1 files changed, 87 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/util/encoders/HexTranslator.java b/core/src/main/java/org/spongycastle/util/encoders/HexTranslator.java
new file mode 100644
index 00000000..066f883d
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/util/encoders/HexTranslator.java
@@ -0,0 +1,87 @@
+package org.spongycastle.util.encoders;
+
+/**
+ * Converters for going from hex to binary and back. Note: this class assumes ASCII processing.
+ */
+public class HexTranslator
+    implements Translator
+{
+    private static final byte[]   hexTable = 
+        { 
+            (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
+            (byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'
+        };
+
+    /**
+     * size of the output block on encoding produced by getDecodedBlockSize()
+     * bytes.
+     */
+    public int getEncodedBlockSize()
+    {
+        return 2;
+    }
+
+    public int encode(
+        byte[]  in,
+        int     inOff,
+        int     length,
+        byte[]  out,
+        int     outOff)
+    {
+        for (int i = 0, j = 0; i < length; i++, j += 2)
+        {
+            out[outOff + j] = hexTable[(in[inOff] >> 4) & 0x0f];
+            out[outOff + j + 1] = hexTable[in[inOff] & 0x0f];
+
+            inOff++;
+        }
+
+        return length * 2;
+    }
+
+    /**
+     * size of the output block on decoding produced by getEncodedBlockSize()
+     * bytes.
+     */
+    public int getDecodedBlockSize()
+    {
+        return 1;
+    }
+
+    public int decode(
+        byte[]  in,
+        int     inOff,
+        int     length,
+        byte[]  out,
+        int     outOff)
+    {
+        int halfLength = length / 2;
+        byte left, right;
+        for (int i = 0; i < halfLength; i++)
+        {
+            left  = in[inOff + i * 2];
+            right = in[inOff + i * 2 + 1];
+            
+            if (left < (byte)'a')
+            {
+                out[outOff] = (byte)((left - '0') << 4);
+            }
+            else
+            {
+                out[outOff] = (byte)((left - 'a' + 10) << 4);
+            }
+            if (right < (byte)'a')
+            {
+                out[outOff] += (byte)(right - '0');
+            }
+            else
+            {
+                out[outOff] += (byte)(right - 'a' + 10);
+            }
+
+            outOff++;
+        }
+
+        return halfLength;
+    }
+}