value.hpp

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// SPDX-License-Identifier: Apache-2.0
 
#ifndef MODDEF_VALUE_HPP
#define MODDEF_VALUE_HPP
 
#include <cstdint>
#include <optional>
#include <string_view>
 
#include "moddef/str.hpp"
 
extern "C" {
#include "moddef/codec.h"
}
 
namespace moddef {
 
enum class ValueKind : std::uint8_t {
    F64 = MD_VAL_F64,
    U64 = MD_VAL_U64,
    I64 = MD_VAL_I64,
    Bool = MD_VAL_BOOL,
    Flags = MD_VAL_FLAGS,
    Fields = MD_VAL_FIELDS,
    DateTime = MD_VAL_DATETIME,
    Unavailable = MD_VAL_UNAVAILABLE,
};
 
class Value {
   public:
    Value() = default;
    explicit Value(md_value_t v) noexcept : v_(v) {}
 
    ValueKind kind() const noexcept { return static_cast<ValueKind>(v_.kind); }
    const md_value_t& raw() const noexcept { return v_; }
 
    bool is_unavailable() const noexcept { return v_.kind == MD_VAL_UNAVAILABLE; }
 
    // §8.4 sentinel meaning (empty unless is_unavailable()).
    std::string_view unavailable_meaning() const noexcept {
        return is_unavailable() ? from_c(v_.na_meaning) : std::string_view{};
    }
 
    std::optional<double> as_f64() const noexcept {
        switch (v_.kind) {
            case MD_VAL_F64: return v_.v.f64;
            case MD_VAL_U64: return static_cast<double>(v_.v.u64);
            case MD_VAL_I64: return static_cast<double>(v_.v.i64);
            case MD_VAL_BOOL: return v_.v.b ? 1.0 : 0.0;
            default: return std::nullopt;
        }
    }
 
    std::optional<std::int64_t> as_i64() const noexcept {
        switch (v_.kind) {
            case MD_VAL_I64: return v_.v.i64;
            case MD_VAL_U64: return static_cast<std::int64_t>(v_.v.u64);
            case MD_VAL_BOOL: return v_.v.b ? 1 : 0;
            case MD_VAL_DATETIME: return v_.v.epoch;
            default: return std::nullopt;
        }
    }
 
    std::optional<std::uint64_t> as_u64() const noexcept {
        if (v_.kind == MD_VAL_U64) return v_.v.u64;
        return std::nullopt;
    }
 
    std::optional<bool> as_bool() const noexcept {
        if (v_.kind == MD_VAL_BOOL) return v_.v.b;
        return std::nullopt;
    }
 
    // Raw mask (§13.2 flags) or packed window (§13 fields).
    std::optional<std::uint64_t> as_bits() const noexcept {
        if (v_.kind == MD_VAL_FLAGS || v_.kind == MD_VAL_FIELDS) return v_.v.bits;
        return std::nullopt;
    }
 
    // Epoch seconds/millis per the point's encoding (§8.5).
    std::optional<std::int64_t> as_datetime() const noexcept {
        if (v_.kind == MD_VAL_DATETIME) return v_.v.epoch;
        return std::nullopt;
    }
 
   private:
    md_value_t v_{};
};
 
}  // namespace moddef
 
#endif  // MODDEF_VALUE_HPP