com.sun.jna.platform.win32.Cfgmgr32Util Maven / Gradle / Ivy
/* Copyright (c) 2018 Daniel Widdis, All Rights Reserved
*
* The contents of this file is dual-licensed under 2
* alternative Open Source/Free licenses: LGPL 2.1 or later and
* Apache License 2.0. (starting with JNA version 4.0.0).
*
* You can freely decide which license you want to apply to
* the project.
*
* You may obtain a copy of the LGPL License at:
*
* http://www.gnu.org/licenses/licenses.html
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "LGPL2.1".
*
* You may obtain a copy of the Apache License at:
*
* http://www.apache.org/licenses/
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "AL2.0".
*/
package com.sun.jna.platform.win32;
import com.sun.jna.Memory;
import com.sun.jna.Native;
import com.sun.jna.ptr.IntByReference;
/**
* Cfgmgr32 utility API.
*
* @author widdis[at]gmail[dot]com
*/
public abstract class Cfgmgr32Util {
@SuppressWarnings("serial")
public static class Cfgmgr32Exception extends RuntimeException {
private final int errorCode;
public Cfgmgr32Exception(int errorCode) {
this.errorCode = errorCode;
}
public int getErrorCode() {
return errorCode;
}
}
/**
* Utility method to call Cfgmgr32's CM_Get_Device_ID that allocates the
* required memory for the Buffer parameter based on the type mapping used,
* calls to CM_Get_Device_ID, and returns the received string.
*
* @param devInst
* Caller-supplied device instance handle that is bound to the
* local machine.
* @return The device instance ID string.
* @throws Cfgmgr32Exception
*/
public static String CM_Get_Device_ID(int devInst) throws Cfgmgr32Exception {
int charToBytes = Boolean.getBoolean("w32.ascii") ? 1 : Native.WCHAR_SIZE;
// Get Device ID character count
IntByReference pulLen = new IntByReference();
int ret = Cfgmgr32.INSTANCE.CM_Get_Device_ID_Size(pulLen, devInst, 0);
if (ret != Cfgmgr32.CR_SUCCESS) {
throw new Cfgmgr32Exception(ret);
}
// Add one to length to allow null terminator
Memory buffer = new Memory((pulLen.getValue() + 1) * charToBytes);
// Zero the buffer (including the extra character)
buffer.clear();
// Fetch the buffer specifying only the current length
ret = Cfgmgr32.INSTANCE.CM_Get_Device_ID(devInst, buffer, pulLen.getValue(), 0);
// In the unlikely event the device id changes this might not be big
// enough, try again. This happens rarely enough one retry should be
// sufficient.
if (ret == Cfgmgr32.CR_BUFFER_SMALL) {
ret = Cfgmgr32.INSTANCE.CM_Get_Device_ID_Size(pulLen, devInst, 0);
if (ret != Cfgmgr32.CR_SUCCESS) {
throw new Cfgmgr32Exception(ret);
}
buffer = new Memory((pulLen.getValue() + 1) * charToBytes);
buffer.clear();
ret = Cfgmgr32.INSTANCE.CM_Get_Device_ID(devInst, buffer, pulLen.getValue(), 0);
}
// If we still aren't successful throw an exception
if (ret != Cfgmgr32.CR_SUCCESS) {
throw new Cfgmgr32Exception(ret);
}
// Convert buffer to Java String
if (charToBytes == 1) {
return buffer.getString(0);
} else {
return buffer.getWideString(0);
}
}
}