GP-432: Committed missing file

Ghidra/Debug/ProposedUtils/src/main/java/ghidra/util/ByteBufferUtils.java

@@ -0,0 +1,94 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package ghidra.util;
+
+import java.nio.ByteBuffer;
+
+/**
+ * Some utilities for manipulating a {@link ByteBuffer}
+ */
+public interface ByteBufferUtils {
+	/**
+	 * Resize a write-mode buffer
+	 * 
+	 * <p>
+	 * This preserves the buffer contents
+	 * 
+	 * @param buf the buffer
+	 * @param capacity the new capacity, greater or equal to the buffer's limit
+	 * @return the new buffer
+	 */
+	public static ByteBuffer resize(ByteBuffer buf, int capacity) {
+		if (capacity < buf.limit()) {
+			throw new IllegalArgumentException("New capacity must fit current contents");
+		}
+		buf.flip();
+		ByteBuffer resized = ByteBuffer.allocate(capacity);
+		resized.put(buf);
+		return resized;
+	}
+
+	/**
+	 * Resize a write-mode buffer to twice its current capacity
+	 * 
+	 * <p>
+	 * This preserves the buffer contents
+	 * 
+	 * @param buf the buffer
+	 * @return the new buffer
+	 */
+	public static ByteBuffer upsize(ByteBuffer buf) {
+		return resize(buf, buf.capacity() * 2);
+	}
+
+	/**
+	 * Checks for equality, with a mask applied
+	 * 
+	 * <p>
+	 * This considers the entire contents of both buffers without regard for position or limit. Both
+	 * buffers must have equal capacities to be considered equal. The mask, if given, must have
+	 * capacity equal to that of the first buffer {@code a} or an exception is thrown.
+	 * 
+	 * @param mask a buffer containing the mask, or null to match all bytes exactly
+	 * @param a the first buffer
+	 * @param b the second buffer
+	 * @return true if matches, false otherwise
+	 * @throws IllegalArgumentException if {@code mask} and {@code a} have unequal capacities
+	 */
+	public static boolean maskedEquals(ByteBuffer mask, ByteBuffer a, ByteBuffer b) {
+		int len = a.capacity();
+		if (mask != null && mask.capacity() != len) {
+			throw new IllegalArgumentException("mask and a must have equal capacities");
+		}
+		if (len != a.capacity()) {
+			return false;
+		}
+		if (mask != null) {
+			for (int i = 0; i < len; i++) {
+				if ((a.get(i) & mask.get(i)) != (b.get(i) & mask.get(i))) {
+					return false;
+				}
+			}
+			return true;
+		}
+		for (int i = 0; i < len; i++) {
+			if (a.get(i) != b.get(i)) {
+				return false;
+			}
+		}
+		return true;
+	}
+}