diff src/com/trilead/ssh2/compression/Zlib.java @ 0:0ce5cc452d02

initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/com/trilead/ssh2/compression/Zlib.java	Thu May 22 10:41:19 2014 -0700
@@ -0,0 +1,131 @@
+/*
+ * ConnectBot: simple, powerful, open-source SSH client for Android
+ * Copyright 2007 Kenny Root, Jeffrey Sharkey
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.trilead.ssh2.compression;
+
+import com.jcraft.jzlib.JZlib;
+import com.jcraft.jzlib.ZStream;
+
+/**
+ * @author Kenny Root
+ *
+ */
+public class Zlib implements ICompressor {
+    static private final int DEFAULT_BUF_SIZE = 4096;
+    static private final int LEVEL = 5;
+
+    private ZStream deflate;
+    private byte[] deflate_tmpbuf;
+
+    private ZStream inflate;
+    private byte[] inflate_tmpbuf;
+    private byte[] inflated_buf;
+
+    public Zlib() {
+        deflate = new ZStream();
+        inflate = new ZStream();
+        deflate.deflateInit(LEVEL);
+        inflate.inflateInit();
+        deflate_tmpbuf = new byte[DEFAULT_BUF_SIZE];
+        inflate_tmpbuf = new byte[DEFAULT_BUF_SIZE];
+        inflated_buf = new byte[DEFAULT_BUF_SIZE];
+    }
+
+    public boolean canCompressPreauth() {
+        return true;
+    }
+
+    public int getBufferSize() {
+        return DEFAULT_BUF_SIZE;
+    }
+
+    public int compress(byte[] buf, int start, int len, byte[] output) {
+        deflate.next_in = buf;
+        deflate.next_in_index = start;
+        deflate.avail_in = len - start;
+
+        if ((buf.length + 1024) > deflate_tmpbuf.length) {
+            deflate_tmpbuf = new byte[buf.length + 1024];
+        }
+
+        deflate.next_out = deflate_tmpbuf;
+        deflate.next_out_index = 0;
+        deflate.avail_out = output.length;
+
+        if (deflate.deflate(JZlib.Z_PARTIAL_FLUSH) != JZlib.Z_OK) {
+            System.err.println("compress: compression failure");
+        }
+
+        if (deflate.avail_in > 0) {
+            System.err.println("compress: deflated data too large");
+        }
+
+        int outputlen = output.length - deflate.avail_out;
+        System.arraycopy(deflate_tmpbuf, 0, output, 0, outputlen);
+        return outputlen;
+    }
+
+    public byte[] uncompress(byte[] buffer, int start, int[] length) {
+        int inflated_end = 0;
+        inflate.next_in = buffer;
+        inflate.next_in_index = start;
+        inflate.avail_in = length[0];
+
+        while (true) {
+            inflate.next_out = inflate_tmpbuf;
+            inflate.next_out_index = 0;
+            inflate.avail_out = DEFAULT_BUF_SIZE;
+            int status = inflate.inflate(JZlib.Z_PARTIAL_FLUSH);
+
+            switch (status) {
+                case JZlib.Z_OK:
+                    if (inflated_buf.length < inflated_end + DEFAULT_BUF_SIZE
+                            - inflate.avail_out) {
+                        byte[] foo = new byte[inflated_end + DEFAULT_BUF_SIZE
+                                              - inflate.avail_out];
+                        System.arraycopy(inflated_buf, 0, foo, 0, inflated_end);
+                        inflated_buf = foo;
+                    }
+
+                    System.arraycopy(inflate_tmpbuf, 0, inflated_buf, inflated_end,
+                                     DEFAULT_BUF_SIZE - inflate.avail_out);
+                    inflated_end += (DEFAULT_BUF_SIZE - inflate.avail_out);
+                    length[0] = inflated_end;
+                    break;
+
+                case JZlib.Z_BUF_ERROR:
+                    if (inflated_end > buffer.length - start) {
+                        byte[] foo = new byte[inflated_end + start];
+                        System.arraycopy(buffer, 0, foo, 0, start);
+                        System.arraycopy(inflated_buf, 0, foo, start, inflated_end);
+                        buffer = foo;
+                    }
+                    else {
+                        System.arraycopy(inflated_buf, 0, buffer, start,
+                                         inflated_end);
+                    }
+
+                    length[0] = inflated_end;
+                    return buffer;
+
+                default:
+                    System.err.println("uncompress: inflate returnd " + status);
+                    return null;
+            }
+        }
+    }
+}