1/*	$NetBSD: streqvcmp.c,v 1.7 2020/05/25 20:47:35 christos Exp $	*/
2
3
4/**
5 * \file streqvcmp.c
6 *
7 *  String Equivalence Comparison
8 *
9 *  These routines allow any character to be mapped to any other
10 *  character before comparison.  In processing long option names,
11 *  the characters "-", "_" and "^" all need to be equivalent
12 *  (because they are treated so by different development environments).
13 *
14 * @addtogroup autoopts
15 * @{
16 */
17/*
18 *  This file is part of AutoOpts, a companion to AutoGen.
19 *  AutoOpts is free software.
20 *  AutoOpts is Copyright (C) 1992-2015 by Bruce Korb - all rights reserved
21 *
22 *  AutoOpts is available under any one of two licenses.  The license
23 *  in use must be one of these two and the choice is under the control
24 *  of the user of the license.
25 *
26 *   The GNU Lesser General Public License, version 3 or later
27 *      See the files "COPYING.lgplv3" and "COPYING.gplv3"
28 *
29 *   The Modified Berkeley Software Distribution License
30 *      See the file "COPYING.mbsd"
31 *
32 *  These files have the following sha256 sums:
33 *
34 *  8584710e9b04216a394078dc156b781d0b47e1729104d666658aecef8ee32e95  COPYING.gplv3
35 *  4379e7444a0e2ce2b12dd6f5a52a27a4d02d39d247901d3285c88cf0d37f477b  COPYING.lgplv3
36 *  13aa749a5b0a454917a944ed8fffc530b784f5ead522b1aacaf4ec8aa55a6239  COPYING.mbsd
37 *
38 * This array is designed for mapping upper and lower case letter
39 * together for a case independent comparison.  The mappings are
40 * based upon ascii character sequences.
41 */
42static unsigned char charmap[] = {
43    NUL,  0x01, 0x02, 0x03,  0x04, 0x05, 0x06, '\a',
44    '\b', '\t', NL,   '\v',  '\f', '\r', 0x0E, 0x0F,
45    0x10, 0x11, 0x12, 0x13,  0x14, 0x15, 0x16, 0x17,
46    0x18, 0x19, 0x1A, 0x1B,  0x1C, 0x1D, 0x1E, 0x1F,
47
48    ' ',  '!',  '"',  '#',   '$',  '%',  '&',  '\'',
49    '(',  ')',  '*',  '+',   ',',  '-',  '.',  '/',
50    '0',  '1',  '2',  '3',   '4',  '5',  '6',  '7',
51    '8',  '9',  ':',  ';',   '<',  '=',  '>',  '?',
52
53    '@',  'a',  'b',  'c',   'd',  'e',  'f',  'g',
54    'h',  'i',  'j',  'k',   'l',  'm',  'n',  'o',
55    'p',  'q',  'r',  's',   't',  'u',  'v',  'w',
56    'x',  'y',  'z',  '[',   '\\', ']',  '^',  '_',
57    '`',  'a',  'b',  'c',   'd',  'e',  'f',  'g',
58    'h',  'i',  'j',  'k',   'l',  'm',  'n',  'o',
59    'p',  'q',  'r',  's',   't',  'u',  'v',  'w',
60    'x',  'y',  'z',  '{',   '|',  '}',  '~',  0x7f,
61
62    0x80, 0x81, 0x82, 0x83,  0x84, 0x85, 0x86, 0x87,
63    0x88, 0x89, 0x8A, 0x8B,  0x8C, 0x8D, 0x8E, 0x8F,
64    0x90, 0x91, 0x92, 0x93,  0x94, 0x95, 0x96, 0x97,
65    0x98, 0x99, 0x9A, 0x9B,  0x9C, 0x9D, 0x9E, 0x9F,
66    0xA0, 0xA1, 0xA2, 0xA3,  0xA4, 0xA5, 0xA6, 0xA7,
67    0xA8, 0xA9, 0xAA, 0xAB,  0xAC, 0xAD, 0xAE, 0xAF,
68    0xB0, 0xB1, 0xB2, 0xB3,  0xB4, 0xB5, 0xB6, 0xB7,
69    0xB8, 0xB9, 0xBA, 0xBB,  0xBC, 0xBD, 0xBE, 0xBF,
70
71    0xC0, 0xC1, 0xC2, 0xC3,  0xC4, 0xC5, 0xC6, 0xC7,
72    0xC8, 0xC9, 0xCA, 0xCB,  0xCC, 0xCD, 0xCE, 0xCF,
73    0xD0, 0xD1, 0xD2, 0xD3,  0xD4, 0xD5, 0xD6, 0xD7,
74    0xD8, 0xD9, 0xDA, 0xDB,  0xDC, 0xDD, 0xDE, 0xDF,
75    0xE0, 0xE1, 0xE2, 0xE3,  0xE4, 0xE5, 0xE6, 0xE7,
76    0xE8, 0xE9, 0xEA, 0xEB,  0xEC, 0xED, 0xEE, 0xEF,
77    0xF0, 0xF1, 0xF2, 0xF3,  0xF4, 0xF5, 0xF6, 0xF7,
78    0xF8, 0xF9, 0xFA, 0xFB,  0xFC, 0xFD, 0xFE, 0xFF,
79};
80
81
82/*=export_func strneqvcmp
83 *
84 * what: compare two strings with an equivalence mapping
85 *
86 * arg:  + char const * + str1 + first string +
87 * arg:  + char const * + str2 + second string +
88 * arg:  + int          + ct   + compare length +
89 *
90 * ret_type:  int
91 * ret_desc:  the difference between two differing characters
92 *
93 * doc:
94 *
95 * Using a character mapping, two strings are compared for "equivalence".
96 * Each input character is mapped to a comparison character and the
97 * mapped-to characters are compared for the two NUL terminated input strings.
98 * The comparison is limited to @code{ct} bytes.
99 * This function name is mapped to option_strneqvcmp so as to not conflict
100 * with the POSIX name space.
101 *
102 * err:  none checked.  Caller responsible for seg faults.
103=*/
104int
105strneqvcmp(char const * s1, char const * s2, int ct)
106{
107    for (; ct > 0; --ct) {
108        unsigned char u1 = (unsigned char) *s1++;
109        unsigned char u2 = (unsigned char) *s2++;
110        int dif;
111        if (u1 == u2) {
112            if (u1 == NUL)
113                return 0;
114            continue;
115        }
116
117        dif = charmap[ u1 ] - charmap[ u2 ];
118
119        if (dif != 0)
120            return dif;
121
122        if (u1 == NUL)
123            return 0;
124    }
125
126    return 0;
127}
128
129
130/*=export_func streqvcmp
131 *
132 * what: compare two strings with an equivalence mapping
133 *
134 * arg:  + char const * + str1 + first string +
135 * arg:  + char const * + str2 + second string +
136 *
137 * ret_type:  int
138 * ret_desc:  the difference between two differing characters
139 *
140 * doc:
141 *
142 * Using a character mapping, two strings are compared for "equivalence".
143 * Each input character is mapped to a comparison character and the
144 * mapped-to characters are compared for the two NUL terminated input strings.
145 * This function name is mapped to option_streqvcmp so as to not conflict
146 * with the POSIX name space.
147 *
148 * err:  none checked.  Caller responsible for seg faults.
149=*/
150int
151streqvcmp(char const * s1, char const * s2)
152{
153    for (;;) {
154        unsigned char u1 = (unsigned char) *s1++;
155        unsigned char u2 = (unsigned char) *s2++;
156        int dif;
157        if (u1 == u2) {
158            if (u1 == NUL)
159                return 0;
160            continue;
161        }
162
163        dif = charmap[ u1 ] - charmap[ u2 ];
164
165        if (dif != 0)
166            return dif;
167
168        if (u1 == NUL)
169            return 0;
170    }
171}
172
173
174/*=export_func streqvmap
175 *
176 * what: Set the character mappings for the streqv functions
177 *
178 * arg:  + char + from + Input character +
179 * arg:  + char + to   + Mapped-to character +
180 * arg:  + int  + ct   + compare length +
181 *
182 * doc:
183 *
184 * Set the character mapping.  If the count (@code{ct}) is set to zero, then
185 * the map is cleared by setting all entries in the map to their index
186 * value.  Otherwise, the "@code{From}" character is mapped to the "@code{To}"
187 * character.  If @code{ct} is greater than 1, then @code{From} and @code{To}
188 * are incremented and the process repeated until @code{ct} entries have been
189 * set. For example,
190 * @example
191 *    streqvmap('a', 'A', 26);
192 * @end example
193 * @noindent
194 * will alter the mapping so that all English lower case letters
195 * will map to upper case.
196 *
197 * This function name is mapped to option_streqvmap so as to not conflict
198 * with the POSIX name space.
199 *
200 * err:  none.
201=*/
202void
203streqvmap(char from, char to, int ct)
204{
205    if (ct == 0) {
206        ct = sizeof(charmap) - 1;
207        do  {
208            charmap[ct] = (unsigned char)ct;
209        } while (--ct >= 0);
210    }
211
212    else {
213        unsigned int i_to   = (int)to   & 0xFF;
214        unsigned int i_from = (int)from & 0xFF;
215
216        do  {
217            charmap[i_from] = (unsigned char)i_to;
218            i_from++;
219            i_to++;
220            if ((i_from >= sizeof(charmap)) || (i_to >= sizeof(charmap)))
221                break;
222        } while (--ct > 0);
223    }
224}
225
226
227/*=export_func strequate
228 *
229 * what: map a list of characters to the same value
230 *
231 * arg:  + char const * + ch_list + characters to equivalence +
232 *
233 * doc:
234 *
235 * Each character in the input string get mapped to the first character
236 * in the string.
237 * This function name is mapped to option_strequate so as to not conflict
238 * with the POSIX name space.
239 *
240 * err:  none.
241=*/
242void
243strequate(char const * s)
244{
245    if ((s != NULL) && (*s != NUL)) {
246        unsigned char equiv = (unsigned char)*s;
247        while (*s != NUL)
248            charmap[(unsigned char)*(s++)] = equiv;
249    }
250}
251
252
253/*=export_func strtransform
254 *
255 * what: convert a string into its mapped-to value
256 *
257 * arg:  + char *       + dest + output string +
258 * arg:  + char const * + src  + input string +
259 *
260 * doc:
261 *
262 * Each character in the input string is mapped and the mapped-to
263 * character is put into the output.
264 * This function name is mapped to option_strtransform so as to not conflict
265 * with the POSIX name space.
266 *
267 * The source and destination may be the same.
268 *
269 * err:  none.
270=*/
271void
272strtransform(char * d, char const * s)
273{
274    do  {
275        *(d++) = (char)charmap[(unsigned char)*s];
276    } while (*(s++) != NUL);
277}
278
279/** @}
280 *
281 * Local Variables:
282 * mode: C
283 * c-file-style: "stroustrup"
284 * indent-tabs-mode: nil
285 * End:
286 * end of autoopts/streqvcmp.c */
287