ShSwizzle.hpp

// Sh: A GPU metaprogramming language.
//
// Copyright (c) 2003 University of Waterloo Computer Graphics Laboratory
// Project administrator: Michael D. McCool
// Authors: Zheng Qin, Stefanus Du Toit, Kevin Moule, Tiberiu S. Popa,
//          Michael D. McCool
// 
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// 
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 
// 1. The origin of this software must not be misrepresented; you must
// not claim that you wrote the original software. If you use this
// software in a product, an acknowledgment in the product documentation
// would be appreciated but is not required.
// 
// 2. Altered source versions must be plainly marked as such, and must
// not be misrepresented as being the original software.
// 
// 3. This notice may not be removed or altered from any source
// distribution.
#ifndef SHSWIZZLE_HPP
#define SHSWIZZLE_HPP

#include <iosfwd>
//#include <vector>
#include "ShDllExport.hpp"
#include "ShException.hpp"

namespace SH {

class
SH_DLLEXPORT
ShSwizzle {
public:

  // Null swizzle
  ShSwizzle();

  ShSwizzle(int srcSize);
  ShSwizzle(int srcSize, int i0);
  ShSwizzle(int srcSize, int i0, int i1);
  ShSwizzle(int srcSize, int i0, int i1, int i2);
  ShSwizzle(int srcSize, int i0, int i1, int i2, int i3);
  ShSwizzle(int srcSize, int size, int* indices);

  ShSwizzle(const ShSwizzle& other);
  ~ShSwizzle();

  ShSwizzle& operator=(const ShSwizzle& other);
  
  ShSwizzle& operator*=(const ShSwizzle& other);

  ShSwizzle operator*(const ShSwizzle& other) const;

  int size() const { return m_size; }

  int operator[](int i) const;

  bool identity() const;

  bool operator==(const ShSwizzle& other) const;
  
private:
  // copies the other swizzle's elements 
  void copy(const ShSwizzle &other, bool islocal);

  // throws an exception if index < 0 or index >= m_srcSize
  void checkSrcSize(int index); 

  // allocates the m_indices array to current m_size
  // returns true 
  bool alloc(); 

  // deallocates the m_indices array 
  void dealloc();

  // returns whether we're using local 
  bool local() const;

  // returns the identity swiz value on this machine
  int idswiz() const;

  // Declare these two first so alignment problems don't make the ShSwizzle struct larger
  int m_srcSize;
  int m_size;

  // when srcSize <= 255 and size <= 4, use local.
  // local is always initialized to 0x03020101, so identity comparison is
  // just an integer comparison using intval
  union {
    unsigned char local[4];
    int intval;
    int* ptr;
  } m_index;

  friend SH_DLLEXPORT std::ostream& operator<<(std::ostream& out, const ShSwizzle& swizzle);
};

class
SH_DLLEXPORT ShSwizzleException : public ShException 
{
public:
  ShSwizzleException(const ShSwizzle& s, int idx, int size);
};
  
}

#include "ShSwizzleImpl.hpp"
  
#endif

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