12 void merge_count(void* userdata,
13 const uint8_t *key, size_t len_key,
14 const uint8_t *val0, size_t len_val0,
15 const uint8_t *val1, size_t len_val1,
16 uint8_t **merged_val, size_t *len_merged_val)
18 assert(len_val0 == sizeof(Count));
19 assert(len_val1 == sizeof(Count));
21 const Count* c0 = reinterpret_cast<const Count*>(val0);
22 const Count* c1 = reinterpret_cast<const Count*>(val1);
23 unique_ptr<Count> c((Count *)malloc(sizeof(Count))); // Needs to be with malloc, per merger spec.
25 c->white = c0->white + c1->white;
26 c->draw = c0->draw + c1->draw;
27 c->black = c0->black + c1->black;
28 c->opening_num = c0->opening_num; // Arbitrary choice.
29 c->sum_white_elo = c0->sum_white_elo + c1->sum_white_elo;
30 c->sum_black_elo = c0->sum_black_elo + c1->sum_black_elo;
31 c->num_elo = c0->num_elo + c1->num_elo;
33 *merged_val = reinterpret_cast<uint8_t *>(c.release());
34 *len_merged_val = sizeof(Count);
37 int main(int argc, char **argv)
39 mtbl_merger_options* mopt = mtbl_merger_options_init();
40 mtbl_merger_options_set_merge_func(mopt, merge_count, NULL);
41 mtbl_merger* merger = mtbl_merger_init(mopt);
43 for (int i = 1; i < argc - 1; ++i) {
44 mtbl_reader* mtbl = mtbl_reader_init(argv[i], NULL);
45 mtbl_merger_add_source(merger, mtbl_reader_source(mtbl));
48 mtbl_writer* writer = mtbl_writer_init(argv[argc - 1], NULL);
49 mtbl_source_write(mtbl_merger_source(merger), writer);
50 mtbl_writer_destroy(&writer);