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/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "sample.hpp"
#include <stdint.h>
#include <cstdint>
#include "komihash.h"
namespace sample {
static uint64_t sSeed1{0};
static uint64_t sSeed2{0};
auto shiftWithDither(int64_t src, uint_fast8_t bits) -> Sample {
// Generate `bits` random bits
uint64_t mask = 0xFFFFFFFF;
mask >>= 32 - bits;
int64_t noise = static_cast<int32_t>(komirand(&sSeed1, &sSeed2) & mask);
// Centre the noise around 0.
noise -= (mask >> 1);
// Apply to the sample, then clip and shift to 16 bit.
Sample clipped = Clip((src + noise) >> bits);
return clipped;
}
} // namespace sample
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