1 files changed, 114 insertions, 0 deletions
diff --git a/core/jni/android_nio_utils.cpp b/core/jni/android_nio_utils.cpp
new file mode 100644
index 0000000..584e7a4
--- /dev/null
+++ b/core/jni/android_nio_utils.cpp
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android_nio_utils.h"
+
+struct NioJNIData {
+    jclass nioAccessClass;
+
+    jmethodID getBasePointerID;
+    jmethodID getBaseArrayID;
+    jmethodID getBaseArrayOffsetID;
+};
+
+static NioJNIData gNioJNI;
+
+void* android::nio_getPointer(JNIEnv *_env, jobject buffer, jarray *array) {
+    assert(array);
+
+    jlong pointer;
+    jint offset;
+    void *data;
+    
+    pointer = _env->CallStaticLongMethod(gNioJNI.nioAccessClass,
+                                         gNioJNI.getBasePointerID, buffer);
+    if (pointer != 0L) {
+        *array = NULL;
+        return (void *) (jint) pointer;
+    }
+    
+    *array = (jarray) _env->CallStaticObjectMethod(gNioJNI.nioAccessClass,
+                                               gNioJNI.getBaseArrayID, buffer);
+    offset = _env->CallStaticIntMethod(gNioJNI.nioAccessClass,
+                                       gNioJNI.getBaseArrayOffsetID, buffer);
+    data = _env->GetPrimitiveArrayCritical(*array, (jboolean *) 0);
+    
+    return (void *) ((char *) data + offset);
+}
+
+
+void android::nio_releasePointer(JNIEnv *_env, jarray array, void *data,
+                                jboolean commit) {
+    _env->ReleasePrimitiveArrayCritical(array, data,
+                                        commit ? 0 : JNI_ABORT);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+android::AutoBufferPointer::AutoBufferPointer(JNIEnv* env, jobject nioBuffer,
+                                              jboolean commit) {
+    fEnv = env;
+    fCommit = commit;
+    fPointer = android::nio_getPointer(env, nioBuffer, &fArray);
+}
+
+android::AutoBufferPointer::~AutoBufferPointer() {
+    if (NULL != fArray) {
+        android::nio_releasePointer(fEnv, fArray, fPointer, fCommit);
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static jclass findClass(JNIEnv* env, const char name[]) {
+    jclass c = env->FindClass(name);
+    LOG_FATAL_IF(!c, "Unable to find class %s", name);
+    return c;
+}
+
+static jmethodID findStaticMethod(JNIEnv* env, jclass c, const char method[],
+                                  const char params[]) {
+    jmethodID m = env->GetStaticMethodID(c, method, params);
+    LOG_FATAL_IF(!m, "Unable to find method %s", method);
+    return m;
+}
+
+static jfieldID getFieldID(JNIEnv* env, jclass c, const char name[],
+                           const char type[]) {
+    jfieldID f = env->GetFieldID(c, name, type);
+    LOG_FATAL_IF(!f, "Unable to find field %s", name);
+    return f;
+}
+
+namespace android {
+    
+int register_android_nio_utils(JNIEnv* env);
+int register_android_nio_utils(JNIEnv* env) {
+    jclass localClass = findClass(env, "java/nio/NIOAccess");
+    gNioJNI.getBasePointerID = findStaticMethod(env, localClass,
+                                    "getBasePointer", "(Ljava/nio/Buffer;)J");
+    gNioJNI.getBaseArrayID = findStaticMethod(env, localClass,
+                    "getBaseArray", "(Ljava/nio/Buffer;)Ljava/lang/Object;");
+    gNioJNI.getBaseArrayOffsetID = findStaticMethod(env, localClass,
+                                "getBaseArrayOffset", "(Ljava/nio/Buffer;)I");
+
+    // now record a permanent version of the class ID
+    gNioJNI.nioAccessClass = (jclass) env->NewGlobalRef(localClass);
+
+    return 0;
+}
+
+}