1 /* Common parts for printing diff output */
2 /*
3  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <inttypes.h>
19 #include <stdbool.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <unistd.h>
23 
24 #include <diff/arraylist.h>
25 #include <diff/diff_main.h>
26 #include <diff/diff_output.h>
27 
28 static char
29 get_atom_byte(struct diff_atom *atom, off_t off)
30 {
31 	char ch;
32 	off_t cur;
33 
34 	if (atom->at != NULL)
35 		return atom->at[off];
36 
37 	cur = lseek(atom->d->root->fd, 0, SEEK_CUR);
38 	if (cur == -1)
39 		abort(); /* XXX cannot return error */
40 
41 	if (cur != atom->pos + off &&
42 	    lseek(atom->d->root->fd, atom->pos + off, SEEK_SET) == -1)
43 		abort(); /* XXX cannot return error */
44 
45 	if (read(atom->d->root->fd, &ch, sizeof(ch)) == -1)
46 		abort(); /* XXX cannot return error */
47 
48 	return ch;
49 }
50 
51 void
52 diff_output_lines(FILE *dest, const char *prefix, struct diff_atom *start_atom,
53 		  unsigned int count)
54 {
55 	struct diff_atom *atom;
56 	foreach_diff_atom(atom, start_atom, count) {
57 		fprintf(dest, "%s", prefix);
58 		int i;
59 		unsigned int len = atom->len;
60 		if (len) {
61 			char ch;
62 			ch = get_atom_byte(atom, len - 1);
63 			if (ch == '\n')
64 				len--;
65 			if (len) {
66 				ch = get_atom_byte(atom, len - 1);
67 				if (ch == '\r')
68 					len--;
69 			}
70 		}
71 
72 		for (i = 0; i < len; i++) {
73 			char c = get_atom_byte(atom, i);
74 			if ((c < 0x20 || c >= 0x7f) && c != '\t')
75 				fprintf(dest, "\\x%02x", (unsigned char)c);
76 			else
77 				fprintf(dest, "%c", c);
78 		}
79 		fprintf(dest, "\n");
80 	}
81 }