Added test for hex encoding method

chernser · chernser · commit 04513dd17945 · 2026-02-09T10:06:36.000-08:00
diff --git a/jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/JdbcUtils.java b/jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/JdbcUtils.java
@@ -604,4 +604,32 @@ public static String convertToUnhexExpression(byte[] bytes) {
         }
         return new String(hexChars, StandardCharsets.US_ASCII);
     }
+
+    /**
+     * Decodes a hex string into a byte array.
+     * Each pair of characters in the input is interpreted as a hexadecimal byte value.
+     *
+     * @param hexString hex-encoded string (must have even length)
+     * @return decoded byte array, or empty array if input is null or empty
+     * @throws IllegalArgumentException if the string has odd length or contains non-hex characters
+     */
+    public static byte[] decodeHexString(String hexString) {
+        if (hexString == null || hexString.isEmpty()) {
+            return new byte[0];
+        }
+        int len = hexString.length();
+        if (len % 2 != 0) {
+            throw new IllegalArgumentException("Hex string must have even length, got " + len);
+        }
+        byte[] result = new byte[len / 2];
+        for (int i = 0; i < result.length; i++) {
+            int hi = Character.digit(hexString.charAt(i * 2), 16);
+            int lo = Character.digit(hexString.charAt(i * 2 + 1), 16);
+            if (hi == -1 || lo == -1) {
+                throw new IllegalArgumentException("Invalid hex character at index " + (hi == -1 ? i * 2 : i * 2 + 1));
+            }
+            result[i] = (byte) ((hi << 4) | lo);
+        }
+        return result;
+    }
 }
diff --git a/jdbc-v2/src/test/java/com/clickhouse/jdbc/internal/JdbcUtilsTest.java b/jdbc-v2/src/test/java/com/clickhouse/jdbc/internal/JdbcUtilsTest.java
@@ -6,12 +6,14 @@
 import org.testng.Assert;
 import org.testng.annotations.*;
 
+import java.io.InputStream;
 import java.math.BigDecimal;
 import java.sql.SQLException;
 import java.time.Instant;
 import java.time.ZoneId;
 import java.util.Arrays;
 import java.util.List;
+import java.util.zip.CRC32;
 
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertNull;
@@ -109,4 +111,35 @@ public void testAllDataTypesMapped() {
             Assert.assertNotNull(JdbcUtils.convertToJavaClass(dt), "Data type " + dt + " has no mapping to java class");
         }
     }
+
+    @Test(groups = {"unit"})
+    public void testConvertToUnhexExpression() throws Exception {
+        // Load binary file from test resources
+        byte[] originalBytes;
+        try (InputStream is = getClass().getResourceAsStream("/ch_logo.png")) {
+            Assert.assertNotNull(is, "ch_logo.png not found in test resources");
+            originalBytes = is.readAllBytes();
+        }
+
+        // Calculate checksum of original bytes
+        CRC32 originalChecksum = new CRC32();
+        originalChecksum.update(originalBytes);
+        long expectedChecksum = originalChecksum.getValue();
+
+        // Convert to unhex expression
+        String unhexExpr = JdbcUtils.convertToUnhexExpression(originalBytes);
+        Assert.assertTrue(unhexExpr.startsWith("unhex('"), "Expression should start with unhex('");
+        Assert.assertTrue(unhexExpr.endsWith("')"), "Expression should end with ')");
+
+        // Extract hex string and decode back to bytes
+        String hexString = unhexExpr.substring("unhex('".length(), unhexExpr.length() - "')".length());
+        assertEquals(hexString.length(), originalBytes.length * 2, "Hex string length should be twice the byte array length");
+
+        byte[] decodedBytes = JdbcUtils.decodeHexString(hexString);
+
+        // Verify checksum of decoded bytes matches original
+        CRC32 decodedChecksum = new CRC32();
+        decodedChecksum.update(decodedBytes);
+        assertEquals(decodedChecksum.getValue(), expectedChecksum, "Checksum of decoded bytes should match original");
+    }
 }
diff --git a/jdbc-v2/src/test/resources/ch_logo.png b/jdbc-v2/src/test/resources/ch_logo.png
