1 files changed, 96 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/util/encoders/BufferedDecoder.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/util/encoders/BufferedDecoder.java
new file mode 100644
index 000000000..cc8cb27b1
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/util/encoders/BufferedDecoder.java
@@ -0,0 +1,96 @@
+package org.spongycastle.util.encoders;
+
+
+/**
+ * a buffering class to allow translation from one format to another to
+ * be done in discrete chunks.
+ */
+public class BufferedDecoder
+{
+    protected byte[]        buf;
+    protected int           bufOff;
+
+    protected Translator    translator;
+
+    /**
+     * @param translator the translator to use.
+     * @param bufSize amount of input to buffer for each chunk.
+     */
+    public BufferedDecoder(
+        Translator  translator,
+        int         bufSize)
+    {
+        this.translator = translator;
+
+        if ((bufSize % translator.getEncodedBlockSize()) != 0)
+        {
+            throw new IllegalArgumentException("buffer size not multiple of input block size");
+        }
+
+        buf = new byte[bufSize];
+        bufOff = 0;
+    }
+
+    public int processByte(
+        byte        in,
+        byte[]      out,
+        int         outOff)
+    {
+        int         resultLen = 0;
+
+        buf[bufOff++] = in;
+
+        if (bufOff == buf.length)
+        {
+            resultLen = translator.decode(buf, 0, buf.length, out, outOff);
+            bufOff = 0;
+        }
+
+        return resultLen;
+    }
+
+    public int processBytes(
+        byte[]      in,
+        int         inOff,
+        int         len,
+        byte[]      out,
+        int         outOff)
+    {
+        if (len < 0)
+        {
+            throw new IllegalArgumentException("Can't have a negative input length!");
+        }
+
+        int resultLen = 0;
+        int gapLen = buf.length - bufOff;
+
+        if (len > gapLen)
+        {
+            System.arraycopy(in, inOff, buf, bufOff, gapLen);
+
+            resultLen += translator.decode(buf, 0, buf.length, out, outOff);
+
+            bufOff = 0;
+
+            len -= gapLen;
+            inOff += gapLen;
+            outOff += resultLen;
+
+            int chunkSize = len - (len % buf.length);
+
+            resultLen += translator.decode(in, inOff, chunkSize, out, outOff);
+
+            len -= chunkSize;
+            inOff += chunkSize;
+        }
+
+        if (len != 0)
+        {
+            System.arraycopy(in, inOff, buf, bufOff, len);
+
+            bufOff += len;
+        }
+
+        return resultLen;
+    }
+}