X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fvalue.h;h=046a9a3aa638a5e69b77bbecca8f8447e30d820b;hb=43513ffd3bd31a0a26c007715a87f846a579afaa;hp=90f8575356a24a873a0dbf4f9df41d60d8fca1ce;hpb=18021ef879fa68dbec546155311d6676653cf7c3;p=pspp-builds.git

diff --git a/src/data/value.h b/src/data/value.h
index 90f85753..046a9a3a 100644
--- a/src/data/value.h
+++ b/src/data/value.h
@@ -23,6 +23,11 @@
 #include <string.h>
 #include "xalloc.h"
 
+/* Maximum length of a "short" string, that is represented in
+   "union value" without a separate pointer.
+
+   This is an implementation detail of the "union value" code.
+   There is little reason for client code to use it. */
 #define MAX_SHORT_STRING 8
 
 /* A numeric or string value.
@@ -73,6 +78,8 @@ bool value_is_resizable (const union value *, int old_width, int new_width);
 bool value_needs_resize (int old_width, int new_width);
 void value_resize (union value *, int old_width, int new_width);
 
+static inline void value_swap (union value *, union value *);
+
 struct pool;
 void value_init_pool (struct pool *, union value *, int width);
 void value_resize_pool (struct pool *, union value *,
@@ -175,4 +182,13 @@ value_copy (union value *dst, const union value *src, int width)
     memcpy (dst->long_string, src->long_string, width);
 }
 
+/* Exchanges the contents of A and B. */
+static inline void
+value_swap (union value *a, union value *b)
+{
+  union value tmp = *a;
+  *a = *b;
+  *b = tmp;
+}
+
 #endif /* data/value.h */