| /* |
| ** Copyright (C) 2002-2011 Erik de Castro Lopo <erikd@mega-nerd.com> |
| ** |
| ** This program is free software; you can redistribute it and/or modify |
| ** it under the terms of the GNU 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 General Public License for more details. |
| ** |
| ** You should have received a copy of the GNU General Public License |
| ** along with this program; if not, write to the Free Software |
| ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. |
| */ |
| |
| /* |
| ** This code is part of Secret Rabbit Code aka libsamplerate. A commercial |
| ** use license for this code is available, please see: |
| ** http://www.mega-nerd.com/SRC/procedure.html |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "config.h" |
| #include "float_cast.h" |
| #include "common.h" |
| |
| static int linear_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ; |
| static void linear_reset (SRC_PRIVATE *psrc) ; |
| |
| /*======================================================================================== |
| */ |
| |
| #define LINEAR_MAGIC_MARKER MAKE_MAGIC ('l', 'i', 'n', 'e', 'a', 'r') |
| |
| #define SRC_DEBUG 0 |
| |
| typedef struct |
| { int linear_magic_marker ; |
| int channels ; |
| int reset ; |
| long in_count, in_used ; |
| long out_count, out_gen ; |
| float last_value [1] ; |
| } LINEAR_DATA ; |
| |
| /*---------------------------------------------------------------------------------------- |
| */ |
| |
| static int |
| linear_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) |
| { LINEAR_DATA *priv ; |
| double src_ratio, input_index, rem ; |
| int ch ; |
| |
| if (data->input_frames <= 0) |
| return SRC_ERR_NO_ERROR ; |
| |
| if (psrc->private_data == NULL) |
| return SRC_ERR_NO_PRIVATE ; |
| |
| priv = (LINEAR_DATA*) psrc->private_data ; |
| |
| if (priv->reset) |
| { /* If we have just been reset, set the last_value data. */ |
| for (ch = 0 ; ch < priv->channels ; ch++) |
| priv->last_value [ch] = data->data_in [ch] ; |
| priv->reset = 0 ; |
| } ; |
| |
| priv->in_count = data->input_frames * priv->channels ; |
| priv->out_count = data->output_frames * priv->channels ; |
| priv->in_used = priv->out_gen = 0 ; |
| |
| src_ratio = psrc->last_ratio ; |
| input_index = psrc->last_position ; |
| |
| /* Calculate samples before first sample in input array. */ |
| while (input_index < 1.0 && priv->out_gen < priv->out_count) |
| { |
| if (priv->in_used + priv->channels * (1.0 + input_index) >= priv->in_count) |
| break ; |
| |
| if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) |
| src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ; |
| |
| for (ch = 0 ; ch < priv->channels ; ch++) |
| { data->data_out [priv->out_gen] = (float) (priv->last_value [ch] + input_index * |
| (data->data_in [ch] - priv->last_value [ch])) ; |
| priv->out_gen ++ ; |
| } ; |
| |
| /* Figure out the next index. */ |
| input_index += 1.0 / src_ratio ; |
| } ; |
| |
| rem = fmod_one (input_index) ; |
| priv->in_used += priv->channels * lrint (input_index - rem) ; |
| input_index = rem ; |
| |
| /* Main processing loop. */ |
| while (priv->out_gen < priv->out_count && priv->in_used + priv->channels * input_index < priv->in_count) |
| { |
| if (priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) |
| src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count ; |
| |
| if (SRC_DEBUG && priv->in_used < priv->channels && input_index < 1.0) |
| { printf ("Whoops!!!! in_used : %ld channels : %d input_index : %f\n", priv->in_used, priv->channels, input_index) ; |
| exit (1) ; |
| } ; |
| |
| for (ch = 0 ; ch < priv->channels ; ch++) |
| { data->data_out [priv->out_gen] = (float) (data->data_in [priv->in_used - priv->channels + ch] + input_index * |
| (data->data_in [priv->in_used + ch] - data->data_in [priv->in_used - priv->channels + ch])) ; |
| priv->out_gen ++ ; |
| } ; |
| |
| /* Figure out the next index. */ |
| input_index += 1.0 / src_ratio ; |
| rem = fmod_one (input_index) ; |
| |
| priv->in_used += priv->channels * lrint (input_index - rem) ; |
| input_index = rem ; |
| } ; |
| |
| if (priv->in_used > priv->in_count) |
| { input_index += (priv->in_used - priv->in_count) / priv->channels ; |
| priv->in_used = priv->in_count ; |
| } ; |
| |
| psrc->last_position = input_index ; |
| |
| if (priv->in_used > 0) |
| for (ch = 0 ; ch < priv->channels ; ch++) |
| priv->last_value [ch] = data->data_in [priv->in_used - priv->channels + ch] ; |
| |
| /* Save current ratio rather then target ratio. */ |
| psrc->last_ratio = src_ratio ; |
| |
| data->input_frames_used = priv->in_used / priv->channels ; |
| data->output_frames_gen = priv->out_gen / priv->channels ; |
| |
| return SRC_ERR_NO_ERROR ; |
| } /* linear_vari_process */ |
| |
| /*------------------------------------------------------------------------------ |
| */ |
| |
| const char* |
| linear_get_name (int src_enum) |
| { |
| if (src_enum == SRC_LINEAR) |
| return "Linear Interpolator" ; |
| |
| return NULL ; |
| } /* linear_get_name */ |
| |
| const char* |
| linear_get_description (int src_enum) |
| { |
| if (src_enum == SRC_LINEAR) |
| return "Linear interpolator, very fast, poor quality." ; |
| |
| return NULL ; |
| } /* linear_get_descrition */ |
| |
| int |
| linear_set_converter (SRC_PRIVATE *psrc, int src_enum) |
| { LINEAR_DATA *priv = NULL ; |
| |
| if (src_enum != SRC_LINEAR) |
| return SRC_ERR_BAD_CONVERTER ; |
| |
| if (psrc->private_data != NULL) |
| { free (psrc->private_data) ; |
| psrc->private_data = NULL ; |
| } ; |
| |
| if (psrc->private_data == NULL) |
| { priv = calloc (1, sizeof (*priv) + psrc->channels * sizeof (float)) ; |
| if (priv == NULL) |
| return SRC_ERR_MALLOC_FAILED ; |
| psrc->private_data = priv ; |
| } ; |
| |
| priv->linear_magic_marker = LINEAR_MAGIC_MARKER ; |
| priv->channels = psrc->channels ; |
| |
| psrc->const_process = linear_vari_process ; |
| psrc->vari_process = linear_vari_process ; |
| psrc->reset = linear_reset ; |
| |
| linear_reset (psrc) ; |
| |
| return SRC_ERR_NO_ERROR ; |
| } /* linear_set_converter */ |
| |
| /*=================================================================================== |
| */ |
| |
| static void |
| linear_reset (SRC_PRIVATE *psrc) |
| { LINEAR_DATA *priv = NULL ; |
| |
| priv = (LINEAR_DATA*) psrc->private_data ; |
| if (priv == NULL) |
| return ; |
| |
| priv->channels = psrc->channels ; |
| priv->reset = 1 ; |
| memset (priv->last_value, 0, sizeof (priv->last_value [0]) * priv->channels) ; |
| |
| return ; |
| } /* linear_reset */ |
| |