godot/thirdparty/bullet/BulletCollision/Gimpact/gim_radixsort.h

#ifndef GIM_RADIXSORT_H_INCLUDED
#define GIM_RADIXSORT_H_INCLUDED
/*! \file gim_radixsort.h
\author Francisco Leon Najera.
Based on the work of Michael Herf : "fast floating-point radix sort"
Avaliable on http://www.stereopsis.com/radix.html
*/
/*
-----------------------------------------------------------------------------
This source file is part of GIMPACT Library.

For the latest info, see http://gimpact.sourceforge.net/

Copyright (c) 2006 Francisco Leon Najera. C.C. 80087371.
email: projectileman@yahoo.com

 This library is free software; you can redistribute it and/or
 modify it under the terms of EITHER:
   (1) The GNU Lesser General Public License as published by the Free
       Software Foundation; either version 2.1 of the License, or (at
       your option) any later version. The text of the GNU Lesser
       General Public License is included with this library in the
       file GIMPACT-LICENSE-LGPL.TXT.
   (2) The BSD-style license that is included with this library in
       the file GIMPACT-LICENSE-BSD.TXT.
   (3) The zlib/libpng license that is included with this library in
       the file GIMPACT-LICENSE-ZLIB.TXT.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files
 GIMPACT-LICENSE-LGPL.TXT, GIMPACT-LICENSE-ZLIB.TXT and GIMPACT-LICENSE-BSD.TXT for more details.

-----------------------------------------------------------------------------
*/

#include "gim_memory.h"

///Macros for sorting.
//! Prototype for comparators
class less_comparator
{
public:
	template <class T, class Z>
	inline int operator()(const T& a, const Z& b)
	{
		return (a < b ? -1 : (a > b ? 1 : 0));
	}
};

//! Prototype for comparators
class integer_comparator
{
public:
	template <class T>
	inline int operator()(const T& a, const T& b)
	{
		return (int)(a - b);
	}
};

//!Prototype for getting the integer representation of an object
class uint_key_func
{
public:
	template <class T>
	inline GUINT operator()(const T& a)
	{
		return (GUINT)a;
	}
};

//!Prototype for copying elements
class copy_elements_func
{
public:
	template <class T>
	inline void operator()(T& a, T& b)
	{
		a = b;
	}
};

//!Prototype for copying elements
class memcopy_elements_func
{
public:
	template <class T>
	inline void operator()(T& a, T& b)
	{
		gim_simd_memcpy(&a, &b, sizeof(T));
	}
};

//! @{
struct GIM_RSORT_TOKEN
{
	GUINT m_key;
	GUINT m_value;
	GIM_RSORT_TOKEN()
	{
	}
	GIM_RSORT_TOKEN(const GIM_RSORT_TOKEN& rtoken)
	{
		m_key = rtoken.m_key;
		m_value = rtoken.m_value;
	}

	inline bool operator<(const GIM_RSORT_TOKEN& other) const
	{
		return (m_key < other.m_key);
	}

	inline bool operator>(const GIM_RSORT_TOKEN& other) const
	{
		return (m_key > other.m_key);
	}
};

//! Prototype for comparators
class GIM_RSORT_TOKEN_COMPARATOR
{
public:
	inline int operator()(const GIM_RSORT_TOKEN& a, const GIM_RSORT_TOKEN& b)
	{
		return (int)((a.m_key) - (b.m_key));
	}
};

#define kHist 2048
// ---- utils for accessing 11-bit quantities
#define D11_0(x) (x & 0x7FF)
#define D11_1(x) (x >> 11 & 0x7FF)
#define D11_2(x) (x >> 22)

///Radix sort for unsigned integer keys
inline void gim_radix_sort_rtokens(
	GIM_RSORT_TOKEN* array,
	GIM_RSORT_TOKEN* sorted, GUINT element_count)
{
	GUINT i;
	GUINT b0[kHist * 3];
	GUINT* b1 = b0 + kHist;
	GUINT* b2 = b1 + kHist;
	for (i = 0; i < kHist * 3; ++i)
	{
		b0[i] = 0;
	}
	GUINT fi;
	GUINT pos;
	for (i = 0; i < element_count; ++i)
	{
		fi = array[i].m_key;
		b0[D11_0(fi)]++;
		b1[D11_1(fi)]++;
		b2[D11_2(fi)]++;
	}
	{
		GUINT sum0 = 0, sum1 = 0, sum2 = 0;
		GUINT tsum;
		for (i = 0; i < kHist; ++i)
		{
			tsum = b0[i] + sum0;
			b0[i] = sum0 - 1;
			sum0 = tsum;
			tsum = b1[i] + sum1;
			b1[i] = sum1 - 1;
			sum1 = tsum;
			tsum = b2[i] + sum2;
			b2[i] = sum2 - 1;
			sum2 = tsum;
		}
	}
	for (i = 0; i < element_count; ++i)
	{
		fi = array[i].m_key;
		pos = D11_0(fi);
		pos = ++b0[pos];
		sorted[pos].m_key = array[i].m_key;
		sorted[pos].m_value = array[i].m_value;
	}
	for (i = 0; i < element_count; ++i)
	{
		fi = sorted[i].m_key;
		pos = D11_1(fi);
		pos = ++b1[pos];
		array[pos].m_key = sorted[i].m_key;
		array[pos].m_value = sorted[i].m_value;
	}
	for (i = 0; i < element_count; ++i)
	{
		fi = array[i].m_key;
		pos = D11_2(fi);
		pos = ++b2[pos];
		sorted[pos].m_key = array[i].m_key;
		sorted[pos].m_value = array[i].m_value;
	}
}

/// Get the sorted tokens from an array. For generic use. Tokens are IRR_RSORT_TOKEN
/*!
*\param array Array of elements to sort
*\param sorted_tokens Tokens of sorted elements
*\param element_count element count
*\param uintkey_macro Functor which retrieves the integer representation of an array element
*/
template <typename T, class GETKEY_CLASS>
void gim_radix_sort_array_tokens(
	T* array,
	GIM_RSORT_TOKEN* sorted_tokens,
	GUINT element_count, GETKEY_CLASS uintkey_macro)
{
	GIM_RSORT_TOKEN* _unsorted = (GIM_RSORT_TOKEN*)gim_alloc(sizeof(GIM_RSORT_TOKEN) * element_count);
	for (GUINT _i = 0; _i < element_count; ++_i)
	{
		_unsorted[_i].m_key = uintkey_macro(array[_i]);
		_unsorted[_i].m_value = _i;
	}
	gim_radix_sort_rtokens(_unsorted, sorted_tokens, element_count);
	gim_free(_unsorted);
	gim_free(_unsorted);
}

/// Sorts array in place. For generic use
/*!
\param type Type of the array
\param array
\param element_count
\param get_uintkey_macro Macro for extract the Integer value of the element. Similar to SIMPLE_GET_UINTKEY
\param copy_elements_macro Macro for copy elements, similar to SIMPLE_COPY_ELEMENTS
*/
template <typename T, class GETKEY_CLASS, class COPY_CLASS>
void gim_radix_sort(
	T* array, GUINT element_count,
	GETKEY_CLASS get_uintkey_macro, COPY_CLASS copy_elements_macro)
{
	GIM_RSORT_TOKEN* _sorted = (GIM_RSORT_TOKEN*)gim_alloc(sizeof(GIM_RSORT_TOKEN) * element_count);
	gim_radix_sort_array_tokens(array, _sorted, element_count, get_uintkey_macro);
	T* _original_array = (T*)gim_alloc(sizeof(T) * element_count);
	gim_simd_memcpy(_original_array, array, sizeof(T) * element_count);
	for (GUINT _i = 0; _i < element_count; ++_i)
	{
		copy_elements_macro(array[_i], _original_array[_sorted[_i].m_value]);
	}
	gim_free(_original_array);
	gim_free(_sorted);
}

//! Failsafe Iterative binary search,
/*!
If the element is not found, it returns the nearest upper element position, may be the further position after the last element.
\param _array
\param _start_i the beginning of the array
\param _end_i the ending  index of the array
\param _search_key Value to find
\param _comp_macro macro for comparing elements
\param _found If true the value has found. Boolean
\param _result_index the index of the found element, or if not found then it will get the index of the  closest bigger value
*/
template <class T, typename KEYCLASS, typename COMP_CLASS>
bool gim_binary_search_ex(
	const T* _array, GUINT _start_i,
	GUINT _end_i, GUINT& _result_index,
	const KEYCLASS& _search_key,
	COMP_CLASS _comp_macro)
{
	GUINT _k;
	int _comp_result;
	GUINT _i = _start_i;
	GUINT _j = _end_i + 1;
	while (_i < _j)
	{
		_k = (_j + _i - 1) / 2;
		_comp_result = _comp_macro(_array[_k], _search_key);
		if (_comp_result == 0)
		{
			_result_index = _k;
			return true;
		}
		else if (_comp_result < 0)
		{
			_i = _k + 1;
		}
		else
		{
			_j = _k;
		}
	}
	_result_index = _i;
	return false;
}

//! Failsafe Iterative binary search,Template version
/*!
If the element is not found, it returns the nearest upper element position, may be the further position after the last element.
\param _array
\param _start_i the beginning of the array
\param _end_i the ending  index of the array
\param _search_key Value to find
\param _result_index the index of the found element, or if not found then it will get the index of the  closest bigger value
\return true if found, else false
*/
template <class T>
bool gim_binary_search(
	const T* _array, GUINT _start_i,
	GUINT _end_i, const T& _search_key,
	GUINT& _result_index)
{
	GUINT _i = _start_i;
	GUINT _j = _end_i + 1;
	GUINT _k;
	while (_i < _j)
	{
		_k = (_j + _i - 1) / 2;
		if (_array[_k] == _search_key)
		{
			_result_index = _k;
			return true;
		}
		else if (_array[_k] < _search_key)
		{
			_i = _k + 1;
		}
		else
		{
			_j = _k;
		}
	}
	_result_index = _i;
	return false;
}

///heap sort from http://www.csse.monash.edu.au/~lloyd/tildeAlgDS/Sort/Heap/
template <typename T, typename COMP_CLASS>
void gim_down_heap(T* pArr, GUINT k, GUINT n, COMP_CLASS CompareFunc)
{
	/*  PRE: a[k+1..N] is a heap */
	/* POST:  a[k..N]  is a heap */

	T temp = pArr[k - 1];
	/* k has child(s) */
	while (k <= n / 2)
	{
		int child = 2 * k;

		if ((child < (int)n) && CompareFunc(pArr[child - 1], pArr[child]) < 0)
		{
			child++;
		}
		/* pick larger child */
		if (CompareFunc(temp, pArr[child - 1]) < 0)
		{
			/* move child up */
			pArr[k - 1] = pArr[child - 1];
			k = child;
		}
		else
		{
			break;
		}
	}
	pArr[k - 1] = temp;
} /*downHeap*/

template <typename T, typename COMP_CLASS>
void gim_heap_sort(T* pArr, GUINT element_count, COMP_CLASS CompareFunc)
{
	/* sort a[0..N-1],  N.B. 0 to N-1 */
	GUINT k;
	GUINT n = element_count;
	for (k = n / 2; k > 0; k--)
	{
		gim_down_heap(pArr, k, n, CompareFunc);
	}

	/* a[1..N] is now a heap */
	while (n >= 2)
	{
		gim_swap_elements(pArr, 0, n - 1); /* largest of a[0..n-1] */
		--n;
		/* restore a[1..i-1] heap */
		gim_down_heap(pArr, 1, n, CompareFunc);
	}
}

#endif  // GIM_RADIXSORT_H_INCLUDED