This is a quick tutorial using the sample code to incorporate a Merge function to your solution. Merging partitions is an effective way to optimize data storage. You can consolidate the disk space from two adjacent partitions (or additionally separated by free blocks), into a single, larger partition. Merging is one of the advanced partitioning tasks performed on a disk storage. You can only merge two adjacent NTFS, FAT32 or FAT partitions, also separated by unallocated space.

Due to internal restrictions, hdmengine cannot work on multiple processes at the same time, so it locks the volume during the process to restrict access from another process. For example, if an additional process is initialized (for example, resize a partition) when the hdmengine is busy with a different process (for example, creating a partition), the engine will not be able to lock the additional process (resize a partition) and will execute it in the Bluescreen mode.

Before you read the code sample: 

  • Include the header files.
  • Add hdmclient_hdmclientlib.dll library to your project.
  • Set up callbacks from hdmclientlib.

For more details on the initial setup, please see the Setting Up the C++ Development Environment section.

Add the header files to copy blocks of memory and pull in the rest of the headers from the clientapp engine, including the callback prototypes.

#include <string.h> // memcpy
 
#include "../hdmclientapp_progress.h"

Set callbacks. You need to implement the abstract interface struct Hdmclient_IProgress.

Hdmclient_Init                proc_Hdmclient_Init                = NULL;
_Hdmclient_Close               proc_Hdmclient_Close               = NULL;
_Hdmclient_GetInterface        proc_Hdmclient_GetInterface        = NULL;
_Hdmclient_GetLog              proc_Hdmclient_GetLog              = NULL;
_Hdmclient_InstallBluescreen   proc_Hdmclient_InstallBluescreen   = NULL;
_Hdmclient_GetErrorDescription proc_Hdmclient_GetErrorDescription = NULL;

Add a helper function to log output messages. Add a helper function to log output messages. How to set LogPrint please see hdmclientapp_main.cpp or look at a code sample here.

static void LogPrint(Hdmclient_ILog * /* pLog */, bool /* rewrite */, const char * /* format */, IN ...)
{
}

Select the disk number and partition number, you want to merge.

HDMCLIENT_ERR Hdmclient_Example_PartitionMerge(unsigned diskNumber,
                                               unsigned partNumber)

Set the variables for the error code, whether a reboot is necessary, and interfaces to log the actions as well as the interface to implement callbacks.

{
    HDMCLIENT_ERR err = SERR_SUCCESS;
 
    BOOL bReboot = FALSE;
 
    Hdmclient_ILog *pLog = NULL;
 
    Hdmclient_Progress hdmclientProgress;

Set the hdmengine initialization flags and enable run multiple instances of Hdmengine application.

    if(!err)
    {
        unsigned int initFlags = Hdmclient_InitFlags::Hdmclient_InitFlag_EnableRunMultiple;

Initialize Hdmengine API: pass engine flags, pass the progress interface to Hdmengine API, pass the application log path. Then get the logging interface.

        err = proc_Hdmclient_Init((Hdmclient_InitFlags)initFlags,
                              &hdmclientProgress,           
                              "hdmclient_hdmclientapp.log",
                              NULL, NULL, NULL);
 
        if(!err)
            proc_Hdmclient_GetLog(&pLog);
    }

Get the partitioning interface.

    if(!err)
    {
        Hdmclient_IInterface* pInterface = NULL;
        if(!err)
            err = proc_Hdmclient_GetInterface(&pInterface);

Search for the selected partition by disk and partition number (all numbers zero based, extended and free partitions are also counted). Hdmclient_IInterface::DiskInfo diskInfo = {}; – Displays selected disk info and Hdmclient_IInterface::PartitionInfo partInfo displayed selected partition info.

        Hdmclient_IInterface::DiskInfo      diskInfo = {};
        Hdmclient_IInterface::PartitionInfo partInfo = {};
 
        if(!err)
        {
            Hdmclient_IInterface::EnumDisksInfo* enumDisksInfo = NULL;

Get the disks enumerator and release the disks enumerator.

            err = pInterface->GetDisksInfo(&enumDisksInfo);
            if(!err)
            {
                if(enumDisksInfo && (enumDisksInfo->disksCount > 0))
                {
                    if(!err)
                    {
                        if(diskNumber == (unsigned)-1)
                        {
                            err = SERR_DISK_NOT_FOUND;
 
                            LogPrint(pLog, false, "Disk is not selected .. Failed\n");
                        }else
                        if((diskNumber + 1) > enumDisksInfo->disksCount)
                        {
                            err = SERR_DISK_NOT_FOUND;
 
                            LogPrint(pLog, false, "Disk number is out of range (maximum number is %lu) .. Failed\n", enumDisksInfo->disksCount - 1);
                        }else
                        {
                            auto pDiskInfo = enumDisksInfo->ppDisksInfo[diskNumber];
 
                            memcpy(&diskInfo, pDiskInfo, sizeof(diskInfo));
 
                            if(partNumber != (unsigned)-1)
                            {
                                if((partNumber + 1) <= pDiskInfo->enumPartitionsInfo.partitionsCount)
                                {
                                    auto pPartitionInfo = pDiskInfo->enumPartitionsInfo.ppPartitionsInfo[partNumber];
 
                                    memcpy(&partInfo, pPartitionInfo, sizeof(partInfo));
                                }else
                                {
                                    err = SERR_PART_NOT_FOUND;
 
                                    LogPrint(pLog, false, "Partition number is out of range (maximum number is %lu) .. Failed\n", pDiskInfo->enumPartitionsInfo.partitionsCount - 1);
                                }
                            }
                        }
                    }
                }
 
                pInterface->ReleaseDisksInfo(enumDisksInfo);
            }
        }

Check that the required action is available for selected object.

        if(!err)
        {
            if(!(partInfo.ActFlags & Hdmclient_IInterface::PartitionActFlags::PartitionActFlag_Can_MergeFs))
            {
                err = SERR_INCOMPATIBLEOP;
 
                LogPrint(pLog, false, "Merge file system is not enabled for selected partition ... Failed\n");
            }else

Enter folder name to place right partition’s content to the parent partition.

            {
                const char* sMergeFolderName = "New_Directory";

Add file masks to skip from merged partition (will be deleted). Then perform the merge (virtual step).

                const char* sExcludeFileMasks = "/Excluded data dir0\0/Excluded data dir1\0*.exe\0\0";
 
                err = pInterface->Partition_MergeFs(partInfo.DiskNumber,
                                                    partInfo.PartitionNumber,
                                                    sMergeFolderName,
                                                    sExcludeFileMasks);
 
                LogPrint(pLog, false, "Merging selected partition file system ... %s\n", err ? "Failed" : "Success");
            }
        }

(Physical step) Then perform the merge action and apply the queue or above operations.

        if(!err)
        {
            if(!err)
            {
                LogPrint(pLog, false, "Applying operations ...\n");
 
                err = pInterface->Apply();
 
                if(!err)
                {
                    LogPrint(pLog, false, "Applying queue of operations ... Success\n");
                }else
                {
                    LogPrint(pLog, false, "Applying queue of operations ... Failed (Result: 0x%x, \"%s\")\n", err, proc_Hdmclient_GetErrorDescription(err));
                }
            }
        }
    }

Close the HDM client API.

   proc_Hdmclient_Close(bReboot, FALSE);

    return err;
}

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