NT4/private/rpc/ndr20/unmrshlp.c

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Copyright (c) 1993 Microsoft Corporation

Module Name :

    unmrshlp.c

Abstract :

    This file contains the routines for unmarshalling an array's or a 
	structure's embedded pointers.

Author :

    David Kays  dkays   September 1993.

Revision History :

  ---------------------------------------------------------------------*/

#include "ndrp.h"


PFORMAT_STRING
NdrpEmbeddedPointerUnmarshall( 
	PMIDL_STUB_MESSAGE	pStubMsg,
	uchar *				pMemory,
	PFORMAT_STRING		pFormat,
	uchar				fNewMemory )
/*++

Routine Description :

    Unmarshalls an array's or a structure's embedded pointers.

Arguments :

    pStubMsg    - Pointer to the stub message.
    pMemory     - Pointer to the structure or array whose embedded pointers
                  are being unmarshalled.
    pFormat     - Pointer layout format string description.
	fNewMemory	- TRUE if the array or structure was allocated during
				  unmarshalling, FALSE otherwise. 

Return :

	Format string pointer after the pointer layout.

--*/
{
	uchar **		ppMemPtr;
	uchar **		ppBufPtr;
	uchar *			pBufferMark;
	uchar *			pBufferSave;
    long            MaxCountSave, OffsetSave;

    MaxCountSave = pStubMsg->MaxCount;
    OffsetSave = pStubMsg->Offset;

    //
    // Check if we're handling pointers in a complex struct, and re-set the
    // Buffer pointer if so.
    //
    if ( pStubMsg->PointerBufferMark )
        {
        pBufferSave = pStubMsg->Buffer;

        pStubMsg->Buffer = pStubMsg->PointerBufferMark;

		pStubMsg->PointerBufferMark = 0;
        }
	else
		pBufferSave = 0;

	// Save BufferMark in a local.
	pBufferMark = pStubMsg->BufferMark;

	// Increment past FC_PP and FC_PAD.
	pFormat += 2;

    for (;;) 
		{
		if ( *pFormat == FC_END ) 
			{
            if ( pBufferSave )
                {
                pStubMsg->PointerBufferMark = pStubMsg->Buffer;

                pStubMsg->Buffer = pBufferSave;
                }

			return pFormat;
			}

		// Check for FC_FIXED_REPEAT or FC_VARIABLE_REPEAT.
        if ( *pFormat != FC_NO_REPEAT )
            {
            pStubMsg->MaxCount = MaxCountSave;
            pStubMsg->Offset = OffsetSave;

            pStubMsg->BufferMark = pBufferMark;

            pFormat = NdrpEmbeddedRepeatPointerUnmarshall( pStubMsg,
                                                   		   pMemory,
                                                   		   pFormat,
														   fNewMemory );

            // Continue to the next pointer.
            continue;
            }

		// Compute the pointer to the current memory pointer to the data.
		ppMemPtr = (uchar **)( pMemory + *((signed short *)(pFormat + 2)) );

		// Compute the pointer to the pointer in the buffer.
		ppBufPtr = (uchar **)(pBufferMark + *((signed short *)(pFormat + 4)));

		// Increment to the pointer description.
		pFormat += 6;

		//
		// If the incomming encapsulating memory pointer was just allocated,
		// then explicitly null out the current pointer.  
		//
		if ( fNewMemory )
			*ppMemPtr = 0;

        NdrpPointerUnmarshall( pStubMsg,
          	     			   ppBufPtr,
							   *ppMemPtr,
          	     			   pFormat );

		// Increment to the next pointer description.
		pFormat += 4;
		}
}


PFORMAT_STRING
NdrpEmbeddedRepeatPointerUnmarshall( 
	PMIDL_STUB_MESSAGE	pStubMsg,
    uchar *				pMemory,
    PFORMAT_STRING		pFormat,
	uchar				fNewMemory )
/*++

Routine Description :

    Unmarshalls an array's embedded pointers.

Arguments :

    pStubMsg    - Pointer to the stub message.
    pMemory     - Pointer to the array whose embedded pointers are being 
				  unmarshalled.
    pFormat     - Pointer layout format string description.
	fNewMemory	- TRUE if the array was allocated during unmarshalling, 
				  FALSE otherwise. 

Return :

	Format string pointer after the pointer layout.

--*/
{
    uchar **		ppMemPtr; 
	uchar **		ppBufPtr;
	PFORMAT_STRING	pFormatSave;
	uchar *			pBufferMark;
    ulong           RepeatCount, RepeatIncrement, Pointers, PointersSave;

	// Get the beginning of the array in the buffer.
	pBufferMark = pStubMsg->BufferMark;

    // Get the repeat count.
    switch ( *pFormat )
        {
        case FC_FIXED_REPEAT :
            pFormat += 2;

            RepeatCount = *((ushort *)pFormat);

            break;

        case FC_VARIABLE_REPEAT :
            RepeatCount = pStubMsg->MaxCount;

            //
            // Check if this variable repeat instance also has a variable
            // offset (this would be the case for a conformant varying array
            // of pointers, or structures which contain pointers).  If so then
            // increment the format string to point to the actual first array
            // element which is being marshalled.
            //
            if ( pFormat[1] == FC_VARIABLE_OFFSET )
                pMemory += *((ushort *)(pFormat + 2)) * pStubMsg->Offset;

            // else pFormat[1] == FC_FIXED_OFFSET - do nothing

            break;

        default :
            NDR_ASSERT(0,"NdrpEmbeddedRepeatPointerUnmarshall : bad format");
            RpcRaiseException( RPC_S_INTERNAL_ERROR );
            return 0;
        }

    // Increment format string to increment field.
    pFormat += 2;

    // Get the increment amount between successive pointers.
    RepeatIncrement = *((ushort *)pFormat)++;

	// Array offset is ignored.
	pFormat += 2;

	// Get number of pointers in each array element.
	PointersSave = Pointers = *((ushort *)pFormat)++;

	pFormatSave = pFormat;

	//
	// Loop over the number of shipped array elements.
	//
    for ( ; RepeatCount--;
            pBufferMark += RepeatIncrement,
            pMemory += RepeatIncrement )
        {
        pFormat = pFormatSave;
		Pointers = PointersSave;

		//
		// Loop over the number of pointer per array element (which can 
		// be greater than one for an array of structures).
		//
        for ( ; Pointers--; )
        	{
			// Pointer to the pointer in memory.
			ppMemPtr = (uchar **)(pMemory + *((signed short *)pFormat)++);

			// Pointer to the pointer's id in the buffer.
			ppBufPtr = (uchar **)(pBufferMark + *((signed short *)pFormat)++);

			//
			// If the incomming encapsulating memory pointer was just 
			// allocated, then explicitly null out the current pointer.  
			//
			if ( fNewMemory )
				*ppMemPtr = 0;

			NdrpPointerUnmarshall( pStubMsg,
						   	   	   ppBufPtr,
						   	   	   *ppMemPtr,
						   	   	   pFormat );

			// Increment past the pointer description.
			pFormat += 4;
			}
		}

	// Return the format string pointer past the array's pointer description.
    return pFormatSave + PointersSave * 8;
}