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, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Davide Libenzi <davidel@xmailserver.org>
20 *
21 */
22#include "xinclude.h"
24static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
26 *rec = xdf->recs[ri]->ptr;
28 return xdf->recs[ri]->size;
30}
31static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
34 long size, psize = strlen(pre);
35 char const *rec;
36 size = xdl_get_rec(xdf, ri, &rec);
38 if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
39 return -1;
41 }
42 return 0;
44}
45/*
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 */
52xdchange_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 /* 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 if (xch == NULL ||
64 xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
65 *xscr = xch;
66 }
67 if (*xscr == NULL)
69 return NULL;
70 lxch = *xscr;
72 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 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) > max_common) {
85 break;
86 } else if (!xch->ignore) {
87 lxch = xch;
88 ignored = 0;
89 } else {
90 ignored += xch->chg2;
91 }
92 }
93 return lxch;
95}
96static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
99{
100 if (len > 0 &&
101 (isalpha((unsigned char)*rec) || /* identifier? */
102 *rec == '_' || /* also identifier? */
103 *rec == '$')) { /* identifiers from VMS and other esoterico */
104 if (len > sz)
105 len = sz;
106 while (0 < len && isspace((unsigned char)rec[len - 1]))
107 len--;
108 memcpy(buf, rec, len);
109 return len;
110 }
111 return -1;
112}
113static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
115 char *buf, long sz)
116{
117 const char *rec;
118 long len = xdl_get_rec(xdf, ri, &rec);
119 if (!xecfg->find_func)
120 return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
121 return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
122}
123struct func_line {
125 long len;
126 char buf[80];
127};
128static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
130 struct func_line *func_line, long start, long limit)
131{
132 long l, size, step = (start > limit) ? -1 : 1;
133 char *buf, dummy[1];
134 buf = func_line ? func_line->buf : dummy;
136 size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
137 for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
139 long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
140 if (len >= 0) {
141 if (func_line)
142 func_line->len = len;
143 return l;
144 }
145 }
146 return -1;
147}
148static int is_empty_rec(xdfile_t *xdf, long ri)
150{
151 const char *rec;
152 long len = xdl_get_rec(xdf, ri, &rec);
153 while (len > 0 && XDL_ISSPACE(*rec)) {
155 rec++;
156 len--;
157 }
158 return !len;
159}
160int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
162 xdemitconf_t const *xecfg) {
163 long s1, s2, e1, e2, lctx;
164 xdchange_t *xch, *xche;
165 long funclineprev = -1;
166 struct func_line func_line = { 0 };
167 for (xch = xscr; xch; xch = xche->next) {
169 xche = xdl_get_hunk(&xch, xecfg);
170 if (!xch)
171 break;
172 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
174 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
175 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
177 long fs1, i1 = xch->i1;
178 /* Appended chunk? */
180 if (i1 >= xe->xdf1.nrec) {
181 char dummy[1];
182 long i2 = xch->i2;
183 /*
185 * We don't need additional context if
186 * a whole function was added, possibly
187 * starting with empty lines.
188 */
189 while (i2 < xe->xdf2.nrec &&
190 is_empty_rec(&xe->xdf2, i2))
191 i2++;
192 if (i2 < xe->xdf2.nrec &&
193 match_func_rec(&xe->xdf2, xecfg, i2,
194 dummy, sizeof(dummy)) >= 0)
195 goto post_context_calculation;
196 /*
198 * Otherwise get more context from the
199 * pre-image.
200 */
201 i1 = xe->xdf1.nrec - 1;
202 }
203 fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
205 if (fs1 < 0)
206 fs1 = 0;
207 if (fs1 < s1) {
208 s2 -= s1 - fs1;
209 s1 = fs1;
210 }
211 }
212 post_context_calculation:
214 lctx = xecfg->ctxlen;
215 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
216 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
217 e1 = xche->i1 + xche->chg1 + lctx;
219 e2 = xche->i2 + xche->chg2 + lctx;
220 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
222 long fe1 = get_func_line(xe, xecfg, NULL,
223 xche->i1 + xche->chg1,
224 xe->xdf1.nrec);
225 while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
226 fe1--;
227 if (fe1 < 0)
228 fe1 = xe->xdf1.nrec;
229 if (fe1 > e1) {
230 e2 += fe1 - e1;
231 e1 = fe1;
232 }
233 /*
235 * Overlap with next change? Then include it
236 * in the current hunk and start over to find
237 * its new end.
238 */
239 if (xche->next) {
240 long l = XDL_MIN(xche->next->i1,
241 xe->xdf1.nrec - 1);
242 if (l - xecfg->ctxlen <= e1 ||
243 get_func_line(xe, xecfg, NULL, l, e1) < 0) {
244 xche = xche->next;
245 goto post_context_calculation;
246 }
247 }
248 }
249 /*
251 * Emit current hunk header.
252 */
253 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
255 get_func_line(xe, xecfg, &func_line,
256 s1 - 1, funclineprev);
257 funclineprev = s1 - 1;
258 }
259 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
260 func_line.buf, func_line.len, ecb) < 0)
261 return -1;
262 /*
264 * Emit pre-context.
265 */
266 for (; s2 < xch->i2; s2++)
267 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
268 return -1;
269 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
271 /*
272 * Merge previous with current change atom.
273 */
274 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
275 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
276 return -1;
277 /*
279 * Removes lines from the first file.
280 */
281 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
282 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
283 return -1;
284 /*
286 * Adds lines from the second file.
287 */
288 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
289 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
290 return -1;
291 if (xch == xche)
293 break;
294 s1 = xch->i1 + xch->chg1;
295 s2 = xch->i2 + xch->chg2;
296 }
297 /*
299 * Emit post-context.
300 */
301 for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
302 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
303 return -1;
304 }
305 return 0;
307}