--- /dev/null
+/*
+ * 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"
+
+
+#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;\
+ }\
+ }\
+ }\
+}