xdiff: factor out get_func_line()
[git/git.git] / xdiff / xemit.c
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
23 #include "xinclude.h"
24
25
26
27
28 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
29 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
30
31
32
33
34 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
35
36 *rec = xdf->recs[ri]->ptr;
37
38 return xdf->recs[ri]->size;
39 }
40
41
42 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
43 long size, psize = strlen(pre);
44 char const *rec;
45
46 size = xdl_get_rec(xdf, ri, &rec);
47 if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
48
49 return -1;
50 }
51
52 return 0;
53 }
54
55
56 /*
57 * Starting at the passed change atom, find the latest change atom to be included
58 * inside the differential hunk according to the specified configuration.
59 */
60 xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
61 xdchange_t *xch, *xchp;
62 long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
63
64 for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
65 if (xch->i1 - (xchp->i1 + xchp->chg1) > max_common)
66 break;
67
68 return xchp;
69 }
70
71
72 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
73 {
74 if (len > 0 &&
75 (isalpha((unsigned char)*rec) || /* identifier? */
76 *rec == '_' || /* also identifier? */
77 *rec == '$')) { /* identifiers from VMS and other esoterico */
78 if (len > sz)
79 len = sz;
80 while (0 < len && isspace((unsigned char)rec[len - 1]))
81 len--;
82 memcpy(buf, rec, len);
83 return len;
84 }
85 return -1;
86 }
87
88 static int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
89 xdemitconf_t const *xecfg) {
90 xdfile_t *xdf = &xe->xdf1;
91 const char *rchg = xdf->rchg;
92 long ix;
93
94 for (ix = 0; ix < xdf->nrec; ix++) {
95 if (rchg[ix])
96 continue;
97 if (xdl_emit_record(xdf, ix, "", ecb))
98 return -1;
99 }
100 return 0;
101 }
102
103 struct func_line {
104 long len;
105 char buf[80];
106 };
107
108 static void get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
109 struct func_line *func_line, long start, long limit)
110 {
111 find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
112 long l, size = sizeof(func_line->buf);
113 char *buf = func_line->buf;
114
115 for (l = start; l > limit && 0 <= l; l--) {
116 const char *rec;
117 long reclen = xdl_get_rec(&xe->xdf1, l, &rec);
118 long len = ff(rec, reclen, buf, size, xecfg->find_func_priv);
119 if (len >= 0) {
120 func_line->len = len;
121 break;
122 }
123 }
124 }
125
126 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
127 xdemitconf_t const *xecfg) {
128 long s1, s2, e1, e2, lctx;
129 xdchange_t *xch, *xche;
130 long funclineprev = -1;
131 struct func_line func_line = { 0 };
132
133 if (xecfg->flags & XDL_EMIT_COMMON)
134 return xdl_emit_common(xe, xscr, ecb, xecfg);
135
136 for (xch = xscr; xch; xch = xche->next) {
137 xche = xdl_get_hunk(xch, xecfg);
138
139 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
140 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
141
142 lctx = xecfg->ctxlen;
143 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
144 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
145
146 e1 = xche->i1 + xche->chg1 + lctx;
147 e2 = xche->i2 + xche->chg2 + lctx;
148
149 /*
150 * Emit current hunk header.
151 */
152
153 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
154 get_func_line(xe, xecfg, &func_line,
155 s1 - 1, funclineprev);
156 funclineprev = s1 - 1;
157 }
158 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
159 func_line.buf, func_line.len, ecb) < 0)
160 return -1;
161
162 /*
163 * Emit pre-context.
164 */
165 for (; s1 < xch->i1; s1++)
166 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
167 return -1;
168
169 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
170 /*
171 * Merge previous with current change atom.
172 */
173 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
174 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
175 return -1;
176
177 /*
178 * Removes lines from the first file.
179 */
180 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
181 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
182 return -1;
183
184 /*
185 * Adds lines from the second file.
186 */
187 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
188 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
189 return -1;
190
191 if (xch == xche)
192 break;
193 s1 = xch->i1 + xch->chg1;
194 s2 = xch->i2 + xch->chg2;
195 }
196
197 /*
198 * Emit post-context.
199 */
200 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
201 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
202 return -1;
203 }
204
205 return 0;
206 }