| /* |
| * 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 "macros.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 */ |
