1 /* Context-format output routines for GNU DIFF. 2 Copyright (C) 1988,1989,1991,1992,1993,1994,1998 Free Software Foundation, Inc. 3 4 This file is part of GNU DIFF. 5 6 GNU DIFF is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU DIFF is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 */ 17 18 #include "diff.h" 19 20 static struct change *find_hunk PARAMS((struct change *)); 21 static void find_function PARAMS((struct file_data const *, int, char const **, size_t *)); 22 static void mark_ignorable PARAMS((struct change *)); 23 static void pr_context_hunk PARAMS((struct change *)); 24 static void pr_unidiff_hunk PARAMS((struct change *)); 25 static void print_context_label PARAMS ((char const *, struct file_data *, char const *)); 26 static void print_context_number_range PARAMS((struct file_data const *, int, int)); 27 static void print_unidiff_number_range PARAMS((struct file_data const *, int, int)); 28 29 /* Last place find_function started searching from. */ 30 static int find_function_last_search; 31 32 /* The value find_function returned when it started searching there. */ 33 static int find_function_last_match; 34 35 /* Print a label for a context diff, with a file name and date or a label. */ 36 37 static void 38 print_context_label (mark, inf, label) 39 char const *mark; 40 struct file_data *inf; 41 char const *label; 42 { 43 if (label) 44 printf_output ("%s %s\n", mark, label); 45 else 46 { 47 char const *ct = ctime (&inf->stat.st_mtime); 48 if (!ct) 49 ct = "?\n"; 50 /* See Posix.2 section 4.17.6.1.4 for this format. */ 51 printf_output ("%s %s\t%s", mark, inf->name, ct); 52 } 53 } 54 55 /* Print a header for a context diff, with the file names and dates. */ 56 57 void 58 print_context_header (inf, unidiff_flag) 59 struct file_data inf[]; 60 int unidiff_flag; 61 { 62 if (unidiff_flag) 63 { 64 print_context_label ("---", &inf[0], file_label[0]); 65 print_context_label ("+++", &inf[1], file_label[1]); 66 } 67 else 68 { 69 print_context_label ("***", &inf[0], file_label[0]); 70 print_context_label ("---", &inf[1], file_label[1]); 71 } 72 } 73 74 /* Print an edit script in context format. */ 75 76 void 77 print_context_script (script, unidiff_flag) 78 struct change *script; 79 int unidiff_flag; 80 { 81 if (ignore_blank_lines_flag || ignore_regexp_list) 82 mark_ignorable (script); 83 else 84 { 85 struct change *e; 86 for (e = script; e; e = e->link) 87 e->ignore = 0; 88 } 89 90 find_function_last_search = - files[0].prefix_lines; 91 find_function_last_match = find_function_last_search - 1; 92 93 if (unidiff_flag) 94 print_script (script, find_hunk, pr_unidiff_hunk); 95 else 96 print_script (script, find_hunk, pr_context_hunk); 97 } 98 99 /* Print a pair of line numbers with a comma, translated for file FILE. 100 If the second number is not greater, use the first in place of it. 101 102 Args A and B are internal line numbers. 103 We print the translated (real) line numbers. */ 104 105 static void 106 print_context_number_range (file, a, b) 107 struct file_data const *file; 108 int a, b; 109 { 110 int trans_a, trans_b; 111 translate_range (file, a, b, &trans_a, &trans_b); 112 113 /* Note: we can have B < A in the case of a range of no lines. 114 In this case, we should print the line number before the range, 115 which is B. */ 116 if (trans_b > trans_a) 117 printf_output ("%d,%d", trans_a, trans_b); 118 else 119 printf_output ("%d", trans_b); 120 } 121 122 /* Print a portion of an edit script in context format. 123 HUNK is the beginning of the portion to be printed. 124 The end is marked by a `link' that has been nulled out. 125 126 Prints out lines from both files, and precedes each 127 line with the appropriate flag-character. */ 128 129 static void 130 pr_context_hunk (hunk) 131 struct change *hunk; 132 { 133 int first0, last0, first1, last1, show_from, show_to, i; 134 struct change *next; 135 char const *prefix; 136 char const *function; 137 size_t function_length; 138 139 /* Determine range of line numbers involved in each file. */ 140 141 analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to); 142 143 if (!show_from && !show_to) 144 return; 145 146 /* Include a context's width before and after. */ 147 148 i = - files[0].prefix_lines; 149 first0 = max (first0 - context, i); 150 first1 = max (first1 - context, i); 151 last0 = min (last0 + context, files[0].valid_lines - 1); 152 last1 = min (last1 + context, files[1].valid_lines - 1); 153 154 /* If desired, find the preceding function definition line in file 0. */ 155 function = 0; 156 if (function_regexp_list) 157 find_function (&files[0], first0, &function, &function_length); 158 159 begin_output (); 160 161 /* If we looked for and found a function this is part of, 162 include its name in the header of the diff section. */ 163 printf_output ("***************"); 164 165 if (function) 166 { 167 printf_output (" "); 168 write_output (function, min (function_length - 1, 40)); 169 } 170 171 printf_output ("\n*** "); 172 print_context_number_range (&files[0], first0, last0); 173 printf_output (" ****\n"); 174 175 if (show_from) 176 { 177 next = hunk; 178 179 for (i = first0; i <= last0; i++) 180 { 181 /* Skip past changes that apply (in file 0) 182 only to lines before line I. */ 183 184 while (next && next->line0 + next->deleted <= i) 185 next = next->link; 186 187 /* Compute the marking for line I. */ 188 189 prefix = " "; 190 if (next && next->line0 <= i) 191 /* The change NEXT covers this line. 192 If lines were inserted here in file 1, this is "changed". 193 Otherwise it is "deleted". */ 194 prefix = (next->inserted > 0 ? "!" : "-"); 195 196 print_1_line (prefix, &files[0].linbuf[i]); 197 } 198 } 199 200 printf_output ("--- "); 201 print_context_number_range (&files[1], first1, last1); 202 printf_output (" ----\n"); 203 204 if (show_to) 205 { 206 next = hunk; 207 208 for (i = first1; i <= last1; i++) 209 { 210 /* Skip past changes that apply (in file 1) 211 only to lines before line I. */ 212 213 while (next && next->line1 + next->inserted <= i) 214 next = next->link; 215 216 /* Compute the marking for line I. */ 217 218 prefix = " "; 219 if (next && next->line1 <= i) 220 /* The change NEXT covers this line. 221 If lines were deleted here in file 0, this is "changed". 222 Otherwise it is "inserted". */ 223 prefix = (next->deleted > 0 ? "!" : "+"); 224 225 print_1_line (prefix, &files[1].linbuf[i]); 226 } 227 } 228 } 229 230 /* Print a pair of line numbers with a comma, translated for file FILE. 231 If the second number is smaller, use the first in place of it. 232 If the numbers are equal, print just one number. 233 234 Args A and B are internal line numbers. 235 We print the translated (real) line numbers. */ 236 237 static void 238 print_unidiff_number_range (file, a, b) 239 struct file_data const *file; 240 int a, b; 241 { 242 int trans_a, trans_b; 243 translate_range (file, a, b, &trans_a, &trans_b); 244 245 /* Note: we can have B < A in the case of a range of no lines. 246 In this case, we should print the line number before the range, 247 which is B. */ 248 if (trans_b <= trans_a) 249 printf_output (trans_b == trans_a ? "%d" : "%d,0", trans_b); 250 else 251 printf_output ("%d,%d", trans_a, trans_b - trans_a + 1); 252 } 253 254 /* Print a portion of an edit script in unidiff format. 255 HUNK is the beginning of the portion to be printed. 256 The end is marked by a `link' that has been nulled out. 257 258 Prints out lines from both files, and precedes each 259 line with the appropriate flag-character. */ 260 261 static void 262 pr_unidiff_hunk (hunk) 263 struct change *hunk; 264 { 265 int first0, last0, first1, last1, show_from, show_to, i, j, k; 266 struct change *next; 267 char const *function; 268 size_t function_length; 269 270 /* Determine range of line numbers involved in each file. */ 271 272 analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to); 273 274 if (!show_from && !show_to) 275 return; 276 277 /* Include a context's width before and after. */ 278 279 i = - files[0].prefix_lines; 280 first0 = max (first0 - context, i); 281 first1 = max (first1 - context, i); 282 last0 = min (last0 + context, files[0].valid_lines - 1); 283 last1 = min (last1 + context, files[1].valid_lines - 1); 284 285 /* If desired, find the preceding function definition line in file 0. */ 286 function = 0; 287 if (function_regexp_list) 288 find_function (&files[0], first0, &function, &function_length); 289 290 begin_output (); 291 292 printf_output ("@@ -"); 293 print_unidiff_number_range (&files[0], first0, last0); 294 printf_output (" +"); 295 print_unidiff_number_range (&files[1], first1, last1); 296 printf_output (" @@"); 297 298 /* If we looked for and found a function this is part of, 299 include its name in the header of the diff section. */ 300 301 if (function) 302 { 303 write_output (" ", 1); 304 write_output (function, min (function_length - 1, 40)); 305 } 306 write_output ("\n", 1); 307 308 next = hunk; 309 i = first0; 310 j = first1; 311 312 while (i <= last0 || j <= last1) 313 { 314 315 /* If the line isn't a difference, output the context from file 0. */ 316 317 if (!next || i < next->line0) 318 { 319 write_output (tab_align_flag ? "\t" : " ", 1); 320 print_1_line (0, &files[0].linbuf[i++]); 321 j++; 322 } 323 else 324 { 325 /* For each difference, first output the deleted part. */ 326 327 k = next->deleted; 328 while (k--) 329 { 330 write_output ("-", 1); 331 if (tab_align_flag) 332 write_output ("\t", 1); 333 print_1_line (0, &files[0].linbuf[i++]); 334 } 335 336 /* Then output the inserted part. */ 337 338 k = next->inserted; 339 while (k--) 340 { 341 write_output ("+", 1); 342 if (tab_align_flag) 343 write_output ("\t", 1); 344 print_1_line (0, &files[1].linbuf[j++]); 345 } 346 347 /* We're done with this hunk, so on to the next! */ 348 349 next = next->link; 350 } 351 } 352 } 353 354 /* Scan a (forward-ordered) edit script for the first place that more than 355 2*CONTEXT unchanged lines appear, and return a pointer 356 to the `struct change' for the last change before those lines. */ 357 358 static struct change * 359 find_hunk (start) 360 struct change *start; 361 { 362 struct change *prev; 363 int top0, top1; 364 int thresh; 365 366 do 367 { 368 /* Compute number of first line in each file beyond this changed. */ 369 top0 = start->line0 + start->deleted; 370 top1 = start->line1 + start->inserted; 371 prev = start; 372 start = start->link; 373 /* Threshold distance is 2*CONTEXT between two non-ignorable changes, 374 but only CONTEXT if one is ignorable. */ 375 thresh = ((prev->ignore || (start && start->ignore)) 376 ? context 377 : 2 * context + 1); 378 /* It is not supposed to matter which file we check in the end-test. 379 If it would matter, crash. */ 380 if (start && start->line0 - top0 != start->line1 - top1) 381 abort (); 382 } while (start 383 /* Keep going if less than THRESH lines 384 elapse before the affected line. */ 385 && start->line0 < top0 + thresh); 386 387 return prev; 388 } 389 390 /* Set the `ignore' flag properly in each change in SCRIPT. 391 It should be 1 if all the lines inserted or deleted in that change 392 are ignorable lines. */ 393 394 static void 395 mark_ignorable (script) 396 struct change *script; 397 { 398 while (script) 399 { 400 struct change *next = script->link; 401 int first0, last0, first1, last1, deletes, inserts; 402 403 /* Turn this change into a hunk: detach it from the others. */ 404 script->link = 0; 405 406 /* Determine whether this change is ignorable. */ 407 analyze_hunk (script, &first0, &last0, &first1, &last1, &deletes, &inserts); 408 /* Reconnect the chain as before. */ 409 script->link = next; 410 411 /* If the change is ignorable, mark it. */ 412 script->ignore = (!deletes && !inserts); 413 414 /* Advance to the following change. */ 415 script = next; 416 } 417 } 418 419 /* Find the last function-header line in FILE prior to line number LINENUM. 420 This is a line containing a match for the regexp in `function_regexp'. 421 Store the address of the line text into LINEP and the length of the 422 line into LENP. 423 Do not store anything if no function-header is found. */ 424 425 static void 426 find_function (file, linenum, linep, lenp) 427 struct file_data const *file; 428 int linenum; 429 char const **linep; 430 size_t *lenp; 431 { 432 int i = linenum; 433 int last = find_function_last_search; 434 find_function_last_search = i; 435 436 while (--i >= last) 437 { 438 /* See if this line is what we want. */ 439 struct regexp_list *r; 440 char const *line = file->linbuf[i]; 441 size_t len = file->linbuf[i + 1] - line; 442 443 for (r = function_regexp_list; r; r = r->next) 444 if (0 <= re_search (&r->buf, line, len, 0, len, 0)) 445 { 446 *linep = line; 447 *lenp = len; 448 find_function_last_match = i; 449 return; 450 } 451 } 452 /* If we search back to where we started searching the previous time, 453 find the line we found last time. */ 454 if (find_function_last_match >= - file->prefix_lines) 455 { 456 i = find_function_last_match; 457 *linep = file->linbuf[i]; 458 *lenp = file->linbuf[i + 1] - *linep; 459 return; 460 } 461 return; 462 } 463