sxt: sxtrdb_cmp() added;

include/sxt/rdb.h

@@ -145,6 +145,9 @@ void sxtrdb_exflags(sxtrdb_t *, int);
 /* reset all the flags */
 #define sxtrdb_flagsreset(a) sxtrdb_exflags((a), 0)
 
+/* compare buffers, returns 0 if equal */
+int sxtrdb_cmp(sxtrdb_t *, sxtrdb_t *);
+
 /* let the buffer to use actually used bytes, not all allocated space
  * will return SXT_SUCCESS on success (or in case if it doesn't required),
  * SXT_ENOMEM or other error if fails

sxt/rdb.c

@@ -692,6 +692,22 @@ int sxtrdb_setlength(sxtrdb_t *b, uint32_t s)
   return SXT_SUCCESS;
 }
 
+/* compare buffers, returns 0 if equal */
+int sxtrdb_cmp(sxtrdb_t *b1, sxtrdb_t *b2)
+{
+  int c = 0;
+
+  if(!b1 | !b2) return -1;
+
+  if((c = sxtrdb_length(b1) - sxtrdb_length(b2)) != 0) return c;
+  else c = memcmp((const void *)sxtrdb_rdata(b1),
+                  (const void *)sxtrdb_rdata(b2),
+                  sxtrdb_length(b1));
+
+  return c;
+}
+
+
 /* let the buffer to use actually used bytes, not all allocated space
  * will return SXT_SUCCESS on success (or in case if it doesn't required),
  * SXT_ENOMEM or other error if fails