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https://gitee.com/openharmony/third_party_libsnd
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74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
/*
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** Copyright (C) 2007-2012 Erik de Castro Lopo <erikd@mega-nerd.com>
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include <sndfile.h>
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#include "utils.h"
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#include "generate.h"
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#define SF_MAX(x, y) ((x) > (y) ? (x) : (y))
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static float crappy_snare (float *output, int len, int offset, float gain, float maxabs) ;
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void
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generate_file (const char * filename, int format, int len)
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{ float * output ;
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float maxabs = 0.0 ;
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output = calloc (len, sizeof (float)) ;
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maxabs = crappy_snare (output, len, 0, 0.95, maxabs) ;
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maxabs = crappy_snare (output, len, len / 4, 0.85, maxabs) ;
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maxabs = crappy_snare (output, len, 2 * len / 4, 0.85, maxabs) ;
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crappy_snare (output, len, 3 * len / 4, 0.85, maxabs) ;
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write_mono_file (filename, format, 44100, output, len) ;
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free (output) ;
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} /* generate_file */
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static inline float
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rand_float (void)
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{ return rand () / (0.5 * RAND_MAX) - 1.0 ;
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} /* rand_float */
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static float
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crappy_snare (float *output, int len, int offset, float gain, float maxabs)
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{ int k ;
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float env = 0.0 ;
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for (k = offset ; k < len && env < gain ; k++)
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{ env += 0.03 ;
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output [k] += env * rand_float () ;
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maxabs = SF_MAX (maxabs, fabs (output [k])) ;
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} ;
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for ( ; k < len && env > 1e-8 ; k++)
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{ env *= 0.995 ;
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output [k] += env * rand_float () ;
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maxabs = SF_MAX (maxabs, fabs (output [k])) ;
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} ;
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return maxabs ;
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} /* crappy_snare */
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