You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
48 lines
1.3 KiB
48 lines
1.3 KiB
/* |
|
sample.h - compact version of famous library mpg123 |
|
Copyright (C) 2017 Uncle Mike |
|
|
|
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 3 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. |
|
*/ |
|
|
|
#ifndef SAMPLE_H |
|
#define SAMPLE_H |
|
|
|
// define the accurate rounding function. |
|
#ifdef IEEE_FLOAT |
|
// rhis function is only available for IEEE754 single-precision values |
|
// rhis is nearly identical to proper rounding, just -+0.5 is rounded to 0 |
|
static _inline int16_t ftoi16( float x ) |
|
{ |
|
union |
|
{ |
|
float f; |
|
int32_t i; |
|
} u_fi; |
|
|
|
u_fi.f = x + 12582912.0f; // Magic Number: 2^23 + 2^22 |
|
return (int16_t)u_fi.i; |
|
} |
|
|
|
#define REAL_TO_SHORT_ACCURATE( x ) ftoi16(x) |
|
#else |
|
// the "proper" rounding, plain C, a bit slow. |
|
#define REAL_TO_SHORT_ACCURATE( x ) (short)((x) > 0.0 ? (x) + 0.5 : (x) - 0.5) |
|
#endif |
|
|
|
// now define the normal rounding. |
|
#ifdef ACCURATE_ROUNDING |
|
#define REAL_TO_SHORT( x ) REAL_TO_SHORT_ACCURATE( x ) |
|
#else |
|
#define REAL_TO_SHORT( x ) (short)( x ) |
|
#endif |
|
|
|
#endif//SAMPLE_H
|