X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fvalue.c;h=34e3fe58bb37bf40d80943d38fc4d5ecafdc76d2;hb=f1681b02fcc7f30319a7be2b9db199b7e5e4967e;hp=20d2a33ec3ef9eae3afa12969ba3927faa9436d5;hpb=480a0746507ce73d26f528b56dc3ed80195096e0;p=pspp

diff --git a/src/data/value.c b/src/data/value.c
index 20d2a33ec3..34e3fe58bb 100644
--- a/src/data/value.c
+++ b/src/data/value.c
@@ -1,24 +1,23 @@
-/* PSPP - computes sample statistics.
+/* PSPP - a program for statistical analysis.
    Copyright (C) 1997-9, 2000 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 the Free Software Foundation; either version 2 of the
-   License, or (at your option) any later version.
+   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
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
 
-   This program is distributed in the hope that it will be useful, but
-   WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-   02110-1301, USA. */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include <config.h>
-#include "value.h"
+#include <data/value.h>
 
+#include <data/val-type.h>
 #include <libpspp/hash.h>
 #include <libpspp/str.h>
 
@@ -32,12 +31,22 @@ value_dup (const union value *val, int width)
   return xmemdup (val, MAX (width, sizeof *val));
 }
 
+
+/* Create a value of specified width.
+   The caller is responsible for freeing the returned value. */
+union value *
+value_create (int width)
+{
+  return xnmalloc (value_cnt_from_width (width), sizeof (union value));
+}
+
+
 /* Compares A and B, which both have the given WIDTH, and returns
    a strcmp()-type result.
    Only the short string portion of longer strings are
    compared. */
 int
-compare_values (const union value *a, const union value *b, int width) 
+compare_values (const union value *a, const union value *b, int width)
 {
   return (width == 0
           ? (a->f < b->f ? -1 : a->f > b->f)
@@ -46,10 +55,61 @@ compare_values (const union value *a, const union value *b, int width)
 
 /* Create a hash of V, which has the given WIDTH.
    Only the short string portion of a longer string is hashed. */
-unsigned 
+unsigned
 hash_value (const union value *v, int width)
 {
   return (width == 0
           ? hsh_hash_double (v->f)
           : hsh_hash_bytes (v->s, MIN (MAX_SHORT_STRING, width)));
 }
+
+/* Copies SRC to DST, given that they both contain data of the
+   given WIDTH. */
+void
+value_copy (union value *dst, const union value *src, int width)
+{
+  if (width == 0)
+    dst->f = src->f;
+  else
+    memcpy (dst->s, src->s, width);
+}
+
+/* Sets V to the system-missing value for data of the given
+   WIDTH. */
+void
+value_set_missing (union value *v, int width)
+{
+  if (width == 0)
+    v->f = SYSMIS;
+  else
+    memset (v->s, ' ', width);
+}
+
+/* Tests whether VALUE may be resized from OLD_WIDTH to
+   NEW_WIDTH, using the following rules that match those for
+   resizing missing values and value labels.  First, OLD_WIDTH
+   and NEW_WIDTH must be both numeric or both string.  Second, if
+   NEW_WIDTH is less than OLD_WIDTH, then the bytes that would be
+   trimmed off the right end of VALUE must be all spaces. */
+bool
+value_is_resizable (const union value *value, int old_width, int new_width)
+{
+  int i;
+
+  if (val_type_from_width (old_width) != val_type_from_width (new_width))
+    return false;
+  for (i = new_width; i < old_width; i++)
+    if (value->s[i] != ' ')
+      return false;
+  return true;
+}
+
+/* Resizes VALUE from OLD_WIDTH to NEW_WIDTH.  The arguments must
+   satisfy the rules specified above for value_is_resizable. */
+void
+value_resize (union value *value, int old_width, int new_width)
+{
+  assert (value_is_resizable (value, old_width, new_width));
+  if (new_width > old_width)
+    memset (&value->s[old_width], ' ', new_width - old_width);
+}