✨ binsort yeah

A1/id_query_binsort.c

@@ -0,0 +1,71 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <stdint.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#include "record.h"
+#include "id_query.h"
+
+struct index_record {
+    int64_t osm_id;
+    const struct record* record;
+};
+
+struct indexed_data {
+    struct index_record* irs;
+    int n;
+};
+
+int comp_func(const void* a, const void* b) {
+    return (
+        ((struct index_record*)a)->osm_id - ((struct index_record*)b)->osm_id
+    );
+}
+
+struct indexed_data* mk_indexed(struct record* rs, int n) {
+    struct index_record irs[n];
+    for (int i = 0 ; i < n ; i++) {
+        struct record* rec = &rs[i];
+        struct index_record irec = { .osm_id = rec->osm_id, .record = rec };
+        irs[i] = irec;
+    }
+    struct indexed_data* data = malloc(sizeof(struct indexed_data*));
+    qsort(&irs, n, sizeof(struct index_record), comp_func);
+
+    data->irs = irs;
+    data->n = n;
+    return data;
+}
+
+void free_indexed(struct indexed_data* data) {
+    free(data);
+}
+
+const struct record* lookup_indexed(struct indexed_data *data, int64_t needle) {
+    int bottom = 0;
+    int top = data->n;
+    while (top >= bottom) {
+        int mid = bottom + ((top - bottom) / 2);
+        if ((&data->irs[mid])->osm_id < needle) {
+            bottom = mid + 1;
+        }
+        else if ((&data->irs[mid])->osm_id > needle) {
+            top = mid - 1;
+        }
+        else if ((&data->irs[mid])->osm_id == needle) {
+            return (&data->irs[mid])->record;
+        }
+    }
+    return NULL;
+}
+
+int main(int argc, char** argv) {
+    return id_query_loop(argc, argv,
+                                        (mk_index_fn)mk_indexed,
+                                        (free_index_fn)free_indexed,
+                                        (lookup_fn)lookup_indexed);
+}