|
1 // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies). |
|
2 // All rights reserved. |
|
3 // This component and the accompanying materials are made available |
|
4 // under the terms of "Eclipse Public License v1.0" |
|
5 // which accompanies this distribution, and is available |
|
6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
|
7 // |
|
8 // Initial Contributors: |
|
9 // Nokia Corporation - initial contribution. |
|
10 // |
|
11 // Contributors: |
|
12 // |
|
13 // Description: |
|
14 // TBase64.cpp |
|
15 // |
|
16 // |
|
17 |
|
18 #include <tconvbase64.h> |
|
19 |
|
20 /** |
|
21 TBase64 constructor |
|
22 */ |
|
23 EXPORT_C TBase64::TBase64(): iShiftStored(0), iMaskShiftStored(ESix) |
|
24 {} |
|
25 |
|
26 |
|
27 /** |
|
28 Encodes an ASCII string to Base64 string. |
|
29 |
|
30 @param aSrcString The source string in ASCII code. |
|
31 @param rDestString The destination string with converted base64 values. |
|
32 @return Number of characters in the source string that were not Encoded. |
|
33 */ |
|
34 EXPORT_C TInt TBase64::Encode(const TDesC8& aSrcString, TDes8& rDestString) |
|
35 { |
|
36 // Clears the destination string |
|
37 rDestString.Zero(); |
|
38 // Initialise variables |
|
39 const TUint8* srcStringPtr=aSrcString.Ptr(); |
|
40 const TUint8* srcStringEnd=aSrcString.Length()+srcStringPtr; |
|
41 TUint8* destStringPtr=(TUint8*)rDestString.Ptr(); |
|
42 TUint8* destStringPtrBase=destStringPtr; |
|
43 TInt character=0; |
|
44 TUint8 encodedChar=0; |
|
45 TInt charStorage=0; |
|
46 TInt maskShift=EZero; |
|
47 TInt destStringCharNum = 0; |
|
48 |
|
49 while(srcStringPtr<=srcStringEnd) |
|
50 { |
|
51 // maskShift is used as a char read counter |
|
52 if(maskShift==ESix) |
|
53 { |
|
54 // If the 3rd char read is also the last char then the while loop |
|
55 // is broken on the next check. |
|
56 if(srcStringPtr==srcStringEnd) |
|
57 srcStringPtr++; |
|
58 maskShift=EZero; |
|
59 character=0; |
|
60 } |
|
61 else |
|
62 { |
|
63 if(srcStringPtr==srcStringEnd) |
|
64 character=0; |
|
65 else |
|
66 character=*srcStringPtr; |
|
67 |
|
68 srcStringPtr++; |
|
69 // Shifts charStorage ready for the next char |
|
70 charStorage=charStorage<<8; |
|
71 maskShift+=ETwo; |
|
72 } |
|
73 charStorage=charStorage|character; |
|
74 // Shifts the mask to the correct bit location |
|
75 // Masks (AND's) the valid bits from charStorage |
|
76 // Shifts the valid bits into the low order 8bits |
|
77 // Converts to BASE64 char, Casts the result to an unsigned char (which it should be ?....I hope) |
|
78 encodedChar=(TUint8)Base64ToAscii[((charStorage>>maskShift)&ESixBitMask)]; |
|
79 |
|
80 *destStringPtr++=encodedChar; |
|
81 destStringCharNum++; |
|
82 |
|
83 // Add a CRLF every KMaxB64EncodedCharsPerLine characters so as not to exceed the line length |
|
84 // limitation specified in RFC 2822. |
|
85 if (destStringCharNum == KMaxB64EncodedCharsPerLine) |
|
86 { |
|
87 destStringCharNum = 0; |
|
88 *destStringPtr++ = '\r'; |
|
89 *destStringPtr++ = '\n'; |
|
90 } |
|
91 } |
|
92 |
|
93 // Check for not enough chars and pad if required |
|
94 if (maskShift==EFour) |
|
95 { |
|
96 *destStringPtr++=KImcvConvEquals; |
|
97 *destStringPtr++=KImcvConvEquals; |
|
98 } |
|
99 else |
|
100 if(maskShift==ESix) |
|
101 *destStringPtr++=KImcvConvEquals; |
|
102 |
|
103 rDestString.SetLength((TInt)(destStringPtr-destStringPtrBase)); |
|
104 return ((TInt)(srcStringPtr-srcStringEnd)); |
|
105 } |
|
106 |
|
107 /** |
|
108 Decodes the Base64 string to ASCII pattern. |
|
109 |
|
110 @param aSrcString The source string in Base64 codeset. |
|
111 @param rDestString The destination string with converted ASCII code values. |
|
112 @return ETrue if aSrcString is not long enough to decode fully, resulting in the storage of |
|
113 the last character and requiring another aSrcString (poss 0 length) to be passed to it to clear this character. |
|
114 Returns EFalse if the line was decoded OK or the end of the encoded file is reached ie "=" |
|
115 */ |
|
116 EXPORT_C TBool TBase64::Decode(const TDesC8& aSrcString, TDes8& rDestString) |
|
117 { |
|
118 TInt decodedInt=0; |
|
119 TInt8 offsetChar=0; |
|
120 TUint8 decodedChar=0; |
|
121 |
|
122 // Clears the destination string |
|
123 rDestString.Zero(); |
|
124 |
|
125 // Initialise variables |
|
126 const TUint8* srcStringPtr=aSrcString.Ptr(); |
|
127 const TUint8* srcStringEnd=aSrcString.Length()+srcStringPtr; |
|
128 TUint8* destStringPtr=(TUint8*)rDestString.Ptr(); |
|
129 TUint8* destStringPtrBase=destStringPtr; |
|
130 |
|
131 TInt maskShift=iMaskShiftStored; |
|
132 TInt shiftStorage=iShiftStored; |
|
133 |
|
134 // Main character process loop |
|
135 while(srcStringPtr<srcStringEnd) |
|
136 { |
|
137 offsetChar=(TInt8)(*srcStringPtr-KImcvLookUpStartOffset); |
|
138 srcStringPtr++; |
|
139 |
|
140 // Check for valid B64 character |
|
141 if((offsetChar>=0)&&(offsetChar<80)) |
|
142 { |
|
143 // Read in next character and B64 decode |
|
144 decodedInt=AsciiToBase64[offsetChar]; |
|
145 |
|
146 // Exits when a PAD char is reached |
|
147 if(decodedInt==EPadChar) |
|
148 { |
|
149 rDestString.SetLength((TInt)(destStringPtr-destStringPtrBase)); |
|
150 return EFalse; |
|
151 } |
|
152 |
|
153 // Ensures the first 2 chars of 4 are received before processing |
|
154 if(maskShift==ESix) |
|
155 maskShift=EFour; |
|
156 else |
|
157 { |
|
158 shiftStorage=shiftStorage<<ESix; |
|
159 shiftStorage=shiftStorage|decodedInt; |
|
160 decodedChar=(TUint8)((shiftStorage>>maskShift)&EEightBitMask); |
|
161 |
|
162 if((maskShift-=ETwo)<EZero) |
|
163 maskShift=ESix; |
|
164 |
|
165 *destStringPtr++=decodedChar; |
|
166 } |
|
167 shiftStorage=decodedInt; |
|
168 } |
|
169 } |
|
170 iShiftStored=shiftStorage; |
|
171 iMaskShiftStored=maskShift; |
|
172 |
|
173 rDestString.SetLength((TInt)(destStringPtr-destStringPtrBase)); |
|
174 |
|
175 return maskShift<ESix; |
|
176 } |