diff src/com/trilead/ssh2/crypto/cipher/CipherOutputStream.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/crypto/cipher/CipherOutputStream.java	Thu May 22 10:41:19 2014 -0700
@@ -0,0 +1,126 @@
+
+package com.trilead.ssh2.crypto.cipher;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * CipherOutputStream.
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: CipherOutputStream.java,v 1.1 2007/10/15 12:49:55 cplattne Exp $
+ */
+public class CipherOutputStream {
+    BlockCipher currentCipher;
+    OutputStream bo;
+    byte[] buffer;
+    byte[] enc;
+    int blockSize;
+    int pos;
+
+    /*
+     * We cannot use java.io.BufferedOutputStream, since that is not available
+     * in J2ME. Everything could be improved here alot.
+     */
+
+    final int BUFF_SIZE = 2048;
+    byte[] out_buffer = new byte[BUFF_SIZE];
+    int out_buffer_pos = 0;
+
+    public CipherOutputStream(BlockCipher tc, OutputStream bo) {
+        this.bo = bo;
+        changeCipher(tc);
+    }
+
+    private void internal_write(byte[] src, int off, int len) throws IOException {
+        while (len > 0) {
+            int space = BUFF_SIZE - out_buffer_pos;
+            int copy = (len > space) ? space : len;
+            System.arraycopy(src, off, out_buffer, out_buffer_pos, copy);
+            off += copy;
+            out_buffer_pos += copy;
+            len -= copy;
+
+            if (out_buffer_pos >= BUFF_SIZE) {
+                bo.write(out_buffer, 0, BUFF_SIZE);
+                out_buffer_pos = 0;
+            }
+        }
+    }
+
+    private void internal_write(int b) throws IOException {
+        out_buffer[out_buffer_pos++] = (byte) b;
+
+        if (out_buffer_pos >= BUFF_SIZE) {
+            bo.write(out_buffer, 0, BUFF_SIZE);
+            out_buffer_pos = 0;
+        }
+    }
+
+    public void flush() throws IOException {
+        if (pos != 0)
+            throw new IOException("FATAL: cannot flush since crypto buffer is not aligned.");
+
+        if (out_buffer_pos > 0) {
+            bo.write(out_buffer, 0, out_buffer_pos);
+            out_buffer_pos = 0;
+        }
+
+        bo.flush();
+    }
+
+    public void changeCipher(BlockCipher bc) {
+        this.currentCipher = bc;
+        blockSize = bc.getBlockSize();
+        buffer = new byte[blockSize];
+        enc = new byte[blockSize];
+        pos = 0;
+    }
+
+    private void writeBlock() throws IOException {
+        try {
+            currentCipher.transformBlock(buffer, 0, enc, 0);
+        }
+        catch (Exception e) {
+            throw(IOException) new IOException("Error while decrypting block.").initCause(e);
+        }
+
+        internal_write(enc, 0, blockSize);
+        pos = 0;
+    }
+
+    public void write(byte[] src, int off, int len) throws IOException {
+        while (len > 0) {
+            int avail = blockSize - pos;
+            int copy = Math.min(avail, len);
+            System.arraycopy(src, off, buffer, pos, copy);
+            pos += copy;
+            off += copy;
+            len -= copy;
+
+            if (pos >= blockSize)
+                writeBlock();
+        }
+    }
+
+    public void write(int b) throws IOException {
+        buffer[pos++] = (byte) b;
+
+        if (pos >= blockSize)
+            writeBlock();
+    }
+
+    public void writePlain(int b) throws IOException {
+        if (pos != 0)
+            throw new IOException("Cannot write plain since crypto buffer is not aligned.");
+
+        internal_write(b);
+    }
+
+    public void writePlain(byte[] b, int off, int len) throws IOException {
+        if (pos != 0)
+            throw new IOException("Cannot write plain since crypto buffer is not aligned.");
+
+        internal_write(b, off, len);
+    }
+}