| … | |
… | |
| 993 | } |
993 | } |
| 994 | |
994 | |
| 995 | static signed char |
995 | static signed char |
| 996 | eio_dent_cmp (const eio_dirent *a, const eio_dirent *b) |
996 | eio_dent_cmp (const eio_dirent *a, const eio_dirent *b) |
| 997 | { |
997 | { |
| 998 | return b->score - a->score ? b->score - a->score /* works because our signed char is always 0..100 */ |
998 | return b->score - a->score ? b->score - a->score /* works because our signed char is always 0..100 */ |
| 999 | : a->inode < b->inode ? -1 : a->inode > b->inode ? 1 : 0; |
999 | : a->inode < b->inode ? -1 : a->inode > b->inode ? 1 : 0; |
| 1000 | } |
1000 | } |
| 1001 | |
1001 | |
|
|
1002 | #define EIO_DENT_CMP(i,op,j) eio_dent_cmp (&i, &j) op 0 |
|
|
1003 | |
| 1002 | #define EIO_QSORT_CUTOFF 20 /* quite high, but performs well on many filesystems */ |
1004 | #define EIO_QSORT_CUTOFF 30 /* quite high, but performs well on many filesystems */ |
|
|
1005 | #define EIO_QSORT_SKIP 60 /* when to skip qsort completely */ |
| 1003 | |
1006 | |
| 1004 | static void |
1007 | static void |
| 1005 | eio_dent_sort (eio_dirent *dents, int size) |
1008 | eio_dent_sort (eio_dirent *dents, int size) |
| 1006 | { |
1009 | { |
| 1007 | int i, j; |
1010 | int i, j; |
| 1008 | |
1011 | |
|
|
1012 | if (size <= 1) |
|
|
1013 | return; /* our insertion sort relies on size > 0 */ |
|
|
1014 | |
| 1009 | if (size > EIO_QSORT_CUTOFF * 3) /* skip quicksort for small directories */ |
1015 | if (size > EIO_QSORT_SKIP) /* skip quicksort for small directories */ |
| 1010 | { |
1016 | { |
| 1011 | /* first, use quicksort */ |
1017 | /* first, use quicksort */ |
| 1012 | /* should be good for 2**31 entries */ |
1018 | /* should be good for 2**31 entries */ |
| 1013 | struct rng { int l, r; } rng [32]; |
1019 | struct rng { int l, r; } rng [32]; |
| 1014 | |
1020 | |
| … | |
… | |
| 1025 | { |
1031 | { |
| 1026 | eio_dirent piv = dents [L]; |
1032 | eio_dirent piv = dents [L]; |
| 1027 | |
1033 | |
| 1028 | while (L < R) |
1034 | while (L < R) |
| 1029 | { |
1035 | { |
| 1030 | while (eio_dent_cmp (&dents [R], &piv) >= 0 && L < R) |
1036 | while (EIO_DENT_CMP (dents [R], >=, piv) && L < R) |
| 1031 | --R; |
1037 | --R; |
| 1032 | |
1038 | |
| 1033 | if (L < R) |
1039 | if (L < R) |
| 1034 | dents [L++] = dents [R]; |
1040 | dents [L++] = dents [R]; |
| 1035 | |
1041 | |
| 1036 | while (eio_dent_cmp (&dents [L], &piv) <= 0 && L < R) |
1042 | while (EIO_DENT_CMP (dents [L], <=, piv) && L < R) |
| 1037 | ++L; |
1043 | ++L; |
| 1038 | |
1044 | |
| 1039 | if (L < R) |
1045 | if (L < R) |
| 1040 | dents [R--] = dents [L]; |
1046 | dents [R--] = dents [L]; |
| 1041 | } |
1047 | } |
| … | |
… | |
| 1057 | else |
1063 | else |
| 1058 | --i; |
1064 | --i; |
| 1059 | } |
1065 | } |
| 1060 | } |
1066 | } |
| 1061 | |
1067 | |
| 1062 | /* use a simple insertion sort at the end */ |
1068 | /* use an insertion sort after qsort, or for small arrays */ |
|
|
1069 | /* first move the smallest element to the front, to act as a sentinel */ |
|
|
1070 | { |
|
|
1071 | int min = 0; |
|
|
1072 | |
|
|
1073 | for (i = size > EIO_QSORT_SKIP ? EIO_QSORT_CUTOFF : size; --i; ) |
|
|
1074 | if (EIO_DENT_CMP (dents [i], <, dents [min])) |
|
|
1075 | min = i; |
|
|
1076 | |
|
|
1077 | /* swap elements 0 and j (minimum) */ |
|
|
1078 | { |
|
|
1079 | eio_dirent tmp = dents [0]; dents [0] = dents [min]; dents [min] = tmp; |
|
|
1080 | } |
|
|
1081 | } |
|
|
1082 | |
|
|
1083 | /* then do standard insertion sort */ |
| 1063 | for (i = 1; i < size; ++i) |
1084 | for (i = 1; i < size; ++i) |
| 1064 | { |
1085 | { |
| 1065 | eio_dirent value = dents [i]; |
1086 | eio_dirent value = dents [i]; |
| 1066 | |
1087 | |
| 1067 | for (j = i - 1; j >= 0 && eio_dent_cmp (&dents [j], &value) > 0; --j) |
1088 | for (j = i - 1; EIO_DENT_CMP (dents [j], >, value); --j) |
| 1068 | dents [j + 1] = dents [j]; |
1089 | dents [j + 1] = dents [j]; |
| 1069 | |
1090 | |
| 1070 | dents [j + 1] = value; |
1091 | dents [j + 1] = value; |
| 1071 | } |
1092 | } |
| 1072 | } |
1093 | } |
