Add method addOne() to ECFieldElement

2 files changed, 30 insertions, 1 deletions

diff --git a/core/src/main/java/org/bouncycastle/math/ec/ECFieldElement.java b/core/src/main/java/org/bouncycastle/math/ec/ECFieldElement.java
index 6e36a84f..c50cedb7 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/ECFieldElement.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/ECFieldElement.java
@@ -12,6 +12,7 @@ public abstract class ECFieldElement
     public abstract String         getFieldName();
     public abstract int            getFieldSize();
     public abstract ECFieldElement add(ECFieldElement b);
+    public abstract ECFieldElement addOne();
     public abstract ECFieldElement subtract(ECFieldElement b);
     public abstract ECFieldElement multiply(ECFieldElement b);
     public abstract ECFieldElement divide(ECFieldElement b);
@@ -139,12 +140,22 @@ public abstract class ECFieldElement
         {
             return q;
         }
-        
+
         public ECFieldElement add(ECFieldElement b)
         {
             return new Fp(q, r, modAdd(x, b.toBigInteger()));
         }
 
+        public ECFieldElement addOne()
+        {
+            BigInteger x2 = x.add(ECConstants.ONE);
+            if (x2.compareTo(q) == 0)
+            {
+                x2 = ECConstants.ZERO;
+            }
+            return new Fp(q, r, x2);
+        }
+
         public ECFieldElement subtract(ECFieldElement b)
         {
             BigInteger x2 = b.toBigInteger();
@@ -1183,6 +1194,13 @@ public abstract class ECFieldElement
             return new F2m(m, k1, k2, k3, iarrClone);
         }
 
+        public ECFieldElement addOne()
+        {
+            IntArray iarrClone = (IntArray)this.x.clone();
+            iarrClone.addOneShifted(0);
+            return new F2m(m, k1, k2, k3, iarrClone);
+        }
+
         public ECFieldElement subtract(final ECFieldElement b)
         {
             // Addition and subtraction are the same in F2m
diff --git a/core/src/main/java/org/bouncycastle/math/ec/IntArray.java b/core/src/main/java/org/bouncycastle/math/ec/IntArray.java
index ead38c48..f13efff6 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/IntArray.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/IntArray.java
@@ -287,6 +287,17 @@ class IntArray
         return new IntArray(newInts);
     }
 
+    public void addOneShifted(int shift)
+    {
+        int newMinUsedLen = 1 + shift;
+        if (newMinUsedLen > m_ints.length)
+        {
+            m_ints = resizedInts(newMinUsedLen);
+        }
+
+        m_ints[shift] ^= 1;
+    }
+
     public void addShifted(IntArray other, int shift)
     {
         int usedLenOther = other.getUsedLength();