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