1 /*
2 * LibXDiff by Davide Libenzi ( File Differential Library )
3 * Copyright (C) 2003 Davide Libenzi
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, see
17 * <http://www.gnu.org/licenses/>.
18 *
19 * Davide Libenzi <[email protected]>
20 *
21 */
22
23 #include "xinclude.h"
24
xdl_get_rec(xdfile_t * xdf,long ri,char const ** rec)25 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
26
27 *rec = xdf->recs[ri]->ptr;
28
29 return xdf->recs[ri]->size;
30 }
31
32
xdl_emit_record(xdfile_t * xdf,long ri,char const * pre,xdemitcb_t * ecb)33 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
34 long size, psize = (long)strlen(pre);
35 char const *rec;
36
37 size = xdl_get_rec(xdf, ri, &rec);
38 if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
39
40 return -1;
41 }
42
43 return 0;
44 }
45
46
47 /*
48 * Starting at the passed change atom, find the latest change atom to be included
49 * inside the differential hunk according to the specified configuration.
50 * Also advance xscr if the first changes must be discarded.
51 */
xdl_get_hunk(xdchange_t ** xscr,xdemitconf_t const * xecfg)52 xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
53 {
54 xdchange_t *xch, *xchp, *lxch;
55 long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
56 long max_ignorable = xecfg->ctxlen;
57 unsigned long ignored = 0; /* number of ignored blank lines */
58
59 /* remove ignorable changes that are too far before other changes */
60 for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
61 xch = xchp->next;
62
63 if (xch == NULL ||
64 xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
65 *xscr = xch;
66 }
67
68 if (*xscr == NULL)
69 return NULL;
70
71 lxch = *xscr;
72
73 for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
74 long distance = xch->i1 - (xchp->i1 + xchp->chg1);
75 if (distance > max_common)
76 break;
77
78 if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
79 lxch = xch;
80 ignored = 0;
81 } else if (distance < max_ignorable && xch->ignore) {
82 ignored += xch->chg2;
83 } else if (lxch != xchp &&
84 xch->i1 + (long)ignored - (lxch->i1 + lxch->chg1) > max_common) {
85 break;
86 } else if (!xch->ignore) {
87 lxch = xch;
88 ignored = 0;
89 } else {
90 ignored += xch->chg2;
91 }
92 }
93
94 return lxch;
95 }
96
97
98 #if 0
99 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv UNUSED)
100 {
101 if (len > 0 &&
102 (isalpha((unsigned char)*rec) || /* identifier? */
103 *rec == '_' || /* also identifier? */
104 *rec == '$')) { /* identifiers from VMS and other esoterico */
105 if (len > sz)
106 len = sz;
107 while (0 < len && isspace((unsigned char)rec[len - 1]))
108 len--;
109 memcpy(buf, rec, len);
110 return len;
111 }
112 return -1;
113 }
114 #endif
115
116 #if 0
117 static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
118 char *buf, long sz)
119 {
120 const char *rec;
121 long len = xdl_get_rec(xdf, ri, &rec);
122 if (!xecfg->find_func)
123 return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
124 return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
125 }
126 #endif
127
128 #if 0
129 static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
130 {
131 char dummy[1];
132 return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
133 }
134 #endif
135
136 struct func_line {
137 long len;
138 char buf[80];
139 };
140
141 #if 0
142 static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
143 struct func_line *func_line, long start, long limit)
144 {
145 long l, size, step = (start > limit) ? -1 : 1;
146 char *buf, dummy[1];
147
148 buf = func_line ? func_line->buf : dummy;
149 size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
150
151 for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
152 long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
153 if (len >= 0) {
154 if (func_line)
155 func_line->len = len;
156 return l;
157 }
158 }
159 return -1;
160 }
161 #endif
162
163 #if 0
164 static int is_empty_rec(xdfile_t *xdf, long ri)
165 {
166 const char *rec;
167 long len = xdl_get_rec(xdf, ri, &rec);
168
169 while (len > 0 && XDL_ISSPACE(*rec)) {
170 rec++;
171 len--;
172 }
173 return !len;
174 }
175 #endif
176
xdl_emit_diff(xdfenv_t * xe,xdchange_t * xscr,xdemitcb_t * ecb,xdemitconf_t const * xecfg)177 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
178 xdemitconf_t const *xecfg) {
179 long s1, s2, e1, e2, lctx;
180 xdchange_t *xch, *xche;
181 #if 0
182 long funclineprev = -1;
183 #endif
184 struct func_line func_line;
185
186 func_line.len = 0;
187
188 for (xch = xscr; xch; xch = xche->next) {
189 xche = xdl_get_hunk(&xch, xecfg);
190 if (!xch)
191 break;
192
193 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
194 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
195
196 #if 0
197 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
198 long fs1, i1 = xch->i1;
199
200 /* Appended chunk? */
201 if (i1 >= xe->xdf1.nrec) {
202 long i2 = xch->i2;
203
204 /*
205 * We don't need additional context if
206 * a whole function was added.
207 */
208 while (i2 < xe->xdf2.nrec) {
209 if (is_func_rec(&xe->xdf2, xecfg, i2))
210 goto post_context_calculation;
211 i2++;
212 }
213
214 /*
215 * Otherwise get more context from the
216 * pre-image.
217 */
218 i1 = xe->xdf1.nrec - 1;
219 }
220
221 fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
222 while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
223 !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
224 fs1--;
225 if (fs1 < 0)
226 fs1 = 0;
227 if (fs1 < s1) {
228 s2 = XDL_MAX(s2 - (s1 - fs1), 0);
229 s1 = fs1;
230
231 /*
232 * Did we extend context upwards into an
233 * ignored change?
234 */
235 while (xchp != xch &&
236 xchp->i1 + xchp->chg1 <= s1 &&
237 xchp->i2 + xchp->chg2 <= s2)
238 xchp = xchp->next;
239
240 /* If so, show it after all. */
241 if (xchp != xch) {
242 xch = xchp;
243 goto pre_context_calculation;
244 }
245 }
246 }
247
248 post_context_calculation:
249 #endif
250 lctx = xecfg->ctxlen;
251 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
252 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
253
254 e1 = xche->i1 + xche->chg1 + lctx;
255 e2 = xche->i2 + xche->chg2 + lctx;
256
257 #if 0
258 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
259 long fe1 = get_func_line(xe, xecfg, NULL,
260 xche->i1 + xche->chg1,
261 xe->xdf1.nrec);
262 while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
263 fe1--;
264 if (fe1 < 0)
265 fe1 = xe->xdf1.nrec;
266 if (fe1 > e1) {
267 e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
268 e1 = fe1;
269 }
270
271 /*
272 * Overlap with next change? Then include it
273 * in the current hunk and start over to find
274 * its new end.
275 */
276 if (xche->next) {
277 long l = XDL_MIN(xche->next->i1,
278 xe->xdf1.nrec - 1);
279 if (l - xecfg->ctxlen <= e1 ||
280 get_func_line(xe, xecfg, NULL, l, e1) < 0) {
281 xche = xche->next;
282 goto post_context_calculation;
283 }
284 }
285 }
286 #endif
287
288 /*
289 * Emit current hunk header.
290 */
291
292 #if 0
293 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
294 get_func_line(xe, xecfg, &func_line,
295 s1 - 1, funclineprev);
296 funclineprev = s1 - 1;
297 }
298 #endif
299 if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
300 xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
301 func_line.buf, func_line.len, ecb) < 0)
302 return -1;
303
304 /*
305 * Emit pre-context.
306 */
307 for (; s2 < xch->i2; s2++)
308 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
309 return -1;
310
311 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
312 /*
313 * Merge previous with current change atom.
314 */
315 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
316 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
317 return -1;
318
319 /*
320 * Removes lines from the first file.
321 */
322 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
323 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
324 return -1;
325
326 /*
327 * Adds lines from the second file.
328 */
329 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
330 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
331 return -1;
332
333 if (xch == xche)
334 break;
335 s1 = xch->i1 + xch->chg1;
336 s2 = xch->i2 + xch->chg2;
337 }
338
339 /*
340 * Emit post-context.
341 */
342 for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
343 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
344 return -1;
345 }
346
347 return 0;
348 }
349