Android MemoryFile内存文件 + Ashmem匿名共享内存

e.printStackTrace();

}

_data.writeFileDescriptor(fd);

b.transact(XXX, _data, _reply, 0);

_reply.readException();

_reply.readInt();

} catch (RemoteException e) {

e.printStackTrace();

} finally {

_reply.recycle();

_data.recycle();

}

//… …

}

MemoryFile

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源码路径：./frameworks/base/core/java/android/os/MemoryFile.java

主要功能

• readBytes(）

• writeBytes()

代码实现

/**

• Reads bytes from the memory file.

• Will throw an IOException if the file has been purged.

• @param buffer byte array to read bytes into.

• @param srcOffset offset into the memory file to read from.

• @param destOffset offset into the byte array buffer to read into.

• @param count number of bytes to read.

• @return number of bytes read.

• @throws IOException if the memory file has been purged or deactivated.

*/

public int readBytes(byte[] buffer, int srcOffset, int destOffset, int count)

throws IOException {

beginAccess();

try {

mMapping.position(srcOffset);

mMapping.get(buffer, destOffset, count);

} finally {

endAccess();

}

return c