Fix the issue of handling negative big decimals

Author: zhicwu

clickhouse-jdbc/src/main/java/ru/yandex/clickhouse/util/ClickHouseRowBinaryStream.java

@@ -188,22 +188,24 @@ public void writeFloat64(double value) throws IOException {
         Utils.writeLong(out, Double.doubleToLongBits(value));
     }
 
-    public void writeDecimal128(BigDecimal num, int scale) throws IOException {
-        BigInteger bi = Utils.toBigInteger(num, scale);
-        byte[] r = bi.toByteArray();
-        for (int i = r.length; i > 0; i--) {
-            out.write(r[i - 1]);
+    public void writeBigInteger(BigInteger value, int byteLength) throws IOException {
+        byte empty = value.signum() == -1 ? (byte) 0xFF : 0x00;
+        byte[] bytes = value.toByteArray();
+        for (int i = bytes.length - 1; i >= 0; i--) {
+            out.write(bytes[i]);
+        }
+
+        for (int i = byteLength - bytes.length; i > 0; i--) {
+            out.write(empty);
         }
-        out.write(new byte[16 - r.length]);
+    }
+
+    public void writeDecimal128(BigDecimal num, int scale) throws IOException {
+        writeBigInteger(Utils.toBigInteger(num, scale), 16);
     }
 
     public void writeDecimal256(BigDecimal num, int scale) throws IOException {
-        BigInteger bi = Utils.toBigInteger(num, scale);
-        byte[] r = bi.toByteArray();
-        for (int i = r.length; i > 0; i--) {
-            out.write(r[i - 1]);
-        }
-        out.write(new byte[32 - r.length]);
+        writeBigInteger(Utils.toBigInteger(num, scale), 32);
     }
 
     public void writeDecimal64(BigDecimal num, int scale) throws IOException {

clickhouse-jdbc/src/test/java/ru/yandex/clickhouse/integration/RowBinaryStreamTest.java

@@ -2,11 +2,11 @@
 
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertFalse;
-import static org.testng.Assert.assertThrows;
 import static org.testng.Assert.assertTrue;
 
 import java.io.EOFException;
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.sql.Date;
 import java.sql.ResultSet;
@@ -276,6 +276,46 @@ public void testBitmap() throws Exception {
         }
     }
 
+    @Test
+    public void testBigDecimals() throws Exception {
+        try (ClickHouseStatement statement = connection.createStatement()) {
+            statement.execute("set allow_experimental_bigint_types=1;"
+                + "create table if not exists test.test_big_decimals(d128 Decimal128(6), d256 Decimal256(12)) engine=Memory");
+        } catch (SQLException e) {
+            return;
+        }
+
+        try (ClickHouseStatement statement = connection.createStatement()) {
+            BigDecimal[] values = new BigDecimal[] {
+                BigDecimal.valueOf(-123.123456789D),
+                BigDecimal.ZERO,
+                BigDecimal.valueOf(123.123456789D)
+            };
+            statement.sendRowBinaryStream("insert into table test.test_big_decimals", new ClickHouseStreamCallback() {
+                @Override
+                public void writeTo(ClickHouseRowBinaryStream stream) throws IOException {
+                    for (int i = 0; i < values.length; i++) {
+                        stream.writeDecimal128(values[i], 6);
+                        stream.writeDecimal256(values[i], 12);
+                    }
+                }
+            });
+
+            try (ResultSet rs = statement.executeQuery("select * from test.test_big_decimals order by d128")) {
+                int rowCounter = 0;
+                while (rs.next()) {
+                    rowCounter++;
+                    assertEquals(rs.getBigDecimal(1, 6), values[rowCounter - 1].setScale(6, BigDecimal.ROUND_DOWN));
+                    assertEquals(rs.getBigDecimal(2, 12), values[rowCounter - 1].setScale(12, BigDecimal.ROUND_DOWN));
+                }
+
+                assertEquals(rowCounter, values.length);
+            }
+
+            statement.execute("drop table if exists test.test_big_decimals");
+        }
+    }
+
     private void testRowBinaryStream(boolean rowBinaryResult) throws Exception {
         createTable("test.raw_binary");
         ClickHouseStatement statement = connection.createStatement();

clickhouse-jdbc/src/test/java/ru/yandex/clickhouse/util/ClickHouseRowBinaryStreamTest.java

@@ -112,9 +112,32 @@ public void testDecimal128() throws Exception {
                     @Override
                     public void write(ClickHouseRowBinaryStream stream) throws Exception {
                         stream.writeDecimal128(new BigDecimal(10.23), 3);
+                        stream.writeDecimal128(new BigDecimal(-10.23), 3);
                     }
                 },
-                new byte[]{-10, 39, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+                new byte[] {
+                    -10, 39, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    10, -40, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+                }
+        );
+    }
+
+    @Test
+    public void testDecimal256() throws Exception {
+        check(
+                new StreamWriter() {
+                    @Override
+                    public void write(ClickHouseRowBinaryStream stream) throws Exception {
+                        stream.writeDecimal256(new BigDecimal(10.23), 3);
+                        stream.writeDecimal256(new BigDecimal(-10.23), 3);
+                    }
+                },
+                new byte[] {
+                    -10, 39, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    10, -40, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+                    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+                }
         );
     }