X-Git-Url: http://git.nikiroo.be/?p=fanfix.git;a=blobdiff_plain;f=src%2Fbe%2Fnikiroo%2Futils%2Fstreams%2FReplaceInputStream.java;fp=src%2Fbe%2Fnikiroo%2Futils%2Fstreams%2FReplaceInputStream.java;h=1cc5139beae1e012053f62dece957076add4dfee;hp=0000000000000000000000000000000000000000;hb=d46b7b96f94e88a776bcd2dfd756549ffb300cc9;hpb=c9994f27667bc421bcd448d39e55774fddf5c431

diff --git a/src/be/nikiroo/utils/streams/ReplaceInputStream.java b/src/be/nikiroo/utils/streams/ReplaceInputStream.java
new file mode 100644
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--- /dev/null
+++ b/src/be/nikiroo/utils/streams/ReplaceInputStream.java
@@ -0,0 +1,162 @@
+package be.nikiroo.utils.streams;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import be.nikiroo.utils.StringUtils;
+
+/**
+ * This {@link InputStream} will change some of its content by replacing it with
+ * something else.
+ * 
+ * @author niki
+ */
+public class ReplaceInputStream extends BufferedInputStream {
+	/**
+	 * The minimum size of the internal buffer (could be more if at least one of
+	 * the 'FROM' bytes arrays is > 2048 bytes — in that case the
+	 * buffer will be twice the largest size of the 'FROM' bytes arrays).
+	 * <p>
+	 * This is a different buffer than the one from the inherited class.
+	 */
+	static private final int MIN_BUFFER_SIZE = 4096;
+
+	private byte[][] froms;
+	private byte[][] tos;
+	private int maxFromSize;
+	private int maxToSize;
+
+	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, StringUtils.getBytes(from), StringUtils.getBytes(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) {
+		this(in, new byte[][] { from }, new byte[][] { to });
+	}
+
+	/**
+	 * Create a {@link ReplaceInputStream} that will replace all <tt>froms</tt>
+	 * with <tt>tos</tt>.
+	 * <p>
+	 * Note that they will be replaced in order, and that for each <tt>from</tt>
+	 * a <tt>to</tt> must correspond.
+	 * 
+	 * @param in
+	 *            the under-laying {@link InputStream}
+	 * @param froms
+	 *            the values to replace
+	 * @param tos
+	 *            the values to replace with
+	 */
+	public ReplaceInputStream(InputStream in, String[] froms, String[] tos) {
+		this(in, StreamUtils.getBytes(froms), StreamUtils.getBytes(tos));
+	}
+
+	/**
+	 * Create a {@link ReplaceInputStream} that will replace all <tt>froms</tt>
+	 * with <tt>tos</tt>.
+	 * <p>
+	 * Note that they will be replaced in order, and that for each <tt>from</tt>
+	 * a <tt>to</tt> must correspond.
+	 * 
+	 * @param in
+	 *            the under-laying {@link InputStream}
+	 * @param froms
+	 *            the values to replace
+	 * @param tos
+	 *            the values to replace with
+	 */
+	public ReplaceInputStream(InputStream in, byte[][] froms, byte[][] tos) {
+		super(in);
+
+		if (froms.length != tos.length) {
+			throw new IllegalArgumentException(
+					"For replacing, each FROM must have a corresponding TO");
+		}
+
+		this.froms = froms;
+		this.tos = tos;
+
+		maxFromSize = 0;
+		for (int i = 0; i < froms.length; i++) {
+			maxFromSize = Math.max(maxFromSize, froms[i].length);
+		}
+
+		maxToSize = 0;
+		for (int i = 0; i < tos.length; i++) {
+			maxToSize = Math.max(maxToSize, tos[i].length);
+		}
+
+		// We need at least maxFromSize so we can iterate and replace
+		source = new byte[Math.max(2 * maxFromSize, MIN_BUFFER_SIZE)];
+		spos = 0;
+		slen = 0;
+	}
+
+	@Override
+	protected int read(InputStream in, byte[] buffer, int off, int len)
+			throws IOException {
+		if (len < maxToSize || source.length < maxToSize * 2) {
+			throw new IOException(
+					"An underlaying buffer is too small for these replace values");
+		}
+
+		// We need at least one byte of data to process
+		if (available() < Math.max(maxFromSize, 1) && !eof) {
+			spos = 0;
+			slen = in.read(source);
+		}
+
+		// Note: very simple, not efficient implementation; sorry.
+		int count = 0;
+		while (spos < slen && count < len - maxToSize) {
+			boolean replaced = false;
+			for (int i = 0; i < froms.length; i++) {
+				if (froms[i] != null && froms[i].length > 0
+						&& StreamUtils.startsWith(froms[i], source, spos, slen)) {
+					if (tos[i] != null && tos[i].length > 0) {
+						System.arraycopy(tos[i], 0, buffer, off + spos,
+								tos[i].length);
+						count += tos[i].length;
+					}
+
+					spos += froms[i].length;
+					replaced = true;
+					break;
+				}
+			}
+
+			if (!replaced) {
+				buffer[off + count++] = source[spos++];
+			}
+		}
+
+		return count;
+	}
+}