[공통] util → framework 유틸 (ACM-CM-002)

boot/common-framework/src/main/java/com/klaro/acquirecore/framework/util/MessageUtil.java

@@ -0,0 +1,145 @@
+package com.klaro.acquirecore.framework.util;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+/**
+ * Static utility class for message/frame processing migrated from legacy C code.
+ * Provides encoding, decoding, and checksum operations for message frames.
+ */
+public final class MessageUtil {
+
+    private static final int HEADER_SIZE = 4;
+    private static final int MAX_MESSAGE_SIZE = 4096;
+    private static final String DELIMITER = "|";
+
+    private MessageUtil() {
+        // Utility class - prevent instantiation
+    }
+
+    public static String encode(String type, byte[] payload) {
+        if (type == null || type.isBlank()) {
+            return null;
+        }
+        int length = (payload != null) ? payload.length : 0;
+        String header = String.format("%s%s%d%s", padRight(type, HEADER_SIZE), DELIMITER, length, DELIMITER);
+        if (payload == null || payload.length == 0) {
+            return header;
+        }
+        return header + new String(payload, StandardCharsets.UTF_8);
+    }
+
+    public static String encode(String type, String payload) {
+        if (payload == null) {
+            return encode(type, (byte[]) null);
+        }
+        return encode(type, payload.getBytes(StandardCharsets.UTF_8));
+    }
+
+    public static MessageFrame decode(String message) {
+        if (message == null || message.isBlank()) {
+            return null;
+        }
+        int firstDelim = message.indexOf(DELIMITER);
+        if (firstDelim < 0 || firstDelim > HEADER_SIZE) {
+            return null;
+        }
+        String type = message.substring(0, firstDelim).trim();
+        int secondDelim = message.indexOf(DELIMITER, firstDelim + 1);
+        if (secondDelim < 0) {
+            return null;
+        }
+        String lengthStr = message.substring(firstDelim + 1, secondDelim).trim();
+        int length;
+        try {
+            length = Integer.parseInt(lengthStr);
+        } catch (NumberFormatException e) {
+            return null;
+        }
+        String payloadStr = message.substring(secondDelim + 1);
+        byte[] payload = payloadStr.getBytes(StandardCharsets.UTF_8);
+        return new MessageFrame(type, length, payload);
+    }
+
+    public static int checksum(byte[] payload) {
+        if (payload == null || payload.length == 0) {
+            return 0;
+        }
+        int sum = 0;
+        for (byte b : payload) {
+            sum += (b & 0xFF);
+        }
+        return sum & 0xFFFF;
+    }
+
+    public static int checksum(String payload) {
+        if (payload == null || payload.isEmpty()) {
+            return 0;
+        }
+        return checksum(payload.getBytes(StandardCharsets.UTF_8));
+    }
+
+    public static String encodeBase64(byte[] data) {
+        if (data == null) {
+            return null;
+        }
+        return Base64.getEncoder().encodeToString(data);
+    }
+
+    public static byte[] decodeBase64(String encoded) {
+        if (encoded == null || encoded.isBlank()) {
+            return null;
+        }
+        try {
+            return Base64.getDecoder().decode(encoded);
+        } catch (IllegalArgumentException e) {
+            return null;
+        }
+    }
+
+    public static boolean isValidSize(String message) {
+        return message != null && message.length() <= MAX_MESSAGE_SIZE;
+    }
+
+    private static String padRight(String str, int length) {
+        if (str == null) {
+            str = "";
+        }
+        if (str.length() >= length) {
+            return str.substring(0, length);
+        }
+        StringBuilder sb = new StringBuilder(str);
+        while (sb.length() < length) {
+            sb.append(' ');
+        }
+        return sb.toString();
+    }
+
+    public static final class MessageFrame {
+        private final String type;
+        private final int length;
+        private final byte[] payload;
+
+        public MessageFrame(String type, int length, byte[] payload) {
+            this.type = type;
+            this.length = length;
+            this.payload = payload;
+        }
+
+        public String getType() { return type; }
+        public int getLength() { return length; }
+        public byte[] getPayload() { return payload; }
+
+        public String getPayloadAsString() {
+            if (payload == null) {
+                return "";
+            }
+            return new String(payload, StandardCharsets.UTF_8);
+        }
+
+        @Override
+        public String toString() {
+            return String.format("MessageFrame{type='%s', length=%d, payload=%s}", type, length, getPayloadAsString());
+        }
+    }
+}