1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 1997-9, 2000, 2009 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/>. */
18 #include <data/value.h>
20 #include <data/val-type.h>
21 #include <data/variable.h>
22 #include <libpspp/hash.h>
23 #include <libpspp/pool.h>
24 #include <libpspp/str.h>
29 /* Copies the contents of string value SRC with width SRC_WIDTH
30 to string value DST with width DST_WIDTH. If SRC_WIDTH is
31 greater than DST_WIDTH, then only the first DST_WIDTH bytes
32 are copied; if DST_WIDTH is greater than SRC_WIDTH, then DST
33 is padded on the right with PAD bytes.
35 SRC and DST must be string values; that is, SRC_WIDTH and
36 DST_WIDTH must both be positive.
38 It is important that SRC_WIDTH and DST_WIDTH be the actual
39 widths with which SRC and DST were initialized. Passing,
40 e.g., smaller values in order to copy only a prefix of SRC or
41 modify only a prefix of DST will not work in every case. */
43 value_copy_rpad (union value *dst, int dst_width,
44 const union value *src, int src_width,
47 buf_copy_rpad (value_str_rw (dst, dst_width), dst_width,
48 value_str (src, src_width), src_width,
52 /* Copies the contents of null-terminated string SRC to string
53 value DST with width DST_WIDTH. If SRC is more than DST_WIDTH
54 bytes long, then only the first DST_WIDTH bytes are copied; if
55 DST_WIDTH is greater than the length of SRC, then DST is
56 padded on the right with PAD bytes.
58 DST must be a string value; that is, DST_WIDTH must be
61 It is important that DST_WIDTH be the actual width with which
62 DST was initialized. Passing, e.g., a smaller value in order
63 to modify only a prefix of DST will not work in every case. */
65 value_copy_str_rpad (union value *dst, int dst_width, const char *src,
68 value_copy_buf_rpad (dst, dst_width, src, strlen (src), pad);
71 /* Copies the SRC_LEN bytes at SRC to string value DST with width
72 DST_WIDTH. If SRC_LEN is greater than DST_WIDTH, then only
73 the first DST_WIDTH bytes are copied; if DST_WIDTH is greater
74 than SRC_LEN, then DST is padded on the right with PAD bytes.
76 DST must be a string value; that is, DST_WIDTH must be
79 It is important that DST_WIDTH be the actual width with which
80 DST was initialized. Passing, e.g., a smaller value in order
81 to modify only a prefix of DST will not work in every case. */
83 value_copy_buf_rpad (union value *dst, int dst_width,
84 const char *src, size_t src_len, char pad)
86 buf_copy_rpad (value_str_rw (dst, dst_width), dst_width, src, src_len, pad);
89 /* Sets V to the system-missing value for data of the given
92 value_set_missing (union value *v, int width)
97 memset (value_str_rw (v, width), ' ', width);
100 /* Compares A and B, which both have the given WIDTH, and returns
101 a strcmp()-type result. */
103 value_compare_3way (const union value *a, const union value *b, int width)
106 ? (a->f < b->f ? -1 : a->f > b->f)
107 : memcmp (value_str (a, width), value_str (b, width), width));
110 /* Returns true if A and B, which must both have the given WIDTH,
111 have equal contents, false if their contents differ. */
113 value_equal (const union value *a, const union value *b, int width)
117 : !memcmp (value_str (a, width), value_str (b, width), width));
120 /* Returns a hash of the data in VALUE, which must have the given
121 WIDTH, folding BASIS into the hash value calculation. */
123 value_hash (const union value *value, int width, unsigned int basis)
126 ? hash_double (value->f, basis)
127 : hash_bytes (value_str (value, width), width, basis));
130 /* Tests whether VALUE may be resized from OLD_WIDTH to
131 NEW_WIDTH, using the following rules that match those for
132 resizing missing values and value labels. First, OLD_WIDTH
133 and NEW_WIDTH must be both numeric or both string. Second, if
134 NEW_WIDTH is less than OLD_WIDTH, then the bytes that would be
135 trimmed off the right end of VALUE must be all spaces. */
137 value_is_resizable (const union value *value, int old_width, int new_width)
139 if (old_width == new_width)
141 else if (val_type_from_width (old_width) != val_type_from_width (new_width))
145 const char *str = value_str (value, old_width);
148 for (i = new_width; i < old_width; i++)
155 /* Resizes VALUE from OLD_WIDTH to NEW_WIDTH. The arguments must
156 satisfy the rules specified above for value_is_resizable. */
158 value_resize (union value *value, int old_width, int new_width)
160 assert (value_is_resizable (value, old_width, new_width));
161 if (new_width != old_width)
164 value_init (&tmp, new_width);
165 value_copy_rpad (&tmp, new_width, value, old_width, ' ');
166 value_destroy (value, old_width);
171 /* Returns true if resizing a value from OLD_WIDTH to NEW_WIDTH
172 actually changes anything, false otherwise. If false is
173 returned, calls to value_resize() with the specified
174 parameters may be omitted without any ill effects.
176 This is generally useful only if many values can skip being
177 resized from OLD_WIDTH to NEW_WIDTH. Otherwise you might as
178 well just call value_resize directly. */
180 value_needs_resize (int old_width, int new_width)
182 assert (val_type_from_width (old_width) == val_type_from_width (new_width));
184 /* We need to call value_resize if either the new width is
185 longer than the old width (in which case the new characters
186 must be set to spaces) or if either width is a long string.
187 (We could omit resizing if both the old and new widths were
188 long and the new width was shorter, but we choose to do so
189 anyway in hopes of saving memory.) */
190 return (old_width != new_width
191 && (new_width > old_width
192 || old_width >= MIN_LONG_STRING
193 || new_width >= MIN_LONG_STRING));
196 /* Same as value_init, except that memory for VALUE (if
197 necessary) is allocated from POOL and will be freed
198 automatically when POOL is destroyed.
200 VALUE must not be freed manually by calling value_destroy. If
201 it needs to be resized, it must be done using
202 value_resize_pool instead of value_resize. */
204 value_init_pool (struct pool *pool, union value *value, int width)
206 if (width > MAX_SHORT_STRING)
207 value->long_string = pool_alloc_unaligned (pool, width);
210 /* Same as value_resize, except that VALUE must have been
211 allocated from POOL using value_init_pool.
213 This function causes some memory in POOL to be wasted in some
214 cases (until the pool is freed), so it should only be done if
215 this is acceptable. */
217 value_resize_pool (struct pool *pool, union value *value,
218 int old_width, int new_width)
220 assert (value_is_resizable (value, old_width, new_width));
221 if (new_width > old_width)
223 if (new_width > MAX_SHORT_STRING)
225 char *new_long_string = pool_alloc_unaligned (pool, new_width);
226 memcpy (new_long_string, value_str (value, old_width), old_width);
227 value->long_string = new_long_string;
229 memset (value_str_rw (value, new_width) + old_width, ' ',
230 new_width - old_width);