/* PSPP - a program for statistical analysis.
- Copyright (C) 1997-9, 2000, 2007 Free Software Foundation, Inc.
+ Copyright (C) 1997-9, 2000, 2007, 2009 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#ifndef DATA_VALUE_H
#define DATA_VALUE_H 1
-#include <libpspp/misc.h>
+#include <assert.h>
#include <stdbool.h>
-#include <stddef.h>
-#include "minmax.h"
-
-/* "Short" strings, which are generally those no more than 8
- characters wide, can participate in more operations than
- longer strings. */
-#define MAX_SHORT_STRING (MAX (ROUND_UP (SIZEOF_DOUBLE, 2), 8))
+#include <stdlib.h>
+#include <string.h>
+#include "xalloc.h"
+\f
+#define MAX_SHORT_STRING 8
#define MIN_LONG_STRING (MAX_SHORT_STRING + 1)
-/* A numeric or short string value.
- Multiple consecutive values represent a long string. */
+/* A numeric or string value.
+
+ The client is responsible for keeping track of the value's
+ width.
+
+ This structure is semi-opaque:
+
+ - If the value is a number, clients may access the 'f'
+ member directly.
+
+ - Clients should not access other members directly.
+*/
union value
{
double f;
- char s[MAX_SHORT_STRING];
+ char short_string[MAX_SHORT_STRING];
+ char *long_string;
};
-union value *value_dup (const union value *, int width);
-union value *value_create (int width);
+static inline void value_init (union value *, int width);
+static inline bool value_needs_init (int width);
+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);
-int compare_values_short (const void *, const void *, const void *var);
-unsigned hash_value_short (const void *, const void *var);
-
-static inline size_t value_cnt_from_width (int width);
-void value_copy (union value *, const 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 *,
+ char pad);
+void value_copy_buf_rpad (union value *dst, int dst_width,
+ const char *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);
+
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);
-int value_compare_3way (const union value *, const union value *, int width);
-/* Number of "union value"s required for a variable of the given
- WIDTH. */
-static inline size_t
-value_cnt_from_width (int width)
+struct pool;
+void value_init_pool (struct pool *, union value *, int width);
+void value_resize_pool (struct pool *, union value *,
+ int old_width, int new_width);
+\f
+/* Initializes V as a value of the given WIDTH, where 0
+ represents a numeric value and a positive integer represents a
+ string value WIDTH bytes long.
+
+ A WIDTH of -1 is ignored.
+
+ The contents of value V are indeterminate after
+ initialization. */
+static inline void
+value_init (union value *v, int width)
+{
+ if (width > MAX_SHORT_STRING)
+ v->long_string = xmalloc (width);
+}
+
+/* Returns true if a value of the given WIDTH actually needs to
+ have the value_init and value_destroy functions called, false
+ if those functions are no-ops for values of the given WIDTH.
+
+ Using this function is only a valuable optimization if a large
+ number of values of the given WIDTH are to be initialized*/
+static inline bool
+value_needs_init (int width)
+{
+ return width > MAX_SHORT_STRING;
+}
+
+/* Same as value_init, except that failure to allocate memory
+ causes it to return false instead of terminating the
+ program. On success, returns true. */
+static inline bool
+value_try_init (union value *v, int width)
+{
+ if (width > MAX_SHORT_STRING)
+ {
+ v->long_string = malloc (width);
+ return v->long_string != NULL;
+ }
+ else
+ return true;
+}
+
+/* Frees any memory allocated by value_init for V, which must
+ have the given WIDTH. */
+static inline void
+value_destroy (union value *v, int width)
+{
+ if (width > MAX_SHORT_STRING)
+ free (v->long_string);
+}
+
+/* Returns the numeric value in V, which must have width 0. */
+static inline double
+value_num (const union value *v)
+{
+ return v->f;
+}
+
+/* Returns the string value in V, which must have width WIDTH.
+
+ The returned value is not null-terminated.
+
+ 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 *
+value_str (const union value *v, int width)
+{
+ assert (width > 0);
+ return (width >= MIN_LONG_STRING ? v->long_string : v->short_string);
+}
+
+/* Returns the string value in V, which must have width WIDTH.
+
+ The returned value is not null-terminated.
+
+ 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 *
+value_str_rw (union value *v, int width)
+{
+ assert (width > 0);
+ return (width >= MIN_LONG_STRING ? v->long_string : v->short_string);
+}
+
+/* Copies SRC to DST, given that they both contain data of the
+ given WIDTH. */
+static inline void
+value_copy (union value *dst, const union value *src, int width)
{
- return width == 0 ? 1 : DIV_RND_UP (width, MAX_SHORT_STRING);
+ if (width <= MAX_SHORT_STRING)
+ *dst = *src;
+ else if (dst != src)
+ memcpy (dst->long_string, src->long_string, width);
}
#endif /* data/value.h */
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