new: ReplaceOutputStream

[nikiroo-utils.git] / src / be / nikiroo / utils / streams / ReplaceOutputStream.java

diff --git a/src/be/nikiroo/utils/streams/ReplaceOutputStream.java b/src/be/nikiroo/utils/streams/ReplaceOutputStream.java
new file mode 100644 (file)
index 0000000..e889b76
--- /dev/null
+++ b/src/be/nikiroo/utils/streams/ReplaceOutputStream.java
@@ -0,0 +1,72 @@
+package be.nikiroo.utils.streams;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * This {@link OutputStream} will change some of its content by replacing it
+ * with something else.
+ * 
+ * @author niki
+ */
+public class ReplaceOutputStream extends BufferedOutputStream {
+       private byte[] from;
+       private byte[] to;
+
+       /**
+        * Create a {@link ReplaceOutputStream} that will replace <tt>from</tt> with
+        * <tt>to</tt>.
+        * 
+        * @param out
+        *            the under-laying {@link OutputStream}
+        * @param from
+        *            the {@link String} to replace
+        * @param to
+        *            the {@link String} to replace with
+        */
+       public ReplaceOutputStream(OutputStream out, String from, String to) {
+               this(out, StreamUtils.bytes(from), StreamUtils.bytes(to));
+       }
+
+       /**
+        * Create a {@link ReplaceOutputStream} that will replace <tt>from</tt> with
+        * <tt>to</tt>.
+        * 
+        * @param out
+        *            the under-laying {@link OutputStream}
+        * @param from
+        *            the value to replace
+        * @param to
+        *            the value to replace with
+        */
+       public ReplaceOutputStream(OutputStream out, byte[] from, byte[] to) {
+               super(out);
+               bypassFlush = false;
+
+               this.from = from;
+               this.to = to;
+       }
+
+       @Override
+       protected void flush(boolean includingSubStream) throws IOException {
+               // Note: very simple, not efficient implementation, sorry.
+               while (start < stop) {
+                       if (from.length > 0
+                                       && StreamUtils.startsWith(from, buffer, start, stop)) {
+                               out.write(to);
+                               bytesWritten += to.length;
+                               start += from.length;
+                       } else {
+                               out.write(buffer[start++]);
+                               bytesWritten++;
+                       }
+               }
+
+               start = 0;
+               stop = 0;
+
+               if (includingSubStream) {
+                       out.flush();
+               }
+       }
+}