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#pragma once
#include <stdint.h>
#include <algorithm>
#include <mad.h>
namespace sample {
// A signed, 32-bit PCM sample.
typedef int16_t Sample;
constexpr auto Clip(int64_t v) -> Sample {
if (v > INT16_MAX)
return INT16_MAX;
if (v < INT16_MIN)
return INT16_MIN;
return v;
}
constexpr auto FromSigned(int32_t src, uint_fast8_t bits) -> Sample {
if (bits > 16) {
// Left-align samples, effectively scaling them up to 32 bits.
return src << (sizeof(Sample) * 8 - bits);
} else if (bits < 16) {
return src << (bits - (sizeof(Sample) * 8));
}
return src;
}
constexpr auto FromUnsigned(uint32_t src, uint_fast8_t bits) -> Sample {
// Left-align, then substract the max value / 2 to make the sample centred
// around zero.
return (src << (sizeof(uint16_t) * 8 - bits)) - (~0UL >> 1);
}
constexpr auto FromFloat(float src) -> Sample {
return std::clamp<float>(src, -1.0f, 1.0f) * static_cast<float>(INT16_MAX);
}
constexpr auto FromDouble(double src) -> Sample {
return std::clamp<double>(src, -1.0, 1.0) * static_cast<double>(INT16_MAX);
}
constexpr auto FromMad(mad_fixed_t src) -> Sample {
// Round the bottom bits.
src += (1L << (MAD_F_FRACBITS - 16));
// Clip the leftover bits to within range.
if (src >= MAD_F_ONE)
src = MAD_F_ONE - 1;
else if (src < -MAD_F_ONE)
src = -MAD_F_ONE;
// Quantize.
return FromSigned(src >> (MAD_F_FRACBITS + 1 - 16), 16);
}
static constexpr float kFactor = 1.0f / static_cast<float>(INT16_MAX);
constexpr auto ToFloat(Sample src) -> float {
return src * kFactor;
}
} // namespace sample
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