diff options
Diffstat (limited to 'libk3b/plugin/libsamplerate/src_zoh.c')
| -rw-r--r-- | libk3b/plugin/libsamplerate/src_zoh.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/libk3b/plugin/libsamplerate/src_zoh.c b/libk3b/plugin/libsamplerate/src_zoh.c new file mode 100644 index 0000000..7e18d87 --- /dev/null +++ b/libk3b/plugin/libsamplerate/src_zoh.c @@ -0,0 +1,186 @@ +/* +** Copyright (C) 2002,2003 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., 51 Franklin Steet, Fifth Floor, Boston, MA 02110-1301, USA. +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "config.h" +#include "float_cast.h" +#include "common.h" + +static void zoh_reset (SRC_PRIVATE *psrc) ; + +/*======================================================================================== +*/ + +#define ZOH_MAGIC_MARKER MAKE_MAGIC('s','r','c','z','o','h') + +typedef struct +{ int zoh_magic_marker ; + int channels ; + long in_count, in_used ; + long out_count, out_gen ; + float last_value [1] ; +} ZOH_DATA ; + +/*---------------------------------------------------------------------------------------- +*/ + +int +zoh_process (SRC_PRIVATE *psrc, SRC_DATA *data) +{ ZOH_DATA *zoh ; + double src_ratio, input_index ; + int ch ; + + if (psrc->private_data == NULL) + return SRC_ERR_NO_PRIVATE ; + + zoh = (ZOH_DATA*) psrc->private_data ; + + zoh->in_count = data->input_frames * zoh->channels ; + zoh->out_count = data->output_frames * zoh->channels ; + zoh->in_used = zoh->out_gen = 0 ; + + src_ratio = psrc->last_ratio ; + input_index = psrc->last_position ; + + /* Calculate samples before first sample in input array. */ + while (input_index > 0.0 && input_index < 1.0 && zoh->out_gen < zoh->out_count) + { + if (zoh->in_used + input_index >= zoh->in_count) + break ; + + if (fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) + src_ratio = psrc->last_ratio + zoh->out_gen * (data->src_ratio - psrc->last_ratio) / (zoh->out_count - 1) ; + + for (ch = 0 ; ch < zoh->channels ; ch++) + { data->data_out [zoh->out_gen] = zoh->last_value [ch] ; + zoh->out_gen ++ ; + } ; + + /* Figure out the next index. */ + input_index += 1.0 / src_ratio ; + } ; + + zoh->in_used += zoh->channels * lrint (floor (input_index)) ; + input_index -= floor (input_index) ; + + /* Main processing loop. */ + while (zoh->out_gen < zoh->out_count && zoh->in_used + input_index < zoh->in_count) + { + if (fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF) + src_ratio = psrc->last_ratio + zoh->out_gen * (data->src_ratio - psrc->last_ratio) / (zoh->out_count - 1) ; + + for (ch = 0 ; ch < zoh->channels ; ch++) + { data->data_out [zoh->out_gen] = data->data_in [zoh->in_used + ch] ; + zoh->out_gen ++ ; + } ; + + /* Figure out the next index. */ + input_index += 1.0 / src_ratio ; + + zoh->in_used += zoh->channels * lrint (floor (input_index)) ; + input_index -= floor (input_index) ; + } ; + + psrc->last_position = input_index ; + + if (zoh->in_used > 0) + for (ch = 0 ; ch < zoh->channels ; ch++) + zoh->last_value [ch] = data->data_in [zoh->in_used - zoh->channels + ch] ; + + /* Save current ratio rather then target ratio. */ + psrc->last_ratio = src_ratio ; + + data->input_frames_used = zoh->in_used / zoh->channels ; + data->output_frames_gen = zoh->out_gen / zoh->channels ; + + return SRC_ERR_NO_ERROR ; +} /* zoh_process */ + +/*------------------------------------------------------------------------------ +*/ + +const char* +zoh_get_name (int src_enum) +{ + if (src_enum == SRC_ZERO_ORDER_HOLD) + return "ZOH Interpolator" ; + + return NULL ; +} /* zoh_get_name */ + +const char* +zoh_get_description (int src_enum) +{ + if (src_enum == SRC_ZERO_ORDER_HOLD) + return "Zero order hold interpolator, very fast, poor quality." ; + + return NULL ; +} /* zoh_get_descrition */ + +int +zoh_set_converter (SRC_PRIVATE *psrc, int src_enum) +{ ZOH_DATA *zoh = NULL; + + if (src_enum != SRC_ZERO_ORDER_HOLD) + return SRC_ERR_BAD_CONVERTER ; + + if (psrc->private_data != NULL) + { zoh = (ZOH_DATA*) psrc->private_data ; + if (zoh->zoh_magic_marker != ZOH_MAGIC_MARKER) + { free (psrc->private_data) ; + psrc->private_data = NULL ; + } ; + } ; + + if (psrc->private_data == NULL) + { zoh = calloc (1, sizeof (*zoh) + psrc->channels * sizeof (float)) ; + if (zoh == NULL) + return SRC_ERR_MALLOC_FAILED ; + psrc->private_data = zoh ; + } ; + + zoh->zoh_magic_marker = ZOH_MAGIC_MARKER ; + zoh->channels = psrc->channels ; + + psrc->process = zoh_process ; + psrc->reset = zoh_reset ; + + zoh_reset (psrc) ; + + return SRC_ERR_NO_ERROR ; +} /* zoh_set_converter */ + +/*=================================================================================== +*/ + +static void +zoh_reset (SRC_PRIVATE *psrc) +{ ZOH_DATA *zoh ; + + zoh = (ZOH_DATA*) psrc->private_data ; + if (zoh == NULL) + return ; + + zoh->channels = psrc->channels ; + memset (zoh->last_value, 0, sizeof (zoh->last_value [0]) * zoh->channels) ; + + return ; +} /* zoh_reset */ |