1 files changed, 137 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/util/io/pem/PemWriter.java b/core/src/main/java/org/spongycastle/util/io/pem/PemWriter.java
new file mode 100644
index 00000000..02dde96b
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/util/io/pem/PemWriter.java
@@ -0,0 +1,137 @@
+package org.spongycastle.util.io.pem;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.util.Iterator;
+
+import org.spongycastle.util.encoders.Base64;
+
+/**
+ * A generic PEM writer, based on RFC 1421
+ */
+public class PemWriter
+    extends BufferedWriter
+{
+    private static final int LINE_LENGTH = 64;
+
+    private final int nlLength;
+    private char[]  buf = new char[LINE_LENGTH];
+
+    /**
+     * Base constructor.
+     *
+     * @param out output stream to use.
+     */
+    public PemWriter(Writer out)
+    {
+        super(out);
+
+        String nl = System.getProperty("line.separator");
+        if (nl != null)
+        {
+            nlLength = nl.length();
+        }
+        else
+        {
+            nlLength = 2;
+        }
+    }
+
+    /**
+     * Return the number of bytes or characters required to contain the
+     * passed in object if it is PEM encoded.
+     *
+     * @param obj pem object to be output
+     * @return an estimate of the number of bytes
+     */
+    public int getOutputSize(PemObject obj)
+    {
+        // BEGIN and END boundaries.
+        int size = (2 * (obj.getType().length() + 10 + nlLength)) + 6 + 4;
+
+        if (!obj.getHeaders().isEmpty())
+        {
+            for (Iterator it = obj.getHeaders().iterator(); it.hasNext();)
+            {
+                PemHeader hdr = (PemHeader)it.next();
+
+                size += hdr.getName().length() + ": ".length() + hdr.getValue().length() + nlLength;
+            }
+
+            size += nlLength;
+        }
+
+        // base64 encoding
+        int dataLen = ((obj.getContent().length + 2) / 3) * 4;
+        
+        size += dataLen + (((dataLen + LINE_LENGTH - 1) / LINE_LENGTH) * nlLength);
+
+        return size;
+    }
+    
+    public void writeObject(PemObjectGenerator objGen)
+        throws IOException
+    {
+        PemObject obj = objGen.generate();
+
+        writePreEncapsulationBoundary(obj.getType());
+
+        if (!obj.getHeaders().isEmpty())
+        {
+            for (Iterator it = obj.getHeaders().iterator(); it.hasNext();)
+            {
+                PemHeader hdr = (PemHeader)it.next();
+
+                this.write(hdr.getName());
+                this.write(": ");
+                this.write(hdr.getValue());
+                this.newLine();
+            }
+
+            this.newLine();
+        }
+        
+        writeEncoded(obj.getContent());
+        writePostEncapsulationBoundary(obj.getType());
+    }
+
+    private void writeEncoded(byte[] bytes)
+        throws IOException
+    {
+        bytes = Base64.encode(bytes);
+
+        for (int i = 0; i < bytes.length; i += buf.length)
+        {
+            int index = 0;
+
+            while (index != buf.length)
+            {
+                if ((i + index) >= bytes.length)
+                {
+                    break;
+                }
+                buf[index] = (char)bytes[i + index];
+                index++;
+            }
+            this.write(buf, 0, index);
+            this.newLine();
+        }
+    }
+
+    private void writePreEncapsulationBoundary(
+        String type)
+        throws IOException
+    {
+        this.write("-----BEGIN " + type + "-----");
+        this.newLine();
+    }
+
+    private void writePostEncapsulationBoundary(
+        String type)
+        throws IOException
+    {
+        this.write("-----END " + type + "-----");
+        this.newLine();
+    }
+}