1 /* sdiff-format output routines for GNU DIFF.
2
3 Copyright (C) 1991-1993, 1998, 2001-2002, 2004, 2009-2013, 2015-2023 Free
4 Software Foundation, Inc.
5
6 This file is part of GNU DIFF.
7
8 GNU DIFF is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY. No author or distributor
10 accepts responsibility to anyone for the consequences of using it
11 or for whether it serves any particular purpose or works at all,
12 unless he says so in writing. Refer to the GNU General Public
13 License for full details.
14
15 Everyone is granted permission to copy, modify and redistribute
16 GNU DIFF, but only under the conditions described in the
17 GNU General Public License. A copy of this license is
18 supposed to have been given to you along with GNU DIFF so you
19 can know your rights and responsibilities. It should be in a
20 file named COPYING. Among other things, the copyright notice
21 and this notice must be preserved on all copies. */
22
23 #include "diff.h"
24
25 #include <wchar.h>
26
27 static void print_sdiff_common_lines (lin, lin);
28 static void print_sdiff_hunk (struct change *);
29
30 /* Next line number to be printed in the two input files. */
31 static lin next0, next1;
32
33 /* Print the edit-script SCRIPT as a sdiff style output. */
34
35 void
36 print_sdiff_script (struct change *script)
37 {
38 begin_output ();
39
40 next0 = next1 = - files[0].prefix_lines;
41 print_script (script, find_change, print_sdiff_hunk);
42
43 print_sdiff_common_lines (files[0].valid_lines, files[1].valid_lines);
44 }
45
46 /* Tab from column FROM to column TO, where FROM <= TO. Yield TO. */
47
48 static size_t
49 tab_from_to (size_t from, size_t to)
50 {
51 FILE *out = outfile;
52 size_t tab;
53 size_t tab_size = tabsize;
54
55 if (!expand_tabs)
56 for (tab = from + tab_size - from % tab_size; tab <= to; tab += tab_size)
57 {
58 putc ('\t', out);
59 from = tab;
60 }
61 while (from++ < to)
62 putc (' ', out);
63 return to;
64 }
65
66 /* Print the text for half an sdiff line. This means truncate to
67 width observing tabs, and trim a trailing newline. Return the
68 last column written (not the number of chars). */
69
70 static size_t
71 print_half_line (char const *const *line, size_t indent, size_t out_bound)
72 {
73 FILE *out = outfile;
74 register size_t in_position = 0;
75 register size_t out_position = 0;
76 register char const *text_pointer = line[0];
77 register char const *text_limit = line[1];
78 mbstate_t mbstate = { 0 };
79
80 while (text_pointer < text_limit)
81 {
82 char const *tp0 = text_pointer;
83 register char c = *text_pointer++;
84
85 switch (c)
86 {
87 case '\t':
88 {
89 size_t spaces = tabsize - in_position % tabsize;
90 if (in_position == out_position)
91 {
92 size_t tabstop = out_position + spaces;
93 if (expand_tabs)
94 {
95 if (out_bound < tabstop)
96 tabstop = out_bound;
97 for (; out_position < tabstop; out_position++)
98 putc (' ', out);
99 }
100 else
101 if (tabstop < out_bound)
102 {
103 out_position = tabstop;
104 putc (c, out);
105 }
106 }
107 in_position += spaces;
108 }
109 break;
110
111 case '\r':
112 {
113 putc (c, out);
114 tab_from_to (0, indent);
115 in_position = out_position = 0;
116 }
117 break;
118
119 case '\b':
120 if (in_position != 0 && --in_position < out_bound)
121 {
122 if (out_position <= in_position)
123 /* Add spaces to make up for suppressed tab past out_bound. */
124 for (; out_position < in_position; out_position++)
125 putc (' ', out);
126 else
127 {
128 out_position = in_position;
129 putc (c, out);
130 }
131 }
132 break;
133
134 default:
135 {
136 wchar_t wc;
137 size_t bytes = mbrtowc (&wc, tp0, text_limit - tp0, &mbstate);
138
139 if (0 < bytes && bytes < (size_t) -2)
140 {
141 int width = wcwidth (wc);
142 if (0 < width)
143 in_position += width;
144 if (in_position <= out_bound)
145 {
146 out_position = in_position;
147 fwrite (tp0, 1, bytes, stdout);
148 }
149 text_pointer = tp0 + bytes;
150 break;
151 }
152 }
153 FALLTHROUGH;
154 case '\f':
155 case '\v':
156 if (in_position < out_bound)
157 putc (c, out);
158 break;
159
160 case ' ': case '!': case '"': case '#': case '%':
161 case '&': case '\'': case '(': case ')': case '*':
162 case '+': case ',': case '-': case '.': case '/':
163 case '0': case '1': case '2': case '3': case '4':
164 case '5': case '6': case '7': case '8': case '9':
165 case ':': case ';': case '<': case '=': case '>':
166 case '?':
167 case 'A': case 'B': case 'C': case 'D': case 'E':
168 case 'F': case 'G': case 'H': case 'I': case 'J':
169 case 'K': case 'L': case 'M': case 'N': case 'O':
170 case 'P': case 'Q': case 'R': case 'S': case 'T':
171 case 'U': case 'V': case 'W': case 'X': case 'Y':
172 case 'Z':
173 case '[': case '\\': case ']': case '^': case '_':
174 case 'a': case 'b': case 'c': case 'd': case 'e':
175 case 'f': case 'g': case 'h': case 'i': case 'j':
176 case 'k': case 'l': case 'm': case 'n': case 'o':
177 case 'p': case 'q': case 'r': case 's': case 't':
178 case 'u': case 'v': case 'w': case 'x': case 'y':
179 case 'z': case '{': case '|': case '}': case '~':
180 /* These characters are printable ASCII characters. */
181 if (in_position++ < out_bound)
182 {
183 out_position = in_position;
184 putc (c, out);
185 }
186 break;
187
188 case '\n':
189 return out_position;
190 }
191 }
192
193 return out_position;
194 }
195
196 /* Print side by side lines with a separator in the middle.
197 0 parameters are taken to indicate white space text.
198 Blank lines that can easily be caught are reduced to a single newline. */
199
200 static void
201 print_1sdiff_line (char const *const *left, char sep,
202 char const *const *right)
203 {
204 FILE *out = outfile;
205 size_t hw = sdiff_half_width;
206 size_t c2o = sdiff_column2_offset;
207 size_t col = 0;
208 bool put_newline = false;
209 bool color_to_reset = false;
210
211 if (sep == '<')
212 {
213 set_color_context (DELETE_CONTEXT);
214 color_to_reset = true;
215 }
216 else if (sep == '>')
217 {
218 set_color_context (ADD_CONTEXT);
219 color_to_reset = true;
220 }
221
222 if (left)
223 {
224 put_newline |= left[1][-1] == '\n';
225 col = print_half_line (left, 0, hw);
226 }
227
228 if (sep != ' ')
229 {
230 col = tab_from_to (col, (hw + c2o - 1) / 2) + 1;
231 if (sep == '|' && put_newline != (right[1][-1] == '\n'))
232 sep = put_newline ? '/' : '\\';
233 putc (sep, out);
234 }
235
236 if (right)
237 {
238 put_newline |= right[1][-1] == '\n';
239 if (**right != '\n')
240 {
241 col = tab_from_to (col, c2o);
242 print_half_line (right, col, hw);
243 }
244 }
245
246 if (put_newline)
247 putc ('\n', out);
248
249 if (color_to_reset)
250 set_color_context (RESET_CONTEXT);
251 }
252
253 /* Print lines common to both files in side-by-side format. */
254 static void
255 print_sdiff_common_lines (lin limit0, lin limit1)
256 {
257 lin i0 = next0, i1 = next1;
258
259 if (!suppress_common_lines && (i0 != limit0 || i1 != limit1))
260 {
261 if (sdiff_merge_assist)
262 fprintf (outfile, "i%"pI"d,%"pI"d\n", limit0 - i0, limit1 - i1);
263
264 if (!left_column)
265 {
266 while (i0 != limit0 && i1 != limit1)
267 print_1sdiff_line (&files[0].linbuf[i0++], ' ',
268 &files[1].linbuf[i1++]);
269 while (i1 != limit1)
270 print_1sdiff_line (0, ')', &files[1].linbuf[i1++]);
271 }
272 while (i0 != limit0)
273 print_1sdiff_line (&files[0].linbuf[i0++], '(', 0);
274 }
275
276 next0 = limit0;
277 next1 = limit1;
278 }
279
280 /* Print a hunk of an sdiff diff.
281 This is a contiguous portion of a complete edit script,
282 describing changes in consecutive lines. */
283
284 static void
285 print_sdiff_hunk (struct change *hunk)
286 {
287 lin first0, last0, first1, last1;
288 register lin i, j;
289
290 /* Determine range of line numbers involved in each file. */
291 enum changes changes =
292 analyze_hunk (hunk, &first0, &last0, &first1, &last1);
293 if (!changes)
294 return;
295
296 /* Print out lines up to this change. */
297 print_sdiff_common_lines (first0, first1);
298
299 if (sdiff_merge_assist)
300 fprintf (outfile, "c%"pI"d,%"pI"d\n",
301 last0 - first0 + 1,
302 last1 - first1 + 1);
303
304 /* Print "xxx | xxx " lines. */
305 if (changes == CHANGED)
306 {
307 for (i = first0, j = first1; i <= last0 && j <= last1; i++, j++)
308 print_1sdiff_line (&files[0].linbuf[i], '|', &files[1].linbuf[j]);
309 changes = (i <= last0 ? OLD : 0) + (j <= last1 ? NEW : 0);
310 next0 = first0 = i;
311 next1 = first1 = j;
312 }
313
314 /* Print " > xxx " lines. */
315 if (changes & NEW)
316 {
317 for (j = first1; j <= last1; ++j)
318 print_1sdiff_line (0, '>', &files[1].linbuf[j]);
319 next1 = j;
320 }
321
322 /* Print "xxx < " lines. */
323 if (changes & OLD)
324 {
325 for (i = first0; i <= last0; ++i)
326 print_1sdiff_line (&files[0].linbuf[i], '<', 0);
327 next0 = i;
328 }
329 }