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rubidium

(svn r17776) -Codechange: [SDL] make "update the video card"-process asynchronious. Profiling with gprof etc. hasn't shown us that DrawSurfaceToScreen takes a significant amount of CPU; only using TIC/TOC it became apparant that it was a heavy CPU-cycle user or that it was waiting for something.
The benefit of making this function asynchronious ranges from 2%-25% (real time) during fast forward on dual core/hyperthreading-enabled CPUs; 8bpp improvements are, in my test cases, significantly smaller than 32bpp improvements.
On single core non-hyperthreading-enabled CPUs the extra locking/scheduling costs up to 1% extra realtime in fast forward. You can use -v sdl:no_threads to disable threading and undo this loss.
During normal non-fast-forwarded games the benefit/costs are negligable except when the gameloop takes more than about 90% of the time of a tick.
Note that allegro's performance does not improve with this system, likely due to their way of getting data to the video card. It is not implemented for the OS X/Windows video backends, unless (ofcourse) SDL is used there.
Funny is that the performance of the 32bpp(-anim) blitter is, at least in some test cases, significantly faster (more than 10%) than the 8bpp(-optimized) blitter when looking at real time in fast forward on a dual core CPU; it was slower.
The idea comes from a paper/report by Idar Borlaug and Knut Imar Hagen.

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD 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 GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file sort_func.hpp Functions related to sorting operations. */

#ifndef SORT_FUNC_HPP
#define SORT_FUNC_HPP

#include <stdlib.h>
#include "math_func.hpp"
#include "mem_func.hpp"

/**
 * Type safe qsort()
 *
 * @note Use this sort for irregular sorted data.
 *
 * @param base Pointer to the first element of the array to be sorted.
 * @param num Number of elements in the array pointed by base.
 * @param comparator Function that compares two elements.
 * @param desc Sort descending.
 */
template <typename T>
static FORCEINLINE void QSortT(T *base, uint num, int (CDECL *comparator)(const T*, const T*), bool desc = false)
{
	if (num < 2) return;

	qsort(base, num, sizeof(T), (int (CDECL *)(const void *, const void *))comparator);

	if (desc) MemReverseT(base, num);
}

/**
 * Type safe Gnome Sort.
 *
 * This is a slightly modifyied Gnome search. The basic
 * Gnome search trys to sort already sorted list parts.
 * The modification skips these.
 *
 * @note Use this sort for presorted / regular sorted data.
 *
 * @param base Pointer to the first element of the array to be sorted.
 * @param num Number of elements in the array pointed by base.
 * @param comparator Function that compares two elements.
 * @param desc Sort descending.
 */
template <typename T>
static inline void GSortT(T *base, uint num, int (CDECL *comparator)(const T*, const T*), bool desc = false)
{
	if (num < 2) return;

	assert(base != NULL);
	assert(comparator != NULL);

	T *a = base;
	T *b = base + 1;
	uint offset = 0;

	while (num > 1) {
		const int diff = comparator(a, b);
		if ((!desc && diff <= 0) || (desc && diff >= 0)) {
			if (offset != 0) {
				/* Jump back to the last direction switch point */
				a += offset;
				b += offset;
				offset = 0;
				continue;
			}

			a++;
			b++;
			num--;
		} else {
			Swap(*a, *b);

			if (a == base) continue;

			a--;
			b--;
			offset++;
		}
	}
}

#endif /* SORT_FUNC_HPP */