 166         return NULL ;
 167 } /* linear_get_descrition */
 168
 169 int
 170 linear_set_converter (SRC_PRIVATE *psrc, int src_enum)
 171 {       LINEAR_DATA *priv = NULL ;
 172
 173         if (src_enum != SRC_LINEAR)
 174                 return SRC_ERR_BAD_CONVERTER ;
 175
 176         if (psrc->private_data != NULL)
 177         {       free (psrc->private_data) ;
 178                 psrc->private_data = NULL ;
 179                 } ;
 180
 181         if (psrc->private_data == NULL)
 182         {       priv = calloc (1, sizeof (*priv) + psrc->channels * sizeof (float)) ;
 183                 if (priv == NULL)
 184                         return SRC_ERR_MALLOC_FAILED ;
 185                 psrc->private_data = priv ;
 186                 } ;
 187
 188         priv->linear_magic_marker = LINEAR_MAGIC_MARKER ;
 189         priv->channels = psrc->channels ;
 190
 191         psrc->const_process = linear_vari_process ;
 192         psrc->vari_process = linear_vari_process ;
 193         psrc->reset = linear_reset ;
 194
 195         linear_reset (psrc) ;
 196
 197         return SRC_ERR_NO_ERROR ;
 198 } /* linear_set_converter */
 199
 200 /*===================================================================================
 201 */
 202
 203 static void
 204 linear_reset (SRC_PRIVATE *psrc)
 205 {       LINEAR_DATA *priv = NULL ;
 206
 207         priv = (LINEAR_DATA*) psrc->private_data ;
 208         if (priv == NULL)
 209                 return ;
 210
 211         priv->channels = psrc->channels ;
 212         priv->reset = 1 ;
 213         memset (priv->last_value, 0, sizeof (priv->last_value [0]) * priv->channels) ;
 214
 215         return ;
 216 } /* linear_reset */
 217