140 lines
3.6 KiB
NASM
140 lines
3.6 KiB
NASM
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; ole.asm
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;
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; Copyright (C) 1991, MicroSoft Corporation
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;
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; Contains pointer vaildation routine
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;
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; History: sriniK 02/01/1991 original
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; srinik 02/21/1991 added GetGDIds, IsMetaDC
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;/
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.286p
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.MODEL SMALL
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.CODE
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;**************************** _CheckPointer ****************************
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;
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; WORD CheckPointer (lp, access)
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;
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; Args:
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; lp pointer to be verified
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; access 0 test the pointer for read access
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; 1 test the pointer for write access
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; returns:
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; FALSE invalid pointer
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; TRUE valid pointer
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;
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;
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;
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public _CheckPointer
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_CheckPointer proc
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push bp
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mov bp, sp
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xor ax, ax
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and word ptr [bp+8], -1
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jnz check_write_access
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verr word ptr [bp+6] ; check selector for read access
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jnz error
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jmp short check_offset
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check_write_access:
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verw word ptr [bp+6] ; check selector for write access
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jnz error
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check_offset:
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lsl bx, word ptr [bp+6] ; segment limit gets copied into BX
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jnz error
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cmp [bp+4], bx
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ja error
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or ax, -1
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error:
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pop bp
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ret
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_CheckPointer endp
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;**************************** _GetGdiDS ****************************
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;
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; WORD GetGDIds (lpGdiFunc)
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;
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; Args:
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; lpGdiFunc long pointer to one of the GDI functions, with selector
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; part being aliased to a data selector
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; returns:
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; GDI DS value
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;
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public _GetGDIds
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_GetGDIds proc
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push bp
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mov bp, sp
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mov ax, word ptr [bp+6] ; data selector
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push ds
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mov ds, ax
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mov bx, word ptr [bp+4]
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mov ax, word ptr ds:[bx+1]
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pop ds
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pop bp
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ret
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_GetGDIds endp
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;**************************** _IsMetaDC ****************************
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;
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; WORD IsMetaDC (hdc, wGDIds)
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;
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; Args:
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; hdc handle device context
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; wGDIds GDI's data segment selector
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;
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; returns:
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; TRUE if hdc is metafile dc
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; FALSE otherwise
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;
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; ilObjHead struc
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; dw ? ; pointer to next obj in chain
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; ilObjType dw ? ; defines type of object
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; ilObjCount dd ? ; the count of the object
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; ilObjMetaList dw ? ; handle to the list of metafile
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; ilObjHead ends
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;
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public _IsMetaDC
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OBJ_METAFILE equ 10
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_IsMetaDC proc
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push bp
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mov bp, sp
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mov ax, [bp+6] ; data selector
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push ds
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mov ds, ax
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mov di, [bp+4] ; hdc
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mov di, [di]
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cmp word ptr [di+2], OBJ_METAFILE
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jz metafile
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xor ax, ax
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metafile:
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pop ds
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pop bp
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ret
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_IsMetaDC endp
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end
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