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1 | // Author: Kirill Gavrilov |
2 | // Copyright (c) 2016-2019 OPEN CASCADE SAS |
3 | // |
4 | // This file is part of Open CASCADE Technology software library. |
5 | // |
6 | // This library is free software; you can redistribute it and/or modify it under |
7 | // the terms of the GNU Lesser General Public License version 2.1 as published |
8 | // by the Free Software Foundation, with special exception defined in the file |
9 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
10 | // distribution for complete text of the license and disclaimer of any warranty. |
11 | // |
12 | // Alternatively, this file may be used under the terms of Open CASCADE |
13 | // commercial license or contractual agreement. |
14 | |
15 | #include <FSD_Base64Decoder.hxx> |
16 | |
17 | #include <Message.hxx> |
18 | #include <Message_Messenger.hxx> |
19 | |
20 | // ======================================================================= |
21 | // function : Decode |
22 | // purpose : |
23 | // ======================================================================= |
24 | Handle(NCollection_Buffer) FSD_Base64Decoder::Decode (const Standard_Byte* theStr, |
25 | const Standard_Size theLen) |
26 | { |
27 | //! Look-up table for decoding base64 stream. |
28 | static const Standard_Byte THE_BASE64_FROM[128] = |
29 | { |
30 | 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, |
31 | 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, |
32 | 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 62, 255, 63, |
33 | 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 0, 255, 255, 255, |
34 | 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, |
35 | 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 63, |
36 | 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, |
37 | 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255, 255, 255, 255, 255 |
38 | }; |
39 | |
40 | Handle(NCollection_Buffer) aData = new NCollection_Buffer (NCollection_BaseAllocator::CommonBaseAllocator()); |
41 | if (!aData->Allocate (3 * theLen / 4)) |
42 | { |
a87b1b37 |
43 | Message::SendFail ("Fail to allocate memory."); |
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44 | return Handle(NCollection_Buffer)(); |
45 | } |
46 | |
47 | Standard_Byte* aDataPtr = aData->ChangeData(); |
48 | const Standard_Byte* anEnd = theStr + theLen; |
49 | for (const Standard_Byte* aByteIter = theStr; aByteIter < anEnd; aByteIter += 4) |
50 | { |
51 | // get values for each group of four base 64 characters |
52 | const Standard_Byte b4[4] = |
53 | { |
54 | aByteIter + 0 < anEnd && aByteIter[0] <= 'z' ? THE_BASE64_FROM[aByteIter[0]] : Standard_Byte(0xFF), |
55 | aByteIter + 1 < anEnd && aByteIter[1] <= 'z' ? THE_BASE64_FROM[aByteIter[1]] : Standard_Byte(0xFF), |
56 | aByteIter + 2 < anEnd && aByteIter[2] <= 'z' ? THE_BASE64_FROM[aByteIter[2]] : Standard_Byte(0xFF), |
57 | aByteIter + 3 < anEnd && aByteIter[3] <= 'z' ? THE_BASE64_FROM[aByteIter[3]] : Standard_Byte(0xFF) |
58 | }; |
59 | |
60 | // transform into a group of three bytes |
61 | const Standard_Byte b3[3] = |
62 | { |
63 | Standard_Byte(((b4[0] & 0x3F) << 2) + ((b4[1] & 0x30) >> 4)), |
64 | Standard_Byte(((b4[1] & 0x0F) << 4) + ((b4[2] & 0x3C) >> 2)), |
65 | Standard_Byte(((b4[2] & 0x03) << 6) + ((b4[3] & 0x3F) >> 0)) |
66 | }; |
67 | |
68 | // add the byte to the return value if it isn't part of an '=' character (indicated by 0xFF) |
69 | if (b4[1] != 0xFF) |
70 | { |
71 | *aDataPtr = b3[0]; |
72 | ++aDataPtr; |
73 | } |
74 | if (b4[2] != 0xFF) |
75 | { |
76 | *aDataPtr = b3[1]; |
77 | ++aDataPtr; |
78 | } |
79 | if (b4[3] != 0xFF) |
80 | { |
81 | *aDataPtr = b3[2]; |
82 | ++aDataPtr; |
83 | } |
84 | } |
85 | |
86 | return aData; |
87 | } |