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1 /* Context-format output routines for GNU DIFF.

4 This file is part of GNU DIFF.

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.

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.

16 */

18 #include "diff.h"

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));

29 /* Last place find_function started searching from. */

30 static int find_function_last_search;

32 /* The value find_function returned when it started searching there. */

33 static int find_function_last_match;

34 \f

35 /* Print a label for a context diff, with a file name and date or a label. */

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 }

55 /* Print a header for a context diff, with the file names and dates. */

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 }

74 /* Print an edit script in context format. */

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 }

90 find_function_last_search = - files[0].prefix_lines;

91 find_function_last_match = find_function_last_search - 1;

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 \f

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 \f

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 \f

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 \f

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 \f

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 \f

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 }