Initial Contribution

1 files changed, 74 insertions, 0 deletions

diff --git a/core/jni/android_nio_utils.h b/core/jni/android_nio_utils.h
new file mode 100644
index 0000000..69c360c
--- /dev/null
+++ b/core/jni/android_nio_utils.h
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+/*
+ * 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.
+ */
+
+#ifndef android_nio_utils_DEFINED
+#define android_nio_utils_DEFINED
+
+#include <android_runtime/AndroidRuntime.h>
+
+namespace android {
+    
+/**
+ * Given an nio.Buffer, return a pointer to it, beginning at its current
+ * position. The returned pointer is only valid for the current JNI stack-frame.
+ * For performance, it does not create any global references, so the getPointer
+ * (and releasePointer if array is returned non-null) must be done in the
+ * same JNI stack-frame.
+ *
+ * @param env   The current JNI env
+ * @param buffer    The nio.Buffer object
+ * @param array     REQUIRED. Output. If on return it is set to non-null, then
+ *                  nio_releasePointer must be called with the array
+ *                  and the returned pointer when the caller is through with it.
+ *                  If on return it is set to null, do not call
+ *                  nio_releasePointer.
+ * @return The pointer to the memory in the buffer object
+ */
+void* nio_getPointer(JNIEnv *env, jobject buffer, jarray *array);
+
+/**
+ * Call this if android_nio_getPointer returned non-null in its array parameter.
+ * Pass that array and the returned pointer when you are done accessing the
+ * pointer. If called (i.e. array is non-null), it must be called in the same
+ * JNI stack-frame as getPointer
+ *
+ * @param env   The current JNI env
+ * @param buffer    The array returned from android_nio_getPointer (!= null)
+ * @param pointer   The pointer returned by android_nio_getPointer
+ * @param commit    JNI_FALSE if the pointer was just read, and JNI_TRUE if
+ *                  the pointer was written to.
+ */
+void nio_releasePointer(JNIEnv *env, jarray array, void *pointer,
+                                jboolean commit);
+
+class AutoBufferPointer {
+public:
+    AutoBufferPointer(JNIEnv* env, jobject nioBuffer, jboolean commit);
+    ~AutoBufferPointer();
+    
+    void* pointer() const { return fPointer; }
+    
+private:
+    JNIEnv* fEnv;
+    void*   fPointer;
+    jarray  fArray;
+    jint    fRemaining;
+    jboolean fCommit;
+};
+
+}   /* namespace android */
+
+#endif