wave_descriptor.hpp

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#pragma once
 
#include <cstdint>
#include <span>
 
namespace ts {

struct WaveDescriptor {
    static constexpr int stride = 0x16;

    int region = 0;
    int loop = 0;
    int end = 0;
    int start = 0;
    int root_key = 0;
    int fine_tune = 0;
    int flags = 0;

    [[nodiscard]] constexpr int bank() const noexcept { return (region >> 4) & 1; }

    [[nodiscard]] constexpr bool reverse() const noexcept { return ((flags >> 2) & 1) != 0; }

    [[nodiscard]] constexpr bool ping_pong() const noexcept { return (flags & 1) != 0; }

    [[nodiscard]] constexpr double native_pitch() const noexcept
    {
        return root_key + ((1024.0 - fine_tune) / 1000.0);
    }

    [[nodiscard]] static constexpr WaveDescriptor
    parse(std::span<const std::uint8_t> record) noexcept
    {
        // The three position fields are 20-bit, stored most-significant nibble first.
        const int loop = ((record[0x01] & 0x0F) << 16) | (record[0x02] << 8) | record[0x03];
        const int end = ((record[0x07] & 0x0F) << 16) | (record[0x08] << 8) | record[0x09];
        const int start = ((record[0x0B] & 0x0F) << 16) | (record[0x0C] << 8) | record[0x0D];
 
        return WaveDescriptor{
            .region = record[0x00] & 0x7F,
            .loop = loop,
            .end = end,
            .start = start,
            .root_key = record[0x06],
            .fine_tune = record[0x04] | (record[0x05] << 8),
            .flags = record[0x0A],
        };
    }
 
    [[nodiscard]] friend constexpr bool operator==(const WaveDescriptor&,
                                                   const WaveDescriptor&) noexcept = default;
};

struct MultisampleZone {
    int key_low = 0;
    int key_high = 0;
    int wave = 0;
};
 
} // namespace ts