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5c25d60244
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files.
146 lines
2.8 KiB
C
146 lines
2.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* fstack.c
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* Fixed format stack definitions.
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/lib/Attic/fstack.c,v 1.14 2000/01/26 05:56:26 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "lib/fstack.h"
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/*
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* Internal function definitions
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*/
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/*
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* FixedItemIsValid
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* True iff item is valid.
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*/
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#define FixedItemIsValid(item) PointerIsValid(item)
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/*
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* FixedStackGetItemBase
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* Returns base of enclosing structure.
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*/
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#define FixedStackGetItemBase(stack, item) \
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((Pointer)((char *)(item) - (stack)->offset))
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/*
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* FixedStackGetItem
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* Returns item of given pointer to enclosing structure.
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*/
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#define FixedStackGetItem(stack, pointer) \
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((FixedItem)((char *)(pointer) + (stack)->offset))
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#define FixedStackIsValid(stack) ((bool)PointerIsValid(stack))
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/*
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* External functions
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*/
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void
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FixedStackInit(FixedStack stack, Offset offset)
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{
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AssertArg(PointerIsValid(stack));
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stack->top = NULL;
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stack->offset = offset;
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}
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Pointer
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FixedStackPop(FixedStack stack)
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{
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Pointer pointer;
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AssertArg(FixedStackIsValid(stack));
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if (!PointerIsValid(stack->top))
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return NULL;
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pointer = FixedStackGetItemBase(stack, stack->top);
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stack->top = stack->top->next;
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return pointer;
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}
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void
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FixedStackPush(FixedStack stack, Pointer pointer)
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{
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FixedItem item = FixedStackGetItem(stack, pointer);
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AssertArg(FixedStackIsValid(stack));
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AssertArg(PointerIsValid(pointer));
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item->next = stack->top;
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stack->top = item;
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}
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#ifdef USE_ASSERT_CHECKING
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/*
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* FixedStackContains
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* True iff ordered stack contains given element.
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*
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* Note:
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* This is inefficient. It is intended for debugging use only.
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*
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* Exceptions:
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* BadArg if stack is invalid.
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* BadArg if pointer is invalid.
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*/
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static bool
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FixedStackContains(FixedStack stack, Pointer pointer)
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{
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FixedItem next;
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FixedItem item;
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AssertArg(FixedStackIsValid(stack));
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AssertArg(PointerIsValid(pointer));
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item = FixedStackGetItem(stack, pointer);
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for (next = stack->top; FixedItemIsValid(next); next = next->next)
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{
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if (next == item)
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return true;
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}
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return false;
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}
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#endif
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Pointer
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FixedStackGetTop(FixedStack stack)
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{
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AssertArg(FixedStackIsValid(stack));
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if (!PointerIsValid(stack->top))
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return NULL;
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return FixedStackGetItemBase(stack, stack->top);
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}
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Pointer
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FixedStackGetNext(FixedStack stack, Pointer pointer)
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{
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FixedItem item;
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/* AssertArg(FixedStackIsValid(stack)); */
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/* AssertArg(PointerIsValid(pointer)); */
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AssertArg(FixedStackContains(stack, pointer));
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item = FixedStackGetItem(stack, pointer)->next;
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if (!PointerIsValid(item))
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return NULL;
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return FixedStackGetItemBase(stack, item);
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}
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