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 <davidel@xmailserver.org>
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 + ignored - (lxch->i1 + lxch->chg1) > (unsigned long)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
def_ff(const char * rec,long len,char * buf,long sz,void * priv)98 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
99 {
100 (void)priv;
101
102 if (len > 0 &&
103 (isalpha((unsigned char)*rec) || /* identifier? */
104 *rec == '_' || /* also identifier? */
105 *rec == '$')) { /* identifiers from VMS and other esoterico */
106 if (len > sz)
107 len = sz;
108 while (0 < len && isspace((unsigned char)rec[len - 1]))
109 len--;
110 memcpy(buf, rec, len);
111 return len;
112 }
113 return -1;
114 }
115
match_func_rec(xdfile_t * xdf,xdemitconf_t const * xecfg,long ri,char * buf,long sz)116 static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
117 char *buf, long sz)
118 {
119 const char *rec;
120 long len = xdl_get_rec(xdf, ri, &rec);
121 if (!xecfg->find_func)
122 return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
123 return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
124 }
125
is_func_rec(xdfile_t * xdf,xdemitconf_t const * xecfg,long ri)126 static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
127 {
128 char dummy[1];
129 return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
130 }
131
132 struct func_line {
133 long len;
134 char buf[80];
135 };
136
get_func_line(xdfenv_t * xe,xdemitconf_t const * xecfg,struct func_line * func_line,long start,long limit)137 static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
138 struct func_line *func_line, long start, long limit)
139 {
140 long l, size, step = (start > limit) ? -1 : 1;
141 char *buf, dummy[1];
142
143 buf = func_line ? func_line->buf : dummy;
144 size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
145
146 for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
147 long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
148 if (len >= 0) {
149 if (func_line)
150 func_line->len = len;
151 return l;
152 }
153 }
154 return -1;
155 }
156
is_empty_rec(xdfile_t * xdf,long ri)157 static int is_empty_rec(xdfile_t *xdf, long ri)
158 {
159 const char *rec;
160 long len = xdl_get_rec(xdf, ri, &rec);
161
162 while (len > 0 && XDL_ISSPACE(*rec)) {
163 rec++;
164 len--;
165 }
166 return !len;
167 }
168
xdl_emit_diff(xdfenv_t * xe,xdchange_t * xscr,xdemitcb_t * ecb,xdemitconf_t const * xecfg)169 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
170 xdemitconf_t const *xecfg) {
171 long s1, s2, e1, e2, lctx;
172 xdchange_t *xch, *xche;
173 long funclineprev = -1;
174 struct func_line func_line = { 0 };
175
176 for (xch = xscr; xch; xch = xche->next) {
177 xche = xdl_get_hunk(&xch, xecfg);
178 if (!xch)
179 break;
180
181 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
182 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
183
184 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
185 long fs1, i1 = xch->i1;
186
187 /* Appended chunk? */
188 if (i1 >= xe->xdf1.nrec) {
189 long i2 = xch->i2;
190
191 /*
192 * We don't need additional context if
193 * a whole function was added.
194 */
195 while (i2 < xe->xdf2.nrec) {
196 if (is_func_rec(&xe->xdf2, xecfg, i2))
197 goto post_context_calculation;
198 i2++;
199 }
200
201 /*
202 * Otherwise get more context from the
203 * pre-image.
204 */
205 i1 = xe->xdf1.nrec - 1;
206 }
207
208 fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
209 while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
210 !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
211 fs1--;
212 if (fs1 < 0)
213 fs1 = 0;
214 if (fs1 < s1) {
215 s2 -= s1 - fs1;
216 s1 = fs1;
217 }
218 }
219
220 post_context_calculation:
221 lctx = xecfg->ctxlen;
222 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
223 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
224
225 e1 = xche->i1 + xche->chg1 + lctx;
226 e2 = xche->i2 + xche->chg2 + lctx;
227
228 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
229 long fe1 = get_func_line(xe, xecfg, NULL,
230 xche->i1 + xche->chg1,
231 xe->xdf1.nrec);
232 while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
233 fe1--;
234 if (fe1 < 0)
235 fe1 = xe->xdf1.nrec;
236 if (fe1 > e1) {
237 e2 += fe1 - e1;
238 e1 = fe1;
239 }
240
241 /*
242 * Overlap with next change? Then include it
243 * in the current hunk and start over to find
244 * its new end.
245 */
246 if (xche->next) {
247 long l = XDL_MIN(xche->next->i1,
248 xe->xdf1.nrec - 1);
249 if (l - xecfg->ctxlen <= e1 ||
250 get_func_line(xe, xecfg, NULL, l, e1) < 0) {
251 xche = xche->next;
252 goto post_context_calculation;
253 }
254 }
255 }
256
257 /*
258 * Emit current hunk header.
259 */
260
261 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
262 get_func_line(xe, xecfg, &func_line,
263 s1 - 1, funclineprev);
264 funclineprev = s1 - 1;
265 }
266 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
267 func_line.buf, func_line.len, ecb) < 0)
268 return -1;
269
270 /*
271 * Emit pre-context.
272 */
273 for (; s2 < xch->i2; s2++)
274 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
275 return -1;
276
277 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
278 /*
279 * Merge previous with current change atom.
280 */
281 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
282 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
283 return -1;
284
285 /*
286 * Removes lines from the first file.
287 */
288 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
289 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
290 return -1;
291
292 /*
293 * Adds lines from the second file.
294 */
295 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
296 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
297 return -1;
298
299 if (xch == xche)
300 break;
301 s1 = xch->i1 + xch->chg1;
302 s2 = xch->i2 + xch->chg2;
303 }
304
305 /*
306 * Emit post-context.
307 */
308 for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
309 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
310 return -1;
311 }
312
313 return 0;
314 }
315