mozglue/android/SharedMemNatives.cpp

   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 }