--- libeio/eio.c 2009/06/12 20:01:42 1.38 +++ libeio/eio.c 2009/06/14 20:36:59 1.41 @@ -995,52 +995,59 @@ static signed char eio_dent_cmp (const eio_dirent *a, const eio_dirent *b) { - return b->score - a->score ? b->score - a->score /* works because our signed char is always 0..100 */ - : a->inode < b->inode ? -1 : a->inode > b->inode ? 1 : 0; + return b->score - a->score ? b->score - a->score /* works because our signed char is always 0..100 */ + : a->inode < b->inode ? -1 : a->inode > b->inode ? 1 : 0; } -#define EIO_QSORT_CUTOFF 20 /* quite high, but performs well on many filesystems */ +#define EIO_DENT_CMP(i,op,j) eio_dent_cmp (&i, &j) op 0 +#define EIO_DENT_NUM_SCORES 9 + +#define EIO_QSORT_CUTOFF 30 /* quite high, but performs well on many filesystems */ +#define EIO_QSORT_SKIP 60 /* when to skip qsort completely */ static void eio_dent_sort (eio_dirent *dents, int size) { - int i, j; + if (size <= 1) + return; /* our insertion sort relies on size > 0 */ - if (size > EIO_QSORT_CUTOFF * 3) /* skip quicksort for small directories */ + if (size > EIO_QSORT_SKIP) /* skip quicksort for small directories */ { /* first, use quicksort */ /* should be good for 2**31 entries */ - struct rng { int l, r; } rng [32]; + int i; + struct rng { eio_dirent *l, *r; } rng [32]; i = 0; - rng[0].l = 0; - rng[0].r = size; + rng[0].l = dents; + rng[0].r = dents + size; while (expect_true (i >= 0)) { - int L = rng [i].l; - int R = rng [i].r - 1; + eio_dirent *L = rng [i].l; + eio_dirent *R = rng [i].r - 1; if (expect_false (L + EIO_QSORT_CUTOFF < R)) { - eio_dirent piv = dents [L]; + eio_dirent *mid = &dents [((L - dents) + (R - dents)) >> 1]; + eio_dirent piv = *mid; *mid = *L; *L = piv; while (L < R) { - while (eio_dent_cmp (&dents [R], &piv) >= 0 && L < R) + while (EIO_DENT_CMP (*R, >=, piv) && L < R) --R; if (L < R) - dents [L++] = dents [R]; + *L++ = *R; - while (eio_dent_cmp (&dents [L], &piv) <= 0 && L < R) + while (EIO_DENT_CMP (*L, <=, piv) && L < R) ++L; if (L < R) - dents [R--] = dents [L]; + *R-- = *L; } - dents [L] = piv; + *L = piv; ++i; rng [i].l = L + 1; @@ -1059,16 +1066,36 @@ } } - /* use a simple insertion sort at the end */ - for (i = 1; i < size; ++i) + /* use an insertion sort after qsort, or for small arrays */ + /* first move the smallest element to the front, to act as a sentinel */ + { + int i; + eio_dirent *min = dents; + + for (i = size > EIO_QSORT_SKIP ? EIO_QSORT_CUTOFF + 1 : size; --i; ) + if (EIO_DENT_CMP (dents [i], <, *min)) + min = &dents [i]; + + /* swap elements 0 and j (minimum) */ { - eio_dirent value = dents [i]; + eio_dirent tmp = *dents; *dents = *min; *min = tmp; + } + } - for (j = i - 1; j >= 0 && eio_dent_cmp (&dents [j], &value) > 0; --j) - dents [j + 1] = dents [j]; + { + /* then do standard insertion sort */ + eio_dirent *i, *j; - dents [j + 1] = value; - } + for (i = dents + 1; i < dents + size; ++i) + { + eio_dirent value = *i; + + for (j = i - 1; EIO_DENT_CMP (*j, >, value); --j) + j [1] = j [0]; + + j [1] = value; + } + } } /* read a full directory */ @@ -1135,7 +1162,10 @@ while (ent > dir) { if (dir->type == DT_DIR) - ++dir; + { + dir->score = 0; + ++dir; + } else { --ent; @@ -1146,6 +1176,7 @@ *dir = *ent; *ent = tmp; + dir->score = 0; ++dir; } } @@ -1208,7 +1239,7 @@ ent->name = (char *)(size_t)namesoffs; /* rather dirtily we store the offset in the pointer */ ent->namelen = len - 1; - ent->inode = D_INO (entp); + ent->inode = D_INO (entp) ? D_INO (entp) : dentoffs; switch (D_TYPE (entp)) { @@ -1268,12 +1299,12 @@ if (ent->type == EIO_DT_UNKNOWN) { if (*name == '.') /* leading dots are likely directories, and, in any case, rare */ - ent->score = 98; + ent->score = 7; else if (!strchr (name, '.')) /* absense of dots indicate likely dirs */ - ent->score = len <= 2 ? len + 6 : len <= 4 ? 5 : len <= 7 ? 4 : 1; /* shorter == more likely dir, but avoid too many classes */ + ent->score = len <= 2 ? len + 4 : len <= 4 ? 3 : len <= 7 ? 2 : 1; /* shorter == more likely dir, but avoid too many classes */ } else if (ent->type == EIO_DT_DIR) - ent->score = 100; + ent->score = 8; } }