Emeric Vigier | eebea67 | 2012-08-06 17:36:30 -0400 | [diff] [blame] | 1 | /* |
| 2 | ** Copyright (C) 2002-2011 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 Rabbit 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 (data->input_frames <= 0) |
| 62 | return SRC_ERR_NO_ERROR ; |
| 63 | |
| 64 | if (psrc->private_data == NULL) |
| 65 | return SRC_ERR_NO_PRIVATE ; |
| 66 | |
| 67 | priv = (LINEAR_DATA*) psrc->private_data ; |
| 68 | |
| 69 | if (priv->reset) |
| 70 | { /* If we have just been reset, set the last_value data. */ |
| 71 | for (ch = 0 ; ch < priv->channels ; ch++) |
| 72 | priv->last_value [ch] = data->data_in [ch] ; |
| 73 | priv->reset = 0 ; |
| 74 | } ; |
| 75 | |
| 76 | priv->in_count = data->input_frames * priv->channels ; |
| 77 | priv->out_count = data->output_frames * priv->channels ; |
| 78 | priv->in_used = priv->out_gen = 0 ; |
| 79 | |
| 80 | src_ratio = psrc->last_ratio ; |
| 81 | input_index = psrc->last_position ; |
| 82 | |
| 83 | /* Calculate samples before first sample in input array. */ |
| 84 | while (input_index < 1.0 && priv->out_gen < priv->out_count) |
| 85 | { |
| 86 | if (priv->in_used + priv->channels * (1.0 + input_index) >= priv->in_count) |
| 87 | break ; |
| 88 | |
| 89 | if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) |
| 90 | src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ; |
| 91 | |
| 92 | for (ch = 0 ; ch < priv->channels ; ch++) |
| 93 | { data->data_out [priv->out_gen] = (float) (priv->last_value [ch] + input_index * |
| 94 | (data->data_in [ch] - priv->last_value [ch])) ; |
| 95 | priv->out_gen ++ ; |
| 96 | } ; |
| 97 | |
| 98 | /* Figure out the next index. */ |
| 99 | input_index += 1.0 / src_ratio ; |
| 100 | } ; |
| 101 | |
| 102 | rem = fmod_one (input_index) ; |
| 103 | priv->in_used += priv->channels * lrint (input_index - rem) ; |
| 104 | input_index = rem ; |
| 105 | |
| 106 | /* Main processing loop. */ |
| 107 | while (priv->out_gen < priv->out_count && priv->in_used + priv->channels * input_index < priv->in_count) |
| 108 | { |
| 109 | if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) |
| 110 | src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ; |
| 111 | |
| 112 | if (SRC_DEBUG && priv->in_used < priv->channels && input_index < 1.0) |
| 113 | { printf ("Whoops!!!! in_used : %ld channels : %d input_index : %f\n", priv->in_used, priv->channels, input_index) ; |
| 114 | exit (1) ; |
| 115 | } ; |
| 116 | |
| 117 | for (ch = 0 ; ch < priv->channels ; ch++) |
| 118 | { data->data_out [priv->out_gen] = (float) (data->data_in [priv->in_used - priv->channels + ch] + input_index * |
| 119 | (data->data_in [priv->in_used + ch] - data->data_in [priv->in_used - priv->channels + ch])) ; |
| 120 | priv->out_gen ++ ; |
| 121 | } ; |
| 122 | |
| 123 | /* Figure out the next index. */ |
| 124 | input_index += 1.0 / src_ratio ; |
| 125 | rem = fmod_one (input_index) ; |
| 126 | |
| 127 | priv->in_used += priv->channels * lrint (input_index - rem) ; |
| 128 | input_index = rem ; |
| 129 | } ; |
| 130 | |
| 131 | if (priv->in_used > priv->in_count) |
| 132 | { input_index += (priv->in_used - priv->in_count) / priv->channels ; |
| 133 | priv->in_used = priv->in_count ; |
| 134 | } ; |
| 135 | |
| 136 | psrc->last_position = input_index ; |
| 137 | |
| 138 | if (priv->in_used > 0) |
| 139 | for (ch = 0 ; ch < priv->channels ; ch++) |
| 140 | priv->last_value [ch] = data->data_in [priv->in_used - priv->channels + ch] ; |
| 141 | |
| 142 | /* Save current ratio rather then target ratio. */ |
| 143 | psrc->last_ratio = src_ratio ; |
| 144 | |
| 145 | data->input_frames_used = priv->in_used / priv->channels ; |
| 146 | data->output_frames_gen = priv->out_gen / priv->channels ; |
| 147 | |
| 148 | return SRC_ERR_NO_ERROR ; |
| 149 | } /* linear_vari_process */ |
| 150 | |
| 151 | /*------------------------------------------------------------------------------ |
| 152 | */ |
| 153 | |
| 154 | const char* |
| 155 | linear_get_name (int src_enum) |
| 156 | { |
| 157 | if (src_enum == SRC_LINEAR) |
| 158 | return "Linear Interpolator" ; |
| 159 | |
| 160 | return NULL ; |
| 161 | } /* linear_get_name */ |
| 162 | |
| 163 | const char* |
| 164 | linear_get_description (int src_enum) |
| 165 | { |
| 166 | if (src_enum == SRC_LINEAR) |
| 167 | return "Linear interpolator, very fast, poor quality." ; |
| 168 | |
| 169 | return NULL ; |
| 170 | } /* linear_get_descrition */ |
| 171 | |
| 172 | int |
| 173 | linear_set_converter (SRC_PRIVATE *psrc, int src_enum) |
| 174 | { LINEAR_DATA *priv = NULL ; |
| 175 | |
| 176 | if (src_enum != SRC_LINEAR) |
| 177 | return SRC_ERR_BAD_CONVERTER ; |
| 178 | |
| 179 | if (psrc->private_data != NULL) |
| 180 | { free (psrc->private_data) ; |
| 181 | psrc->private_data = NULL ; |
| 182 | } ; |
| 183 | |
| 184 | if (psrc->private_data == NULL) |
| 185 | { priv = calloc (1, sizeof (*priv) + psrc->channels * sizeof (float)) ; |
| 186 | if (priv == NULL) |
| 187 | return SRC_ERR_MALLOC_FAILED ; |
| 188 | psrc->private_data = priv ; |
| 189 | } ; |
| 190 | |
| 191 | priv->linear_magic_marker = LINEAR_MAGIC_MARKER ; |
| 192 | priv->channels = psrc->channels ; |
| 193 | |
| 194 | psrc->const_process = linear_vari_process ; |
| 195 | psrc->vari_process = linear_vari_process ; |
| 196 | psrc->reset = linear_reset ; |
| 197 | |
| 198 | linear_reset (psrc) ; |
| 199 | |
| 200 | return SRC_ERR_NO_ERROR ; |
| 201 | } /* linear_set_converter */ |
| 202 | |
| 203 | /*=================================================================================== |
| 204 | */ |
| 205 | |
| 206 | static void |
| 207 | linear_reset (SRC_PRIVATE *psrc) |
| 208 | { LINEAR_DATA *priv = NULL ; |
| 209 | |
| 210 | priv = (LINEAR_DATA*) psrc->private_data ; |
| 211 | if (priv == NULL) |
| 212 | return ; |
| 213 | |
| 214 | priv->channels = psrc->channels ; |
| 215 | priv->reset = 1 ; |
| 216 | memset (priv->last_value, 0, sizeof (priv->last_value [0]) * priv->channels) ; |
| 217 | |
| 218 | return ; |
| 219 | } /* linear_reset */ |
| 220 | |