Merge commit 'origin/data-encoding'

[pspp-builds.git] / src / data / value.h

diff --git a/src/data/value.h b/src/data/value.h
index 8f1746337ea37ceaefa3523fa73ff0c2666b63f8..f9782e2d867d47028f134c4b406dbfd53313d68c 100644 (file)
--- a/src/data/value.h
+++ b/src/data/value.h
@@ -20,11 +20,16 @@
 #include <assert.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 #include "xalloc.h"
 \f
+/* 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
-#define MIN_LONG_STRING (MAX_SHORT_STRING + 1)
 
 /* A numeric or string value.
 
@@ -41,8 +46,8 @@
 union value
   {
     double f;
-    char short_string[MAX_SHORT_STRING];
-    char *long_string;
+    uint8_t short_string[MAX_SHORT_STRING];
+    uint8_t *long_string;
   };
 
 static inline void value_init (union value *, int width);
@@ -51,29 +56,28 @@ static inline bool value_try_init (union value *, int width);
 static inline void value_destroy (union value *, int width);
 
 static inline double value_num (const union value *);
-static inline const char *value_str (const union value *, int width);
-static inline char *value_str_rw (union value *, int width);
-
-int compare_values (const void *, const void *, const void *var);
-unsigned hash_value (const void *, const void *var);
+static inline const uint8_t *value_str (const union value *, int width);
+static inline uint8_t *value_str_rw (union value *, int width);
 
 static inline void value_copy (union value *, const union value *, int width);
 void value_copy_rpad (union value *, int dst_width,
                       const union value *, int src_width,
                       char pad);
-void value_copy_str_rpad (union value *, int dst_width, const char *,
+void value_copy_str_rpad (union value *, int dst_width, const uint8_t *,
                           char pad);
 void value_copy_buf_rpad (union value *dst, int dst_width,
-                          const char *src, size_t src_len, char pad);
+                          const uint8_t *src, size_t src_len, char pad);
 void value_set_missing (union value *, int width);
 int value_compare_3way (const union value *, const union value *, int width);
 bool value_equal (const union value *, const union value *, int width);
-size_t value_hash (const union value *, int width, unsigned int basis);
+unsigned int value_hash (const union value *, int width, unsigned int basis);
 
 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 *,
@@ -144,11 +148,11 @@ value_num (const union value *v)
    It is important that WIDTH be the actual value that was passed
    to value_init.  Passing, e.g., a smaller value because only
    that number of bytes will be accessed will not always work. */
-static inline const char *
+static inline const uint8_t *
 value_str (const union value *v, int width)
 {
   assert (width > 0);
-  return (width >= MIN_LONG_STRING ? v->long_string : v->short_string);
+  return (width > MAX_SHORT_STRING ? v->long_string : v->short_string);
 }
 
 /* Returns the string value in V, which must have width WIDTH.
@@ -158,11 +162,11 @@ value_str (const union value *v, int width)
    It is important that WIDTH be the actual value that was passed
    to value_init.  Passing, e.g., a smaller value because only
    that number of bytes will be accessed will not always work. */
-static inline char *
+static inline uint8_t *
 value_str_rw (union value *v, int width)
 {
   assert (width > 0);
-  return (width >= MIN_LONG_STRING ? v->long_string : v->short_string);
+  return (width > MAX_SHORT_STRING ? v->long_string : v->short_string);
 }
 
 /* Copies SRC to DST, given that they both contain data of the
@@ -176,4 +180,13 @@ 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 */