rescale.h

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#ifndef RESCALE_H
#define RESCALE_H
 
[[gnu::always_inline]]
static inline float rescale_float(
    float input,
    float input_min,
    float input_max,
    float output_min,
    float output_max
) {
    float input_range = input_max - input_min;
    float output_range = output_max - output_min;
 
    if (input_range == 0.0f) return output_min; // prevent div by 0
 
    float ratio = (input - input_min) / input_range;
    float output = output_min + (ratio * output_range);
 
    return output;
}
 
[[gnu::always_inline]]
static inline signed int rescale_signed(
    signed int input,
    signed int input_min,
    signed int input_max,
    signed int output_min,
    signed int output_max
) {
    float output = rescale_float(
        (float)input,
        (float)input_min,
        (float)input_max,
        (float)output_min,
        (float)output_max
    );
 
    return (signed int)output;
}
 
[[gnu::always_inline]]
static inline unsigned int rescale_unsigned(
    unsigned int input,
    unsigned int input_min,
    unsigned int input_max,
    unsigned int output_min,
    unsigned int output_max
) {
    float output = rescale_float(
        (float)input,
        (float)input_min,
        (float)input_max,
        (float)output_min,
        (float)output_max
    );
 
    return (unsigned int)output;
}
 
#define RESCALE(input, input_min, input_max, output_min, output_max) \
    _Generic((input) + (input_min) + (input_max) + (output_min) + (output_max), \
    signed int: rescale_signed, \
    unsigned int: rescale_unsigned, \
    float: rescale_float \
)(input, input_min, input_max, output_min, output_max)
 
#endif // RESCALE_H