Subversion Repositories Kolibri OS

Rev

Blame | Last modification | View Log | RSS feed

  1. /*
  2.  * copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
  3.  *
  4.  * This file is part of FFmpeg.
  5.  *
  6.  * FFmpeg is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU Lesser General Public
  8.  * License as published by the Free Software Foundation; either
  9.  * version 2.1 of the License, or (at your option) any later version.
  10.  *
  11.  * FFmpeg is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14.  * Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public
  17.  * License along with FFmpeg; if not, write to the Free Software
  18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19.  */
  20.  
  21. #include "common.h"
  22.  
  23.  
  24. /**
  25.  * Quicksort
  26.  * This sort is fast, and fully inplace but not stable and it is possible
  27.  * to construct input that requires O(n^2) time but this is very unlikely to
  28.  * happen with non constructed input.
  29.  */
  30. #define AV_QSORT(p, num, type, cmp) {\
  31.     void *stack[64][2];\
  32.     int sp= 1;\
  33.     stack[0][0] = p;\
  34.     stack[0][1] = (p)+(num)-1;\
  35.     while(sp){\
  36.         type *start= stack[--sp][0];\
  37.         type *end  = stack[  sp][1];\
  38.         while(start < end){\
  39.             if(start < end-1) {\
  40.                 int checksort=0;\
  41.                 type *right = end-2;\
  42.                 type *left  = start+1;\
  43.                 type *mid = start + ((end-start)>>1);\
  44.                 if(cmp(start, end) > 0) {\
  45.                     if(cmp(  end, mid) > 0) FFSWAP(type, *start, *mid);\
  46.                     else                    FFSWAP(type, *start, *end);\
  47.                 }else{\
  48.                     if(cmp(start, mid) > 0) FFSWAP(type, *start, *mid);\
  49.                     else checksort= 1;\
  50.                 }\
  51.                 if(cmp(mid, end) > 0){ \
  52.                     FFSWAP(type, *mid, *end);\
  53.                     checksort=0;\
  54.                 }\
  55.                 if(start == end-2) break;\
  56.                 FFSWAP(type, end[-1], *mid);\
  57.                 while(left <= right){\
  58.                     while(left<=right && cmp(left, end-1) < 0)\
  59.                         left++;\
  60.                     while(left<=right && cmp(right, end-1) > 0)\
  61.                         right--;\
  62.                     if(left <= right){\
  63.                         FFSWAP(type, *left, *right);\
  64.                         left++;\
  65.                         right--;\
  66.                     }\
  67.                 }\
  68.                 FFSWAP(type, end[-1], *left);\
  69.                 if(checksort && (mid == left-1 || mid == left)){\
  70.                     mid= start;\
  71.                     while(mid<end && cmp(mid, mid+1) <= 0)\
  72.                         mid++;\
  73.                     if(mid==end)\
  74.                         break;\
  75.                 }\
  76.                 if(end-left < left-start){\
  77.                     stack[sp  ][0]= start;\
  78.                     stack[sp++][1]= right;\
  79.                     start = left+1;\
  80.                 }else{\
  81.                     stack[sp  ][0]= left+1;\
  82.                     stack[sp++][1]= end;\
  83.                     end = right;\
  84.                 }\
  85.             }else{\
  86.                 if(cmp(start, end) > 0)\
  87.                     FFSWAP(type, *start, *end);\
  88.                 break;\
  89.             }\
  90.         }\
  91.     }\
  92. }
  93.  
  94. /**
  95.  * Merge sort, this sort requires a temporary buffer and is stable, its worst
  96.  * case time is O(n log n)
  97.  * @param p     must be a lvalue pointer, this function may exchange it with tmp
  98.  * @param tmp   must be a lvalue pointer, this function may exchange it with p
  99.  */
  100. #define AV_MSORT(p, tmp, num, type, cmp) {\
  101.     unsigned i, j, step;\
  102.     for(step=1; step<(num); step+=step){\
  103.         for(i=0; i<(num); i+=2*step){\
  104.             unsigned a[2] = {i, i+step};\
  105.             unsigned end = FFMIN(i+2*step, (num));\
  106.             for(j=i; a[0]<i+step && a[1]<end; j++){\
  107.                 int idx= cmp(p+a[0], p+a[1]) > 0;\
  108.                 tmp[j] = p[ a[idx]++ ];\
  109.             }\
  110.             if(a[0]>=i+step) a[0] = a[1];\
  111.             for(; j<end; j++){\
  112.                 tmp[j] = p[ a[0]++ ];\
  113.             }\
  114.         }\
  115.         FFSWAP(type*, p, tmp);\
  116.     }\
  117. }
  118.