+#include <stdio.h>
+#include <mtbl.h>
+#include <memory>
+#include <string>
+#include <string.h>
+#include <assert.h>
+#include "count.h"
+
+using namespace std;
+
+
+void merge_count(void* userdata,
+ const uint8_t *key, size_t len_key,
+ const uint8_t *val0, size_t len_val0,
+ const uint8_t *val1, size_t len_val1,
+ uint8_t **merged_val, size_t *len_merged_val)
+{
+ assert(len_val0 == sizeof(Count));
+ assert(len_val1 == sizeof(Count));
+
+ const Count* c0 = reinterpret_cast<const Count*>(val0);
+ const Count* c1 = reinterpret_cast<const Count*>(val1);
+ unique_ptr<Count> c((Count *)malloc(sizeof(Count))); // Needs to be with malloc, per merger spec.
+
+ c->white = c0->white + c1->white;
+ c->draw = c0->draw + c1->draw;
+ c->black = c0->black + c1->black;
+ c->opening_num = c0->opening_num; // Arbitrary choice.
+ c->sum_white_elo = c0->sum_white_elo + c1->sum_white_elo;
+ c->sum_black_elo = c0->sum_black_elo + c1->sum_black_elo;
+ c->num_elo = c0->num_elo + c1->num_elo;
+
+ *merged_val = reinterpret_cast<uint8_t *>(c.release());
+ *len_merged_val = sizeof(Count);
+}
+
+int main(int argc, char **argv)
+{
+ mtbl_merger_options* mopt = mtbl_merger_options_init();
+ mtbl_merger_options_set_merge_func(mopt, merge_count, NULL);
+ mtbl_merger* merger = mtbl_merger_init(mopt);
+
+ for (int i = 1; i < argc - 1; ++i) {
+ mtbl_reader* mtbl = mtbl_reader_init(argv[i], NULL);
+ mtbl_merger_add_source(merger, mtbl_reader_source(mtbl));
+ }
+
+ mtbl_writer* writer = mtbl_writer_init(argv[argc - 1], NULL);
+ mtbl_source_write(mtbl_merger_source(merger), writer);
+ mtbl_writer_destroy(&writer);
+}