Initial code

src/PacketParser.cpp

@@ -0,0 +1,82 @@
+#include "PacketParser.h"
+
+PacketParser::PacketParser()
+{
+}
+
+PacketParser::~PacketParser()
+{
+}
+
+bool PacketParser::parsePacket(const uint8_t *buffer, Packet& message)
+{
+    message.source = (uint16_t)(buffer[14] << 8 | buffer[15]);
+    message.destination = (uint16_t)(buffer[12] << 8 | buffer[13]);
+
+    if (buffer[16] == 0x52 && buffer[17] == 0x53) {
+        message.type = PacketType::STOP;
+        message.parameters = std::monostate{};
+    } else if (buffer[16] == 0x52 && buffer[17] == 0x44) {
+        message.type = PacketType::CLOSE;
+        message.parameters = std::monostate{};
+    } else if (buffer[16] == 0x52 && buffer[17] == 0x55) {
+        message.type = PacketType::OPEN;
+        message.parameters = std::monostate{};
+    } else if (buffer[16] == 0x21 && buffer[17] == 0x5A) { 
+        message.type = PacketType::FIELDS;
+        std::vector<Field> fields;
+        parseFields(buffer, fields);
+        message.parameters = FieldsParameters{fields};
+    } else if (buffer[16] == 0x3F && buffer[17] == 0x5A) {
+        message.type = PacketType::FIELD_COMMAND;
+        std::vector<Field> fields;
+        parseFields(buffer, fields);
+        message.parameters = FieldsParameters{fields};
+    } else {
+        message.type = PacketType::UNKNOWN;
+        message.parameters = std::monostate{};
+        return false;
+    }
+
+    return true;
+}
+
+bool PacketParser::parseFields(const uint8_t *buffer, std::vector<Field>& fields) {
+    uint8_t length = buffer[1] + 2;
+
+    uint8_t offset = 18;
+    while (offset < length) {
+        uint8_t fieldLength = buffer[offset];
+        if (offset + fieldLength >= length) {
+            // Not enough space to parse the field
+            return false;
+        }
+        FieldType type;
+        switch (buffer[offset + 1]) {
+            case 0x40:
+                type = FieldType::SET;
+                break;
+            case 0x3F:
+                type = FieldType::FETCH;
+                break;
+            case 0x21:
+                type = FieldType::VALUE;
+                break;
+            default:
+                type = FieldType::UNKNOWN;
+                break;
+        } 
+        uint8_t identifier = buffer[offset + 2];
+        if (fieldLength == 2) {
+            fields.push_back(Field{identifier, type, false, std::monostate{}});
+        } else if (fieldLength == 3) {
+            uint8_t value = buffer[offset + 3];
+            fields.push_back(Field{identifier, type, true, value});
+        } else if (fieldLength == 4) {
+            uint16_t value = (uint16_t)(buffer[offset + 3] | buffer[offset + 4] << 8);
+            fields.push_back(Field{identifier, type, true, value});
+        }
+        offset += fieldLength + 1;
+    }
+    return true;
+}