1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
struct linehash {
unsigned long bytes;
unsigned long hash;
};
static unsigned long hash_extended_line(const unsigned char **buf_p,
unsigned long left)
{
/* An extended line is zero or more whitespace letters (including LF)
* followed by one non whitespace letter followed by zero or more
* non LF, and terminated with by a LF (or EOF).
*/
const unsigned char *bol = *buf_p;
const unsigned char *buf = bol;
unsigned long hashval = 0;
while (left) {
unsigned c = *buf++;
if (!c)
goto binary;
left--;
if (' ' < c) {
hashval = c;
break;
}
}
while (left) {
unsigned c = *buf++;
if (!c)
goto binary;
left--;
if (c == '\n')
break;
if (' ' < c)
hashval = hashval * 11 + c;
}
*buf_p = buf;
return hashval;
binary:
*buf_p = NULL;
return 0;
}
static int linehash_compare(const void *a_, const void *b_)
{
struct linehash *a = (struct linehash *) a_;
struct linehash *b = (struct linehash *) b_;
if (a->hash < b->hash) return -1;
if (a->hash > b->hash) return 1;
return 0;
}
static struct linehash *hash_lines(const unsigned char *buf,
unsigned long size)
{
const unsigned char *eobuf = buf + size;
struct linehash *line = NULL;
int alloc = 0, used = 0;
while (buf < eobuf) {
const unsigned char *ptr = buf;
unsigned long hash = hash_extended_line(&buf, eobuf-ptr);
if (!buf) {
free(line);
return NULL;
}
if (alloc <= used) {
alloc = alloc_nr(alloc);
line = xrealloc(line, sizeof(*line) * alloc);
}
line[used].bytes = buf - ptr;
line[used].hash = hash;
used++;
}
qsort(line, used, sizeof(*line), linehash_compare);
/* Terminate the list */
if (alloc <= used)
line = xrealloc(line, sizeof(*line) * (used+1));
line[used].bytes = line[used].hash = 0;
return line;
}
int diffcore_count_changes(void *src, unsigned long src_size,
void *dst, unsigned long dst_size,
unsigned long delta_limit,
unsigned long *src_copied,
unsigned long *literal_added)
{
struct linehash *src_lines, *dst_lines;
unsigned long sc, la;
src_lines = hash_lines(src, src_size);
if (!src_lines)
return -1;
dst_lines = hash_lines(dst, dst_size);
if (!dst_lines) {
free(src_lines);
return -1;
}
sc = la = 0;
while (src_lines->bytes && dst_lines->bytes) {
int cmp = linehash_compare(src_lines, dst_lines);
if (!cmp) {
sc += src_lines->bytes;
src_lines++;
dst_lines++;
continue;
}
if (cmp < 0) {
src_lines++;
continue;
}
la += dst_lines->bytes;
dst_lines++;
}
while (dst_lines->bytes) {
la += dst_lines->bytes;
dst_lines++;
}
*src_copied = sc;
*literal_added = la;
return 0;
}
|
