mirror of
https://github.com/xenia-project/FFmpeg.git
synced 2024-12-05 01:56:41 +00:00
123 lines
4.2 KiB
C
123 lines
4.2 KiB
C
/*
|
|
* copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef AVUTIL_QSORT_H
|
|
#define AVUTIL_QSORT_H
|
|
|
|
#include "common.h"
|
|
|
|
|
|
/**
|
|
* Quicksort
|
|
* This sort is fast, and fully inplace but not stable and it is possible
|
|
* to construct input that requires O(n^2) time but this is very unlikely to
|
|
* happen with non constructed input.
|
|
*/
|
|
#define AV_QSORT(p, num, type, cmp) do {\
|
|
void *stack[64][2];\
|
|
int sp= 1;\
|
|
stack[0][0] = p;\
|
|
stack[0][1] = (p)+(num)-1;\
|
|
while(sp){\
|
|
type *start= stack[--sp][0];\
|
|
type *end = stack[ sp][1];\
|
|
while(start < end){\
|
|
if(start < end-1) {\
|
|
int checksort=0;\
|
|
type *right = end-2;\
|
|
type *left = start+1;\
|
|
type *mid = start + ((end-start)>>1);\
|
|
if(cmp(start, end) > 0) {\
|
|
if(cmp( end, mid) > 0) FFSWAP(type, *start, *mid);\
|
|
else FFSWAP(type, *start, *end);\
|
|
}else{\
|
|
if(cmp(start, mid) > 0) FFSWAP(type, *start, *mid);\
|
|
else checksort= 1;\
|
|
}\
|
|
if(cmp(mid, end) > 0){ \
|
|
FFSWAP(type, *mid, *end);\
|
|
checksort=0;\
|
|
}\
|
|
if(start == end-2) break;\
|
|
FFSWAP(type, end[-1], *mid);\
|
|
while(left <= right){\
|
|
while(left<=right && cmp(left, end-1) < 0)\
|
|
left++;\
|
|
while(left<=right && cmp(right, end-1) > 0)\
|
|
right--;\
|
|
if(left <= right){\
|
|
FFSWAP(type, *left, *right);\
|
|
left++;\
|
|
right--;\
|
|
}\
|
|
}\
|
|
FFSWAP(type, end[-1], *left);\
|
|
if(checksort && (mid == left-1 || mid == left)){\
|
|
mid= start;\
|
|
while(mid<end && cmp(mid, mid+1) <= 0)\
|
|
mid++;\
|
|
if(mid==end)\
|
|
break;\
|
|
}\
|
|
if(end-left < left-start){\
|
|
stack[sp ][0]= start;\
|
|
stack[sp++][1]= right;\
|
|
start = left+1;\
|
|
}else{\
|
|
stack[sp ][0]= left+1;\
|
|
stack[sp++][1]= end;\
|
|
end = right;\
|
|
}\
|
|
}else{\
|
|
if(cmp(start, end) > 0)\
|
|
FFSWAP(type, *start, *end);\
|
|
break;\
|
|
}\
|
|
}\
|
|
}\
|
|
} while (0)
|
|
|
|
/**
|
|
* Merge sort, this sort requires a temporary buffer and is stable, its worst
|
|
* case time is O(n log n)
|
|
* @param p must be a lvalue pointer, this function may exchange it with tmp
|
|
* @param tmp must be a lvalue pointer, this function may exchange it with p
|
|
*/
|
|
#define AV_MSORT(p, tmp, num, type, cmp) do {\
|
|
unsigned i, j, step;\
|
|
for(step=1; step<(num); step+=step){\
|
|
for(i=0; i<(num); i+=2*step){\
|
|
unsigned a[2] = {i, i+step};\
|
|
unsigned end = FFMIN(i+2*step, (num));\
|
|
for(j=i; a[0]<i+step && a[1]<end; j++){\
|
|
int idx= cmp(p+a[0], p+a[1]) > 0;\
|
|
tmp[j] = p[ a[idx]++ ];\
|
|
}\
|
|
if(a[0]>=i+step) a[0] = a[1];\
|
|
for(; j<end; j++){\
|
|
tmp[j] = p[ a[0]++ ];\
|
|
}\
|
|
}\
|
|
FFSWAP(type*, p, tmp);\
|
|
}\
|
|
} while (0)
|
|
|
|
#endif /* AVUTIL_QSORT_H */
|