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[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 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
31
32
33
34
35 static 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
43 static 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  */
61 static 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
72 int 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