75 lines
2.6 KiB
C++
75 lines
2.6 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef android_nio_utils_DEFINED
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#define android_nio_utils_DEFINED
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#include <android_runtime/AndroidRuntime.h>
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namespace android {
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/**
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* Given an nio.Buffer, return a pointer to it, beginning at its current
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* position. The returned pointer is only valid for the current JNI stack-frame.
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* For performance, it does not create any global references, so the getPointer
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* (and releasePointer if array is returned non-null) must be done in the
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* same JNI stack-frame.
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*
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* @param env The current JNI env
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* @param buffer The nio.Buffer object
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* @param array REQUIRED. Output. If on return it is set to non-null, then
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* nio_releasePointer must be called with the array
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* and the returned pointer when the caller is through with it.
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* If on return it is set to null, do not call
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* nio_releasePointer.
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* @return The pointer to the memory in the buffer object
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*/
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void* nio_getPointer(JNIEnv *env, jobject buffer, jarray *array);
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/**
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* Call this if android_nio_getPointer returned non-null in its array parameter.
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* Pass that array and the returned pointer when you are done accessing the
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* pointer. If called (i.e. array is non-null), it must be called in the same
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* JNI stack-frame as getPointer
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*
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* @param env The current JNI env
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* @param buffer The array returned from android_nio_getPointer (!= null)
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* @param pointer The pointer returned by android_nio_getPointer
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* @param commit JNI_FALSE if the pointer was just read, and JNI_TRUE if
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* the pointer was written to.
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*/
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void nio_releasePointer(JNIEnv *env, jarray array, void *pointer,
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jboolean commit);
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class AutoBufferPointer {
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public:
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AutoBufferPointer(JNIEnv* env, jobject nioBuffer, jboolean commit);
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~AutoBufferPointer();
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void* pointer() const { return fPointer; }
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private:
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JNIEnv* fEnv;
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void* fPointer;
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jarray fArray;
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jint fRemaining;
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jboolean fCommit;
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};
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} /* namespace android */
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#endif
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