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/*
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sample.h - compact version of famous library mpg123
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Copyright (C) 2017 Uncle Mike
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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 3 of the License, or
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(at your option) any later version.
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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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#ifndef SAMPLE_H
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#define SAMPLE_H
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// define the accurate rounding function.
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#ifdef IEEE_FLOAT
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// rhis function is only available for IEEE754 single-precision values
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// rhis is nearly identical to proper rounding, just -+0.5 is rounded to 0
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static _inline int16_t ftoi16( float x )
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{
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union
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{
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float f;
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int32_t i;
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} u_fi;
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u_fi.f = x + 12582912.0f; // Magic Number: 2^23 + 2^22
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return (int16_t)u_fi.i;
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}
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#define REAL_TO_SHORT_ACCURATE( x ) ftoi16(x)
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#else
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// the "proper" rounding, plain C, a bit slow.
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#define REAL_TO_SHORT_ACCURATE( x ) (short)((x) > 0.0f ? (x) + 0.5f : (x) - 0.5f)
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#endif
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// now define the normal rounding.
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#ifdef ACCURATE_ROUNDING
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#define REAL_TO_SHORT( x ) REAL_TO_SHORT_ACCURATE( x )
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#else
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#define REAL_TO_SHORT( x ) (short)( x )
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#endif
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#endif//SAMPLE_H
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