61 lines
3.3 KiB
C++
61 lines
3.3 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <https://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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*/
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#include "mve_audio.h"
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#include "dxxsconf.h"
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#include <array>
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#include "d_enumerate.h"
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#include "backports-ranges.h"
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constexpr std::array<int, 256> audio_exp_table{
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{
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
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16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
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32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 47, 51, 56, 61,
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66, 72, 79, 86, 94, 102, 112, 122, 133, 145, 158, 173, 189, 206, 225, 245,
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267, 292, 318, 348, 379, 414, 452, 493, 538, 587, 640, 699, 763, 832, 908, 991,
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1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993, 2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008,
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4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059, 8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206,
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17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589, -29973, -26728, -23186, -19322, -15105, -10503, -5481, -1,
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1, 1, 5481, 10503, 15105, 19322, 23186, 26728, 29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
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-17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597, -8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772,
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-4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373, -2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180,
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-1081, -991, -908, -832, -763, -699, -640, -587, -538, -493, -452, -414, -379, -348, -318, -292,
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-267, -245, -225, -206, -189, -173, -158, -145, -133, -122, -112, -102, -94, -86, -79, -72,
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-66, -61, -56, -51, -47, -43, -42, -41, -40, -39, -38, -37, -36, -35, -34, -33,
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-32, -31, -30, -29, -28, -27, -26, -25, -24, -23, -22, -21, -20, -19, -18, -17,
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-16, -15, -14, -13, -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1
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}
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};
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static void processSwath(std::span<int16_t> fout, const uint8_t *const data, std::array<int32_t, 2> offsets)
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{
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for (const auto &&[i, d] : enumerate(ranges::subrange(data, std::next(data, fout.size()))))
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{
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auto &o = offsets[i & 1];
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o += audio_exp_table[d];
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fout.front() = o;
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fout = fout.subspan<1>();
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}
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}
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void mveaudio_uncompress(std::span<int16_t> buffer, const uint8_t *data)
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{
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/* Skip 4 bytes. Then, skip over the swath value in the input, since the
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* caller provided that value as the extent of `buffer`.
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*/
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data += 6;
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const uint16_t c0 = data[0] | (data[1] << 8);
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data += 2;
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const uint16_t c1 = data[0] | (data[1] << 8);
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data += 2;
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buffer.front() = c0;
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buffer = buffer.subspan<1>();
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buffer.front() = c1;
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buffer = buffer.subspan<1>();
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processSwath(buffer, data, {{c0, c1}});
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}
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