The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef android_nio_utils_DEFINED |
| 18 | #define android_nio_utils_DEFINED |
| 19 | |
| 20 | #include <android_runtime/AndroidRuntime.h> |
| 21 | |
| 22 | namespace android { |
| 23 | |
| 24 | /** |
| 25 | * Given an nio.Buffer, return a pointer to it, beginning at its current |
| 26 | * position. The returned pointer is only valid for the current JNI stack-frame. |
| 27 | * For performance, it does not create any global references, so the getPointer |
| 28 | * (and releasePointer if array is returned non-null) must be done in the |
| 29 | * same JNI stack-frame. |
| 30 | * |
| 31 | * @param env The current JNI env |
| 32 | * @param buffer The nio.Buffer object |
| 33 | * @param array REQUIRED. Output. If on return it is set to non-null, then |
| 34 | * nio_releasePointer must be called with the array |
| 35 | * and the returned pointer when the caller is through with it. |
| 36 | * If on return it is set to null, do not call |
| 37 | * nio_releasePointer. |
| 38 | * @return The pointer to the memory in the buffer object |
| 39 | */ |
| 40 | void* nio_getPointer(JNIEnv *env, jobject buffer, jarray *array); |
| 41 | |
| 42 | /** |
| 43 | * Call this if android_nio_getPointer returned non-null in its array parameter. |
| 44 | * Pass that array and the returned pointer when you are done accessing the |
| 45 | * pointer. If called (i.e. array is non-null), it must be called in the same |
| 46 | * JNI stack-frame as getPointer |
| 47 | * |
| 48 | * @param env The current JNI env |
| 49 | * @param buffer The array returned from android_nio_getPointer (!= null) |
| 50 | * @param pointer The pointer returned by android_nio_getPointer |
| 51 | * @param commit JNI_FALSE if the pointer was just read, and JNI_TRUE if |
| 52 | * the pointer was written to. |
| 53 | */ |
| 54 | void nio_releasePointer(JNIEnv *env, jarray array, void *pointer, |
| 55 | jboolean commit); |
| 56 | |
| 57 | class AutoBufferPointer { |
| 58 | public: |
| 59 | AutoBufferPointer(JNIEnv* env, jobject nioBuffer, jboolean commit); |
| 60 | ~AutoBufferPointer(); |
| 61 | |
| 62 | void* pointer() const { return fPointer; } |
| 63 | |
| 64 | private: |
| 65 | JNIEnv* fEnv; |
| 66 | void* fPointer; |
| 67 | jarray fArray; |
| 68 | jint fRemaining; |
| 69 | jboolean fCommit; |
| 70 | }; |
| 71 | |
| 72 | } /* namespace android */ |
| 73 | |
| 74 | #endif |