Add 'src/be/nikiroo/utils/' from commit '46add0670fdee4bd936a13fe2448c5e20a7ffd0a'

[fanfix.git] / src / be / nikiroo / utils / streams / ReplaceInputStream.java

diff --git a/src/be/nikiroo/utils/streams/ReplaceInputStream.java b/src/be/nikiroo/utils/streams/ReplaceInputStream.java
new file mode 100644 (file)
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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;
+       }
+}