mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
117 lines
4.1 KiB
117 lines
4.1 KiB
/* |
|
* 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 |
|
*/ |
|
|
|
#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) {\ |
|
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;\ |
|
}\ |
|
}\ |
|
}\ |
|
} |
|
|
|
/** |
|
* 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) {\ |
|
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);\ |
|
}\ |
|
}
|
|
|