SharedMemNatives.cpp (2666B)
1 /* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*- 2 * This Source Code Form is subject to the terms of the Mozilla Public 3 * License, v. 2.0. If a copy of the MPL was not distributed with this 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 5 6 #include <errno.h> 7 #include <jni.h> 8 #include <stdio.h> 9 #include <string.h> 10 #include <sys/mman.h> 11 12 #include "mozilla/Sprintf.h" 13 14 extern "C" { 15 16 JNIEXPORT 17 void JNICALL 18 Java_org_mozilla_gecko_media_SampleBuffer_nativeReadFromDirectBuffer( 19 JNIEnv* jenv, jclass, jobject src, jlong dest, jint offset, jint size) { 20 uint8_t* from = static_cast<uint8_t*>(jenv->GetDirectBufferAddress(src)); 21 if (from == nullptr) { 22 jenv->ThrowNew(jenv->FindClass("java/lang/NullPointerException"), 23 "Null direct buffer"); 24 return; 25 } 26 27 void* to = reinterpret_cast<void*>(dest); 28 if (to == nullptr) { 29 jenv->ThrowNew(jenv->FindClass("java/lang/NullPointerException"), 30 "Null shared memory buffer"); 31 return; 32 } 33 34 memcpy(to, from + offset, size); 35 } 36 37 JNIEXPORT 38 void JNICALL 39 Java_org_mozilla_gecko_media_SampleBuffer_nativeWriteToDirectBuffer( 40 JNIEnv* jenv, jclass, jlong src, jobject dest, jint offset, jint size) { 41 uint8_t* from = reinterpret_cast<uint8_t*>(src); 42 if (from == nullptr) { 43 jenv->ThrowNew(jenv->FindClass("java/lang/NullPointerException"), 44 "Null shared memory buffer"); 45 return; 46 } 47 48 void* to = jenv->GetDirectBufferAddress(dest); 49 if (to == nullptr) { 50 jenv->ThrowNew(jenv->FindClass("java/lang/NullPointerException"), 51 "Null direct buffer"); 52 return; 53 } 54 55 memcpy(to, from + offset, size); 56 } 57 58 JNIEXPORT 59 jlong JNICALL Java_org_mozilla_gecko_mozglue_SharedMemory_map(JNIEnv* env, 60 jobject jobj, 61 jint fd, 62 jint length) { 63 void* address = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); 64 if (address == MAP_FAILED) { 65 char msg[128]; 66 SprintfLiteral(msg, "mmap failed. errno=%d", errno); 67 env->ThrowNew(env->FindClass("java/lang/NullPointerException"), msg); 68 return 0; 69 } 70 return jlong(address); 71 } 72 73 JNIEXPORT 74 void JNICALL Java_org_mozilla_gecko_mozglue_SharedMemory_unmap(JNIEnv* env, 75 jobject jobj, 76 jlong address, 77 jint size) { 78 munmap((void*)address, (size_t)size); 79 } 80 }