PARQUET-1246: Changes according to zi's comments

Author: Gabor Szadovszky

parquet-column/src/main/java/org/apache/parquet/column/statistics/Statistics.java

@@ -92,12 +92,13 @@ public Statistics<?> build() {
           ((Statistics<?>) stats).hasNonNullValue = false;
         } else {
           // Updating min to -0.0 and max to +0.0 to ensure that no 0.0 values would be skipped
-          if (min == 0.0f) {
-            stats.setMinMax(-0.0f, max);
+          if (Float.compare(min, 0.0f) == 0) {
             min = -0.0f;
+            stats.setMinMax(min, max);
           }
-          if (max == -0.0f) {
-            stats.setMinMax(min, 0.0f);
+          if (Float.compare(max, -0.0f) == 0) {
+            max = 0.0f;
+            stats.setMinMax(min, max);
           }
         }
       }
@@ -124,12 +125,13 @@ public Statistics<?> build() {
           ((Statistics<?>) stats).hasNonNullValue = false;
         } else {
           // Updating min to -0.0 and max to +0.0 to ensure that no 0.0 values would be skipped
-          if (min == 0.0) {
-            stats.setMinMax(-0.0, max);
+          if (Double.compare(min, 0.0) == 0) {
             min = -0.0;
+            stats.setMinMax(min, max);
           }
-          if (max == -0.0) {
-            stats.setMinMax(min, 0.0);
+          if (Double.compare(max, -0.0) == 0) {
+            max = 0.0;
+            stats.setMinMax(min, max);
           }
         }
       }

parquet-column/src/test/java/org/apache/parquet/column/statistics/TestStatistics.java

@@ -724,6 +724,24 @@ public void testSpecBuilderForFloat() {
     assertTrue(stats.isNumNullsSet());
     assertEquals(42, stats.getNumNulls());
     assertFalse(stats.hasNonNullValue());
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(intToBytes(floatToIntBits(0.0f)))
+        .withMax(intToBytes(floatToIntBits(42.0f))).build();
+    assertEquals(0, Float.compare(-0.0f, (Float) stats.genericGetMin()));
+    assertEquals(0, Float.compare(42.0f, (Float) stats.genericGetMax()));
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(intToBytes(floatToIntBits(-42.0f)))
+        .withMax(intToBytes(floatToIntBits(-0.0f))).build();
+    assertEquals(0, Float.compare(-42.0f, (Float) stats.genericGetMin()));
+    assertEquals(0, Float.compare(0.0f, (Float) stats.genericGetMax()));
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(intToBytes(floatToIntBits(0.0f)))
+        .withMax(intToBytes(floatToIntBits(-0.0f))).build();
+    assertEquals(0, Float.compare(-0.0f, (Float) stats.genericGetMin()));
+    assertEquals(0, Float.compare(0.0f, (Float) stats.genericGetMax()));
   }
 
   @Test
@@ -749,5 +767,23 @@ public void testSpecBuilderForDouble() {
     assertTrue(stats.isNumNullsSet());
     assertEquals(42, stats.getNumNulls());
     assertFalse(stats.hasNonNullValue());
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(longToBytes(doubleToLongBits(0.0)))
+        .withMax(longToBytes(doubleToLongBits(42.0))).build();
+    assertEquals(0, Double.compare(-0.0, (Double) stats.genericGetMin()));
+    assertEquals(0, Double.compare(42.0, (Double) stats.genericGetMax()));
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(longToBytes(doubleToLongBits(-42.0)))
+        .withMax(longToBytes(doubleToLongBits(-0.0))).build();
+    assertEquals(0, Double.compare(-42.0, (Double) stats.genericGetMin()));
+    assertEquals(0, Double.compare(0.0, (Double) stats.genericGetMax()));
+
+    builder = Statistics.getBuilderForReading(type);
+    stats = builder.withMin(longToBytes(doubleToLongBits(0.0)))
+        .withMax(longToBytes(doubleToLongBits(-0.0))).build();
+    assertEquals(0, Double.compare(-0.0, (Double) stats.genericGetMin()));
+    assertEquals(0, Double.compare(0.0, (Double) stats.genericGetMax()));
   }
 }