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
|
/*
* adler32.c (c) 2006 Bjorn Lindeijer
* License: GPL, v2 or later
*
* Calculates Adler-32 checksums for all files passed as argument.
*
* Usage: adler32 [file]...
*/
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
//#include <zlib.h>
const uint32_t MOD_ADLER = 65521;
uint32_t adler32(unsigned char *data, size_t len)
/*
where data is the location of the data in physical memory and
len is the length of the data in bytes
*/
{
uint32_t a = 1, b = 0;
size_t index;
// Process each byte of the data in order
for (index = 0; index < len; ++index)
{
a = (a + data[index]) % MOD_ADLER;
b = (b + a) % MOD_ADLER;
}
return (b << 16) | a;
}
/**
* Calculates the Adler-32 checksum for the given file.
*/
unsigned long fadler32(FILE *file)
{
// Obtain file size
fseek(file, 0, SEEK_END);
long fileSize = ftell(file);
rewind(file);
// Calculate Adler-32 checksum
unsigned char *buffer = (unsigned char*) malloc(fileSize);
fread(buffer, 1, fileSize, file);
//unsigned long adler = adler32(0L, Z_NULL, 0);
//adler = adler32(adler, (Bytef*) buffer, fileSize);
unsigned long adler = adler32(buffer, fileSize);
free(buffer);
return adler;
}
/**
* Prints out usage and exists.
*/
void print_usage()
{
printf("Usage: adler32 mode [file]...\n");
exit(0);
}
int main(int argc, char *argv[])
{
int i; /**< Loops through arguments. */
if (argc < 2)
{
print_usage();
}
int mode = atoi(argv[1]);
for (i = 2; i < argc; ++i)
{
FILE *file = fopen(argv[i], "r");
if (!file)
{
printf("Error while opening '%s' for reading!\n", argv[i]);
exit(1);
}
unsigned long adler = fadler32(file);
switch (mode)
{
case 0:
default:
printf("%s %lx\n", argv[i], adler);
break;
case 1:
printf("%lx", adler);
break;
}
fclose(file);
}
return 0;
}
|
