1 /* $OpenBSD: trim_sgr0.c,v 1.2 2023/10/17 09:52:09 nicm Exp $ */ 2 3 /**************************************************************************** 4 * Copyright 2020,2021 Thomas E. Dickey * 5 * Copyright 2005-2012,2017 Free Software Foundation, Inc. * 6 * * 7 * Permission is hereby granted, free of charge, to any person obtaining a * 8 * copy of this software and associated documentation files (the * 9 * "Software"), to deal in the Software without restriction, including * 10 * without limitation the rights to use, copy, modify, merge, publish, * 11 * distribute, distribute with modifications, sublicense, and/or sell * 12 * copies of the Software, and to permit persons to whom the Software is * 13 * furnished to do so, subject to the following conditions: * 14 * * 15 * The above copyright notice and this permission notice shall be included * 16 * in all copies or substantial portions of the Software. * 17 * * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * 19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * 20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * 21 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * 24 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * 25 * * 26 * Except as contained in this notice, the name(s) of the above copyright * 27 * holders shall not be used in advertising or otherwise to promote the * 28 * sale, use or other dealings in this Software without prior written * 29 * authorization. * 30 ****************************************************************************/ 31 32 /**************************************************************************** 33 * Author: Thomas Dickey * 34 ****************************************************************************/ 35 36 #include <curses.priv.h> 37 38 #include <ctype.h> 39 40 #include <tic.h> 41 42 MODULE_ID("$Id: trim_sgr0.c,v 1.2 2023/10/17 09:52:09 nicm Exp $") 43 44 #undef CUR 45 #define CUR tp-> 46 47 #define CSI 233 48 #define ESC 033 /* ^[ */ 49 #define L_BRACK '[' 50 51 static char * 52 set_attribute_9(TERMTYPE2 *tp, int flag) 53 { 54 const char *value; 55 char *result; 56 57 value = TIPARM_9(set_attributes, 0, 0, 0, 0, 0, 0, 0, 0, flag); 58 if (PRESENT(value)) 59 result = strdup(value); 60 else 61 result = 0; 62 return result; 63 } 64 65 static int 66 is_csi(const char *s) 67 { 68 int result = 0; 69 if (s != 0) { 70 if (UChar(s[0]) == CSI) 71 result = 1; 72 else if (s[0] == ESC && s[1] == L_BRACK) 73 result = 2; 74 } 75 return result; 76 } 77 78 static char * 79 skip_zero(char *s) 80 { 81 if (s[0] == '0') { 82 if (s[1] == ';') 83 s += 2; 84 else if (isalpha(UChar(s[1]))) 85 s += 1; 86 } 87 return s; 88 } 89 90 static const char * 91 skip_delay(const char *s) 92 { 93 if (s[0] == '$' && s[1] == '<') { 94 s += 2; 95 while (isdigit(UChar(*s)) || *s == '/') 96 ++s; 97 if (*s == '>') 98 ++s; 99 } 100 return s; 101 } 102 103 /* 104 * Improve similar_sgr a little by moving the attr-string from the beginning 105 * to the end of the s-string. 106 */ 107 static bool 108 rewrite_sgr(char *s, char *attr) 109 { 110 if (s != 0) { 111 if (PRESENT(attr)) { 112 size_t len_s = strlen(s); 113 size_t len_a = strlen(attr); 114 115 if (len_s > len_a && !strncmp(attr, s, len_a)) { 116 unsigned n; 117 TR(TRACE_DATABASE, ("rewrite:\n\t%s", s)); 118 for (n = 0; n < len_s - len_a; ++n) { 119 s[n] = s[n + len_a]; 120 } 121 _nc_STRCPY(s + n, attr, strlen(s) + 1); 122 TR(TRACE_DATABASE, ("to:\n\t%s", s)); 123 } 124 } 125 return TRUE; 126 } 127 return FALSE; /* oops */ 128 } 129 130 static bool 131 similar_sgr(char *a, char *b) 132 { 133 bool result = FALSE; 134 if (a != 0 && b != 0) { 135 int csi_a = is_csi(a); 136 int csi_b = is_csi(b); 137 size_t len_a; 138 size_t len_b; 139 140 TR(TRACE_DATABASE, ("similar_sgr:\n\t%s\n\t%s", 141 _nc_visbuf2(1, a), 142 _nc_visbuf2(2, b))); 143 if (csi_a != 0 && csi_b != 0 && csi_a == csi_b) { 144 a += csi_a; 145 b += csi_b; 146 if (*a != *b) { 147 a = skip_zero(a); 148 b = skip_zero(b); 149 } 150 } 151 len_a = strlen(a); 152 len_b = strlen(b); 153 if (len_a && len_b) { 154 if (len_a > len_b) 155 result = (strncmp(a, b, len_b) == 0); 156 else 157 result = (strncmp(a, b, len_a) == 0); 158 } 159 TR(TRACE_DATABASE, ("...similar_sgr: %d\n\t%s\n\t%s", result, 160 _nc_visbuf2(1, a), 161 _nc_visbuf2(2, b))); 162 } 163 return result; 164 } 165 166 static unsigned 167 chop_out(char *string, unsigned i, unsigned j) 168 { 169 TR(TRACE_DATABASE, ("chop_out %d..%d from %s", i, j, _nc_visbuf(string))); 170 while (string[j] != '\0') { 171 string[i++] = string[j++]; 172 } 173 string[i] = '\0'; 174 return i; 175 } 176 177 /* 178 * Compare, ignoring delays. Some of the delay values are inconsistent, and 179 * we do not want to be stopped by that. 180 * 181 * Returns the number of chars from 'full' that we matched. If any mismatch 182 * occurs, return zero. 183 */ 184 static unsigned 185 compare_part(const char *part, const char *full) 186 { 187 const char *next_part; 188 const char *next_full; 189 unsigned used_full = 0; 190 unsigned used_delay = 0; 191 192 while (*part != 0) { 193 if (*part != *full) { 194 used_full = 0; 195 break; 196 } 197 198 /* 199 * Adjust the return-value to allow the rare case of 200 * string<delay>string 201 * to remove the whole piece. The most common case is a delay at the 202 * end of the string. The adjusted string will retain the delay, which 203 * is conservative. 204 */ 205 if (used_delay != 0) { 206 used_full += used_delay; 207 used_delay = 0; 208 } 209 if (*part == '$' && *full == '$') { 210 next_part = skip_delay(part); 211 next_full = skip_delay(full); 212 if (next_part != part && next_full != full) { 213 used_delay += (unsigned) (next_full - full); 214 full = next_full; 215 part = next_part; 216 continue; 217 } 218 } 219 ++used_full; 220 ++part; 221 ++full; 222 } 223 return used_full; 224 } 225 226 /* 227 * While 'sgr0' is the "same" as termcap 'me', there is a compatibility issue. 228 * The sgr/sgr0 capabilities include setting/clearing alternate character set 229 * mode. A termcap application cannot use sgr, so sgr0 strings that reset 230 * alternate character set mode will be misinterpreted. Here, we remove those 231 * from the more common ISO/ANSI/VT100 entries, which have sgr0 agreeing with 232 * sgr. 233 * 234 * This function returns the modified sgr0 if it can be modified, a null if 235 * an error occurs, or the original sgr0 if no change is needed. 236 */ 237 NCURSES_EXPORT(char *) 238 _nc_trim_sgr0(TERMTYPE2 *tp) 239 { 240 char *result = exit_attribute_mode; 241 242 T((T_CALLED("_nc_trim_sgr0()"))); 243 244 if (PRESENT(exit_attribute_mode) 245 && PRESENT(set_attributes)) { 246 bool found = FALSE; 247 char *on = set_attribute_9(tp, 1); 248 char *off = set_attribute_9(tp, 0); 249 char *end = strdup(exit_attribute_mode); 250 char *tmp; 251 size_t i, j, k; 252 253 TR(TRACE_DATABASE, ("checking if we can trim sgr0 based on sgr")); 254 TR(TRACE_DATABASE, ("sgr0 %s", _nc_visbuf(end))); 255 TR(TRACE_DATABASE, ("sgr(9:off) %s", _nc_visbuf(off))); 256 TR(TRACE_DATABASE, ("sgr(9:on) %s", _nc_visbuf(on))); 257 258 if (!rewrite_sgr(on, enter_alt_charset_mode) 259 || !rewrite_sgr(off, exit_alt_charset_mode) 260 || !rewrite_sgr(end, exit_alt_charset_mode)) { 261 FreeIfNeeded(off); 262 } else if (similar_sgr(off, end) 263 && !similar_sgr(off, on)) { 264 TR(TRACE_DATABASE, ("adjusting sgr(9:off) : %s", _nc_visbuf(off))); 265 result = off; 266 /* 267 * If rmacs is a substring of sgr(0), remove that chunk. 268 */ 269 if (PRESENT(exit_alt_charset_mode)) { 270 TR(TRACE_DATABASE, ("scan for rmacs %s", _nc_visbuf(exit_alt_charset_mode))); 271 j = strlen(off); 272 k = strlen(exit_alt_charset_mode); 273 if (j > k) { 274 for (i = 0; i <= (j - k); ++i) { 275 unsigned k2 = compare_part(exit_alt_charset_mode, 276 off + i); 277 if (k2 != 0) { 278 found = TRUE; 279 chop_out(off, (unsigned) i, (unsigned) (i + k2)); 280 break; 281 } 282 } 283 } 284 } 285 /* 286 * SGR 10 would reset to normal font. 287 */ 288 if (!found) { 289 if ((i = (size_t) is_csi(off)) != 0 290 && off[strlen(off) - 1] == 'm') { 291 TR(TRACE_DATABASE, ("looking for SGR 10 in %s", 292 _nc_visbuf(off))); 293 tmp = skip_zero(off + i); 294 if (tmp[0] == '1' 295 && skip_zero(tmp + 1) != tmp + 1) { 296 i = (size_t) (tmp - off); 297 if (off[i - 1] == ';') 298 i--; 299 j = (size_t) (skip_zero(tmp + 1) - off); 300 (void) chop_out(off, (unsigned) i, (unsigned) j); 301 found = TRUE; 302 } 303 } 304 } 305 if (!found 306 && (tmp = strstr(end, off)) != 0 307 && strcmp(end, off) != 0) { 308 i = (size_t) (tmp - end); 309 j = strlen(off); 310 tmp = strdup(end); 311 chop_out(tmp, (unsigned) i, (unsigned) j); 312 free(off); 313 result = tmp; 314 } 315 TR(TRACE_DATABASE, ("...adjusted sgr0 : %s", _nc_visbuf(result))); 316 if (!strcmp(result, exit_attribute_mode)) { 317 TR(TRACE_DATABASE, ("...same result, discard")); 318 free(result); 319 result = exit_attribute_mode; 320 } 321 } else { 322 /* 323 * Either the sgr does not reference alternate character set, 324 * or it is incorrect. That's too hard to decide right now. 325 */ 326 free(off); 327 } 328 FreeIfNeeded(end); 329 FreeIfNeeded(on); 330 } else { 331 /* 332 * Possibly some applications are confused if sgr0 contains rmacs, 333 * but that would be a different bug report -TD 334 */ 335 } 336 337 returnPtr(result); 338 } 339