compared to qsort this is slower but its stable and doesnt have a O(n^2) worst case
Unified · Split
| @@ -90,3 +90,28 @@ · 89 unmodified lines | |||
| 90 | }\ | 90 | }\ |
| 91 | }\ | 91 | }\ |
| 92 | } | 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 | } | ||