Base64
1
public class Base64Decoder
2
{
3
char[] source;
4 int length, length2, length3;
5 int blockCount;
6 int paddingCount;
7 public Base64Decoder(char[] input)
8
{
9 int temp=0;
10 source=input;
11 length=input.Length;
12
13 //find how many padding are there
14 for (int x=0;x<2;x++)
15 {
16 if(input[length-x-1]=='=')
17 temp++;
18
}
19 paddingCount=temp;
20 //calculate the blockCount;
21 //assuming all whitespace and carriage returns/newline were removed.
22 blockCount=length/4;
23 length2=blockCount*3;
24 }
25
26 public byte[] GetDecoded()
27 {
28 byte[] buffer=new byte[length];//first conversion result
29 byte[] buffer2=new byte[length2];//decoded array with padding
30
31 for(int x=0;x<length;x++)
32 {
33 buffer[x]=char2sixbit(source[x]);
34 }
35
36 byte b, b1,b2,b3;
37 byte temp1, temp2, temp3, temp4;
38
39 for(int x=0;x<blockCount;x++)
40 {
41 temp1=buffer[x*4];
42 temp2=buffer[x*4+1];
43 temp3=buffer[x*4+2];
44 temp4=buffer[x*4+3];
45
46 b=(byte)(temp1<<2);
47 b1=(byte)((temp2 & 48)>>4);
48 b1+=b;
49
50 b=(byte)((temp2 & 15)<<4);
51 b2=(byte)((temp3 & 60)>>2);
52 b2+=b;
53
54 b=(byte)((temp3 & 3)<<6);
55 b3=temp4;
56 b3+=b;
57
58 buffer2[x*3]=b1;
59 buffer2[x*3+1]=b2;
60 buffer2[x*3+2]=b3;
61 }
62 //remove paddings
63 length3=length2-paddingCount;
64 byte[] result=new byte[length3];
65
66 for(int x=0;x<length3;x++)
67 {
68 result[x]=buffer2[x];
69 }
70
71 return result;
72 }
73
74 private byte char2sixbit(char c)
75 {
76 char[] lookupTable=new char[64]
77 { 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
78 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
79 '0','1','2','3','4','5','6','7','8','9','+','/'};
80 if(c=='=')
81 return 0;
82 else
83 {
84 for (int x=0;x<64;x++)
85 {
86 if (lookupTable[x]==c)
87 return (byte)x;
88 }
89 //should not reach here
90 return 0;
91 }
92
93 }
94
95
}
96
public class Base64Decoder2
{
3
char[] source;4
int length, length2, length3;5
int blockCount;6
int paddingCount;7
public Base64Decoder(char[] input)8
{
9
int temp=0;10
source=input;11
length=input.Length;12
13
//find how many padding are there14
for (int x=0;x<2;x++)15
{16
if(input[length-x-1]=='=')17
temp++;18
}19
paddingCount=temp;20
//calculate the blockCount;21
//assuming all whitespace and carriage returns/newline were removed.22
blockCount=length/4;23
length2=blockCount*3;24
}25
26
public byte[] GetDecoded()27
{28
byte[] buffer=new byte[length];//first conversion result29
byte[] buffer2=new byte[length2];//decoded array with padding30
31
for(int x=0;x<length;x++)32
{33
buffer[x]=char2sixbit(source[x]);34
}35
36
byte b, b1,b2,b3;37
byte temp1, temp2, temp3, temp4;38
39
for(int x=0;x<blockCount;x++)40
{41
temp1=buffer[x*4];42
temp2=buffer[x*4+1];43
temp3=buffer[x*4+2];44
temp4=buffer[x*4+3]; 45
46
b=(byte)(temp1<<2);47
b1=(byte)((temp2 & 48)>>4);48
b1+=b;49
50
b=(byte)((temp2 & 15)<<4);51
b2=(byte)((temp3 & 60)>>2);52
b2+=b;53
54
b=(byte)((temp3 & 3)<<6);55
b3=temp4;56
b3+=b;57
58
buffer2[x*3]=b1;59
buffer2[x*3+1]=b2;60
buffer2[x*3+2]=b3;61
}62
//remove paddings63
length3=length2-paddingCount;64
byte[] result=new byte[length3];65
66
for(int x=0;x<length3;x++)67
{68
result[x]=buffer2[x];69
}70
71
return result;72
}73
74
private byte char2sixbit(char c)75
{76
char[] lookupTable=new char[64]77
{ 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',78
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',79
'0','1','2','3','4','5','6','7','8','9','+','/'};80
if(c=='=')81
return 0;82
else83
{84
for (int x=0;x<64;x++)85
{86
if (lookupTable[x]==c)87
return (byte)x;88
}89
//should not reach here90
return 0;91
}92
93
}94
95
}96
1public class Base64Encoder
2 {
3 byte[] source;
4 int length,length2;
5 int blockCount;
6 int paddingCount;
7 public Base64Encoder(byte[] input)
8 {
9 source=input;
10 length=input.Length;
11 if((length % 3)==0)
12 {
13 paddingCount=0;
14 blockCount=length/3;
15 }
16 else
17 {
18 paddingCount=3-(length % 3);//need to add padding
19 blockCount=(length+paddingCount) / 3;
20 }
21 length2=length+paddingCount;//or blockCount *3
22 }
23
24 public char[] GetEncoded()
25 {
26 byte[] source2;
27 source2=new byte[length2];
28 //copy data over insert padding
29 for (int x=0; x<length2;x++)
30 {
31 if (x<length)
32 {
33 source2[x]=source[x];
34 }
35 else
36 {
37 source2[x]=0;
38 }
39 }
40
41 byte b1, b2, b3;
42 byte temp, temp1, temp2, temp3, temp4;
43 byte[] buffer=new byte[blockCount*4];
44 char[] result=new char[blockCount*4];
45 for (int x=0;x<blockCount;x++)
46 {
47 b1=source2[x*3];
48 b2=source2[x*3+1];
49 b3=source2[x*3+2];
50
51 temp1=(byte)((b1 & 252)>>2);//first
52
53 temp=(byte)((b1 & 3)<<4);
54 temp2=(byte)((b2 & 240)>>4);
55 temp2+=temp; //second
56
57 temp=(byte)((b2 & 15)<<2);
58 temp3=(byte)((b3 & 192)>>6);
59 temp3+=temp; //third
60
61 temp4=(byte)(b3 & 63); //fourth
62
63 buffer[x*4]=temp1;
64 buffer[x*4+1]=temp2;
65 buffer[x*4+2]=temp3;
66 buffer[x*4+3]=temp4;
67
68 }
69
70 for (int x=0; x<blockCount*4;x++)
71 {
72 result[x]=sixbit2char(buffer[x]);
73 }
74
75 //covert last "A"s to "=", based on paddingCount
76 switch (paddingCount)
77 {
78 case 0:break;
79 case 1:result[blockCount*4-1]='=';break;
80 case 2:result[blockCount*4-1]='=';
81 result[blockCount*4-2]='=';
82 break;
83 default:break;
84 }
85 return result;
86 }
87
88 private char sixbit2char(byte b)
89 {
90 char[] lookupTable=new char[64]
91 { 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
92 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
93 '0','1','2','3','4','5','6','7','8','9','+','/'};
94
95 if((b>=0) &&(b<=63))
96 {
97 return lookupTable[(int)b];
98 }
99 else
100 {
101 //should not happen;
102 return ' ';
103 }
104 }
105 }
106
public class Base64Encoder2
{3
byte[] source;4
int length,length2;5
int blockCount;6
int paddingCount;7
public Base64Encoder(byte[] input)8
{9
source=input;10
length=input.Length;11
if((length % 3)==0)12
{13
paddingCount=0;14
blockCount=length/3;15
}16
else17
{18
paddingCount=3-(length % 3);//need to add padding19
blockCount=(length+paddingCount) / 3;20
}21
length2=length+paddingCount;//or blockCount *322
}23
24
public char[] GetEncoded()25
{26
byte[] source2;27
source2=new byte[length2];28
//copy data over insert padding29
for (int x=0; x<length2;x++)30
{31
if (x<length)32
{33
source2[x]=source[x];34
}35
else36
{37
source2[x]=0;38
}39
}40
41
byte b1, b2, b3;42
byte temp, temp1, temp2, temp3, temp4;43
byte[] buffer=new byte[blockCount*4];44
char[] result=new char[blockCount*4];45
for (int x=0;x<blockCount;x++)46
{47
b1=source2[x*3];48
b2=source2[x*3+1];49
b3=source2[x*3+2];50
51
temp1=(byte)((b1 & 252)>>2);//first52
53
temp=(byte)((b1 & 3)<<4);54
temp2=(byte)((b2 & 240)>>4);55
temp2+=temp; //second56
57
temp=(byte)((b2 & 15)<<2);58
temp3=(byte)((b3 & 192)>>6);59
temp3+=temp; //third60
61
temp4=(byte)(b3 & 63); //fourth62
63
buffer[x*4]=temp1;64
buffer[x*4+1]=temp2;65
buffer[x*4+2]=temp3;66
buffer[x*4+3]=temp4;67
68
}69
70
for (int x=0; x<blockCount*4;x++)71
{72
result[x]=sixbit2char(buffer[x]);73
}74
75
//covert last "A"s to "=", based on paddingCount76
switch (paddingCount)77
{78
case 0:break;79
case 1:result[blockCount*4-1]='=';break;80
case 2:result[blockCount*4-1]='=';81
result[blockCount*4-2]='=';82
break;83
default:break;84
}85
return result;86
}87
88
private char sixbit2char(byte b)89
{90
char[] lookupTable=new char[64]91
{ 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',92
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',93
'0','1','2','3','4','5','6','7','8','9','+','/'};94
95
if((b>=0) &&(b<=63))96
{97
return lookupTable[(int)b];98
}99
else100
{101
//should not happen;102
return ' ';103
}104
}105
}106
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