From 84c10ed96deb2e6812f1ffa791e583d721a95813 Mon Sep 17 00:00:00 2001
From: Harald Kuhr <harald.kuhr@gmail.com>
Date: Thu, 26 Sep 2024 10:31:27 +0200
Subject: [PATCH] Fully support period == 1 (no subsampling) in subsampleRow
 even if different arrays

---
 .../twelvemonkeys/imageio/util/IIOUtil.java   | 12 ++++
 .../imageio/util/IIOUtilTest.java             | 63 +++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java b/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java
index c3009826..fded5f04 100644
--- a/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java
+++ b/imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java
@@ -232,6 +232,10 @@ public final class IIOUtil {
                                     int samplesPerPixel, int bitsPerSample, int samplePeriod) {
         // Period == 1 is a no-op...
         if (samplePeriod == 1) {
+            if (srcRow != destRow) {
+                System.arraycopy(srcRow, srcPos, destRow, destPos, srcWidth);
+            }
+
             return;
         }
 
@@ -275,6 +279,10 @@ public final class IIOUtil {
                                     int samplesPerPixel, int bitsPerSample, int samplePeriod) {
         // Period == 1 is a no-op...
         if (samplePeriod == 1) {
+            if (srcRow != destRow) {
+                System.arraycopy(srcRow, srcPos, destRow, destPos, srcWidth);
+            }
+
             return;
         }
 
@@ -297,6 +305,10 @@ public final class IIOUtil {
                                     int samplesPerPixel, int bitsPerSample, int samplePeriod) {
         // Period == 1 is a no-op...
         if (samplePeriod == 1) {
+            if (srcRow != destRow) {
+                System.arraycopy(srcRow, srcPos, destRow, destPos, srcWidth);
+            }
+
             return;
         }
 
diff --git a/imageio/imageio-core/src/test/java/com/twelvemonkeys/imageio/util/IIOUtilTest.java b/imageio/imageio-core/src/test/java/com/twelvemonkeys/imageio/util/IIOUtilTest.java
index 05b9fa64..1406f9c9 100644
--- a/imageio/imageio-core/src/test/java/com/twelvemonkeys/imageio/util/IIOUtilTest.java
+++ b/imageio/imageio-core/src/test/java/com/twelvemonkeys/imageio/util/IIOUtilTest.java
@@ -139,6 +139,69 @@ public class IIOUtilTest {
         assertArrayEquals(expected, output);
     }
 
+    @Test
+    public void subsampleRowPeriod1ByteSameArray() {
+        byte[] inputOutput = {-1, 0, (byte) 0xAA, 0, -1};
+        byte[] expected = {-1, 0, (byte) 0xAA, 0, -1};
+
+        IIOUtil.subsampleRow(inputOutput, 0, inputOutput.length, inputOutput, 0, 1, 8, 1);
+
+        assertArrayEquals(expected, inputOutput);
+    }
+
+    @Test
+    public void subsampleRowPeriod1ByteDifferentArray() {
+        byte[] input = {-1, 0, (byte) 0xAA, 0, -1};
+        byte[] output = new byte[input.length];
+        byte[] expected = {-1, 0, (byte) 0xAA, 0, -1};
+
+        IIOUtil.subsampleRow(input, 0, input.length, output, 0, 1, 8, 1);
+
+        assertArrayEquals(expected, output);
+    }
+
+    @Test
+    public void subsampleRowPeriod1ShortSameArray() {
+        short[] inputOutput = {-1, 0, (short) 0xAA77, 0, -1};
+        short[] expected = {-1, 0, (short) 0xAA77, 0, -1};
+
+        IIOUtil.subsampleRow(inputOutput, 0, inputOutput.length, inputOutput, 0, 4, 4, 1);
+
+        assertArrayEquals(expected, inputOutput);
+    }
+
+    @Test
+    public void subsampleRowPeriod1ShortDifferentArray() {
+        short[] input = {-1, 0, (short) 0xAA77, 0, -1};
+        short[] output = new short[input.length];
+        short[] expected = {-1, 0, (short) 0xAA77, 0, -1};
+
+        IIOUtil.subsampleRow(input, 0, input.length, output, 0, 1, 16, 1);
+
+        assertArrayEquals(expected, output);
+    }
+
+    @Test
+    public void subsampleRowPeriod1IntSameArray() {
+        int[] inputOutput = {-1, 0, 0xAA997755, 0, -1};
+        int[] expected = {-1, 0, 0xAA997755, 0, -1};
+
+        IIOUtil.subsampleRow(inputOutput, 0, inputOutput.length, inputOutput, 0, 1, 32, 1);
+
+        assertArrayEquals(expected, inputOutput);
+    }
+
+    @Test
+    public void subsampleRowPeriod1IntDifferentArray() {
+        int[] input = {-1, 0, 0xAA997755, 0, -1};
+        int[] output = new int[input.length];
+        int[] expected = {-1, 0, 0xAA997755, 0, -1};
+
+        IIOUtil.subsampleRow(input, 0, input.length, output, 0, 4, 8, 1);
+
+        assertArrayEquals(expected, output);
+    }
+
     private int divCeil(int numerator, int denominator) {
         return (numerator + denominator - 1) / denominator;
     }