feat(lsm): add entry data reading

lsm/example/test.c

@@ -1,5 +1,46 @@
+#include <assert.h>
 #include <stdio.h>
 
 #include "lsm.h"
+#include "lsm/store.h"
+#include "lsm/str.h"
 
-int main() { printf("yuh"); }
+int main() {
+  lsm_str *db_path, *data_dir;
+  lsm_str_init_copy(&db_path, "data/data.db");
+  lsm_str_init_copy(&data_dir, "data");
+
+  lsm_store *store;
+  lsm_store_load(&store, db_path, data_dir);
+
+  lsm_str *key;
+  lsm_str_init_copy(&key, "key");
+
+  lsm_entry_handle *handle;
+  assert(lsm_store_insert(&handle, store, key) == lsm_error_ok);
+
+  lsm_str *data;
+  lsm_str_init_copy(&data, "hello");
+
+  for (int i = 0; i < 50; i++) {
+    lsm_entry_data_append(store, handle, data);
+  }
+
+  lsm_entry_close(handle);
+
+  assert(lsm_store_open_read(&handle, store, key) == lsm_error_ok);
+
+  char buf[24];
+  uint64_t read;
+  uint64_t total = 0;
+
+  lsm_entry_data_read(&read, buf, handle, 24);
+  total += read;
+
+  while (read > 0) {
+    printf("%.*s", read, buf);
+    lsm_entry_data_read(&read, buf, handle, 24);
+    total += read;
+  }
+  printf("\n%lu", total);
+}