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Diffstat (limited to 'media/ffvpx/libavutil/qsort.h')
| -rw-r--r-- | media/ffvpx/libavutil/qsort.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/media/ffvpx/libavutil/qsort.h b/media/ffvpx/libavutil/qsort.h new file mode 100644 index 0000000000..6014f88be3 --- /dev/null +++ b/media/ffvpx/libavutil/qsort.h @@ -0,0 +1,122 @@ +/* + * 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 */ |