1 files changed, 202 insertions, 0 deletions
diff --git a/libraries/spongycastle/jce/src/main/java/javax/crypto/JCEUtil.java b/libraries/spongycastle/jce/src/main/java/javax/crypto/JCEUtil.java
new file mode 100644
index 000000000..913c01b03
--- /dev/null
+++ b/libraries/spongycastle/jce/src/main/java/javax/crypto/JCEUtil.java
@@ -0,0 +1,202 @@
+package javax.crypto;
+
+import java.security.NoSuchProviderException;
+import java.security.Provider;
+import java.security.Security;
+import java.util.Locale;
+
+class JCEUtil
+{
+    static class Implementation
+    {
+        Object      engine;
+        Provider    provider;
+
+        Implementation(
+            Object      engine,
+            Provider    provider)
+        {
+            this.engine = engine;
+            this.provider = provider;
+        }
+
+        Object getEngine()
+        {
+            return engine;
+        }
+
+        Provider getProvider()
+        {
+            return provider;
+        }
+    }
+
+    /**
+     * see if we can find an algorithm (or its alias and what it represents) in
+     * the property table for the given provider.
+     *
+     * @return null if no algorithm found, an Implementation if it is.
+     */
+    static private Implementation findImplementation(
+        String      baseName,
+        String      algorithm,
+        Provider    prov)
+    {
+        String      alias;
+
+        while ((alias = prov.getProperty("Alg.Alias." + baseName + "." + algorithm)) != null)
+        {
+            algorithm = alias;
+        }
+
+        String      className = prov.getProperty(baseName + "." + algorithm);
+
+        if (className != null)
+        {
+            try
+            {
+                Class       cls;
+                ClassLoader clsLoader = prov.getClass().getClassLoader();
+
+                if (clsLoader != null)
+                {
+                    cls = clsLoader.loadClass(className);
+                }
+                else
+                {
+                    cls = Class.forName(className);
+                }
+
+                return new Implementation(cls.newInstance(), prov);
+            }
+            catch (ClassNotFoundException e)
+            {
+                throw new IllegalStateException(
+                    "algorithm " + algorithm + " in provider " + prov.getName() + " but no class \"" + className + "\" found!");
+            }
+            catch (Exception e)
+            {
+                throw new IllegalStateException(
+                    "algorithm " + algorithm + " in provider " + prov.getName() + " but class \"" + className + "\" inaccessible!");
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * return an implementation for a given algorithm/provider.
+     * If the provider is null, we grab the first avalaible who has the required algorithm.
+     *
+     * @return null if no algorithm found, an Implementation if it is.
+     * @exception NoSuchProviderException if a provider is specified and not found.
+     */
+    static Implementation getImplementation(
+        String      baseName,
+        String      algorithm,
+        String      provider)
+        throws NoSuchProviderException
+    {
+        if (provider == null)
+        {
+            Provider[] prov = Security.getProviders();
+
+            //
+            // search every provider looking for the algorithm we want.
+            //
+            for (int i = 0; i != prov.length; i++)
+            {
+                //
+                // try case insensitive
+                //
+                Implementation imp = findImplementation(baseName, algorithm.toUpperCase(Locale.ENGLISH), prov[i]);
+                if (imp != null)
+                {
+                    return imp;
+                }
+
+                imp = findImplementation(baseName, algorithm, prov[i]);
+                if (imp != null)
+                {
+                    return imp;
+                }
+            }
+        }
+        else
+        {
+            Provider prov = Security.getProvider(provider);
+
+            if (prov == null)
+            {
+                throw new NoSuchProviderException("Provider " + provider + " not found");
+            }
+
+            //
+            // try case insensitive
+            //
+            Implementation imp = findImplementation(baseName, algorithm.toUpperCase(Locale.ENGLISH), prov);
+            if (imp != null)
+            {
+                return imp;
+            }
+
+            return findImplementation(baseName, algorithm, prov);
+        }
+
+        return null;
+    }
+
+    /**
+     * return an implementation for a given algorithm/provider.
+     * If the provider is null, we grab the first avalaible who has the required algorithm.
+     *
+     * @return null if no algorithm found, an Implementation if it is.
+     * @exception NoSuchProviderException if a provider is specified and not found.
+     */
+    static Implementation getImplementation(
+        String      baseName,
+        String      algorithm,
+        Provider    provider)
+    {
+        if (provider == null)
+        {
+            Provider[] prov = Security.getProviders();
+
+            //
+            // search every provider looking for the algorithm we want.
+            //
+            for (int i = 0; i != prov.length; i++)
+            {
+                //
+                // try case insensitive
+                //
+                Implementation imp = findImplementation(baseName, algorithm.toUpperCase(Locale.ENGLISH), prov[i]);
+                if (imp != null)
+                {
+                    return imp;
+                }
+
+                imp = findImplementation(baseName, algorithm, prov[i]);
+                if (imp != null)
+                {
+                    return imp;
+                }
+            }
+        }
+        else
+        {
+            //
+            // try case insensitive
+            //
+            Implementation imp = findImplementation(baseName, algorithm.toUpperCase(Locale.ENGLISH), provider);
+            if (imp != null)
+            {
+                return imp;
+            }
+
+            return findImplementation(baseName, algorithm, provider);
+        }
+
+        return null;
+    }
+}