161 lines
3.3 KiB
C
161 lines
3.3 KiB
C
/* $XConsortium: Pstack.c /main/4 1995/11/08 11:47:39 rswiston $ */
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/************************************<+>*************************************
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****************************************************************************
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*
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* File: PStack.c
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*
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* Project: Cache Creek (Rivers) Project
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* Description: Utility functions for volumegen program
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* Author: Brian Cripe
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* Modifications by (Mike Wilson)
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* Language: C
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*
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* (C) Copyright 1992, Hewlett-Packard, all rights reserved.
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*
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****************************************************************************
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************************************<+>*************************************/
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#include <stdio.h>
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#include "PstackI.h"
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#define REALLOC_INCR 10
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/*****************************************************************************
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* Function: PStack PStackCreate();
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*
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* Parameters: NONE.
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*
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* Return Value: PStack.
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*
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* Purpose: Generates a PStack structure and returns it to the
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* caller.
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*
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*****************************************************************************/
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PStack PStackCreate()
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{
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PStack stack;
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stack = (PStack) malloc (sizeof (struct PStackRec));
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stack->count = 0;
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stack->size = REALLOC_INCR;
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stack->items = (void **) malloc (stack->size * sizeof (void **));
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return (stack);
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}
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/*****************************************************************************
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* Function: PStack PStackDestroy();
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*
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* Parameters: stack:
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*
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* Return Value: void.
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*
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* Purpose: Destroys a PStack structure.
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*
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*****************************************************************************/
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void PStackDestroy(
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PStack stack)
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{
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free (stack->items);
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free (stack);
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}
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/*****************************************************************************
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* Function: PStack PStackPush();
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*
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* Parameters: stack:
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* ptr:
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*
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* Return Value: void
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*
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* Purpose: Pushes a PStack structure on the current stack.
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*
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*****************************************************************************/
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void PStackPush(
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PStack stack,
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void *ptr)
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{
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if (stack->count == stack->size) {
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stack->size += REALLOC_INCR;
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stack->items = (void **) realloc (stack->items,
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stack->size * sizeof (void **));
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}
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*(stack->items + stack->count) = ptr;
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stack->count++;
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}
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/*****************************************************************************
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* Function: PStack *PStackPeek();
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*
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* Parameters: stack:
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*
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* Return Value: void.
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*
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* Purpose: Gets a PStack.
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*
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*****************************************************************************/
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void *PStackPeek(
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PStack stack)
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{
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if (stack->count == 0)
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return (NULL);
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else
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return (*(stack->items + stack->count - 1));
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}
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/*****************************************************************************
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* Function: PStack *PStackPop();
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*
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* Parameters: stack:
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*
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* Return Value: void.
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*
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* Purpose: Pops the top element off the stack
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*
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*****************************************************************************/
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void *PStackPop(
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PStack stack)
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{
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if (stack->count == 0)
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return (NULL);
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else {
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stack->count--;
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return (*(stack->items + stack->count));
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}
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}
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