1 files changed, 91 insertions, 0 deletions
diff --git a/repackaged_platform/bcprov/src/main/java/com/android/internal/org/bouncycastle/math/ec/FixedPointUtil.java b/repackaged_platform/bcprov/src/main/java/com/android/internal/org/bouncycastle/math/ec/FixedPointUtil.java
new file mode 100644
index 00000000..44290cba
--- /dev/null
+++ b/repackaged_platform/bcprov/src/main/java/com/android/internal/org/bouncycastle/math/ec/FixedPointUtil.java
@@ -0,0 +1,91 @@
+/* GENERATED SOURCE. DO NOT MODIFY. */
+package com.android.internal.org.bouncycastle.math.ec;
+
+import java.math.BigInteger;
+
+/**
+ * @hide This class is not part of the Android public SDK API
+ */
+public class FixedPointUtil
+{
+    public static final String PRECOMP_NAME = "bc_fixed_point";
+
+    public static int getCombSize(ECCurve c)
+    {
+        BigInteger order = c.getOrder();
+        return order == null ? c.getFieldSize() + 1 : order.bitLength(); 
+    }
+
+    public static FixedPointPreCompInfo getFixedPointPreCompInfo(PreCompInfo preCompInfo)
+    {
+        return (preCompInfo instanceof FixedPointPreCompInfo) ? (FixedPointPreCompInfo)preCompInfo : null;
+    }
+
+    public static FixedPointPreCompInfo precompute(final ECPoint p)
+    {
+        final ECCurve c = p.getCurve();
+
+        return (FixedPointPreCompInfo)c.precompute(p, PRECOMP_NAME, new PreCompCallback()
+        {
+            public PreCompInfo precompute(PreCompInfo existing)
+            {
+                FixedPointPreCompInfo existingFP = (existing instanceof FixedPointPreCompInfo) ? (FixedPointPreCompInfo)existing : null;
+
+                int bits = getCombSize(c);
+                int minWidth = bits > 250 ? 6 : 5;
+                int n = 1 << minWidth;
+
+                if (checkExisting(existingFP, n))
+                {
+                    return existingFP;
+                }
+
+                int d = (bits + minWidth - 1) / minWidth;
+
+                ECPoint[] pow2Table = new ECPoint[minWidth + 1];
+                pow2Table[0] = p;
+                for (int i = 1; i < minWidth; ++i)
+                {
+                    pow2Table[i] = pow2Table[i - 1].timesPow2(d);
+                }
+
+                // This will be the 'offset' value 
+                pow2Table[minWidth] = pow2Table[0].subtract(pow2Table[1]);
+
+                c.normalizeAll(pow2Table);
+
+                ECPoint[] lookupTable = new ECPoint[n];
+                lookupTable[0] = pow2Table[0];
+
+                for (int bit = minWidth - 1; bit >= 0; --bit)
+                {
+                    ECPoint pow2 = pow2Table[bit];
+
+                    int step = 1 << bit;
+                    for (int i = step; i < n; i += (step << 1))
+                    {
+                        lookupTable[i] = lookupTable[i - step].add(pow2);
+                    }
+                }
+
+                c.normalizeAll(lookupTable);
+
+                FixedPointPreCompInfo result = new FixedPointPreCompInfo();
+                result.setLookupTable(c.createCacheSafeLookupTable(lookupTable, 0, lookupTable.length));
+                result.setOffset(pow2Table[minWidth]);
+                result.setWidth(minWidth);
+                return result;
+            }
+
+            private boolean checkExisting(FixedPointPreCompInfo existingFP, int n)
+            {
+                return existingFP != null && checkTable(existingFP.getLookupTable(), n);
+            }
+
+            private boolean checkTable(ECLookupTable table, int n)
+            {
+                return table != null && table.getSize() >= n;
+            }
+        });
+    }
+}