pcm_utils.cc

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/*
    Copyright (C) 2006 Paul Davis , portions Erik de Castro Lopo

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifdef COMPILER_MSVC
#include <ardourext/float_cast.h>
#endif
#include "ardour/pcm_utils.h"
#include <cmath>

using namespace std;

// TODO: check CPU_CLIPS_POSITIVE and CPU_CLIPS_NEGATIVE with scons
#define CPU_CLIPS_NEGATIVE 0
#define CPU_CLIPS_POSITIVE 0

/* these routines deal with 24 bit int handling (tribytes)
 *   originally from libsndfile, but modified.  XXX - Copyright Erik de Castro Lopo
 */

void
pcm_let2f_array (tribyte *src, int count, float *dest)
{
        /* Special normfactor because tribyte value is read into an int. */
        static const float normfact = 1.0 / ((float) 0x80000000);

        unsigned char   *ucptr ;
        int                             value ;

        ucptr = ((unsigned char*) src) + 3 * count ;
        while (--count >= 0)
        {       ucptr -= 3 ;
                value = LET2H_INT_PTR (ucptr) ;
                dest [count] = ((float) value) * normfact ;
                } ;
} /* let2f_array */

void
pcm_bet2f_array (tribyte *src, int count, float *dest)
{
        /* Special normfactor because tribyte value is read into an int. */
        static const float normfact = 1.0 / ((float) 0x80000000);

        unsigned char   *ucptr ;
        int                             value ;


        ucptr = ((unsigned char*) src) + 3 * count ;
        while (--count >= 0)
        {       ucptr -= 3 ;
                value = BET2H_INT_PTR (ucptr) ;
                dest [count] = ((float) value) * normfact ;
                        } ;
} /* bet2f_array */

void
pcm_f2let_array (float *src, tribyte *dest, int count)
{
        static const float normfact = (1.0 * 0x7FFFFF);

        unsigned char   *ucptr ;
        int                             value ;

        ucptr = ((unsigned char*) dest) + 3 * count ;

        while (count)
        {       count -- ;
                ucptr -= 3 ;
                value = lrintf (src [count] * normfact) ;
                ucptr [0] = value ;
                ucptr [1] = value >> 8 ;
                ucptr [2] = value >> 16 ;
                } ;
} /* f2let_array */

void
pcm_f2let_clip_array (float *src, tribyte *dest, int count)
{
        static const float normfact = (8.0 * 0x10000000);

        unsigned char   *ucptr ;
        float                   scaled_value ;
        int                             value ;

        ucptr = ((unsigned char*) dest) + 3 * count ;

        while (count)
        {       count -- ;
                ucptr -= 3 ;
                scaled_value = src [count] * normfact ;
                if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
                {       ucptr [0] = 0xFF ;
                        ucptr [1] = 0xFF ;
                        ucptr [2] = 0x7F ;
                        continue ;
                        } ;
                if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
                {       ucptr [0] = 0x00 ;
                        ucptr [1] = 0x00 ;
                        ucptr [2] = 0x80 ;
                        continue ;
                        } ;

                value = lrintf (scaled_value) ;
                ucptr [0] = value >> 8 ;
                ucptr [1] = value >> 16 ;
                ucptr [2] = value >> 24 ;
                } ;
} /* f2let_clip_array */

void
pcm_f2bet_array (const float *src, tribyte *dest, int count)
{
        static const float normfact = (1.0 * 0x7FFFFF);

        unsigned char   *ucptr ;
        int                             value ;

        ucptr = ((unsigned char*) dest) + 3 * count ;

        while (--count >= 0)
        {       ucptr -= 3 ;
                value = lrintf (src [count] * normfact) ;
                ucptr [0] = value >> 16 ;
                ucptr [1] = value >> 8 ;
                ucptr [2] = value ;
                } ;
} /* f2bet_array */

void
pcm_f2bet_clip_array (const float *src, tribyte *dest, int count)
{
        static const float normfact = (8.0 * 0x10000000);

        unsigned char   *ucptr ;
        float                   scaled_value ;
        int                             value ;

        ucptr = ((unsigned char*) dest) + 3 * count ;

        while (--count >= 0)
        {       ucptr -= 3 ;
                scaled_value = src [count] * normfact ;
                if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
                {       ucptr [0] = 0x7F ;
                        ucptr [1] = 0xFF ;
                        ucptr [2] = 0xFF ;
                        continue ;
                        } ;
                if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
                {       ucptr [0] = 0x80 ;
                        ucptr [1] = 0x00 ;
                        ucptr [2] = 0x00 ;
                        continue ;
                } ;

                value = lrint (scaled_value) ;
                ucptr [0] = value >> 24 ;
                ucptr [1] = value >> 16 ;
                ucptr [2] = value >> 8 ;
                } ;
} /* f2bet_clip_array */

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