0,0 → 1,117 |
/* |
* 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);\ |
}\ |
} |