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/* SPDX-License-Identifier: BSD-3-Clause */
/* SPDX-FileCopyrightText: OpenMPT Project Developers and Contributors */
#pragma once
#include "openmpt/all/BuildSettings.hpp"
#include "mpt/base/bit.hpp"
#include "mpt/base/macros.hpp"
#include "mpt/base/memory.hpp"
#include "openmpt/base/Types.hpp"
#include <algorithm>
#include <cmath>
#include <cstddef>
#include <cstdlib>
OPENMPT_NAMESPACE_BEGIN
namespace SC
{ // SC = _S_ample_C_onversion
struct EncodeuLaw
{
using input_t = int16;
using output_t = std::byte;
static constexpr uint8 exp_table[17] = {0, 7 << 4, 6 << 4, 5 << 4, 4 << 4, 3 << 4, 2 << 4, 1 << 4, 0 << 4, 0, 0, 0, 0, 0, 0, 0, 0};
static constexpr uint8 mant_table[17] = {0, 10, 9, 8, 7, 6, 5, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3};
MPT_FORCEINLINE output_t operator()(input_t val)
{
uint16 x = static_cast<uint16>(val);
uint8 out = (x >> 8) & 0x80;
uint32 abs = x & 0x7fff;
if(x & 0x8000)
{
abs ^= 0x7fff;
abs += 1;
}
x = static_cast<uint16>(std::clamp(static_cast<uint32>(abs + (33 << 2)), static_cast<uint32>(0), static_cast<uint32>(0x7fff)));
int index = mpt::countl_zero(x);
out |= exp_table[index];
out |= (x >> mant_table[index]) & 0x0f;
out ^= 0xff;
return mpt::byte_cast<std::byte>(out);
}
};
struct EncodeALaw
{
using input_t = int16;
using output_t = std::byte;
static constexpr uint8 exp_table[17] = {0, 7 << 4, 6 << 4, 5 << 4, 4 << 4, 3 << 4, 2 << 4, 1 << 4, 0 << 4, 0, 0, 0, 0, 0, 0, 0, 0};
static constexpr uint8 mant_table[17] = {0, 10, 9, 8, 7, 6, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4};
MPT_FORCEINLINE output_t operator()(input_t val)
{
int16 sx = std::clamp(val, static_cast<int16>(-32767), static_cast<int16>(32767));
uint16 x = static_cast<uint16>(sx);
uint8 out = ((x & 0x8000) ^ 0x8000) >> 8;
x = static_cast<uint16>(std::abs(sx));
int index = mpt::countl_zero(x);
out |= exp_table[index];
out |= (x >> mant_table[index]) & 0x0f;
out ^= 0x55;
return mpt::byte_cast<std::byte>(out);
}
};
} // namespace SC
OPENMPT_NAMESPACE_END
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