Use a *real* built-in diff generator
[git/git.git] / xdiff / xemit.c
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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
28static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
29static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
30static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
31
32
33
34
35static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
36
37 *rec = xdf->recs[ri]->ptr;
38
39 return xdf->recs[ri]->size;
40}
41
42
43static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
44 long size, psize = strlen(pre);
45 char const *rec;
46
47 size = xdl_get_rec(xdf, ri, &rec);
48 if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
49
50 return -1;
51 }
52
53 return 0;
54}
55
56
57/*
58 * Starting at the passed change atom, find the latest change atom to be included
59 * inside the differential hunk according to the specified configuration.
60 */
61static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
62 xdchange_t *xch, *xchp;
63
64 for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
65 if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
66 break;
67
68 return xchp;
69}
70
71
72int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
73 xdemitconf_t const *xecfg) {
74 long s1, s2, e1, e2, lctx;
75 xdchange_t *xch, *xche;
76
77 for (xch = xche = xscr; xch; xch = xche->next) {
78 xche = xdl_get_hunk(xch, xecfg);
79
80 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
81 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
82
83 lctx = xecfg->ctxlen;
84 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
85 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
86
87 e1 = xche->i1 + xche->chg1 + lctx;
88 e2 = xche->i2 + xche->chg2 + lctx;
89
90 /*
91 * Emit current hunk header.
92 */
93 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2, ecb) < 0)
94 return -1;
95
96 /*
97 * Emit pre-context.
98 */
99 for (; s1 < xch->i1; s1++)
100 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
101 return -1;
102
103 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
104 /*
105 * Merge previous with current change atom.
106 */
107 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
108 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
109 return -1;
110
111 /*
112 * Removes lines from the first file.
113 */
114 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
115 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
116 return -1;
117
118 /*
119 * Adds lines from the second file.
120 */
121 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
122 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
123 return -1;
124
125 if (xch == xche)
126 break;
127 s1 = xch->i1 + xch->chg1;
128 s2 = xch->i2 + xch->chg2;
129 }
130
131 /*
132 * Emit post-context.
133 */
134 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
135 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
136 return -1;
137 }
138
139 return 0;
140}
141