memblk.cpp

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// $Id: memblk.cpp 1467 2006-07-18 17:00:07Z gerry $
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----------------------------------

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 */

// class to handle large memory blocks

/*
*/

#include "camtypes.h"

#include <errno.h>

//#include "errors.h" - in camtypes.h [AUTOMATICALLY REMOVED]
//#include "andy.h"
//#include "simon.h"                // for _R(IDS_CONTINUE)
//#include "memblk.h" - in camtypes.h [AUTOMATICALLY REMOVED]
//#include "ensure.h" - in camtypes.h [AUTOMATICALLY REMOVED]
#include "camelot.h"

#ifndef WIN32
#define MAX_BLOCK   0xFFFCL     // 64k-4
#endif

#if USE_VM_BLOCKS
UINT32 MemoryBlock::PageSize;               // page size used in Virtual Mem API
#endif

/*********************************************************************************************

>   class MemoryBlock

    Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
    Created:    3/3/94
    Purpose:    Some items start small and get large. The MemoryBlock class encapsulates
                memory management for objects that generally need to be fixed in memory
                but need to grow, and are generally large. Items that use the class
                include the handles table and the relocatable heap.
        
*********************************************************************************************/

/*********************************************************************************************

>   MemoryBlock::MemoryBlock()

    Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
    Created:    3/3/94
    Inputs:     -
    Returns:    -
    Purpose:    Constructor. Initialises some fields to zero. Does not do any allocations.
        
*********************************************************************************************/

MemoryBlock::MemoryBlock()
{
#if USE_STD_ALLOC
#elif USE_VM_BLOCKS
    MemBase = NULL;
#else
    MemHandle = 0;
#endif
}

/*********************************************************************************************

>   MemoryBlock::~MemoryBlock()

    Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
    Created:    3/3/94
    Inputs:     -
    Returns:    -
    Purpose:    Destructor. Doesn't do anything really, though might do a DeInit one day.
    SeeAlso:    MemoryBlock::DeInit
        
*********************************************************************************************/

MemoryBlock::~MemoryBlock()
{
}

/*********************************************************************************************

>   LPVOID MemoryBlock::Init( INT32 InitSize, BOOL bAutoZero, MemoryBlockType Type )

    Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
    Created:    3/3/94
    Inputs:     InitSize    initial size of block required
                bAutoZero   TRUE if new memory required to be zeroed
                Type        one of MEMORYBLOCK_xxx constants. Determines maximum size of
                            block.
    Returns:    Pointer to memory if worked, NULL if failed to initialise.
    Purpose:    Sets up block for subsequent allocations.
        
*********************************************************************************************/

LPVOID MemoryBlock::Init( INT32 InitSize, BOOL bAutoZero, MemoryBlockType Type )
{
#if USE_STD_ALLOC

    m_RoundedSize = GetRoundedSize( InitSize );

    // now physically grab the starting size
    LPVOID              pNewPtr;
    if( bAutoZero )
    {
        pNewPtr = CCMalloc( m_RoundedSize );
        memset(pNewPtr, 0, m_RoundedSize);
    }
    else
    {
        pNewPtr = CCMalloc( m_RoundedSize );
    }
        
    if( pNewPtr == NULL )
    {
        TRACEUSER( "Andy", wxT("malloc() failed because %lx\n"), errno );
        return NULL;
    }

    TRACEUSER( "Andy", wxT("malloc OK at %p\n"), pNewPtr );
    m_pMemBlk = pNewPtr;
    return pNewPtr;

#elif USE_VM_BLOCKS

    // first time we are called get the page size
    if (PageSize==0L)
    {
        SYSTEM_INFO SysInfo;
        GetSystemInfo( &SysInfo );
        PageSize = SysInfo.dwPageSize;
    }

    // Note that the Virtual API always gives us zeroed memory whether we want it or not


    // calculate a suitable maximum size for the type of block
    INT32 LargestSize;

    switch (Type)
    {
        case MEMORYBLOCK_HANDLETABLE:
            LargestSize = 0x01000000;               // 16M of handles is enough
            break;
        case MEMORYBLOCK_RELOCHEAP:
            LargestSize = 0x10000000;               // 256M of reloc heap
            break;
        case MEMORYBLOCK_SCREENBUFFER:
            LargestSize = 0x01000000;               // 1024x768x32bits x4 for good measure
            break;
        default:
            ENSURE( FALSE, "Bad type in MemoryBlock::Init");
            return NULL;
    }

    // firstly reserve a gratuitously large chunk of address space

    MemBase = VirtualAlloc( NULL, LargestSize, MEM_RESERVE, PAGE_NOACCESS );
    if (MemBase==NULL)
    {
        TRACEUSER( "Andy", wxT("VirtualAlloc(reserve) failed because %lx\n"), GetLastError() );
        return NULL;
    }

    RoundedSize = GetRoundedSize( InitSize );

    // now physically grab the starting size
    LPVOID NewPtr = VirtualAlloc( MemBase, RoundedSize, MEM_COMMIT, PAGE_READWRITE );
    if (NewPtr==NULL)
    {
        TRACEUSER( "Andy", wxT("VirtualAlloc(commit) failed because %lx\n"), GetLastError() );
        VirtualFree(MemBase, 0L, MEM_RELEASE );
        MemBase = NULL;
        return NULL;
    }

    TRACEUSER( "Andy", wxT("VirtualAlloced OK at %lx from %lx\n"), NewPtr, MemBase );

    return NewPtr;
#else

    #ifndef WIN32
    if (InitSize > MAX_BLOCK)
        return NULL;
    #endif

    AutoZero = bAutoZero;                                           // remember flag in struct

    UINT32 Flags = GMEM_MOVEABLE;
    if (AutoZero)
        Flags |= GMEM_ZEROINIT;

    MemHandle = GlobalAlloc( Flags, InitSize );
TRACE( wxT("GlobalAlloc %u %lx returned %x\n"), Flags, InitSize, (INT32)MemHandle);
    if (MemHandle==NULL)
        return NULL;

    LPVOID Ptr = GlobalLock( MemHandle );
    if (Ptr == NULL)
    {
        GlobalFree( MemHandle );
        MemHandle = 0;
        return NULL;
    }

    return Ptr;
#endif
}

/*********************************************************************************************

>   void MemoryBlock::DeInit()

    Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
    Created:    3/3/94
    Inputs:     -
    Returns:    -
    Purpose:    Frees up any allocations on this memory block. Should always be called
                during exit for a tidy cleanup.
        
*********************************************************************************************/

void MemoryBlock::DeInit()
{
#if USE_STD_ALLOC
    if( NULL != m_pMemBlk )
    {
        CCFree(  m_pMemBlk );
        m_pMemBlk = NULL;
    }
#elif USE_VM_BLOCKS
    if (MemBase)
    {
        BOOL Result = VirtualFree(MemBase, 0L, MEM_RELEASE);
        MemBase = NULL;
        ENSURE( Result, "VirtualFree failed");
    }
#else
    if (MemHandle)
    {
        GlobalUnlock( MemHandle );
        GlobalFree( MemHandle );
        MemHandle = 0;
    }
#endif
}

/*********************************************************************************************

    static BOOL DoGrowGlobalHandle( HGLOBAL *pHandle, UINT32 OldSize, UINT32 NewSize, UINT32 MoreFlags, LPVOID *Pointer)

        Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
        Created:    24/2/94
        Inputs:     pHandle     pointer to global handle whose block we want bigger, might be
                                updated upon return
                    OldSize     size it is at the moment
                    NewSize     desired size of new block
                    MoreFlags   extra flags to pass to GlobalReAlloc
                    Pointer     where new pointer is to be stored
        Returns:    TRUE if worked, FALSE if failed
        Purpose:    Low-level private primitve for MemoryBlock::Grow. Actually does the
                    work. Function does not exist if using VM_BLOCKs.
        SeeAlso:    MemoryBlock::Grow
        
*********************************************************************************************/

#if !USE_VM_BLOCKS && !USE_STD_ALLOC

static BOOL DoGrowGlobalHandle( HGLOBAL *pHandle, UINT32 OldSize, UINT32 NewSize, UINT32 MoreFlags, LPVOID *Pointer)
{
    if (GlobalUnlock( *pHandle ))
    {
        // if didn't unlock then we won't be able to realloc, so better stop now
        TRACE( wxT("GlobalUnlock failed in GrowGlobalHandle\n") );
        return FALSE;
    }

    // get Windows to grab us a new bigger block. Important to use GMEM_MOVEABLE as we want
    // our block to move if possible to satisfy the request
    HGLOBAL hNewHandle = GlobalReAlloc( *pHandle, NewSize, GMEM_MOVEABLE | MoreFlags );

    if (hNewHandle)
    {
        ADDR NewPtr = (ADDR)GlobalLock( hNewHandle );
        if (NewPtr == NULL)
        {
            // careful here as we really do want to get our old data back - at the moment
            // all we have is a handle to an unlocked block of memory. To try and recover the
            // situation we'll try setting it back to its old size
            hNewHandle = GlobalReAlloc( hNewHandle, OldSize, GMEM_MOVEABLE );
            if (hNewHandle)
            {
                NewPtr = (ADDR)GlobalLock( hNewHandle );
                if (NewPtr)
                {
                    // OK, got old data back but might be in different place so tidy up
                    // then exit gracefully
                    *Pointer = NewPtr;
                    *pHandle = hNewHandle;
                    TRACE( wxT("WARNING: Made hasty exit from GrowGlobalHandle\n") );
                    return FALSE;                                   // indicate failure
                }
            }
            // this is very catastrophic - we cannot get our old data back, so
            // we will communicate this to the user. The program is likely to
            // crash and burn after this
            TRACE( wxT("DANGER: Catastrophic failure in GrowGlobalHandle\n") );
            if (InformSeriousError( _R(IDE_BAD_GROWHEAP), _R(IDS_ABORT), _R(IDS_CONTINUE) ) == 1)
                AfxAbort();

            return FALSE;                                   // although system is v. unstable
        }

        TRACEUSER( "Andy", wxT("Handle %x changed to %x (%lx-%lx) (%ld-%ld) %x\n"),
            (INT32)*pHandle, (INT32)hNewHandle,
            (INT32)*Pointer, (INT32)NewPtr,
            (INT32)OldSize, (INT32)NewSize,
            (INT32)MoreFlags
        );

        // we've got our new block, update the callers variables
        *Pointer = NewPtr;
        *pHandle = hNewHandle;
        return TRUE;
    }

    // couldn't reallocate it, the old one will still be there though
    TRACE( wxT("GlobalReAlloc failed in GrowGlobalHandle\n") );
    TRACEUSER( "Andy", wxT("Failed to grow handle %x from %ld.%ld at %lx\n"),
                (INT32)*pHandle,
                (INT32)OldSize,(INT32)NewSize,
                (INT32)*Pointer
            );

    return FALSE;

}
#endif


/*********************************************************************************************

>   BOOL MemoryBlock::Grow( UINT32 OldSize, UINT32 NewSize, LPVOID *Pointer )

        Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
        Created:    24/2/94
        Inputs:     OldSize     size it is at the moment
                    NewSize     desired size of new block
                    Pointer     where new pointer is to be stored
        Returns:    TRUE if worked, FALSE if failed
        Purpose:    Like GlobalReAlloc in a way, but a safer version that does all it can
                    to ensure existing data doesn't get thrown away. Handles unlocking,
                    reallocing and relocking the result. Even if the return value is
                    FALSE, the data might still have been moved - see if *Pointer has changed
                    if this is important to you.
        SeeAlso:    DoGrowGlobalHeap;MemoryBlock::Shrink
        
*********************************************************************************************/

BOOL MemoryBlock::Grow( UINT32 OldSize, UINT32 NewSize, LPVOID *Pointer )
{
#if USE_STD_ALLOC
    NewSize = GetRoundedSize( NewSize );                // round new size up
    if( NewSize == m_RoundedSize )
        return TRUE;                                    // if same physical size

    LPVOID              NewPtr = CCRealloc( *Pointer, NewSize );
    if (NewPtr==NULL)
    {
        TRACEUSER( "Andy", wxT("CCRealloc growing from %ld to %ld failed\n"), OldSize, NewSize);
        return FALSE;
    }
    *Pointer = m_pMemBlk = NewPtr;
    m_RoundedSize = NewSize;
    return TRUE;
    
#elif USE_VM_BLOCKS
    NewSize = GetRoundedSize( NewSize );                // round new size up
    if (NewSize == RoundedSize)
        return TRUE;                                    // if same physical size

    LPVOID NewPtr = VirtualAlloc( MemBase, NewSize, MEM_COMMIT, PAGE_READWRITE );
    if (NewPtr==NULL)
    {
        TRACEUSER( "Andy", wxT("VirtualAlloc growing from %ld to %ld failed\n"), OldSize, NewSize);
        return FALSE;
    }
    *Pointer = NewPtr;
    RoundedSize = NewSize;
    return TRUE;

#else
    const UINT32 Flags = AutoZero ? GMEM_ZEROINIT : 0;

    #ifndef WIN32
    if (NewSize > MAX_BLOCK)
        return FALSE;
    #endif

    return DoGrowGlobalHandle( &MemHandle, OldSize, NewSize, Flags, Pointer );
#endif
}

/*********************************************************************************************

>   BOOL MemoryBlock::Shrink( UINT32 OldSize, UINT32 NewSize, LPVOID *Pointer )

        Author:     Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>
        Created:    3/3/94
        Inputs:     OldSize     size it is at the moment
                    NewSize     desired size of new block, smaller than OldSize
                    Pointer     where new pointer is to be stored
        Returns:    TRUE if worked, FALSE if failed
        Purpose:    Reduces the current allocation, without throwing away data. Normally
                    this should always work, as giving memory back shouldn't ever fail,
                    but a FALSE return means we couldn't. If a FALSE return is combined
                    with a NULL Pointer return, it means an extremely bad thing occurred
                    and the original data has been lost.
        SeeAlso:    MemoryBlock::Grow
        
*********************************************************************************************/

BOOL MemoryBlock::Shrink( UINT32 OldSize, UINT32 NewSize, LPVOID *Pointer )
{
#if USE_STD_ALLOC
    
    OldSize = GetRoundedSize( OldSize );
    NewSize = GetRoundedSize( NewSize );
    
    if (OldSize == NewSize)
        return TRUE;                                        // no change required

    if (OldSize < NewSize)
    {
        ENSURE(FALSE, "Cannot Shrink backwards");
        return FALSE;
    }                                   // if same physical size

    LPVOID              NewPtr = CCRealloc( *Pointer, NewSize );
    if (NewPtr==NULL)
    {
        TRACEUSER( "Andy", wxT("CCRealloc growing from %ld to %ld failed\n"), OldSize, NewSize);
        return FALSE;
    }
    *Pointer = m_pMemBlk = NewPtr;
    m_RoundedSize = NewSize;
    return TRUE;
    
#elif USE_VM_BLOCKS

    // we do a shrink by freeing up spare blocks

    OldSize = GetRoundedSize( OldSize );
    NewSize = GetRoundedSize( NewSize );

    if (OldSize == NewSize)
        return TRUE;                                        // no change required

    if (OldSize < NewSize)
    {
        ENSURE(FALSE, "Cannot Shrink backwards");
        return FALSE;
    }

    // lets free up the unwanted bits now
    BOOL Result = VirtualFree( ((LPBYTE)MemBase)+NewSize, OldSize-NewSize, MEM_DECOMMIT );

    if (Result==FALSE)
    {
        TRACEUSER( "Andy", wxT("VirtualFree Shrink from %ld to %ld failed\n"), OldSize, NewSize);
        return FALSE;
    }

    RoundedSize = NewSize;
    return TRUE;

#else
    // the data will be left alone
    ENSURE( FALSE, "Cannot shrink memory blocks");
    return FALSE;

#endif
}

---