Add demo programs for random access mode.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/XZSeekEncDemo.java b/src/XZSeekEncDemo.java
new file mode 100644
index 0000000..785d234
--- /dev/null
+++ b/src/XZSeekEncDemo.java
@@ -0,0 +1,68 @@
+/*
+ * XZSeekEncDemo
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+import java.io.*;
+import org.tukaani.xz.*;
+
+/**
+ * Compresses a single file from standard input to standard ouput into
+ * a random-accessible .xz file.
+ * <p>
+ * Arguments: [preset [block size]]
+ * <p>
+ * Preset is an LZMA2 preset level which is an integer in the range [0, 9].
+ * The default is 6.
+ * <p>
+ * Block size specifies the amount of uncompressed data to store per
+ * XZ Block. The default is 1 MiB (1048576 bytes). Bigger means better
+ * compression ratio. Smaller means faster random access.
+ */
+class XZSeekEncDemo {
+    public static void main(String[] args) throws Exception {
+        LZMA2Options options = new LZMA2Options();
+
+        if (args.length >= 1)
+            options.setPreset(Integer.parseInt(args[0]));
+
+        int blockSize = 1024 * 1024;
+        if (args.length >= 2)
+            blockSize = Integer.parseInt(args[1]);
+
+        options.setDictSize(Math.min(options.getDictSize(),
+                                     Math.max(LZMA2Options.DICT_SIZE_MIN,
+                                              blockSize)));
+
+        System.err.println("Encoder memory usage: "
+                           + options.getEncoderMemoryUsage() + " KiB");
+        System.err.println("Decoder memory usage: "
+                           + options.getDecoderMemoryUsage() + " KiB");
+        System.err.println("Block size:           " + blockSize + " B");
+
+        XZOutputStream out = new XZOutputStream(System.out, options);
+
+        byte[] buf = new byte[8192];
+        int left = blockSize;
+
+        while (true) {
+            int size = System.in.read(buf, 0, Math.min(buf.length, left));
+            if (size == -1)
+                break;
+
+            out.write(buf, 0, size);
+            left -= size;
+
+            if (left == 0) {
+                out.flushBlock();
+                left = blockSize;
+            }
+        }
+
+        out.finish();
+    }
+}