1 /****************************************************************************
2 * Copyright 2020 Thomas E. Dickey *
3 * Copyright 2005-2012,2017 Free Software Foundation, Inc. *
4 * *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
12 * *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
15 * *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
27 * authorization. *
28 ****************************************************************************/
29
30 /****************************************************************************
31 * Author: Thomas Dickey *
32 ****************************************************************************/
33
34 #include <curses.priv.h>
35
36 #include <ctype.h>
37
38 #include <tic.h>
39
40 MODULE_ID("$Id: trim_sgr0.c,v 1.18 2020/02/02 23:34:34 tom Exp $")
41
42 #undef CUR
43 #define CUR tp->
44
45 #define CSI 233
46 #define ESC 033 /* ^[ */
47 #define L_BRACK '['
48
49 static char *
set_attribute_9(TERMTYPE2 * tp,int flag)50 set_attribute_9(TERMTYPE2 *tp, int flag)
51 {
52 const char *value;
53 char *result;
54
55 value = tparm(set_attributes, 0, 0, 0, 0, 0, 0, 0, 0, flag);
56 if (PRESENT(value))
57 result = strdup(value);
58 else
59 result = 0;
60 return result;
61 }
62
63 static int
is_csi(const char * s)64 is_csi(const char *s)
65 {
66 int result = 0;
67 if (s != 0) {
68 if (UChar(s[0]) == CSI)
69 result = 1;
70 else if (s[0] == ESC && s[1] == L_BRACK)
71 result = 2;
72 }
73 return result;
74 }
75
76 static char *
skip_zero(char * s)77 skip_zero(char *s)
78 {
79 if (s[0] == '0') {
80 if (s[1] == ';')
81 s += 2;
82 else if (isalpha(UChar(s[1])))
83 s += 1;
84 }
85 return s;
86 }
87
88 static const char *
skip_delay(const char * s)89 skip_delay(const char *s)
90 {
91 if (s[0] == '$' && s[1] == '<') {
92 s += 2;
93 while (isdigit(UChar(*s)) || *s == '/')
94 ++s;
95 if (*s == '>')
96 ++s;
97 }
98 return s;
99 }
100
101 /*
102 * Improve similar_sgr a little by moving the attr-string from the beginning
103 * to the end of the s-string.
104 */
105 static bool
rewrite_sgr(char * s,char * attr)106 rewrite_sgr(char *s, char *attr)
107 {
108 if (s != 0) {
109 if (PRESENT(attr)) {
110 size_t len_s = strlen(s);
111 size_t len_a = strlen(attr);
112
113 if (len_s > len_a && !strncmp(attr, s, len_a)) {
114 unsigned n;
115 TR(TRACE_DATABASE, ("rewrite:\n\t%s", s));
116 for (n = 0; n < len_s - len_a; ++n) {
117 s[n] = s[n + len_a];
118 }
119 _nc_STRCPY(s + n, attr, strlen(s) + 1);
120 TR(TRACE_DATABASE, ("to:\n\t%s", s));
121 }
122 }
123 return TRUE;
124 }
125 return FALSE; /* oops */
126 }
127
128 static bool
similar_sgr(char * a,char * b)129 similar_sgr(char *a, char *b)
130 {
131 bool result = FALSE;
132 if (a != 0 && b != 0) {
133 int csi_a = is_csi(a);
134 int csi_b = is_csi(b);
135 size_t len_a;
136 size_t len_b;
137
138 TR(TRACE_DATABASE, ("similar_sgr:\n\t%s\n\t%s",
139 _nc_visbuf2(1, a),
140 _nc_visbuf2(2, b)));
141 if (csi_a != 0 && csi_b != 0 && csi_a == csi_b) {
142 a += csi_a;
143 b += csi_b;
144 if (*a != *b) {
145 a = skip_zero(a);
146 b = skip_zero(b);
147 }
148 }
149 len_a = strlen(a);
150 len_b = strlen(b);
151 if (len_a && len_b) {
152 if (len_a > len_b)
153 result = (strncmp(a, b, len_b) == 0);
154 else
155 result = (strncmp(a, b, len_a) == 0);
156 }
157 TR(TRACE_DATABASE, ("...similar_sgr: %d\n\t%s\n\t%s", result,
158 _nc_visbuf2(1, a),
159 _nc_visbuf2(2, b)));
160 }
161 return result;
162 }
163
164 static unsigned
chop_out(char * string,unsigned i,unsigned j)165 chop_out(char *string, unsigned i, unsigned j)
166 {
167 TR(TRACE_DATABASE, ("chop_out %d..%d from %s", i, j, _nc_visbuf(string)));
168 while (string[j] != '\0') {
169 string[i++] = string[j++];
170 }
171 string[i] = '\0';
172 return i;
173 }
174
175 /*
176 * Compare, ignoring delays. Some of the delay values are inconsistent, and
177 * we do not want to be stopped by that.
178 *
179 * Returns the number of chars from 'full' that we matched. If any mismatch
180 * occurs, return zero.
181 */
182 static unsigned
compare_part(const char * part,const char * full)183 compare_part(const char *part, const char *full)
184 {
185 const char *next_part;
186 const char *next_full;
187 unsigned used_full = 0;
188 unsigned used_delay = 0;
189
190 while (*part != 0) {
191 if (*part != *full) {
192 used_full = 0;
193 break;
194 }
195
196 /*
197 * Adjust the return-value to allow the rare case of
198 * string<delay>string
199 * to remove the whole piece. The most common case is a delay at the
200 * end of the string. The adjusted string will retain the delay, which
201 * is conservative.
202 */
203 if (used_delay != 0) {
204 used_full += used_delay;
205 used_delay = 0;
206 }
207 if (*part == '$' && *full == '$') {
208 next_part = skip_delay(part);
209 next_full = skip_delay(full);
210 if (next_part != part && next_full != full) {
211 used_delay += (unsigned) (next_full - full);
212 full = next_full;
213 part = next_part;
214 continue;
215 }
216 }
217 ++used_full;
218 ++part;
219 ++full;
220 }
221 return used_full;
222 }
223
224 /*
225 * While 'sgr0' is the "same" as termcap 'me', there is a compatibility issue.
226 * The sgr/sgr0 capabilities include setting/clearing alternate character set
227 * mode. A termcap application cannot use sgr, so sgr0 strings that reset
228 * alternate character set mode will be misinterpreted. Here, we remove those
229 * from the more common ISO/ANSI/VT100 entries, which have sgr0 agreeing with
230 * sgr.
231 *
232 * This function returns the modified sgr0 if it can be modified, a null if
233 * an error occurs, or the original sgr0 if no change is needed.
234 */
235 NCURSES_EXPORT(char *)
_nc_trim_sgr0(TERMTYPE2 * tp)236 _nc_trim_sgr0(TERMTYPE2 *tp)
237 {
238 char *result = exit_attribute_mode;
239
240 T((T_CALLED("_nc_trim_sgr0()")));
241
242 if (PRESENT(exit_attribute_mode)
243 && PRESENT(set_attributes)) {
244 bool found = FALSE;
245 char *on = set_attribute_9(tp, 1);
246 char *off = set_attribute_9(tp, 0);
247 char *end = strdup(exit_attribute_mode);
248 char *tmp;
249 size_t i, j, k;
250
251 TR(TRACE_DATABASE, ("checking if we can trim sgr0 based on sgr"));
252 TR(TRACE_DATABASE, ("sgr0 %s", _nc_visbuf(end)));
253 TR(TRACE_DATABASE, ("sgr(9:off) %s", _nc_visbuf(off)));
254 TR(TRACE_DATABASE, ("sgr(9:on) %s", _nc_visbuf(on)));
255
256 if (!rewrite_sgr(on, enter_alt_charset_mode)
257 || !rewrite_sgr(off, exit_alt_charset_mode)
258 || !rewrite_sgr(end, exit_alt_charset_mode)) {
259 FreeIfNeeded(off);
260 } else if (similar_sgr(off, end)
261 && !similar_sgr(off, on)) {
262 TR(TRACE_DATABASE, ("adjusting sgr(9:off) : %s", _nc_visbuf(off)));
263 result = off;
264 /*
265 * If rmacs is a substring of sgr(0), remove that chunk.
266 */
267 if (PRESENT(exit_alt_charset_mode)) {
268 TR(TRACE_DATABASE, ("scan for rmacs %s", _nc_visbuf(exit_alt_charset_mode)));
269 j = strlen(off);
270 k = strlen(exit_alt_charset_mode);
271 if (j > k) {
272 for (i = 0; i <= (j - k); ++i) {
273 unsigned k2 = compare_part(exit_alt_charset_mode,
274 off + i);
275 if (k2 != 0) {
276 found = TRUE;
277 chop_out(off, (unsigned) i, (unsigned) (i + k2));
278 break;
279 }
280 }
281 }
282 }
283 /*
284 * SGR 10 would reset to normal font.
285 */
286 if (!found) {
287 if ((i = (size_t) is_csi(off)) != 0
288 && off[strlen(off) - 1] == 'm') {
289 TR(TRACE_DATABASE, ("looking for SGR 10 in %s",
290 _nc_visbuf(off)));
291 tmp = skip_zero(off + i);
292 if (tmp[0] == '1'
293 && skip_zero(tmp + 1) != tmp + 1) {
294 i = (size_t) (tmp - off);
295 if (off[i - 1] == ';')
296 i--;
297 j = (size_t) (skip_zero(tmp + 1) - off);
298 (void) chop_out(off, (unsigned) i, (unsigned) j);
299 found = TRUE;
300 }
301 }
302 }
303 if (!found
304 && (tmp = strstr(end, off)) != 0
305 && strcmp(end, off) != 0) {
306 i = (size_t) (tmp - end);
307 j = strlen(off);
308 tmp = strdup(end);
309 chop_out(tmp, (unsigned) i, (unsigned) j);
310 free(off);
311 result = tmp;
312 }
313 TR(TRACE_DATABASE, ("...adjusted sgr0 : %s", _nc_visbuf(result)));
314 if (!strcmp(result, exit_attribute_mode)) {
315 TR(TRACE_DATABASE, ("...same result, discard"));
316 free(result);
317 result = exit_attribute_mode;
318 }
319 } else {
320 /*
321 * Either the sgr does not reference alternate character set,
322 * or it is incorrect. That's too hard to decide right now.
323 */
324 free(off);
325 }
326 FreeIfNeeded(end);
327 FreeIfNeeded(on);
328 } else {
329 /*
330 * Possibly some applications are confused if sgr0 contains rmacs,
331 * but that would be a different bug report -TD
332 */
333 }
334
335 returnPtr(result);
336 }
337