* sampler.c : improved usage

src/sampler.c

@@ -3,22 +3,44 @@
 #include "bitmap.h"
 #include "sample.h"
 
+void usage() {
+  puts("Usage: imdb-sample <db path> <id> <sample path>");
+  exit(EXIT_FAILURE);
+}
+
 int main(int argc, char **argv)
 {
+  imdb_t  db;
   imdb_rec_t rec;
 
-  if (argc < 2) {
-    puts("Usage: sampler-test <file>");
-    exit(EXIT_FAILURE);
+  memset(&db,  0x0, sizeof(imdb_t));
+  memset(&rec, 0x0, sizeof(imdb_rec_t));
+
+  if (argc < 4)
+    usage();
+
+  rec.num = strtoll(argv[2], NULL, 10);
+  if (errno != 0) {
+    puts("arg 1 not a number");
+    usage();
   }
 
-  memset(&rec, 0x0, sizeof(imdb_rec_t));
+  if (imdb_open(&db, argv[1]) != 0) {
+    puts(db.errstr);
+    usage();
+  }
 
-  if (imdb_sample(&rec, argv[1]) != 0) {
+  if (imdb_sample(&rec, argv[3]) != 0) {
     puts("sampler failure");
-    exit(EXIT_FAILURE);
+    usage();
+  }
+
+  if(imdb_write_rec(&db, &rec) < 1) {
+    puts(db.errstr);
+    usage();
   }
 
+  imdb_close(&db);
   bitmap_print(&rec.data[REC_OFF_BM]);
 
   exit(EXIT_SUCCESS);