| 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); |