fix(driver-compat) make Bits.readFully support offset for buffer array

trnl · trnl · commit 4e230513cfae · 2013-06-23T10:43:27.000+03:00
diff --git a/driver-compat/src/main/org/bson/io/Bits.java b/driver-compat/src/main/org/bson/io/Bits.java
@@ -16,7 +16,6 @@
 
 package org.bson.io;
 
-import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -35,7 +34,7 @@ public static void readFully(final InputStream in, final byte[] buffer, final in
 
     public static void readFully(final InputStream in, final byte[] buffer, final int offset, final int length)
             throws IOException {
-        if (buffer.length < length) {
+        if (buffer.length < length + offset) {
             throw new IllegalArgumentException("Buffer is too small");
         }
 
@@ -108,14 +107,4 @@ public static long readLong(final byte[] buffer, final int offset) {
         x |= (0xFFL & buffer[offset + 7]) << 56;
         return x;
     }
-
-    private static class BufferExposingByteArrayOutputStream extends ByteArrayOutputStream {
-        BufferExposingByteArrayOutputStream(final int size) {
-            super(size);
-        }
-
-        byte[] getInternalBytes() {
-            return buf;
-        }
-    }
 }
diff --git a/driver-compat/src/test/unit/org/bson/io/BitsTest.java b/driver-compat/src/test/unit/org/bson/io/BitsTest.java
@@ -36,18 +36,40 @@ public class BitsTest {
     };
 
     @Test
-    public void testReadFully() throws IOException {
+    public void testReadFullyWithBufferLargerThanExpected() throws IOException {
         final byte[] buffer = new byte[8192];
         Bits.readFully(new ByteArrayInputStream(BYTES), buffer, BYTES.length);
         assertArrayEquals(BYTES, Arrays.copyOfRange(buffer, 0, BYTES.length));
     }
 
+    @Test
+    public void testReadFullyWithOffset() throws IOException {
+        final int offset = 10;
+        final byte[] buffer = new byte[8192];
+        Bits.readFully(new ByteArrayInputStream(BYTES), buffer, offset, BYTES.length);
+        assertArrayEquals(BYTES, Arrays.copyOfRange(buffer, offset, BYTES.length + offset));
+    }
+
+    @Test
+    public void testReadFullyWithBufferEqualsToExpected() throws IOException {
+        final int offset = 10;
+        final byte[] buffer = new byte[offset + BYTES.length];
+        Bits.readFully(new ByteArrayInputStream(BYTES), buffer, offset, BYTES.length);
+        assertArrayEquals(BYTES, Arrays.copyOfRange(buffer, offset, BYTES.length + offset));
+    }
 
-    @Test (expected = IllegalArgumentException.class)
+    @Test(expected = IllegalArgumentException.class)
     public void testReadFullyUsingNotEnoughBigBuffer() throws IOException {
         Bits.readFully(new ByteArrayInputStream(BYTES), new byte[2], BYTES.length);
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testReadFullyUsingNotEnoughBigBufferWithOffset() throws IOException {
+        final int offset = 10;
+        final byte[] buffer = new byte[BYTES.length];
+        Bits.readFully(new ByteArrayInputStream(BYTES), buffer, offset, BYTES.length);
+    }
+
     @Test
     public void testReadInt() {
         assertEquals(41, Bits.readInt(BYTES));
@@ -68,7 +90,6 @@ public void testReadIntInBigEndianNotation() {
         assertEquals(-12, Bits.readIntBE(new byte[]{-1, -1, -1, -12}, 0));
     }
 
-
     @Test
     public void testReadLong() {
         assertEquals(Long.MAX_VALUE, Bits.readLong(BYTES, 24));
@@ -79,5 +100,4 @@ public void testReadLongWithNotEnoughData() {
         Bits.readLong(Arrays.copyOfRange(BYTES, 24, 30), 0);
     }
 
-
 }
