blob: b7f288eb77d2a8bcc98510f0894ee57947bdbf3d (
plain) (
blame)
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
|
package org.openslx.imagemaster.crcchecker;
import java.io.IOException;
import java.util.zip.CRC32;
public class CRCChecker
{
private static final int blockSize = 16 * 1024 * 1024;
private ImageFile imageFile;
private CRCFile crcFile;
private byte[] block = new byte[ blockSize ]; // array that is used to read the blocks
/**
* Initialize a crc checker with an image file and a crc file.
*
* @param imageFile The image file to check
* @param crcFile The crc file to check against
*/
public CRCChecker( String imageFilename, String crcFilename )
{
this.imageFile = new ImageFile( imageFilename, blockSize );
}
public void done()
{
imageFile.close();
}
public boolean hasValidCrcFile()
{
try {
return crcFile.isValid();
} catch ( IOException e ) {
return false;
}
}
/**
* Checks a chosen block against the crc file.
*
* @param block The block to check
* @return Whether the block was valid or not
* @throws IOException When image or crc file could not be read.
*/
public boolean checkBlock( int blockNumber ) throws IOException
{
if ( !this.hasValidCrcFile() )
return false;
int length;
try {
length = imageFile.getBlock( blockNumber, block );
} catch ( IOException e ) {
throw new IOException( "Could not read image file", e );
}
if ( length <= 0 )
return false;
CRC32 crcCalc = new CRC32();
if ( length == blockSize ) {
crcCalc.update( block );
} else {
crcCalc.update( block, 0, length );
}
int crcSum = Integer.reverseBytes( (int)crcCalc.getValue() );
int crcSumFromFile;
try {
crcSumFromFile = crcFile.getCRCSum( blockNumber );
} catch ( IOException e ) {
throw new IOException( "Could not read CRC file", e );
}
return ( crcSum == crcSumFromFile );
}
}
|
