yading@11: /*
yading@11:  * copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "common.h"
yading@11: 
yading@11: 
yading@11: /**
yading@11:  * Quicksort
yading@11:  * This sort is fast, and fully inplace but not stable and it is possible
yading@11:  * to construct input that requires O(n^2) time but this is very unlikely to
yading@11:  * happen with non constructed input.
yading@11:  */
yading@11: #define AV_QSORT(p, num, type, cmp) {\
yading@11:     void *stack[64][2];\
yading@11:     int sp= 1;\
yading@11:     stack[0][0] = p;\
yading@11:     stack[0][1] = (p)+(num)-1;\
yading@11:     while(sp){\
yading@11:         type *start= stack[--sp][0];\
yading@11:         type *end  = stack[  sp][1];\
yading@11:         while(start < end){\
yading@11:             if(start < end-1) {\
yading@11:                 int checksort=0;\
yading@11:                 type *right = end-2;\
yading@11:                 type *left  = start+1;\
yading@11:                 type *mid = start + ((end-start)>>1);\
yading@11:                 if(cmp(start, end) > 0) {\
yading@11:                     if(cmp(  end, mid) > 0) FFSWAP(type, *start, *mid);\
yading@11:                     else                    FFSWAP(type, *start, *end);\
yading@11:                 }else{\
yading@11:                     if(cmp(start, mid) > 0) FFSWAP(type, *start, *mid);\
yading@11:                     else checksort= 1;\
yading@11:                 }\
yading@11:                 if(cmp(mid, end) > 0){ \
yading@11:                     FFSWAP(type, *mid, *end);\
yading@11:                     checksort=0;\
yading@11:                 }\
yading@11:                 if(start == end-2) break;\
yading@11:                 FFSWAP(type, end[-1], *mid);\
yading@11:                 while(left <= right){\
yading@11:                     while(left<=right && cmp(left, end-1) < 0)\
yading@11:                         left++;\
yading@11:                     while(left<=right && cmp(right, end-1) > 0)\
yading@11:                         right--;\
yading@11:                     if(left <= right){\
yading@11:                         FFSWAP(type, *left, *right);\
yading@11:                         left++;\
yading@11:                         right--;\
yading@11:                     }\
yading@11:                 }\
yading@11:                 FFSWAP(type, end[-1], *left);\
yading@11:                 if(checksort && (mid == left-1 || mid == left)){\
yading@11:                     mid= start;\
yading@11:                     while(mid<end && cmp(mid, mid+1) <= 0)\
yading@11:                         mid++;\
yading@11:                     if(mid==end)\
yading@11:                         break;\
yading@11:                 }\
yading@11:                 if(end-left < left-start){\
yading@11:                     stack[sp  ][0]= start;\
yading@11:                     stack[sp++][1]= right;\
yading@11:                     start = left+1;\
yading@11:                 }else{\
yading@11:                     stack[sp  ][0]= left+1;\
yading@11:                     stack[sp++][1]= end;\
yading@11:                     end = right;\
yading@11:                 }\
yading@11:             }else{\
yading@11:                 if(cmp(start, end) > 0)\
yading@11:                     FFSWAP(type, *start, *end);\
yading@11:                 break;\
yading@11:             }\
yading@11:         }\
yading@11:     }\
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Merge sort, this sort requires a temporary buffer and is stable, its worst
yading@11:  * case time is O(n log n)
yading@11:  * @param p     must be a lvalue pointer, this function may exchange it with tmp
yading@11:  * @param tmp   must be a lvalue pointer, this function may exchange it with p
yading@11:  */
yading@11: #define AV_MSORT(p, tmp, num, type, cmp) {\
yading@11:     unsigned i, j, step;\
yading@11:     for(step=1; step<(num); step+=step){\
yading@11:         for(i=0; i<(num); i+=2*step){\
yading@11:             unsigned a[2] = {i, i+step};\
yading@11:             unsigned end = FFMIN(i+2*step, (num));\
yading@11:             for(j=i; a[0]<i+step && a[1]<end; j++){\
yading@11:                 int idx= cmp(p+a[0], p+a[1]) > 0;\
yading@11:                 tmp[j] = p[ a[idx]++ ];\
yading@11:             }\
yading@11:             if(a[0]>=i+step) a[0] = a[1];\
yading@11:             for(; j<end; j++){\
yading@11:                 tmp[j] = p[ a[0]++ ];\
yading@11:             }\
yading@11:         }\
yading@11:         FFSWAP(type*, p, tmp);\
yading@11:     }\
yading@11: }