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/*-------------------------------------------------------------------------
*
* fstack.h--
* Fixed format stack definitions.
*
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: fstack.h,v 1.5 1997/09/08 21:52:20 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/*
* Note:
* Fixed format stacks assist in the construction of FIFO stacks of
* fixed format structures. Structures which are to be stackable
* should contain a FixedItemData component. A stack is initilized
* with the offset of the FixedItemData component of the structure
* it will hold. By doing so, push and pop operations are simplified
* for the callers. All references to stackable items are pointers
* to the base of the structure instead of pointers to the
* FixedItemData component.
*
*/
#ifndef FSTACK_H
#define FSTACK_H
/*
* FixedItem --
* Fixed format stackable item chain component.
*
* Note:
* Structures must contain one FixedItemData component per stack in
* which it will be an item.
*/
typedef struct FixedItemData FixedItemData;
typedef FixedItemData *FixedItem;
struct FixedItemData
{
FixedItem next; /* next item or NULL */
};
/*
* FixedStack --
* Fixed format stack.
*/
typedef struct FixedStackData
{
FixedItem top; /* Top item on the stack or NULL */
Offset offset; /* Offset from struct base to item */
/* this could be signed short int! */
} FixedStackData;
typedef FixedStackData *FixedStack;
/*
* FixedStackInit --
* Iniitializes stack for structures with given fixed component offset.
*
* Exceptions:
* BadArg if stack is invalid pointer.
*/
extern void FixedStackInit(FixedStack stack, Offset offset);
/*
* FixedStackPop --
* Returns pointer to top structure on stack or NULL if empty stack.
*
* Exceptions:
* BadArg if stack is invalid.
*/
Pointer FixedStackPop(FixedStack stack);
/*
* FixedStackPush --
* Places structure associated with pointer onto top of stack.
*
* Exceptions:
* BadArg if stack is invalid.
* BadArg if pointer is invalid.
*/
extern void FixedStackPush(FixedStack stack, Pointer pointer);
/*
* FixedStackGetTop --
* Returns pointer to top structure of a stack. This item is not poped.
*
* Note:
* This is not part of the normal stack interface. It is intended for
* debugging use only.
*
* Exceptions:
* BadArg if stack is invalid.
*/
extern Pointer FixedStackGetTop(FixedStack stack);
/*
* FixedStackGetNext --
* Returns pointer to next structure after pointer of a stack.
*
* Note:
* This is not part of the normal stack interface. It is intended for
* debugging use only.
*
* Exceptions:
* BadArg if stack is invalid.
* BadArg if pointer is invalid.
* BadArg if stack does not contain pointer.
*/
extern Pointer FixedStackGetNext(FixedStack stack, Pointer pointer);
#endif /* FSTACK_H */
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