Closes #11

core/decode_database.h

@@ -0,0 +1,116 @@
+/**
+ * @file decode_database.h
+ * @brief
+ *
+ * Created: 2026-03-13
+ * Author: Deeaitch (Dim. Himro)
+ *
+ * Licensed under the MIT License.
+ * See LICENSE file in the project root for full license text.
+ */
+
+#ifndef DECODE_DATABASE_H
+#define DECODE_DATABASE_H
+
+#include <cstdint>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+/**
+ * @brief Signal byte order used for runtime decoding.
+ */
+enum class ByteOrder {
+    Intel,
+    Motorola
+};
+
+/**
+ * @brief Signal numeric type.
+ */
+enum class ValueType {
+    Unsigned,
+    Signed
+};
+
+/**
+ * @brief Runtime-ready signal definition.
+ */
+struct DecodeSignal {
+    std::string name;                   /**< Signal name. */
+    std::uint32_t startBit;             /**< DBC start bit. */
+    std::uint32_t length;               /**< Signal length in bits. */
+    ByteOrder byteOrder;                /**< Intel or Motorola. */
+    ValueType valueType;                /**< Signed or unsigned. */
+    double factor;                      /**< Scaling factor. */
+    double offset;                      /**< Physical offset. */
+    double minimum;                     /**< Minimum physical value. */
+    double maximum;                     /**< Maximum physical value. */
+    std::string unit;                   /**< Physical unit. */
+    std::vector<std::string> receivers; /**< Receivers. */
+    std::string comment;                /**< Comment. */
+
+    DecodeSignal()
+        : name(), startBit(0U), length(0U), byteOrder(ByteOrder::Intel), valueType(ValueType::Unsigned), factor(1.0), offset(0.0), minimum(0.0), maximum(0.0), unit(), receivers(), comment() {
+    }
+};
+
+/**
+ * @brief Runtime-ready frame definition.
+ */
+struct DecodeFrame {
+    std::string name;                  /**< Frame name. */
+    std::uint32_t canId;               /**< Normalized CAN ID. */
+    bool isExtended;                   /**< true for extended frame. */
+    std::uint8_t dlc;                  /**< Payload length. */
+    std::uint32_t pgn;                 /**< PGN if available. */
+    bool hasPgn;                       /**< true if PGN is valid. */
+    std::string transmitter;           /**< Transmitter ECU. */
+    std::string comment;               /**< Frame comment. */
+    std::vector<DecodeSignal> signals; /**< Signal definitions. */
+
+    DecodeFrame()
+        : name(), canId(0U), isExtended(false), dlc(0U), pgn(0U), hasPgn(false), transmitter(), comment(), signals() {
+    }
+};
+
+/**
+ * @brief Key for fast frame lookup.
+ */
+struct FrameKey {
+    std::uint32_t canId;
+    bool isExtended;
+
+    FrameKey()
+        : canId(0U), isExtended(false) {
+    }
+
+    FrameKey(std::uint32_t id, bool extended)
+        : canId(id), isExtended(extended) {
+    }
+
+    bool operator==(const FrameKey &other) const {
+        return (canId == other.canId) && (isExtended == other.isExtended);
+    }
+};
+
+/**
+ * @brief Hasher for frame key.
+ */
+struct FrameKeyHasher {
+    std::size_t operator()(const FrameKey &key) const {
+        const std::size_t a = static_cast<std::size_t>(key.canId);
+        const std::size_t b = key.isExtended ? 1U : 0U;
+        return (a * 1315423911U) ^ b;
+    }
+};
+
+/**
+ * @brief Runtime decode database with fast lookup by CAN ID.
+ */
+struct DecodeDatabase {
+    std::vector<DecodeFrame> frames;
+    std::unordered_map<FrameKey, std::size_t, FrameKeyHasher> frameIndexByKey;
+};
+
+#endif /* DECODE_DATABASE_H */