70322ae3 |
1 | /* |
2 | * index.h: Manage indexes for agedu. |
3 | */ |
4 | |
5 | #include <sys/types.h> |
6 | |
7 | /* |
8 | * Given the size of an existing data file and the number of |
9 | * entries required in the index, calculate and return an upper |
10 | * bound on the required size of the index file after an index has |
11 | * been written on to the end of it. |
12 | */ |
13 | off_t index_compute_size(off_t currentsize, int nodecount); |
14 | |
15 | /* |
16 | * Build an index, given the address of a memory-mapped data file |
17 | * and the starting offset within it. |
18 | * |
19 | * trie_file structures passed to tf must of course be within the |
20 | * bounds of the memory-mapped file. |
21 | * |
22 | * indexbuild_realsize returns the total amount of data _actually_ |
23 | * written into the file, to allow it to be truncated afterwards. |
24 | */ |
25 | typedef struct indexbuild indexbuild; |
26 | indexbuild *indexbuild_new(void *t, off_t startoff, int nodecount); |
27 | void indexbuild_add(indexbuild *ib, const struct trie_file *tf); |
28 | off_t indexbuild_realsize(indexbuild *ib); |
29 | void indexbuild_free(indexbuild *ib); |
30 | |
31 | /* |
32 | * Query an index to find the total size of records with name |
33 | * index strictly less than n, with atime less than at. |
34 | */ |
35 | unsigned long long index_query(const void *t, int n, unsigned long long at); |
36 | |
37 | /* |
38 | * Retrieve an order statistic from the index: given a fraction f, |
39 | * return an atime such that (at most) the requested fraction of |
40 | * the total data is older than it. |
41 | */ |
42 | unsigned long long index_order_stat(const void *t, double f); |