Source file: /~heha/hsn/borg.zip/STACK.CPP

/************************************************************************
*		   stack.cpp						*
* This is a simple stack class for a stack of lptr's. It is used in	*
* keeping track of jump locations, so that when a jump is followed it	*
* can be reversed. The stack is of a set size, and when it becomes too	*
* large the bottom of the stack is lost. I did have some plans on using *
* this class in a front end unpacker-emulator but my plans have changed *
* and any unpacker-emulator will use a different method more akin to	*
* single step tracing.							*
* The stack was added in Version 2.11					*
************************************************************************/

#include <windows.h>
#include "stacks.h"
#include "debug.h"

/************************************************************************
* constructor function							*
* - simply reset the top of the stack					*
************************************************************************/
stack::stack()
{  stacktop=0;
}

/************************************************************************
* destructor function							*
* - nothing to do since the stack is a fixed array			*
************************************************************************/
stack::~stack()
{
}

/************************************************************************
* push									*
* - places an item on top of the stack. If there is no room then we	*
*   lose an item from the bottom and move the others down		*
************************************************************************/
void stack::push(lptr loc)
{ int i;
  if(stacktop==CALLSTACKSIZE)  // need to remove bottom item from stack
  { for(i=0;i<CALLSTACKSIZE-1;i++)
    { callstack[i]=callstack[i+1];
      stacktop--;
    }
  }
  callstack[stacktop]=loc;
  stacktop++;
}

/************************************************************************
* pop									*
* - gets an item from the top of the stack, or returns nlptr if the	*
*   stack is empty							*
************************************************************************/
lptr stack::pop(void) {
 if (!stacktop) return nlptr;
 return callstack[--stacktop];
}