windows-server-2003/inetsrv/iis/svcs/infocomm/metadata/inc/ptrmap.hxx

/*++

Copyright (c) 1996  Microsoft Corporation

Module Name:

    ptrmap.hxx

Abstract:

    A helper class for mapping ID to 32 or 64 bit ptr

Author:
    Kestutis Patiejunas (kestutip)        08-Dec-1998


Revision History:

Notes:

--*/

#ifndef PTRMAP_HXX
#define PTRMAP_HXX


#define DEFAULT_START_NUMBER_OF_MAPS            4096
#define DEFAULT_INCREASE_NUMBER_OF_MAPS         4096


// for 32 bit DWORD only. intentionally the same  for 32 and 64 bits
#define MAPPING_NO_EMPTY_PLACE_IDX      ((DWORD)0xffffffff)


typedef struct
{
    BOOL  fInUse;
    //
    // The pData member is valid when fInUse is true, otherwise the dwIndex
    // member is valid
    //
    union
    {
        PVOID pData;
        DWORD dwIndex;
    };
} MapperElement;

class CIdToPointerMapper
{
public:



    /*++
    Routine Description:

        Constructor

    Arguments:
        nStartMaps - initial nubmer of possible mappings in table
        nIncreaseMaps - number of increase for table when there is not enought space

    Return Value:
        sucess is tored in m_fInitialized

    --*/
    CIdToPointerMapper(DWORD nStartMaps,DWORD nIncreaseMaps);
    ~CIdToPointerMapper();


    /*++
    Routine Description:

        Takes a PVOID pointer and returns a DWORD ID associated,which should be used
        in mapping it back to ptr

    Arguments:
        PVOID ptr - a pointer of 32/64 bits which should be mapped into dword

    Return Value:

        DWORD - an ID associated with a given pointer . Starts from 1.
                Zero indicates  a failure to create mapping.

    --*/
    DWORD   AddMapping(PVOID ptr);



    /*++
    Routine Description:

        Deletes a mapping from mapping table between dword ID and PTR

    Arguments:
        DWORD ID - and ID to which mapping should be deleted.

    Return Value:

        BOOL TRUE is succeded
    --*/
    BOOL    DeleteMapping(DWORD id);


    /*++
    Routine Description:

        Finds a mapping in mapping table between DWORD ID and pointer associated

    Arguments:
        DWORD ID - and ID to which mapping should be deleted.

    Return Value:

        DWORD - an ID associated with a given pointer . Starts from 1.
                Zero indicates  a failure to craete mapping.

    --*/
    PVOID   FindMapping(DWORD id);


    VOID    VerifyOutstandinMappings();


#ifndef _X86_
private:
    // size in sizeof(pvoid) of memory allocated for mapper
    // later can be increased where reallocating
    DWORD   m_nStartMaps;

    // the increment for mapper for reallocation
    DWORD   m_nIncreaseMaps;

    // was it initialized succesfully
    BOOL    m_fInitialized;

    // an array of pointers what are mapped
    // an element contains a pointer of right size for a given platform
    // if is not used then it contains the index to the next element
    // in free element list.
    MapperElement *m_Map;
    BUFFER  *m_pBufferObj;

    // first element in fre element list
    DWORD   m_EmptyPlace;

    // counter for number of mappings
    DWORD   m_nMappings;
#endif
};



#endif PTRMAP_HXX