1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 1997-9, 2000, 2006, 2007, 2009, 2011, 2013 Free Software Foundation, Inc.
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.
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.
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/>. */
19 #include "data/case-map.h"
24 #include "data/casereader.h"
25 #include "data/casewriter.h"
26 #include "data/dictionary.h"
27 #include "data/variable.h"
28 #include "data/case.h"
29 #include "libpspp/assertion.h"
30 #include "libpspp/hash-functions.h"
31 #include "libpspp/hmap.h"
33 #include "gl/xalloc.h"
38 struct caseproto *proto; /* Prototype for output cases. */
39 int *map; /* For each destination index, the
40 corresponding source index. */
43 static struct ccase *translate_case (struct ccase *, void *map_);
44 static bool destroy_case_map (void *map_);
46 /* Creates and returns an empty map that outputs cases matching
48 static struct case_map *
49 create_case_map (const struct caseproto *proto)
51 size_t n_values = caseproto_get_n_widths (proto);
55 map = xmalloc (sizeof *map);
56 map->proto = caseproto_ref (proto);
57 map->map = xnmalloc (n_values, sizeof *map->map);
58 for (i = 0; i < n_values; i++)
64 /* Inserts into MAP a mapping of the value at index FROM in the
65 source case to the value at index TO in the destination
68 insert_mapping (struct case_map *map, size_t from, size_t to)
70 assert (to < caseproto_get_n_widths (map->proto));
71 assert (map->map[to] == -1);
75 /* Returns a copy of OLD, if OLD is nonnull, and otherwise returns NULL. */
77 case_map_clone (const struct case_map *old)
82 size_t n_values = caseproto_get_n_widths (old->proto);
83 struct case_map *new = xmalloc (sizeof *new);
84 *new = (struct case_map) {
85 .proto = caseproto_ref (old->proto),
86 .map = xmemdup (old->proto, n_values * sizeof *new->map),
91 /* Destroys case map MAP. */
93 case_map_destroy (struct case_map *map)
97 caseproto_unref (map->proto);
103 /* If MAP is nonnull, returns a new case that is the result of
104 applying case map MAP to SRC, and unrefs SRC.
106 If MAP is null, returns SRC unchanged. */
108 case_map_execute (const struct case_map *map, struct ccase *src)
112 size_t n_values = caseproto_get_n_widths (map->proto);
116 dst = case_create (map->proto);
117 for (dst_idx = 0; dst_idx < n_values; dst_idx++)
119 int src_idx = map->map[dst_idx];
121 value_copy (case_data_rw_idx (dst, dst_idx), case_data_idx (src, src_idx), caseproto_get_width (map->proto, dst_idx));
130 /* Returns the prototype for output cases created by MAP. The
131 caller must not unref the returned case prototype. */
132 const struct caseproto *
133 case_map_get_proto (const struct case_map *map)
138 /* Creates and returns a new casereader whose cases are produced
139 by reading from SUBREADER and executing the actions of MAP.
140 The casereader will have as many `union value's as MAP. When
141 the new casereader is destroyed, MAP will be destroyed too.
143 After this function is called, SUBREADER must not ever again
144 be referenced directly. It will be destroyed automatically
145 when the returned casereader is destroyed. */
147 case_map_create_input_translator (struct case_map *map,
148 struct casereader *subreader)
150 return casereader_create_translator (subreader,
151 case_map_get_proto (map),
157 /* Creates and returns a new casewriter. Cases written to the
158 new casewriter will be passed through MAP and written to
159 SUBWRITER. The casewriter will have as many `union value's as
160 MAP. When the new casewriter is destroyed, MAP will be
163 After this function is called, SUBWRITER must not ever again
164 be referenced directly. It will be destroyed automatically
165 when the returned casewriter is destroyed. */
167 case_map_create_output_translator (struct case_map *map,
168 struct casewriter *subwriter)
170 return casewriter_create_translator (subwriter,
171 case_map_get_proto (map),
177 /* Casereader/casewriter translation callback. */
178 static struct ccase *
179 translate_case (struct ccase *input, void *map_)
181 struct case_map *map = map_;
182 return case_map_execute (map, input);
185 /* Casereader/casewriter destruction callback. */
187 destroy_case_map (void *map_)
189 struct case_map *map = map_;
190 case_map_destroy (map);
194 /* Creates and returns a case_map that can be used to compact
195 cases for dictionary D.
197 Compacting a case eliminates "holes" between values and after
198 the last value. (Holes are created by deleting variables.)
200 All variables are compacted if EXCLUDE_CLASSES is 0, or it may
201 contain one or more of DC_ORDINARY, DC_SYSTEM, or DC_SCRATCH
202 to cause the corresponding type of variable to be deleted
203 during compaction. */
205 case_map_to_compact_dict (const struct dictionary *d,
206 unsigned int exclude_classes)
208 size_t n_vars = dict_get_n_vars (d);
209 struct caseproto *proto;
210 struct case_map *map;
214 /* Create the case mapping. */
215 proto = dict_get_compacted_proto (d, exclude_classes);
216 map = create_case_map (proto);
217 caseproto_unref (proto);
219 /* Add the values to the case mapping. */
221 for (i = 0; i < n_vars; i++)
223 struct variable *v = dict_get_var (d, i);
224 if (!(exclude_classes & var_get_dict_class (v)))
225 insert_mapping (map, var_get_case_index (v), n_values++);
233 struct hmap_node hmap_node; /* In struct case_map_stage's 'stage_vars'. */
234 const struct variable *var;
238 struct case_map_stage
240 const struct dictionary *dict;
241 struct hmap stage_vars;
244 /* Prepares and returns a "struct case_map_stage" for producing a case map for
245 DICT. Afterward, the caller may delete, reorder, or rename variables within
246 DICT at will before using case_map_stage_get_case_map() to produce the case
249 The caller must *not* add new variables to DICT. */
250 struct case_map_stage *
251 case_map_stage_create (const struct dictionary *dict)
253 size_t n_vars = dict_get_n_vars (dict);
254 struct case_map_stage *stage;
257 stage = xmalloc (sizeof *stage);
259 hmap_init (&stage->stage_vars);
261 for (i = 0; i < n_vars; i++)
263 const struct variable *var = dict_get_var (dict, i);
264 struct stage_var *stage_var;
266 stage_var = xmalloc (sizeof *stage_var);
267 stage_var->var = var;
268 stage_var->case_index = var_get_case_index (var);
269 hmap_insert (&stage->stage_vars, &stage_var->hmap_node,
270 hash_pointer (var, 0));
276 /* Destroys STAGE, which was created by case_map_stage_create(). */
278 case_map_stage_destroy (struct case_map_stage *stage)
282 struct stage_var *stage_var, *next_stage_var;
284 HMAP_FOR_EACH_SAFE (stage_var, next_stage_var,
285 struct stage_var, hmap_node, &stage->stage_vars)
287 hmap_delete (&stage->stage_vars, &stage_var->hmap_node);
290 hmap_destroy (&stage->stage_vars);
295 static const struct stage_var *
296 case_map_stage_find_var (const struct case_map_stage *stage,
297 const struct variable *var)
299 const struct stage_var *stage_var;
301 HMAP_FOR_EACH_IN_BUCKET (stage_var, struct stage_var, hmap_node,
302 hash_pointer (var, 0), &stage->stage_vars)
303 if (stage_var->var == var)
306 /* If the following assertion is reached, it indicates a bug in the
307 case_map_stage client: the client allowed a new variable to be added to
308 the dictionary. This is not allowed, because of the risk that the new
309 varaible might have the same address as an old variable that has been
314 /* Produces a case map from STAGE, which must have been previously created with
315 case_map_stage_create(). The case map maps from the original case index of
316 the variables in STAGE's dictionary to their current case indexes.
318 Returns the new case map, or a null pointer if no mapping is required (that
319 is, no data has changed position). */
321 case_map_stage_get_case_map (const struct case_map_stage *stage)
323 struct case_map *map;
324 size_t n_vars = dict_get_n_vars (stage->dict);
327 bool identity_map = true;
329 map = create_case_map (dict_get_proto (stage->dict));
330 for (i = 0; i < n_vars; i++)
332 const struct variable *var = dict_get_var (stage->dict, i);
333 const struct stage_var *stage_var = case_map_stage_find_var (stage, var);
335 if (var_get_case_index (var) != stage_var->case_index)
336 identity_map = false;
338 insert_mapping (map, stage_var->case_index, var_get_case_index (var));
343 case_map_destroy (map);
347 n_values = caseproto_get_n_widths (map->proto);
348 while (n_values > 0 && caseproto_get_width (map->proto, n_values - 1) == -1)
349 map->proto = caseproto_remove_widths (map->proto, --n_values, 1);
354 /* Creates and returns a case map for mapping variables in OLD to
355 variables in NEW based on their name. For every variable in
356 NEW, there must be a variable in OLD with the same name, type,
359 case_map_by_name (const struct dictionary *old,
360 const struct dictionary *new)
362 size_t n_vars = dict_get_n_vars (new);
363 struct case_map *map = create_case_map (dict_get_proto (new));
364 for (size_t i = 0; i < n_vars; i++)
366 struct variable *nv = dict_get_var (new, i);
367 struct variable *ov = dict_lookup_var_assert (old, var_get_name (nv));
368 assert (var_get_width (nv) == var_get_width (ov));
369 insert_mapping (map, var_get_case_index (ov), var_get_case_index (nv));
374 /* Prints the mapping represented by case map CM to stdout, for
375 debugging purposes. */
377 case_map_dump (const struct case_map *cm)
380 for (i = 0 ; i < caseproto_get_n_widths (cm->proto); ++i)
381 printf ("%d -> %d\n", i, cm->map[i]);