/*
Generic version of spreadsort
Copyright (c) 2002-2008 Steven J. Ross
Some improvements suggested by:
Phil Endecott and Frank Gennari

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/


#ifndef SPREADSORT_H
#define SPREADSORT_H
#include "constants.h"
#include <algorithm>
#include <vector>

//This only works on unsigned data types
template <typename T>
inline unsigned 
RoughLog2Size(const T& input) 
{
	unsigned result = 0;
	//The && is necessary on some compilers to avoid infinite loops; it doesn't significantly impair performance
	while((input >> result) && (result < (8*sizeof(T)))) ++result;
	return result;
}

//Gets the maximum size which we'll call spreadsort on to control worst-case performance
//Maintains both a minimum size to recurse and a check of distribution size versus count
//This is called for a set of bins, instead of bin-by-bin, to avoid performance overhead
inline size_t
GetMaxCount(unsigned log_range, size_t count)
{
	unsigned divisor = RoughLog2Size(count);
	//Making sure the divisor is positive
	if(divisor > LOG_MEAN_BIN_SIZE)
		divisor -= LOG_MEAN_BIN_SIZE;
	else
		divisor = 1;
	unsigned relative_width = (LOG_CONST * log_range)/((divisor > MAX_SPLITS) ? MAX_SPLITS : divisor);
	//Don't try to bitshift more than the size of an element
	if((8*sizeof(size_t)) <= relative_width)
		relative_width = (8*sizeof(size_t)) - 1;
	return 1 << ((relative_width < (LOG_MEAN_BIN_SIZE + LOG_MIN_SPLIT_COUNT)) ? 
		(LOG_MEAN_BIN_SIZE + LOG_MIN_SPLIT_COUNT) :  relative_width);
}

//Find the minimum and maximum
template <class RandomAccessIter>
inline void 
FindExtremes(RandomAccessIter current, RandomAccessIter last, RandomAccessIter & max, RandomAccessIter & min)
{
	min = max = current;
	//Start from the second item, as max and min are initialized to the first
	while(++current < last) {
		if(*max < *current)
			max = current;
		else if(*current < *min)
			min = current;
	}
}


template <class RandomAccessIter, class Compare>
inline void 
FindExtremes(RandomAccessIter current, RandomAccessIter last, RandomAccessIter & max, RandomAccessIter & min, Compare comp)
{
	min = max = current;
	while(++current < last) {
		if(comp(*max, *current))
			max = current;
		else if(comp(*current, *min))
			min = current;
	}
}

//Implementation for recursive sorting
template <class RandomAccessIter, class div_type, class data_type>
inline void 
SpreadSortRec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, size_t cache_offset
			  , std::vector<size_t> &bin_sizes)
{
	size_t bin_count;
	unsigned log_range;
	//This step is roughly 10% of runtime, but it helps avoid worst-case behavior and improve behavior with real data
	//If you know the maximum and minimum ahead of time, you can pass those values in and skip this step for the first iteration
	RandomAccessIter max, min;
	FindExtremes(first, last, max, min);
	//max and min will be the same (the first item) iff all values are equivalent
	if(max == min)
		return;
	size_t u;
	int log_divisor;
	RandomAccessIter * target_bin;
	unsigned count = last - first;
	log_range = RoughLog2Size((size_t)(*max >> 0) - (*min >> 0));
	//If we can finish in one iteration without exceeding either (2 to the MAX_SPLITS) or n bins, do so
	if((log_divisor = log_range - RoughLog2Size(count)) <= 0 && log_range < MAX_SPLITS)
		log_divisor = 0;
	else {
		//otherwise divide the data into an optimized number of pieces
		log_divisor += LOG_MEAN_BIN_SIZE;
		if(log_divisor < 0)
			log_divisor = 0;
		//Cannot exceed MAX_SPLITS or cache misses slow down bin lookups dramatically
		if((log_range - log_divisor) > MAX_SPLITS)
			log_divisor = log_range - MAX_SPLITS;
	}
	div_type div_min = *min >> log_divisor;
	div_type div_max = *max >> log_divisor;
	bin_count = div_max - div_min + 1;
	
	//Assure space for the size of each bin, followed by initializing sizes
	if(bin_count > bin_sizes.size())
		bin_sizes.resize(bin_count);
	for(u = 0; u < bin_count; u++)
		bin_sizes[u] = 0;
	//Make sure there is space for the bins
	size_t cache_end = cache_offset + bin_count;
	if(cache_end > bin_cache.size())
		bin_cache.resize(cache_end);
	RandomAccessIter *bins = &(bin_cache[cache_offset]);
		
	//Calculating the size of each bin; this takes roughly 10% of runtime
	for (RandomAccessIter current = first; current != last;)
		bin_sizes[(*(current++) >> log_divisor) - div_min]++;
	//Assign the bin positions
	bins[0] = first;
	for(u = 0; u < bin_count - 1; u++)
		bins[u + 1] = bins[u] + bin_sizes[u];
	
	//Swap into place
	//This dominates runtime, mostly in the swap and bin lookups
	RandomAccessIter nextbinstart = first;
	for(unsigned ii = 0; ii < bin_count; ++ii) {
		RandomAccessIter * local_bin = bins + ii;
		nextbinstart += bin_sizes[ii];
		//Iterating over each element in this bin
		for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
			//Swapping elements in current into place until the correct element has been swapped in
			for(target_bin = (bins + ((*current >> log_divisor) - div_min));  target_bin != local_bin; 
				target_bin = bins + ((*current >> log_divisor) - div_min)) {
				//3-way swap; this is about 1% faster than a 2-way swap with integers
				//The main advantage is less copies are involved per item put in the correct place
				data_type tmp;
				RandomAccessIter b = (*target_bin)++;
				RandomAccessIter * b_bin = bins + ((*b >> log_divisor) - div_min);
				if (b_bin != local_bin) {
					RandomAccessIter c = (*b_bin)++;
					tmp = *c;
					*c = *b;
				} 
				else
					tmp = *b;
				*b = *current;
				*current = tmp;
			}
		}
		*local_bin = nextbinstart;
	}
	
	//If we've bucketsorted, the array is sorted and we should skip recursion
	if(!log_divisor)
		return;
	
	//Recursing; log_divisor is the remaining range
	size_t max_count = GetMaxCount(log_divisor, last - first);
	RandomAccessIter lastPos = first;
	for(size_t u = cache_offset; u < cache_end; lastPos = bin_cache[u], ++u) {
		size_t count = bin_cache[u] - lastPos;
		//don't sort unless there are at least two items to compare
		if(count < 2)
			continue;
		//using std::sort if its worst-case is better
		if(count < max_count)
			std::sort(lastPos, bin_cache[u]);
		else
			SpreadSortRec<RandomAccessIter, div_type, data_type>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes);
	}
}

//Functor implementation for recursive sorting
template <class RandomAccessIter, class div_type, class data_type, class RightShift, class Compare>
inline void 
SpreadSortRec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, size_t cache_offset
			  , std::vector<size_t> &bin_sizes, RightShift shift, Compare comp)
{
	size_t bin_count;
	unsigned log_range;
	RandomAccessIter max, min;
	FindExtremes(first, last, max, min, comp);
	if(max == min)
		return;
	size_t u;
	int log_divisor;
	RandomAccessIter * target_bin;
	unsigned count = last - first;
	log_range = RoughLog2Size((size_t)(shift(*max, 0)) - (shift(*min, 0)));
	if((log_divisor = log_range - RoughLog2Size(count)) <= 0 && log_range < MAX_SPLITS)
		log_divisor = 0;
	else {
		log_divisor += LOG_MEAN_BIN_SIZE;
		if(log_divisor < 0)
			log_divisor = 0;
		if((log_range - log_divisor) > MAX_SPLITS)
			log_divisor = log_range - MAX_SPLITS;
	}
	div_type div_min = shift(*min, log_divisor);
	div_type div_max = shift(*max, log_divisor);
	bin_count = div_max - div_min + 1;
	
	//Assure space for the size of each bin, followed by initializing sizes
	if(bin_count > bin_sizes.size())
		bin_sizes.resize(bin_count);
	for(u = 0; u < bin_count; u++)
		bin_sizes[u] = 0;
	size_t cache_end = cache_offset + bin_count;
	if(cache_end > bin_cache.size())
		bin_cache.resize(cache_end);
	RandomAccessIter *bins = &(bin_cache[cache_offset]);
		
	//Calculating the size of each bin
	for (RandomAccessIter current = first; current != last;)
		bin_sizes[shift(*(current++), log_divisor) - div_min]++;
	bins[0] = first;
	for(u = 0; u < bin_count - 1; u++)
		bins[u + 1] = bins[u] + bin_sizes[u];
	
	//Swap into place
	RandomAccessIter nextbinstart = first;
	for(unsigned ii = 0; ii < bin_count; ++ii) {
		RandomAccessIter * local_bin = bins + ii;
		nextbinstart += bin_sizes[ii];
		for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
			for(target_bin = (bins + (shift(*current, log_divisor) - div_min));  target_bin != local_bin; 
				target_bin = bins + (shift(*current, log_divisor) - div_min)) {
				data_type tmp;
				RandomAccessIter b = (*target_bin)++;
				RandomAccessIter * b_bin = bins + (shift(*b, log_divisor) - div_min);
				if (b_bin != local_bin) {
					RandomAccessIter c = (*b_bin)++;
					tmp = *c;
					*c = *b;
				} 
				else
					tmp = *b;
				*b = *current;
				*current = tmp;
			}
		}
		*local_bin = nextbinstart;
	}
	
	if(!log_divisor)
		return;
	
	size_t max_count = GetMaxCount(log_divisor, last - first);
	RandomAccessIter lastPos = first;
	for(size_t u = cache_offset; u < cache_end; lastPos = bin_cache[u], ++u) {
		size_t count = bin_cache[u] - lastPos;
		if(count < 2)
			continue;
		if(count < max_count)
			std::sort(lastPos, bin_cache[u], comp);
		else
			SpreadSortRec<RandomAccessIter, div_type, data_type, RightShift, Compare>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes, shift, comp);
	}
}

//Functor implementation for recursive sorting with only Shift overridden
template <class RandomAccessIter, class div_type, class data_type, class RightShift>
inline void 
SpreadSortRec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, size_t cache_offset
			  , std::vector<size_t> &bin_sizes, RightShift shift)
{
	size_t bin_count;
	unsigned log_range;
	RandomAccessIter max, min;
	FindExtremes(first, last, max, min);
	if(max == min)
		return;
	size_t u;
	int log_divisor;
	RandomAccessIter * target_bin;
	unsigned count = last - first;
	log_range = RoughLog2Size((size_t)(shift(*max, 0)) - (shift(*min, 0)));
	if((log_divisor = log_range - RoughLog2Size(count)) <= 0 && log_range < MAX_SPLITS)
		log_divisor = 0;
	else {
		log_divisor += LOG_MEAN_BIN_SIZE;
		if(log_divisor < 0)
			log_divisor = 0;
		if((log_range - log_divisor) > MAX_SPLITS)
			log_divisor = log_range - MAX_SPLITS;
	}
	div_type div_min = shift(*min, log_divisor);
	div_type div_max = shift(*max, log_divisor);
	bin_count = div_max - div_min + 1;
	
	//Assure space for the size of each bin, followed by initializing sizes
	if(bin_count > bin_sizes.size())
		bin_sizes.resize(bin_count);
	for(u = 0; u < bin_count; u++)
		bin_sizes[u] = 0;
	size_t cache_end = cache_offset + bin_count;
	if(cache_end > bin_cache.size())
		bin_cache.resize(cache_end);
	RandomAccessIter *bins = &(bin_cache[cache_offset]);
		
	//Calculating the size of each bin
	for (RandomAccessIter current = first; current != last;)
		bin_sizes[shift(*(current++), log_divisor) - div_min]++;
	bins[0] = first;
	for(u = 0; u < bin_count - 1; u++)
		bins[u + 1] = bins[u] + bin_sizes[u];
	
	//Swap into place
	RandomAccessIter nextbinstart = first;
	for(unsigned ii = 0; ii < bin_count; ++ii) {
		RandomAccessIter * local_bin = bins + ii;
		nextbinstart += bin_sizes[ii];
		for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
			for(target_bin = (bins + (shift(*current, log_divisor) - div_min));  target_bin != local_bin; 
				target_bin = bins + (shift(*current, log_divisor) - div_min)) {
				data_type tmp;
				RandomAccessIter b = (*target_bin)++;
				RandomAccessIter * b_bin = bins + (shift(*b, log_divisor) - div_min);
				if (b_bin != local_bin) {
					RandomAccessIter c = (*b_bin)++;
					tmp = *c;
					*c = *b;
				} 
				else
					tmp = *b;
				*b = *current;
				*current = tmp;
			}
		}
		*local_bin = nextbinstart;
	}
	
	if(!log_divisor)
		return;
	
	size_t max_count = GetMaxCount(log_divisor, last - first);
	RandomAccessIter lastPos = first;
	for(size_t u = cache_offset; u < cache_end; lastPos = bin_cache[u], ++u) {
		size_t count = bin_cache[u] - lastPos;
		if(count < 2)
			continue;
		if(count < max_count)
			std::sort(lastPos, bin_cache[u]);
		else
			SpreadSortRec<RandomAccessIter, div_type, data_type, RightShift>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes, shift);
	}
}

//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class div_type, class data_type>
inline void 
SpreadSort(RandomAccessIter first, RandomAccessIter last, div_type, data_type)
{
	std::vector<size_t> bin_sizes;
	std::vector<RandomAccessIter> bin_cache;
	SpreadSortRec<RandomAccessIter, div_type, data_type>(first, last, bin_cache, 0, bin_sizes);
}

template <class RandomAccessIter, class div_type, class data_type, class RightShift, class Compare>
inline void 
SpreadSort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, RightShift shift, Compare comp)
{
	std::vector<size_t> bin_sizes;
	std::vector<RandomAccessIter> bin_cache;
	SpreadSortRec<RandomAccessIter, div_type, data_type, RightShift, Compare>(first, last, bin_cache, 0, bin_sizes, shift, comp);
}

template <class RandomAccessIter, class div_type, class data_type, class RightShift>
inline void 
SpreadSort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, RightShift shift)
{
	std::vector<size_t> bin_sizes;
	std::vector<RandomAccessIter> bin_cache;
	SpreadSortRec<RandomAccessIter, div_type, data_type, RightShift>(first, last, bin_cache, 0, bin_sizes, shift);
}

//Top-level sorting call
template <class RandomAccessIter>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last) 
{
	//Don't sort if it's too small to optimize
	if(last - first < MIN_SORT_SIZE)
		std::sort(first, last);
	else
		SpreadSort(first, last, *first >> 0, *first);
}

//integer_sort with functors
template <class RandomAccessIter, class RightShift, class Compare>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
						RightShift shift, Compare comp) {
	if(last - first < MIN_SORT_SIZE)
		std::sort(first, last, comp);
	else
		SpreadSort(first, last, shift(*first, 0), *first, shift, comp);
}

//integer_sort with RightShift functor
template <class RandomAccessIter, class RightShift>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
						RightShift shift) {
	if(last - first < MIN_SORT_SIZE)
		std::sort(first, last);
	else
		SpreadSort(first, last, shift(*first, 0), *first, shift);
}

//------------------------------------------------------float_sort code
template <class RandomAccessIter, class div_type, class RightShift>
inline void 
FindExtremes(RandomAccessIter current, RandomAccessIter last, div_type & max, div_type & min, RightShift shift)
{
	min = max = shift(*current, 0);
	while(++current < last) {
		div_type value = shift(*current, 0);
		if(max < value)
			max = value;
		else if(value < min)
			min = value;
	}
}

//Sorting Negative Floats
//Note that bins are iterated in reverse order because max_neg_float = min_neg_int
template <class RandomAccessIter, class div_type, class data_type, class RightShift>
inline void 
NegativeFloatSortRec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, size_t cache_offset
			  , std::vector<size_t> &bin_sizes, RightShift shift)
{
	div_type max, min;
	FindExtremes(first, last, max, min, shift);
	if(max == min)
		return;
	size_t u;
	int log_divisor;
	RandomAccessIter * target_bin;
	unsigned count = last - first;
	unsigned log_range = RoughLog2Size((size_t)(max) - min);
	if((log_divisor = log_range - RoughLog2Size(count)) <= 0 && log_range < MAX_SPLITS)
		log_divisor = 0;
	else {
		log_divisor += LOG_MEAN_BIN_SIZE;
		if(log_divisor < 0)
			log_divisor = 0;
		if((log_range - log_divisor) > MAX_SPLITS)
			log_divisor = log_range - MAX_SPLITS;
	}
	div_type div_min = min >> log_divisor;
	div_type div_max = max >> log_divisor;
	size_t bin_count = div_max - div_min + 1;
	
	//Assure space for the size of each bin, followed by initializing sizes
	if(bin_count > bin_sizes.size())
		bin_sizes.resize(bin_count);
	for(u = 0; u < bin_count; u++)
		bin_sizes[u] = 0;
	size_t cache_end = cache_offset + bin_count;
	if(cache_end > bin_cache.size())
		bin_cache.resize(cache_end);
	RandomAccessIter *bins = &(bin_cache[cache_offset]);
		
	//Calculating the size of each bin
	for (RandomAccessIter current = first; current != last;)
		bin_sizes[shift(*(current++), log_divisor) - div_min]++;
	bins[bin_count - 1] = first;
	for(int ii = bin_count - 2; ii >= 0; --ii)
		bins[ii] = bins[ii + 1] + bin_sizes[ii + 1];
	
	//Swap into place
	RandomAccessIter nextbinstart = first;
	//The last bin will always have the correct elements in it
	for(int ii = bin_count - 1; ii >= 0; --ii) {
		RandomAccessIter * local_bin = bins + ii;
		nextbinstart += bin_sizes[ii];
		for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
			for(target_bin = (bins + (shift(*current, log_divisor) - div_min));  target_bin != local_bin; 
				target_bin = bins + (shift(*current, log_divisor) - div_min)) {
				data_type tmp;
				RandomAccessIter b = (*target_bin)++;
				RandomAccessIter * b_bin = bins + (shift(*b, log_divisor) - div_min);
				if (b_bin != local_bin) {
					RandomAccessIter c = (*b_bin)++;
					tmp = *c;
					*c = *b;
				} 
				else
					tmp = *b;
				*b = *current;
				*current = tmp;
			}
		}
		*local_bin = nextbinstart;
	}
	//Since we don't process the last bin, we need to update its end position
	bin_cache[cache_offset] = last;
	
	if(!log_divisor)
		return;
	
	size_t max_count = GetMaxCount(log_divisor, last - first);
	RandomAccessIter lastPos = first;
	for(int ii = cache_end - 1; ii >= (int)cache_offset; lastPos = bin_cache[ii], --ii) {
		size_t count = bin_cache[ii] - lastPos;
		if(count < 2)
			continue;
		if(count < max_count)
			std::sort(lastPos, bin_cache[ii]);
		else
			NegativeFloatSortRec<RandomAccessIter, div_type, data_type, RightShift>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift);
	}
}

//Functor implementation for recursive sorting
template <class RandomAccessIter, class div_type, class data_type, class RightShift>
inline void 
FloatSortRec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, size_t cache_offset
			  , std::vector<size_t> &bin_sizes, RightShift shift)
{
	div_type max, min;
	FindExtremes(first, last, max, min, shift);
	if(max == min)
		return;
	size_t u;
	int log_divisor;
	RandomAccessIter * target_bin;
	unsigned count = last - first;
	unsigned log_range = RoughLog2Size((size_t)(max) - min);
	if((log_divisor = log_range - RoughLog2Size(count)) <= 0 && log_range < MAX_SPLITS)
		log_divisor = 0;
	else {
		log_divisor += LOG_MEAN_BIN_SIZE;
		if(log_divisor < 0)
			log_divisor = 0;
		if((log_range - log_divisor) > MAX_SPLITS)
			log_divisor = log_range - MAX_SPLITS;
	}
	div_type div_min = min >> log_divisor;
	div_type div_max = max >> log_divisor;
	size_t bin_count = div_max - div_min + 1;
	
	//Assure space for the size of each bin, followed by initializing sizes
	if(bin_count > bin_sizes.size())
		bin_sizes.resize(bin_count);
	for(u = 0; u < bin_count; u++)
		bin_sizes[u] = 0;
	size_t cache_end = cache_offset + bin_count;
	if(cache_end > bin_cache.size())
		bin_cache.resize(cache_end);
	RandomAccessIter *bins = &(bin_cache[cache_offset]);
		
	//Calculating the size of each bin
	for (RandomAccessIter current = first; current != last;)
		bin_sizes[shift(*(current++), log_divisor) - div_min]++;
	//The index of the first positive bin
	div_type first_positive = (div_min < 0) ? -div_min : 0;
	//Reversing the order of the negative bins
	//Note that because of the negative/positive ordering direction flip
	//We can not depend upon bin order and positions matching up
	//so bin_sizes must be reused to contain the end of the bin
	if(first_positive > 0) {
		bins[first_positive - 1] = first;
		for(int ii = first_positive - 2; ii >= 0; --ii) {
			bins[ii] = first + bin_sizes[ii + 1];
			bin_sizes[ii] += bin_sizes[ii + 1];
		}
		//Handling positives following negatives
		if((unsigned)first_positive < bin_count) {
			bins[first_positive] = first + bin_sizes[0];
			bin_sizes[first_positive] += bin_sizes[0];
		}
	}
	else
		bins[0] = first;
	for(u = first_positive; u < bin_count - 1; u++) {
		bins[u + 1] = first + bin_sizes[u];
		bin_sizes[u + 1] += bin_sizes[u];
	}
	
	//Swap into place
	RandomAccessIter nextbinstart = first;
	for(unsigned ii = 0; ii < bin_count; ++ii) {
		RandomAccessIter * local_bin = bins + ii;
		nextbinstart = first + bin_sizes[ii];
		for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
			for(target_bin = (bins + (shift(*current, log_divisor) - div_min));  target_bin != local_bin; 
				target_bin = bins + (shift(*current, log_divisor) - div_min)) {
				data_type tmp;
				RandomAccessIter b = (*target_bin)++;
				RandomAccessIter * b_bin = bins + (shift(*b, log_divisor) - div_min);
				if (b_bin != local_bin) {
					RandomAccessIter c = (*b_bin)++;
					tmp = *c;
					*c = *b;
				} 
				else
					tmp = *b;
				*b = *current;
				*current = tmp;
			}
		}
		*local_bin = nextbinstart;
	}
	
	if(!log_divisor)
		return;
	
	//Handling negative values first
	size_t max_count = GetMaxCount(log_divisor, last - first);
	RandomAccessIter lastPos = first;
	for(int ii = cache_offset + first_positive - 1; ii >= (int)cache_offset ; lastPos = bin_cache[ii--]) {
		size_t count = bin_cache[ii] - lastPos;
		if(count < 2)
			continue;
		if(count < max_count)
			std::sort(lastPos, bin_cache[ii]);
		//sort negative values using reversed-bin Spreadsort
		else
			NegativeFloatSortRec<RandomAccessIter, div_type, data_type, RightShift>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift);
	}
	
	//Note: we don't bother sorting the last_bin, which is nans
	for(size_t u = cache_offset + first_positive; u < cache_end; lastPos = bin_cache[u], ++u) {
		size_t count = bin_cache[u] - lastPos;
		if(count < 2)
			continue;
		if(count < max_count)
			std::sort(lastPos, bin_cache[u]);
		//sort positive values using normal Spreadsort
		else
			SpreadSortRec<RandomAccessIter, div_type, data_type, RightShift>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes, shift);
	}
}

template <class RandomAccessIter, class div_type, class data_type, class RightShift>
inline void 
FloatSort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, RightShift shift)
{
	std::vector<size_t> bin_sizes;
	std::vector<RandomAccessIter> bin_cache;
	FloatSortRec<RandomAccessIter, div_type, data_type, RightShift>(first, last, bin_cache, 0, bin_sizes, shift);
}

//integer_sort with functors
template <class RandomAccessIter, class RightShift>
inline void float_sort(RandomAccessIter first, RandomAccessIter last,
						RightShift shift) {
	if(last - first < MIN_SORT_SIZE)
		std::sort(first, last);
	else
		FloatSort(first, last, shift(*first, 0), *first, shift);
}

#endif