* more error codes

src/database.c

@@ -152,6 +152,10 @@ imdb_error(int error) {
      return "database corrupted";
    } else if (error == IMDB_ERR_WRONGVERS) {
      return "database version differs from library version";
+   } else if (error == IMDB_ERR_READONLY) {
+     return "database opened in read-only mode";
+   } else if (error == IMDB_ERR_NXRECORD) {
+     return "no such record in database";
    }
    return "unknown error";
 }
@@ -167,7 +171,7 @@ int imdb_read_rec(imdb_db_t *db, imdb_rec_t *rec)
   DB_READ(db, rec->data, IMDB_REC_LEN, rec->num * IMDB_REC_LEN);
 
   if (bytes != IMDB_REC_LEN)
-    return errno ? IMDB_ERR_SYSTEM : 0;
+    return errno ? IMDB_ERR_SYSTEM : IMDB_ERR_NXRECORD;
 
   if (rec->data[0] != 0xFF)
     return 0;
@@ -183,6 +187,9 @@ int imdb_write_rec(imdb_db_t *db, imdb_rec_t *rec)
   assert(rec != NULL);
   assert(rec->num > 0);
 
+  if (!(db->flags & IMDB_FLAG_WRITE))
+    return IMDB_ERR_READONLY;
+
   DB_WRITE(db, rec->data, IMDB_REC_LEN, rec->num * IMDB_REC_LEN);
 
   if (bytes != IMDB_REC_LEN)
@@ -259,10 +266,8 @@ imdb_search(imdb_db_t     * const db,
   blk.start = 1;
   blk.records = blk_size;
 
-  if ((ret = imdb_read_rec(db, sample)) < 1) {
-    strncpy(db->error, "Can't read source sample", sizeof(db->error));
+  if ((ret = imdb_read_rec(db, sample)) < 1)
     return ret;
-  }
 
   if (search->limit == 0)
     search->limit = -1; /* unsigned -> max */

src/database.h

@@ -19,6 +19,8 @@
 #define IMDB_ERR_OOM         -2 /* can't allocate memory */
 #define IMDB_ERR_CORRUPTDB   -3 /* empty or currupted database */
 #define IMDB_ERR_WRONGVERS   -4 /* database version mismatch */
+#define IMDB_ERR_NXRECORD    -5 /* no such record in database */
+#define IMDB_ERR_READONLY    -6 /* database opened in read-only mode */
 
 typedef struct {
   int fd;

tests/database.c

@@ -24,13 +24,13 @@ int main()
 
   rec[0].num = 1;
   err = imdb_read_rec(db, rec);
-  assert(err == 0); /* no such record */
+  assert(err == IMDB_ERR_NXRECORD);
 
   memset(rec[0].data, 0xAA, IMDB_REC_LEN);
   memset(rec[0].data, 0xFF, 1); /* record is used */
 
   num = imdb_write_rec(db, rec);
-  assert(num != 1); /* database open in read-only mode */
+  assert(num == IMDB_ERR_READONLY); /* database open in read-only mode */
 
   imdb_close(db);