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authorMike Buland <eichlan@xagasoft.com>2012-05-03 07:23:37 +0000
committerMike Buland <eichlan@xagasoft.com>2012-05-03 07:23:37 +0000
commit0214b67982bfbba8184057f8423bd69b50c6dd3f (patch)
tree8cfb6b4d83ea19ee955c0ef49cda654e14b88f0e /src/experimental/cipher.h
parentdf6a899ad6c9a1c792582ef1a3b838c7eb6d330c (diff)
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The cipher base class does nice buffering now based on the blocksize. This
means that you can write odd numbers of bytes or read odd numbers of bytes from/to the ciphers and it'll just buffer until it gets a full block. Next up is adding padding support. Right now it doesn't flush the buffers with padding if you don't fill the last block. For that matter, it doesn't do any padding at all.
Diffstat (limited to '')
-rw-r--r--src/experimental/cipher.h87
1 files changed, 55 insertions, 32 deletions
diff --git a/src/experimental/cipher.h b/src/experimental/cipher.h
index 9e6f87d..6e1fa69 100644
--- a/src/experimental/cipher.h
+++ b/src/experimental/cipher.h
@@ -2,6 +2,7 @@
2#define BU_CIPHER_H 2#define BU_CIPHER_H
3 3
4#include "bu/filter.h" 4#include "bu/filter.h"
5#include "bu/util.h"
5 6
6namespace Bu 7namespace Bu
7{ 8{
@@ -10,7 +11,10 @@ namespace Bu
10 { 11 {
11 public: 12 public:
12 Cipher( Bu::Stream &rNext ) : 13 Cipher( Bu::Stream &rNext ) :
13 Bu::Filter( rNext ) 14 Bu::Filter( rNext ),
15 iReadBufFill( 0 ),
16 iReadBufPos( 0 ),
17 iWriteBufFill( 0 )
14 { 18 {
15 } 19 }
16 20
@@ -29,47 +33,59 @@ namespace Bu
29 33
30 virtual Bu::size read( void *pBuf, Bu::size iBytes ) 34 virtual Bu::size read( void *pBuf, Bu::size iBytes )
31 { 35 {
32 uint32_t i; 36 Bu::size iRead = 0;
33 37 while( iRead < iBytes )
34 if (iBytes%iBlockSize)
35 {
36 return 0;
37 }
38
39 iBytes /= iBlockSize;
40
41 for (i=0;i<iBytes;i++)
42 { 38 {
43 void *pSeg = ((char *)pBuf)+(i*iBlockSize); 39 if( iReadBufFill < iBlockSize )
44 int iRead = rNext.read( pSeg, iBlockSize ); 40 {
45 decipher( pSeg ); 41 int iR = rNext.read(
42 aReadBuf+iReadBufFill,
43 iBlockSize-iReadBufFill
44 );
45 if( iR == 0 )
46 return iRead;
47
48 iReadBufFill += iR;
49
50 if( iReadBufFill == iBlockSize )
51 decipher( aReadBuf );
52 }
53
54 if( iReadBufFill == iBlockSize )
55 {
56 int iCpy = Bu::min( (int)(iBytes-iRead), iBlockSize-iReadBufPos );
57 memcpy( ((char *)pBuf)+iRead, aReadBuf+iReadBufPos, iCpy );
58 iRead += iCpy;
59 iReadBufPos += iCpy;
60 if( iReadBufPos == iBlockSize )
61 {
62 iReadBufPos = iReadBufFill = 0;
63 }
64 }
46 } 65 }
47 66
48 return iBytes*iBlockSize; 67 return iRead;
49 } 68 }
50 69
51 virtual Bu::size write( const void *pBuf, Bu::size iBytes ) 70 virtual Bu::size write( const void *pBuf, Bu::size iBytes )
52 { 71 {
53 uint32_t i; 72 Bu::size iPos = 0;
54 73
55 if (iBytes%iBlockSize) 74 while( iPos < iBytes )
56 { 75 {
57 return 0; 76 int iLeft = Bu::min((int)(iBytes-iPos),iBlockSize-iReadBufFill);
77 memcpy( aReadBuf+iReadBufFill, (char *)pBuf+iPos, iLeft );
78 iPos += iLeft;
79 iReadBufFill += iLeft;
80 if( iReadBufFill == iBlockSize )
81 {
82 encipher( aReadBuf );
83 rNext.write( aReadBuf, iBlockSize );
84 iReadBufFill = 0;
85 }
58 } 86 }
59 87
60 iBytes /= iBlockSize; 88 return iPos;
61
62 char buf[iBlockSize];
63
64 for (i=0;i<iBytes;i++)
65 {
66 memcpy( buf, ((const char *)pBuf)+(i*iBlockSize), 8 );
67 encipher( buf );
68 rNext.write( buf, iBlockSize );
69 }
70
71 memset( &buf, 0, iBlockSize );
72 return iBytes*iBlockSize;
73 } 89 }
74 90
75 using Bu::Stream::read; 91 using Bu::Stream::read;
@@ -78,6 +94,13 @@ namespace Bu
78 protected: 94 protected:
79 virtual void encipher( void *pData )=0; 95 virtual void encipher( void *pData )=0;
80 virtual void decipher( void *pData )=0; 96 virtual void decipher( void *pData )=0;
97
98 private:
99 char aReadBuf[iBlockSize];
100 char aWriteBuf[iBlockSize];
101 int iReadBufFill;
102 int iReadBufPos;
103 int iWriteBufFill;
81 }; 104 };
82}; 105};
83 106