source-engine/public/tier1/utlstack.h

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2020-04-22 16:56:21 +00:00
//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//
// A stack based on a growable array
//=============================================================================//
#ifndef UTLSTACK_H
#define UTLSTACK_H
#include <assert.h>
#include <string.h>
#include "utlmemory.h"
//-----------------------------------------------------------------------------
// The CUtlStack class:
// A growable stack class which doubles in size by default.
// It will always keep all elements consecutive in memory, and may move the
// elements around in memory (via a realloc) when elements are pushed or
// popped. Clients should therefore refer to the elements of the stack
// by index (they should *never* maintain pointers to elements in the stack).
//-----------------------------------------------------------------------------
template< class T, class M = CUtlMemory< T > >
class CUtlStack
{
public:
// constructor, destructor
CUtlStack( int growSize = 0, int initSize = 0 );
~CUtlStack();
void CopyFrom( const CUtlStack<T, M> &from );
// element access
T& operator[]( int i );
T const& operator[]( int i ) const;
T& Element( int i );
T const& Element( int i ) const;
// Gets the base address (can change when adding elements!)
T* Base();
T const* Base() const;
// Looks at the stack top
T& Top();
T const& Top() const;
// Size
int Count() const;
// Is element index valid?
bool IsIdxValid( int i ) const;
// Adds an element, uses default constructor
int Push();
// Adds an element, uses copy constructor
int Push( T const& src );
// Pops the stack
void Pop();
void Pop( T& oldTop );
void PopMultiple( int num );
// Makes sure we have enough memory allocated to store a requested # of elements
void EnsureCapacity( int num );
// Clears the stack, no deallocation
void Clear();
// Memory deallocation
void Purge();
private:
// Grows the stack allocation
void GrowStack();
// For easier access to the elements through the debugger
void ResetDbgInfo();
M m_Memory;
int m_Size;
// For easier access to the elements through the debugger
T* m_pElements;
};
//-----------------------------------------------------------------------------
// For easier access to the elements through the debugger
//-----------------------------------------------------------------------------
template< class T, class M >
inline void CUtlStack<T,M>::ResetDbgInfo()
{
m_pElements = m_Memory.Base();
}
//-----------------------------------------------------------------------------
// constructor, destructor
//-----------------------------------------------------------------------------
template< class T, class M >
CUtlStack<T,M>::CUtlStack( int growSize, int initSize ) :
m_Memory(growSize, initSize), m_Size(0)
{
ResetDbgInfo();
}
template< class T, class M >
CUtlStack<T,M>::~CUtlStack()
{
Purge();
}
//-----------------------------------------------------------------------------
// copy into
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::CopyFrom( const CUtlStack<T, M> &from )
{
Purge();
EnsureCapacity( from.Count() );
for ( int i = 0; i < from.Count(); i++ )
{
Push( from[i] );
}
}
//-----------------------------------------------------------------------------
// element access
//-----------------------------------------------------------------------------
template< class T, class M >
inline T& CUtlStack<T,M>::operator[]( int i )
{
assert( IsIdxValid(i) );
return m_Memory[i];
}
template< class T, class M >
inline T const& CUtlStack<T,M>::operator[]( int i ) const
{
assert( IsIdxValid(i) );
return m_Memory[i];
}
template< class T, class M >
inline T& CUtlStack<T,M>::Element( int i )
{
assert( IsIdxValid(i) );
return m_Memory[i];
}
template< class T, class M >
inline T const& CUtlStack<T,M>::Element( int i ) const
{
assert( IsIdxValid(i) );
return m_Memory[i];
}
//-----------------------------------------------------------------------------
// Gets the base address (can change when adding elements!)
//-----------------------------------------------------------------------------
template< class T, class M >
inline T* CUtlStack<T,M>::Base()
{
return m_Memory.Base();
}
template< class T, class M >
inline T const* CUtlStack<T,M>::Base() const
{
return m_Memory.Base();
}
//-----------------------------------------------------------------------------
// Returns the top of the stack
//-----------------------------------------------------------------------------
template< class T, class M >
inline T& CUtlStack<T,M>::Top()
{
assert( m_Size > 0 );
return Element(m_Size-1);
}
template< class T, class M >
inline T const& CUtlStack<T,M>::Top() const
{
assert( m_Size > 0 );
return Element(m_Size-1);
}
//-----------------------------------------------------------------------------
// Size
//-----------------------------------------------------------------------------
template< class T, class M >
inline int CUtlStack<T,M>::Count() const
{
return m_Size;
}
//-----------------------------------------------------------------------------
// Is element index valid?
//-----------------------------------------------------------------------------
template< class T, class M >
inline bool CUtlStack<T,M>::IsIdxValid( int i ) const
{
return (i >= 0) && (i < m_Size);
}
//-----------------------------------------------------------------------------
// Grows the stack
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::GrowStack()
{
if (m_Size >= m_Memory.NumAllocated())
m_Memory.Grow();
++m_Size;
ResetDbgInfo();
}
//-----------------------------------------------------------------------------
// Makes sure we have enough memory allocated to store a requested # of elements
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::EnsureCapacity( int num )
{
m_Memory.EnsureCapacity(num);
ResetDbgInfo();
}
//-----------------------------------------------------------------------------
// Adds an element, uses default constructor
//-----------------------------------------------------------------------------
template< class T, class M >
int CUtlStack<T,M>::Push()
{
GrowStack();
Construct( &Element(m_Size-1) );
return m_Size - 1;
}
//-----------------------------------------------------------------------------
// Adds an element, uses copy constructor
//-----------------------------------------------------------------------------
template< class T, class M >
int CUtlStack<T,M>::Push( T const& src )
{
GrowStack();
CopyConstruct( &Element(m_Size-1), src );
return m_Size - 1;
}
//-----------------------------------------------------------------------------
// Pops the stack
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::Pop()
{
assert( m_Size > 0 );
Destruct( &Element(m_Size-1) );
--m_Size;
}
template< class T, class M >
void CUtlStack<T,M>::Pop( T& oldTop )
{
assert( m_Size > 0 );
oldTop = Top();
Pop();
}
template< class T, class M >
void CUtlStack<T,M>::PopMultiple( int num )
{
assert( m_Size >= num );
for ( int i = 0; i < num; ++i )
Destruct( &Element( m_Size - i - 1 ) );
m_Size -= num;
}
//-----------------------------------------------------------------------------
// Element removal
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::Clear()
{
for (int i = m_Size; --i >= 0; )
Destruct(&Element(i));
m_Size = 0;
}
//-----------------------------------------------------------------------------
// Memory deallocation
//-----------------------------------------------------------------------------
template< class T, class M >
void CUtlStack<T,M>::Purge()
{
Clear();
m_Memory.Purge( );
ResetDbgInfo();
}
#endif // UTLSTACK_H