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webrtc/system_wrappers/source/spreadsortlib/spreadsort.hpp

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//Templated spread_sort library
// Copyright Steven J. Ross 2001 - 2009.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// See http://www.boost.org/ for updates, documentation, and revision history.
/*
Some improvements suggested by:
Phil Endecott and Frank Gennari
Cygwin fix provided by:
Scott McMurray
*/
#ifndef BOOST_SPREAD_SORT_H
#define BOOST_SPREAD_SORT_H
#include <algorithm>
#include <vector>
#include "constants.hpp"
#include <cstring>
namespace boost {
namespace detail {
//This only works on unsigned data types
template <typename T>
inline unsigned
rough_log_2_size(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 spread_sort 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
get_max_count(unsigned log_range, size_t count)
{
unsigned divisor = rough_log_2_size(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 (size_t)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 using <
template <class RandomAccessIter>
inline void
find_extremes(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;
}
}
//Uses a user-defined comparison operator to find minimum and maximum
template <class RandomAccessIter, class compare>
inline void
find_extremes(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;
}
}
//Gets a non-negative right bit shift to operate as a logarithmic divisor
inline int
get_log_divisor(size_t count, unsigned log_range)
{
int log_divisor;
//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 - rough_log_2_size(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;
}
return log_divisor;
}
template <class RandomAccessIter>
inline RandomAccessIter *
size_bins(std::vector<size_t> &bin_sizes, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset, unsigned &cache_end, unsigned bin_count)
{
//Assure space for the size of each bin, followed by initializing sizes
if(bin_count > bin_sizes.size())
bin_sizes.resize(bin_count);
for(size_t u = 0; u < bin_count; u++)
bin_sizes[u] = 0;
//Make sure there is space for the bins
cache_end = cache_offset + bin_count;
if(cache_end > bin_cache.size())
bin_cache.resize(cache_end);
return &(bin_cache[cache_offset]);
}
//Implementation for recursive integer sorting
template <class RandomAccessIter, class div_type, class data_type>
inline void
spread_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes)
{
//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;
find_extremes(first, last, max, min);
//max and min will be the same (the first item) iff all values are equivalent
if(max == min)
return;
RandomAccessIter * target_bin;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(*max >> 0) - (*min >> 0)));
div_type div_min = *min >> log_divisor;
div_type div_max = *max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//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(unsigned 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 u = 0; u < bin_count - 1; ++u) {
RandomAccessIter * local_bin = bins + u;
nextbinstart += bin_sizes[u];
//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;
}
bins[bin_count - 1] = last;
//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 = get_max_count(log_divisor, last - first);
RandomAccessIter lastPos = first;
for(unsigned 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
spread_sort_rec<RandomAccessIter, div_type, data_type>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes);
}
}
//Generic bitshift-based 3-way swapping code
template <class RandomAccessIter, class div_type, class data_type, class right_shift>
inline void inner_swap_loop(RandomAccessIter * bins, const RandomAccessIter & nextbinstart, unsigned ii, right_shift &shift
, const unsigned log_divisor, const div_type div_min)
{
RandomAccessIter * local_bin = bins + ii;
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
for(RandomAccessIter * 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);
//Three-way swap; if the item to be swapped doesn't belong in the current bin, swap it to where it belongs
if (b_bin != local_bin) {
RandomAccessIter c = (*b_bin)++;
tmp = *c;
*c = *b;
}
//Note: we could increment current once the swap is done in this case, but that seems to impair performance
else
tmp = *b;
*b = *current;
*current = tmp;
}
}
*local_bin = nextbinstart;
}
//Standard swapping wrapper for ascending values
template <class RandomAccessIter, class div_type, class data_type, class right_shift>
inline void swap_loop(RandomAccessIter * bins, RandomAccessIter & nextbinstart, unsigned ii, right_shift &shift
, const std::vector<size_t> &bin_sizes, const unsigned log_divisor, const div_type div_min)
{
nextbinstart += bin_sizes[ii];
inner_swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, ii, shift, log_divisor, div_min);
}
//Functor implementation for recursive sorting
template <class RandomAccessIter, class div_type, class data_type, class right_shift, class compare>
inline void
spread_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift, compare comp)
{
RandomAccessIter max, min;
find_extremes(first, last, max, min, comp);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(shift(*max, 0)) - (shift(*min, 0))));
div_type div_min = shift(*min, log_divisor);
div_type div_max = shift(*max, log_divisor);
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//Calculating the size of each bin
for (RandomAccessIter current = first; current != last;)
bin_sizes[shift(*(current++), log_divisor) - div_min]++;
bins[0] = first;
for(unsigned u = 0; u < bin_count - 1; u++)
bins[u + 1] = bins[u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = first;
for(unsigned u = 0; u < bin_count - 1; ++u)
swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, u, shift, bin_sizes, log_divisor, div_min);
bins[bin_count - 1] = last;
//If we've bucketsorted, the array is sorted and we should skip recursion
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(log_divisor, last - first);
RandomAccessIter lastPos = first;
for(unsigned 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
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift, 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 right_shift>
inline void
spread_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift)
{
RandomAccessIter max, min;
find_extremes(first, last, max, min);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(shift(*max, 0)) - (shift(*min, 0))));
div_type div_min = shift(*min, log_divisor);
div_type div_max = shift(*max, log_divisor);
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//Calculating the size of each bin
for (RandomAccessIter current = first; current != last;)
bin_sizes[shift(*(current++), log_divisor) - div_min]++;
bins[0] = first;
for(unsigned 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 - 1; ++ii)
swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, ii, shift, bin_sizes, log_divisor, div_min);
bins[bin_count - 1] = last;
//If we've bucketsorted, the array is sorted and we should skip recursion
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(log_divisor, last - first);
RandomAccessIter lastPos = first;
for(unsigned 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
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(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
spread_sort(RandomAccessIter first, RandomAccessIter last, div_type, data_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
spread_sort_rec<RandomAccessIter, div_type, data_type>(first, last, bin_cache, 0, bin_sizes);
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift, class compare>
inline void
spread_sort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, right_shift shift, compare comp)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift, compare>(first, last, bin_cache, 0, bin_sizes, shift, comp);
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift>
inline void
spread_sort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, right_shift shift)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(first, last, bin_cache, 0, bin_sizes, shift);
}
}
//Top-level sorting call for integers
template <class RandomAccessIter>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else
detail::spread_sort(first, last, *first >> 0, *first);
}
//integer_sort with functors
template <class RandomAccessIter, class right_shift, class compare>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
right_shift shift, compare comp) {
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last, comp);
else
detail::spread_sort(first, last, shift(*first, 0), *first, shift, comp);
}
//integer_sort with right_shift functor
template <class RandomAccessIter, class right_shift>
inline void integer_sort(RandomAccessIter first, RandomAccessIter last,
right_shift shift) {
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else
detail::spread_sort(first, last, shift(*first, 0), *first, shift);
}
//------------------------------------------------------ float_sort source --------------------------------------
//Casts a RandomAccessIter to the specified data type
template<class cast_type, class RandomAccessIter>
inline cast_type
cast_float_iter(const RandomAccessIter & floatiter)
{
cast_type result;
std::memcpy(&result, &(*floatiter), sizeof(cast_type));
return result;
}
//Casts a data element to the specified datinner_float_a type
template<class data_type, class cast_type>
inline cast_type
mem_cast(const data_type & data)
{
cast_type result;
std::memcpy(&result, &data, sizeof(cast_type));
return result;
}
namespace detail {
template <class RandomAccessIter, class div_type, class right_shift>
inline void
find_extremes(RandomAccessIter current, RandomAccessIter last, div_type & max, div_type & min, right_shift 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;
}
}
//Specialized swap loops for floating-point casting
template <class RandomAccessIter, class div_type, class data_type>
inline void inner_float_swap_loop(RandomAccessIter * bins, const RandomAccessIter & nextbinstart, unsigned ii
, const unsigned log_divisor, const div_type div_min)
{
RandomAccessIter * local_bin = bins + ii;
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
for(RandomAccessIter * target_bin = (bins + ((cast_float_iter<div_type, RandomAccessIter>(current) >> log_divisor) - div_min)); target_bin != local_bin;
target_bin = bins + ((cast_float_iter<div_type, RandomAccessIter>(current) >> log_divisor) - div_min)) {
data_type tmp;
RandomAccessIter b = (*target_bin)++;
RandomAccessIter * b_bin = bins + ((cast_float_iter<div_type, RandomAccessIter>(b) >> log_divisor) - div_min);
//Three-way swap; if the item to be swapped doesn't belong in the current bin, swap it to where it belongs
if (b_bin != local_bin) {
RandomAccessIter c = (*b_bin)++;
tmp = *c;
*c = *b;
}
else
tmp = *b;
*b = *current;
*current = tmp;
}
}
*local_bin = nextbinstart;
}
template <class RandomAccessIter, class div_type, class data_type>
inline void float_swap_loop(RandomAccessIter * bins, RandomAccessIter & nextbinstart, unsigned ii
, const std::vector<size_t> &bin_sizes, const unsigned log_divisor, const div_type div_min)
{
nextbinstart += bin_sizes[ii];
inner_float_swap_loop<RandomAccessIter, div_type, data_type>(bins, nextbinstart, ii, log_divisor, div_min);
}
template <class RandomAccessIter, class cast_type>
inline void
find_extremes(RandomAccessIter current, RandomAccessIter last, cast_type & max, cast_type & min)
{
min = max = cast_float_iter<cast_type, RandomAccessIter>(current);
while(++current < last) {
cast_type value = cast_float_iter<cast_type, RandomAccessIter>(current);
if(max < value)
max = value;
else if(value < min)
min = value;
}
}
//Special-case sorting of positive floats with casting instead of a right_shift
template <class RandomAccessIter, class div_type, class data_type>
inline void
positive_float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes)
{
div_type max, min;
find_extremes(first, last, max, min);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//Calculating the size of each bin
for (RandomAccessIter current = first; current != last;)
bin_sizes[(cast_float_iter<div_type, RandomAccessIter>(current++) >> log_divisor) - div_min]++;
bins[0] = first;
for(unsigned u = 0; u < bin_count - 1; u++)
bins[u + 1] = bins[u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = first;
for(unsigned u = 0; u < bin_count - 1; ++u)
float_swap_loop<RandomAccessIter, div_type, data_type>(bins, nextbinstart, u, bin_sizes, log_divisor, div_min);
bins[bin_count - 1] = last;
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(log_divisor, last - first);
RandomAccessIter lastPos = first;
for(unsigned 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
positive_float_sort_rec<RandomAccessIter, div_type, data_type>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes);
}
}
//Sorting negative_ float_s
//Note that bins are iterated in reverse order because max_neg_float = min_neg_int
template <class RandomAccessIter, class div_type, class data_type>
inline void
negative_float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes)
{
div_type max, min;
find_extremes(first, last, max, min);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//Calculating the size of each bin
for (RandomAccessIter current = first; current != last;)
bin_sizes[(cast_float_iter<div_type, RandomAccessIter>(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)
float_swap_loop<RandomAccessIter, div_type, data_type>(bins, nextbinstart, ii, bin_sizes, log_divisor, div_min);
//Since we don't process the last bin, we need to update its end position
bin_cache[cache_offset] = last;
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(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
negative_float_sort_rec<RandomAccessIter, div_type, data_type>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes);
}
}
//Sorting negative_ float_s
//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 right_shift>
inline void
negative_float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift)
{
div_type max, min;
find_extremes(first, last, max, min, shift);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//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)
swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, ii, shift, bin_sizes, log_divisor, div_min);
//Since we don't process the last bin, we need to update its end position
bin_cache[cache_offset] = last;
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(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
negative_float_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift);
}
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift, class compare>
inline void
negative_float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift, compare comp)
{
div_type max, min;
find_extremes(first, last, max, min, shift);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//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)
swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, ii, shift, bin_sizes, log_divisor, div_min);
//Since we don't process the last bin, we need to update its end position
bin_cache[cache_offset] = last;
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Recursing
size_t max_count = get_max_count(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], comp);
else
negative_float_sort_rec<RandomAccessIter, div_type, data_type, right_shift, compare>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift, comp);
}
}
//Casting special-case for floating-point sorting
template <class RandomAccessIter, class div_type, class data_type>
inline void
float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes)
{
div_type max, min;
find_extremes(first, last, max, min);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//Calculating the size of each bin
for (RandomAccessIter current = first; current != last;)
bin_sizes[(cast_float_iter<div_type, RandomAccessIter>(current++) >> log_divisor) - div_min]++;
//The index of the first positive bin
div_type first_positive = (div_min < 0) ? -div_min : 0;
//Resetting if all bins are negative
if(cache_offset + first_positive > cache_end)
first_positive = cache_end - cache_offset;
//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(unsigned 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 u = 0; u < bin_count; ++u) {
nextbinstart = first + bin_sizes[u];
inner_float_swap_loop<RandomAccessIter, div_type, data_type>(bins, nextbinstart, u, log_divisor, div_min);
}
if(!log_divisor)
return;
//Handling negative values first
size_t max_count = get_max_count(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 spread_sort
else
negative_float_sort_rec<RandomAccessIter, div_type, data_type>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes);
}
for(unsigned 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 spread_sort
else
positive_float_sort_rec<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 right_shift>
inline void
float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift)
{
div_type max, min;
find_extremes(first, last, max, min, shift);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//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;
//Resetting if all bins are negative
if(cache_offset + first_positive > cache_end)
first_positive = cache_end - cache_offset;
//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(unsigned 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 u = 0; u < bin_count; ++u) {
nextbinstart = first + bin_sizes[u];
inner_swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, u, shift, log_divisor, div_min);
}
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Handling negative values first
size_t max_count = get_max_count(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 spread_sort
else
negative_float_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift);
}
for(unsigned 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 spread_sort
else
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes, shift);
}
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift, class compare>
inline void
float_sort_rec(RandomAccessIter first, RandomAccessIter last, std::vector<RandomAccessIter> &bin_cache, unsigned cache_offset
, std::vector<size_t> &bin_sizes, right_shift shift, compare comp)
{
div_type max, min;
find_extremes(first, last, max, min, shift);
if(max == min)
return;
unsigned log_divisor = get_log_divisor(last - first, rough_log_2_size((size_t)(max) - min));
div_type div_min = min >> log_divisor;
div_type div_max = max >> log_divisor;
unsigned bin_count = div_max - div_min + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, bin_count);
//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;
//Resetting if all bins are negative
if(cache_offset + first_positive > cache_end)
first_positive = cache_end - cache_offset;
//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(unsigned 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 u = 0; u < bin_count; ++u) {
nextbinstart = first + bin_sizes[u];
inner_swap_loop<RandomAccessIter, div_type, data_type, right_shift>(bins, nextbinstart, u, shift, log_divisor, div_min);
}
//Return if we've completed bucketsorting
if(!log_divisor)
return;
//Handling negative values first
size_t max_count = get_max_count(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 spread_sort
else
negative_float_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(lastPos, bin_cache[ii], bin_cache, cache_end, bin_sizes, shift, comp);
}
for(unsigned 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 spread_sort
else
spread_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(lastPos, bin_cache[u], bin_cache, cache_end, bin_sizes, shift, comp);
}
}
template <class RandomAccessIter, class cast_type, class data_type>
inline void
float_Sort(RandomAccessIter first, RandomAccessIter last, cast_type, data_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
float_sort_rec<RandomAccessIter, cast_type, data_type>(first, last, bin_cache, 0, bin_sizes);
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift>
inline void
float_Sort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, right_shift shift)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
float_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(first, last, bin_cache, 0, bin_sizes, shift);
}
template <class RandomAccessIter, class div_type, class data_type, class right_shift, class compare>
inline void
float_Sort(RandomAccessIter first, RandomAccessIter last, div_type, data_type, right_shift shift, compare comp)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
float_sort_rec<RandomAccessIter, div_type, data_type, right_shift>(first, last, bin_cache, 0, bin_sizes, shift, comp);
}
}
//float_sort with casting
//The cast_type must be equal in size to the data type, and must be a signed integer
template <class RandomAccessIter, class cast_type>
inline void float_sort_cast(RandomAccessIter first, RandomAccessIter last, cast_type cVal)
{
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else
detail::float_Sort(first, last, cVal, *first);
}
//float_sort with casting to an int
//Only use this with IEEE floating-point numbers
template <class RandomAccessIter>
inline void float_sort_cast_to_int(RandomAccessIter first, RandomAccessIter last)
{
int cVal = 0;
float_sort_cast(first, last, cVal);
}
//float_sort with functors
template <class RandomAccessIter, class right_shift>
inline void float_sort(RandomAccessIter first, RandomAccessIter last, right_shift shift)
{
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else
detail::float_Sort(first, last, shift(*first, 0), *first, shift);
}
template <class RandomAccessIter, class right_shift, class compare>
inline void float_sort(RandomAccessIter first, RandomAccessIter last, right_shift shift, compare comp)
{
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last, comp);
else
detail::float_Sort(first, last, shift(*first, 0), *first, shift, comp);
}
//------------------------------------------------- string_sort source ---------------------------------------------
namespace detail {
//Offsetting on identical characters. This function works a character at a time for optimal worst-case performance.
template<class RandomAccessIter>
inline void
update_offset(RandomAccessIter first, RandomAccessIter finish, unsigned &char_offset)
{
unsigned nextOffset = char_offset;
bool done = false;
while(!done) {
RandomAccessIter curr = first;
do {
//ignore empties, but if the nextOffset would exceed the length or not match, exit; we've found the last matching character
if((*curr).size() > char_offset && ((*curr).size() <= (nextOffset + 1) || (*curr)[nextOffset] != (*first)[nextOffset])) {
done = true;
break;
}
} while(++curr != finish);
if(!done)
++nextOffset;
}
char_offset = nextOffset;
}
//Offsetting on identical characters. This function works a character at a time for optimal worst-case performance.
template<class RandomAccessIter, class get_char, class get_length>
inline void
update_offset(RandomAccessIter first, RandomAccessIter finish, unsigned &char_offset, get_char getchar, get_length length)
{
unsigned nextOffset = char_offset;
bool done = false;
while(!done) {
RandomAccessIter curr = first;
do {
//ignore empties, but if the nextOffset would exceed the length or not match, exit; we've found the last matching character
if(length(*curr) > char_offset && (length(*curr) <= (nextOffset + 1) || getchar((*curr), nextOffset) != getchar((*first), nextOffset))) {
done = true;
break;
}
} while(++curr != finish);
if(!done)
++nextOffset;
}
char_offset = nextOffset;
}
//A comparison functor for strings that assumes they are identical up to char_offset
template<class data_type, class unsignedchar_type>
struct offset_lessthan {
offset_lessthan(unsigned char_offset) : fchar_offset(char_offset){}
inline bool operator()(const data_type &x, const data_type &y) const
{
unsigned minSize = std::min(x.size(), y.size());
for(unsigned u = fchar_offset; u < minSize; ++u) {
if(static_cast<unsignedchar_type>(x[u]) < static_cast<unsignedchar_type>(y[u]))
return true;
else if(static_cast<unsignedchar_type>(y[u]) < static_cast<unsignedchar_type>(x[u]))
return false;
}
return x.size() < y.size();
}
unsigned fchar_offset;
};
//A comparison functor for strings that assumes they are identical up to char_offset
template<class data_type, class unsignedchar_type>
struct offset_greaterthan {
offset_greaterthan(unsigned char_offset) : fchar_offset(char_offset){}
inline bool operator()(const data_type &x, const data_type &y) const
{
unsigned minSize = std::min(x.size(), y.size());
for(unsigned u = fchar_offset; u < minSize; ++u) {
if(static_cast<unsignedchar_type>(x[u]) > static_cast<unsignedchar_type>(y[u]))
return true;
else if(static_cast<unsignedchar_type>(y[u]) > static_cast<unsignedchar_type>(x[u]))
return false;
}
return x.size() > y.size();
}
unsigned fchar_offset;
};
//A comparison functor for strings that assumes they are identical up to char_offset
template<class data_type, class get_char, class get_length>
struct offset_char_lessthan {
offset_char_lessthan(unsigned char_offset) : fchar_offset(char_offset){}
inline bool operator()(const data_type &x, const data_type &y) const
{
unsigned minSize = std::min(length(x), length(y));
for(unsigned u = fchar_offset; u < minSize; ++u) {
if(getchar(x, u) < getchar(y, u))
return true;
else if(getchar(y, u) < getchar(x, u))
return false;
}
return length(x) < length(y);
}
unsigned fchar_offset;
get_char getchar;
get_length length;
};
//String sorting recursive implementation
template <class RandomAccessIter, class data_type, class unsignedchar_type>
inline void
string_sort_rec(RandomAccessIter first, RandomAccessIter last, unsigned char_offset, std::vector<RandomAccessIter> &bin_cache
, unsigned cache_offset, std::vector<size_t> &bin_sizes)
{
//This section is not strictly necessary, but makes handling of long identical substrings much faster, with a mild average performance impact.
//Iterate to the end of the empties. If all empty, return
while((*first).size() <= char_offset) {
if(++first == last)
return;
}
RandomAccessIter finish = last - 1;
//Getting the last non-empty
for(;(*finish).size() <= char_offset; --finish) { }
++finish;
//Offsetting on identical characters. This section works a character at a time for optimal worst-case performance.
update_offset(first, finish, char_offset);
const unsigned bin_count = (1 << (sizeof(unsignedchar_type)*8));
//Equal worst-case between radix and comparison-based is when bin_count = n*log(n).
const unsigned max_size = bin_count;
const unsigned membin_count = bin_count + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, membin_count) + 1;
//Calculating the size of each bin; this takes roughly 10% of runtime
for (RandomAccessIter current = first; current != last; ++current) {
if((*current).size() <= char_offset) {
bin_sizes[0]++;
}
else
bin_sizes[static_cast<unsignedchar_type>((*current)[char_offset]) + 1]++;
}
//Assign the bin positions
bin_cache[cache_offset] = first;
for(unsigned u = 0; u < membin_count - 1; u++)
bin_cache[cache_offset + u + 1] = bin_cache[cache_offset + u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = first;
//handling empty bins
RandomAccessIter * local_bin = &(bin_cache[cache_offset]);
nextbinstart += bin_sizes[0];
RandomAccessIter * target_bin;
//Iterating over each element in the bin of empties
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
//empties belong in this bin
while((*current).size() > char_offset) {
target_bin = bins + static_cast<unsignedchar_type>((*current)[char_offset]);
iter_swap(current, (*target_bin)++);
}
}
*local_bin = nextbinstart;
//iterate backwards to find the last bin with elements in it; this saves iterations in multiple loops
unsigned last_bin = bin_count - 1;
for(; last_bin && !bin_sizes[last_bin + 1]; --last_bin) { }
//This dominates runtime, mostly in the swap and bin lookups
for(unsigned u = 0; u < last_bin; ++u) {
local_bin = bins + u;
nextbinstart += bin_sizes[u + 1];
//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 + static_cast<unsignedchar_type>((*current)[char_offset]); target_bin != local_bin;
target_bin = bins + static_cast<unsignedchar_type>((*current)[char_offset]))
iter_swap(current, (*target_bin)++);
}
*local_bin = nextbinstart;
}
bins[last_bin] = last;
//Recursing
RandomAccessIter lastPos = bin_cache[cache_offset];
//Skip this loop for empties
for(unsigned u = cache_offset + 1; u < cache_offset + last_bin + 2; 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_size)
std::sort(lastPos, bin_cache[u], offset_lessthan<data_type, unsignedchar_type>(char_offset + 1));
else
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type>(lastPos, bin_cache[u], char_offset + 1, bin_cache, cache_end, bin_sizes);
}
}
//Sorts strings in reverse order, with empties at the end
template <class RandomAccessIter, class data_type, class unsignedchar_type>
inline void
reverse_string_sort_rec(RandomAccessIter first, RandomAccessIter last, unsigned char_offset, std::vector<RandomAccessIter> &bin_cache
, unsigned cache_offset, std::vector<size_t> &bin_sizes)
{
//This section is not strictly necessary, but makes handling of long identical substrings much faster, with a mild average performance impact.
RandomAccessIter curr = first;
//Iterate to the end of the empties. If all empty, return
while((*curr).size() <= char_offset) {
if(++curr == last)
return;
}
//Getting the last non-empty
while((*(--last)).size() <= char_offset) { }
++last;
//Offsetting on identical characters. This section works a character at a time for optimal worst-case performance.
update_offset(curr, last, char_offset);
RandomAccessIter * target_bin;
const unsigned bin_count = (1 << (sizeof(unsignedchar_type)*8));
//Equal worst-case between radix and comparison-based is when bin_count = n*log(n).
const unsigned max_size = bin_count;
const unsigned membin_count = bin_count + 1;
const unsigned max_bin = bin_count - 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, membin_count);
RandomAccessIter * end_bin = &(bin_cache[cache_offset + max_bin]);
//Calculating the size of each bin; this takes roughly 10% of runtime
for (RandomAccessIter current = first; current != last; ++current) {
if((*current).size() <= char_offset) {
bin_sizes[bin_count]++;
}
else
bin_sizes[max_bin - static_cast<unsignedchar_type>((*current)[char_offset])]++;
}
//Assign the bin positions
bin_cache[cache_offset] = first;
for(unsigned u = 0; u < membin_count - 1; u++)
bin_cache[cache_offset + u + 1] = bin_cache[cache_offset + u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = last;
//handling empty bins
RandomAccessIter * local_bin = &(bin_cache[cache_offset + bin_count]);
RandomAccessIter lastFull = *local_bin;
//Iterating over each element in the bin of empties
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
//empties belong in this bin
while((*current).size() > char_offset) {
target_bin = end_bin - static_cast<unsignedchar_type>((*current)[char_offset]);
iter_swap(current, (*target_bin)++);
}
}
*local_bin = nextbinstart;
nextbinstart = first;
//iterate backwards to find the last bin with elements in it; this saves iterations in multiple loops
unsigned last_bin = max_bin;
for(; last_bin && !bin_sizes[last_bin]; --last_bin) { }
//This dominates runtime, mostly in the swap and bin lookups
for(unsigned u = 0; u < last_bin; ++u) {
local_bin = bins + u;
nextbinstart += bin_sizes[u];
//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 = end_bin - static_cast<unsignedchar_type>((*current)[char_offset]); target_bin != local_bin;
target_bin = end_bin - static_cast<unsignedchar_type>((*current)[char_offset]))
iter_swap(current, (*target_bin)++);
}
*local_bin = nextbinstart;
}
bins[last_bin] = lastFull;
//Recursing
RandomAccessIter lastPos = first;
//Skip this loop for empties
for(unsigned u = cache_offset; u <= cache_offset + last_bin; 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_size)
std::sort(lastPos, bin_cache[u], offset_greaterthan<data_type, unsignedchar_type>(char_offset + 1));
else
reverse_string_sort_rec<RandomAccessIter, data_type, unsignedchar_type>(lastPos, bin_cache[u], char_offset + 1, bin_cache, cache_end, bin_sizes);
}
}
//String sorting recursive implementation
template <class RandomAccessIter, class data_type, class unsignedchar_type, class get_char, class get_length>
inline void
string_sort_rec(RandomAccessIter first, RandomAccessIter last, unsigned char_offset, std::vector<RandomAccessIter> &bin_cache
, unsigned cache_offset, std::vector<size_t> &bin_sizes, get_char getchar, get_length length)
{
//This section is not strictly necessary, but makes handling of long identical substrings much faster, with a mild average performance impact.
//Iterate to the end of the empties. If all empty, return
while(length(*first) <= char_offset) {
if(++first == last)
return;
}
RandomAccessIter finish = last - 1;
//Getting the last non-empty
for(;length(*finish) <= char_offset; --finish) { }
++finish;
update_offset(first, finish, char_offset, getchar, length);
const unsigned bin_count = (1 << (sizeof(unsignedchar_type)*8));
//Equal worst-case between radix and comparison-based is when bin_count = n*log(n).
const unsigned max_size = bin_count;
const unsigned membin_count = bin_count + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, membin_count) + 1;
//Calculating the size of each bin; this takes roughly 10% of runtime
for (RandomAccessIter current = first; current != last; ++current) {
if(length(*current) <= char_offset) {
bin_sizes[0]++;
}
else
bin_sizes[getchar((*current), char_offset) + 1]++;
}
//Assign the bin positions
bin_cache[cache_offset] = first;
for(unsigned u = 0; u < membin_count - 1; u++)
bin_cache[cache_offset + u + 1] = bin_cache[cache_offset + u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = first;
//handling empty bins
RandomAccessIter * local_bin = &(bin_cache[cache_offset]);
nextbinstart += bin_sizes[0];
RandomAccessIter * target_bin;
//Iterating over each element in the bin of empties
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
//empties belong in this bin
while(length(*current) > char_offset) {
target_bin = bins + getchar((*current), char_offset);
iter_swap(current, (*target_bin)++);
}
}
*local_bin = nextbinstart;
//iterate backwards to find the last bin with elements in it; this saves iterations in multiple loops
unsigned last_bin = bin_count - 1;
for(; last_bin && !bin_sizes[last_bin + 1]; --last_bin) { }
//This dominates runtime, mostly in the swap and bin lookups
for(unsigned ii = 0; ii < last_bin; ++ii) {
local_bin = bins + ii;
nextbinstart += bin_sizes[ii + 1];
//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 + getchar((*current), char_offset); target_bin != local_bin;
target_bin = bins + getchar((*current), char_offset))
iter_swap(current, (*target_bin)++);
}
*local_bin = nextbinstart;
}
bins[last_bin] = last;
//Recursing
RandomAccessIter lastPos = bin_cache[cache_offset];
//Skip this loop for empties
for(unsigned u = cache_offset + 1; u < cache_offset + last_bin + 2; 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_size)
std::sort(lastPos, bin_cache[u], offset_char_lessthan<data_type, get_char, get_length>(char_offset + 1));
else
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length>(lastPos, bin_cache[u], char_offset + 1, bin_cache, cache_end, bin_sizes, getchar, length);
}
}
//String sorting recursive implementation
template <class RandomAccessIter, class data_type, class unsignedchar_type, class get_char, class get_length, class compare>
inline void
string_sort_rec(RandomAccessIter first, RandomAccessIter last, unsigned char_offset, std::vector<RandomAccessIter> &bin_cache
, unsigned cache_offset, std::vector<size_t> &bin_sizes, get_char getchar, get_length length, compare comp)
{
//This section is not strictly necessary, but makes handling of long identical substrings much faster, with a mild average performance impact.
//Iterate to the end of the empties. If all empty, return
while(length(*first) <= char_offset) {
if(++first == last)
return;
}
RandomAccessIter finish = last - 1;
//Getting the last non-empty
for(;length(*finish) <= char_offset; --finish) { }
++finish;
update_offset(first, finish, char_offset, getchar, length);
const unsigned bin_count = (1 << (sizeof(unsignedchar_type)*8));
//Equal worst-case between radix and comparison-based is when bin_count = n*log(n).
const unsigned max_size = bin_count;
const unsigned membin_count = bin_count + 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, membin_count) + 1;
//Calculating the size of each bin; this takes roughly 10% of runtime
for (RandomAccessIter current = first; current != last; ++current) {
if(length(*current) <= char_offset) {
bin_sizes[0]++;
}
else
bin_sizes[getchar((*current), char_offset) + 1]++;
}
//Assign the bin positions
bin_cache[cache_offset] = first;
for(unsigned u = 0; u < membin_count - 1; u++)
bin_cache[cache_offset + u + 1] = bin_cache[cache_offset + u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = first;
//handling empty bins
RandomAccessIter * local_bin = &(bin_cache[cache_offset]);
nextbinstart += bin_sizes[0];
RandomAccessIter * target_bin;
//Iterating over each element in the bin of empties
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
//empties belong in this bin
while(length(*current) > char_offset) {
target_bin = bins + getchar((*current), char_offset);
iter_swap(current, (*target_bin)++);
}
}
*local_bin = nextbinstart;
//iterate backwards to find the last bin with elements in it; this saves iterations in multiple loops
unsigned last_bin = bin_count - 1;
for(; last_bin && !bin_sizes[last_bin + 1]; --last_bin) { }
//This dominates runtime, mostly in the swap and bin lookups
for(unsigned u = 0; u < last_bin; ++u) {
local_bin = bins + u;
nextbinstart += bin_sizes[u + 1];
//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 + getchar((*current), char_offset); target_bin != local_bin;
target_bin = bins + getchar((*current), char_offset))
iter_swap(current, (*target_bin)++);
}
*local_bin = nextbinstart;
}
bins[last_bin] = last;
//Recursing
RandomAccessIter lastPos = bin_cache[cache_offset];
//Skip this loop for empties
for(unsigned u = cache_offset + 1; u < cache_offset + last_bin + 2; 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_size)
std::sort(lastPos, bin_cache[u], comp);
else
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length, compare>(lastPos
, bin_cache[u], char_offset + 1, bin_cache, cache_end, bin_sizes, getchar, length, comp);
}
}
//Sorts strings in reverse order, with empties at the end
template <class RandomAccessIter, class data_type, class unsignedchar_type, class get_char, class get_length, class compare>
inline void
reverse_string_sort_rec(RandomAccessIter first, RandomAccessIter last, unsigned char_offset, std::vector<RandomAccessIter> &bin_cache
, unsigned cache_offset, std::vector<size_t> &bin_sizes, get_char getchar, get_length length, compare comp)
{
//This section is not strictly necessary, but makes handling of long identical substrings much faster, with a mild average performance impact.
RandomAccessIter curr = first;
//Iterate to the end of the empties. If all empty, return
while(length(*curr) <= char_offset) {
if(++curr == last)
return;
}
//Getting the last non-empty
while(length(*(--last)) <= char_offset) { }
++last;
//Offsetting on identical characters. This section works a character at a time for optimal worst-case performance.
update_offset(first, last, char_offset, getchar, length);
const unsigned bin_count = (1 << (sizeof(unsignedchar_type)*8));
//Equal worst-case between radix and comparison-based is when bin_count = n*log(n).
const unsigned max_size = bin_count;
const unsigned membin_count = bin_count + 1;
const unsigned max_bin = bin_count - 1;
unsigned cache_end;
RandomAccessIter * bins = size_bins(bin_sizes, bin_cache, cache_offset, cache_end, membin_count);
RandomAccessIter *end_bin = &(bin_cache[cache_offset + max_bin]);
//Calculating the size of each bin; this takes roughly 10% of runtime
for (RandomAccessIter current = first; current != last; ++current) {
if(length(*current) <= char_offset) {
bin_sizes[bin_count]++;
}
else
bin_sizes[max_bin - getchar((*current), char_offset)]++;
}
//Assign the bin positions
bin_cache[cache_offset] = first;
for(unsigned u = 0; u < membin_count - 1; u++)
bin_cache[cache_offset + u + 1] = bin_cache[cache_offset + u] + bin_sizes[u];
//Swap into place
RandomAccessIter nextbinstart = last;
//handling empty bins
RandomAccessIter * local_bin = &(bin_cache[cache_offset + bin_count]);
RandomAccessIter lastFull = *local_bin;
RandomAccessIter * target_bin;
//Iterating over each element in the bin of empties
for(RandomAccessIter current = *local_bin; current < nextbinstart; ++current) {
//empties belong in this bin
while(length(*current) > char_offset) {
target_bin = end_bin - getchar((*current), char_offset);
iter_swap(current, (*target_bin)++);
}
}
*local_bin = nextbinstart;
nextbinstart = first;
//iterate backwards to find the last bin with elements in it; this saves iterations in multiple loops
unsigned last_bin = max_bin;
for(; last_bin && !bin_sizes[last_bin]; --last_bin) { }
//This dominates runtime, mostly in the swap and bin lookups
for(unsigned u = 0; u < last_bin; ++u) {
local_bin = bins + u;
nextbinstart += bin_sizes[u];
//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 = end_bin - getchar((*current), char_offset); target_bin != local_bin;
target_bin = end_bin - getchar((*current), char_offset))
iter_swap(current, (*target_bin)++);
}
*local_bin = nextbinstart;
}
bins[last_bin] = lastFull;
//Recursing
RandomAccessIter lastPos = first;
//Skip this loop for empties
for(unsigned u = cache_offset; u <= cache_offset + last_bin; 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_size)
std::sort(lastPos, bin_cache[u], comp);
else
reverse_string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length, compare>(lastPos
, bin_cache[u], char_offset + 1, bin_cache, cache_end, bin_sizes, getchar, length, comp);
}
}
//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class data_type, class unsignedchar_type>
inline void
string_sort(RandomAccessIter first, RandomAccessIter last, data_type, unsignedchar_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type>(first, last, 0, bin_cache, 0, bin_sizes);
}
//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class data_type, class unsignedchar_type>
inline void
reverse_string_sort(RandomAccessIter first, RandomAccessIter last, data_type, unsignedchar_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
reverse_string_sort_rec<RandomAccessIter, data_type, unsignedchar_type>(first, last, 0, bin_cache, 0, bin_sizes);
}
//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class get_char, class get_length, class data_type, class unsignedchar_type>
inline void
string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length, data_type, unsignedchar_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length>(first, last, 0, bin_cache, 0, bin_sizes, getchar, length);
}
//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class get_char, class get_length, class compare, class data_type, class unsignedchar_type>
inline void
string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length, compare comp, data_type, unsignedchar_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length, compare>(first, last, 0, bin_cache, 0, bin_sizes, getchar, length, comp);
}
//Holds the bin vector and makes the initial recursive call
template <class RandomAccessIter, class get_char, class get_length, class compare, class data_type, class unsignedchar_type>
inline void
reverse_string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length, compare comp, data_type, unsignedchar_type)
{
std::vector<size_t> bin_sizes;
std::vector<RandomAccessIter> bin_cache;
reverse_string_sort_rec<RandomAccessIter, data_type, unsignedchar_type, get_char, get_length, compare>(first, last, 0, bin_cache, 0, bin_sizes, getchar, length, comp);
}
}
//Allows character-type overloads
template <class RandomAccessIter, class unsignedchar_type>
inline void string_sort(RandomAccessIter first, RandomAccessIter last, unsignedchar_type unused)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else
detail::string_sort(first, last, *first, unused);
}
//Top-level sorting call; wraps using default of unsigned char
template <class RandomAccessIter>
inline void string_sort(RandomAccessIter first, RandomAccessIter last)
{
unsigned char unused = '\0';
string_sort(first, last, unused);
}
//Allows character-type overloads
template <class RandomAccessIter, class compare, class unsignedchar_type>
inline void reverse_string_sort(RandomAccessIter first, RandomAccessIter last, compare comp, unsignedchar_type unused)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last, comp);
else
detail::reverse_string_sort(first, last, *first, unused);
}
//Top-level sorting call; wraps using default of unsigned char
template <class RandomAccessIter, class compare>
inline void reverse_string_sort(RandomAccessIter first, RandomAccessIter last, compare comp)
{
unsigned char unused = '\0';
reverse_string_sort(first, last, comp, unused);
}
template <class RandomAccessIter, class get_char, class get_length>
inline void string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last);
else {
//skipping past empties at the beginning, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while(!length(*first)) {
if(++first == last)
return;
}
detail::string_sort(first, last, getchar, length, *first, getchar((*first), 0));
}
}
template <class RandomAccessIter, class get_char, class get_length, class compare>
inline void string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length, compare comp)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last, comp);
else {
//skipping past empties at the beginning, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while(!length(*first)) {
if(++first == last)
return;
}
detail::string_sort(first, last, getchar, length, comp, *first, getchar((*first), 0));
}
}
template <class RandomAccessIter, class get_char, class get_length, class compare>
inline void reverse_string_sort(RandomAccessIter first, RandomAccessIter last, get_char getchar, get_length length, compare comp)
{
//Don't sort if it's too small to optimize
if(last - first < detail::MIN_SORT_SIZE)
std::sort(first, last, comp);
else {
//skipping past empties at the beginning, which allows us to get the character type
//.empty() is not used so as not to require a user declaration of it
while(!length(*(--last))) {
//Note: if there is just one non-empty, and it's at the beginning, then it's already in sorted order
if(first == last)
return;
}
//making last just after the end of the non-empty part of the array
++last;
detail::reverse_string_sort(first, last, getchar, length, comp, *first, getchar((*first), 0));
}
}
}
#endif
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