Update #0 - First Release

sources/main/java/com/google/common/io/CountingInputStream.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2007 The Guava Authors
+ *
+ * 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 com.google.common.io;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * An {@link InputStream} that counts the number of bytes read.
+ *
+ * @author Chris Nokleberg
+ * @since 1.0
+ */
+@Beta
+public final class CountingInputStream extends FilterInputStream {
+
+	private long count;
+	private long mark = -1;
+
+	/**
+	 * Wraps another input stream, counting the number of bytes read.
+	 *
+	 * @param in the input stream to be wrapped
+	 */
+	public CountingInputStream(@Nullable InputStream in) {
+		super(in);
+	}
+
+	/** Returns the number of bytes read. */
+	public long getCount() {
+		return count;
+	}
+
+	@Override
+	public int read() throws IOException {
+		int result = in.read();
+		if (result != -1) {
+			count++;
+		}
+		return result;
+	}
+
+	@Override
+	public int read(byte[] b, int off, int len) throws IOException {
+		int result = in.read(b, off, len);
+		if (result != -1) {
+			count += result;
+		}
+		return result;
+	}
+
+	@Override
+	public long skip(long n) throws IOException {
+		long result = in.skip(n);
+		count += result;
+		return result;
+	}
+
+	@Override
+	public synchronized void mark(int readlimit) {
+		in.mark(readlimit);
+		mark = count;
+		// it's okay to mark even if mark isn't supported, as reset won't work
+	}
+
+	@Override
+	public synchronized void reset() throws IOException {
+		if (!in.markSupported()) {
+			throw new IOException("Mark not supported");
+		}
+		if (mark == -1) {
+			throw new IOException("Mark not set");
+		}
+
+		in.reset();
+		count = mark;
+	}
+}