src/data/vector.c

   1 /* PSPP - a program for statistical analysis.
   2    Copyright (C) 2006, 2010, 2011, 2012  Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
  16
  17 #include <config.h>
  18
  19 #include "data/vector.h"
  20
  21 #include <stdlib.h>
  22
  23 #include "data/dictionary.h"
  24 #include "data/identifier.h"
  25 #include "libpspp/assertion.h"
  26 #include "libpspp/i18n.h"
  27 #include "libpspp/str.h"
  28
  29 #include "gl/xalloc.h"
  30
  31 /* Vector of variables. */
  32 struct vector
  33   {
  34     char *name;                         /* Name. */
  35     struct variable **vars;             /* Set of variables. */
  36     size_t n_vars;                      /* Number of variables. */
  37   };
  38
  39 /* Checks that all the variables in VECTOR have consistent
  40    width. */
  41 static void
  42 check_widths (const struct vector *vector)
  43 {
  44   int width = var_get_width (vector->vars[0]);
  45   size_t i;
  46
  47   for (i = 1; i < vector->n_vars; i++)
  48     assert (width == var_get_width (vector->vars[i]));
  49 }
  50
  51 /* Creates and returns a new vector with the given UTF-8 encoded NAME
  52    that contains the N_VARS variables in VARS.
  53    All variables in VARS must have the same type and width. */
  54 struct vector *
  55 vector_create (const char *name, struct variable **vars, size_t n_vars)
  56 {
  57   struct vector *vector = xmalloc (sizeof *vector);
  58
  59   assert (n_vars > 0);
  60   assert (id_is_plausible (name));
  61
  62   vector->name = xstrdup (name);
  63   vector->vars = xmemdup (vars, n_vars * sizeof *vector->vars);
  64   vector->n_vars = n_vars;
  65   check_widths (vector);
  66
  67   return vector;
  68 }
  69
  70 /* Creates and returns a new vector as a clone of OLD, but that
  71    contains variables from NEW_DICT that are in the same position
  72    as those in OLD are in OLD_DICT.
  73    All variables in the new vector must have the same type and
  74    width. */
  75 struct vector *
  76 vector_clone (const struct vector *old,
  77               const struct dictionary *old_dict,
  78               const struct dictionary *new_dict)
  79 {
  80   struct vector *new = xmalloc (sizeof *new);
  81   size_t i;
  82
  83   new->name = xstrdup (old->name);
  84   new->vars = xnmalloc (old->n_vars, sizeof *new->vars);
  85   new->n_vars = old->n_vars;
  86   for (i = 0; i < new->n_vars; i++)
  87     {
  88       assert (dict_contains_var (old_dict, old->vars[i]));
  89       new->vars[i] = dict_get_var (new_dict,
  90                                    var_get_dict_index (old->vars[i]));
  91     }
  92   check_widths (new);
  93
  94   return new;
  95 }
  96
  97 /* Destroys VECTOR. */
  98 void
  99 vector_destroy (struct vector *vector)
 100 {
 101   free (vector->name);
 102   free (vector->vars);
 103   free (vector);
 104 }
 105
 106 /* Returns VECTOR's name, as a UTF-8 encoded string. */
 107 const char *
 108 vector_get_name (const struct vector *vector)
 109 {
 110   return vector->name;
 111 }
 112
 113 /* Returns the type of the variables in VECTOR. */
 114 enum val_type vector_get_type (const struct vector *vector)
 115 {
 116   return var_get_type (vector->vars[0]);
 117 }
 118
 119 /* Returns the variable in VECTOR with the given INDEX. */
 120 struct variable *
 121 vector_get_var (const struct vector *vector, size_t index)
 122 {
 123   assert (index < vector->n_vars);
 124   return vector->vars[index];
 125 }
 126
 127 /* Returns the number of variables in VECTOR. */
 128 size_t
 129 vector_get_n_vars (const struct vector *vector)
 130 {
 131   return vector->n_vars;
 132 }
 133
 134 /* Compares two pointers to vectors represented by A and B and
 135    returns a strcmp()-type result. */
 136 int
 137 compare_vector_ptrs_by_name (const void *a_, const void *b_)
 138 {
 139   struct vector *const *pa = a_;
 140   struct vector *const *pb = b_;
 141   struct vector *a = *pa;
 142   struct vector *b = *pb;
 143
 144   return utf8_strcasecmp (a->name, b->name);
 145 }
 146