X-Git-Url: http://git.nikiroo.be/?a=blobdiff_plain;f=src%2Fbe%2Fnikiroo%2Futils%2Fstreams%2FReplaceInputStream.java;fp=src%2Fbe%2Fnikiroo%2Futils%2Fstreams%2FReplaceInputStream.java;h=5eac0b448fef0262b9f2ded53a4c199a2c41d0b7;hb=8e76f6ab13a8a4a651f2518b6c91d5e6424c7922;hp=0000000000000000000000000000000000000000;hpb=a26188d393b11040b8ee8476338a73bfadabffb6;p=fanfix.git

diff --git a/src/be/nikiroo/utils/streams/ReplaceInputStream.java b/src/be/nikiroo/utils/streams/ReplaceInputStream.java
new file mode 100644
index 0000000..5eac0b4
--- /dev/null
+++ b/src/be/nikiroo/utils/streams/ReplaceInputStream.java
@@ -0,0 +1,101 @@
+package be.nikiroo.utils.streams;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+
+/**
+ * This {@link InputStream} will replace some of its content by replacing it
+ * with something else.
+ * 
+ * @author niki
+ */
+public class ReplaceInputStream extends BufferedInputStream {
+	private byte[] from;
+	private byte[] to;
+
+	private byte[] source;
+	private int spos;
+	private int slen;
+
+	/**
+	 * Create a {@link ReplaceInputStream} that will replace <tt>from</tt> with
+	 * <tt>to</tt>.
+	 * 
+	 * @param in
+	 *            the under-laying {@link InputStream}
+	 * @param from
+	 *            the {@link String} to replace
+	 * @param to
+	 *            the {@link String} to replace with
+	 */
+	public ReplaceInputStream(InputStream in, String from, String to) {
+		this(in, bytes(from), bytes(to));
+	}
+
+	/**
+	 * Create a {@link ReplaceInputStream} that will replace <tt>from</tt> with
+	 * <tt>to</tt>.
+	 * 
+	 * @param in
+	 *            the under-laying {@link InputStream}
+	 * @param from
+	 *            the value to replace
+	 * @param to
+	 *            the value to replace with
+	 */
+	public ReplaceInputStream(InputStream in, byte[] from, byte[] to) {
+		super(in);
+		this.from = from;
+		this.to = to;
+
+		source = new byte[4096];
+		spos = 0;
+		slen = 0;
+	}
+
+	@Override
+	protected int read(InputStream in, byte[] buffer) throws IOException {
+		if (buffer.length < to.length || source.length < to.length * 2) {
+			throw new IOException(
+					"An underlaying buffer is too small for this replace value");
+		}
+
+		if (spos >= slen) {
+			spos = 0;
+			slen = in.read(source);
+		}
+
+		// Note: very simple, not efficient implementation, sorry.
+		int count = 0;
+		while (spos < slen && count < buffer.length - to.length) {
+			if (from.length > 0 && startsWith(from, source, spos, slen)) {
+				System.arraycopy(to, 0, buffer, spos, to.length);
+				count += to.length;
+				spos += from.length;
+			} else {
+				buffer[count++] = source[spos++];
+			}
+		}
+
+		return count;
+	}
+
+	/**
+	 * Return the bytes array representation of the given {@link String} in
+	 * UTF-8.
+	 * 
+	 * @param str
+	 *            the string to transform into bytes
+	 * @return the content in bytes
+	 */
+	static private byte[] bytes(String str) {
+		try {
+			return str.getBytes("UTF-8");
+		} catch (UnsupportedEncodingException e) {
+			// All conforming JVM must support UTF-8
+			e.printStackTrace();
+			return null;
+		}
+	}
+}