comphelper/source/misc/base64.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <sal/config.h>
  21
  22 #include <cstddef>
  23
  24 #include <comphelper/base64.hxx>
  25
  26 #include <com/sun/star/uno/Sequence.hxx>
  27
  28 #include <o3tl/safeint.hxx>
  29 #include <osl/diagnose.h>
  30
  31 using namespace com::sun::star;
  32
  33 namespace comphelper {
  34
  35 const
  36   char aBase64EncodeTable[] =
  37     { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
  38       'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
  39       'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
  40       'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  41       '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };
  42
  43 const
  44   sal_uInt8 aBase64DecodeTable[]  =
  45     {                                            62,255,255,255, 63, // 43-47
  46 //                                                +               /
  47
  48      52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,  0,255,255, // 48-63
  49 //    0   1   2   3   4   5   6   7   8   9               =
  50
  51     255,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, // 64-79
  52 //        A   B   C   D   E   F   G   H   I   J   K   L   M   N   O
  53
  54      15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255, // 80-95
  55 //    P   Q   R   S   T   U   V   W   X   Y   Z
  56
  57       0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 96-111
  58 //        a   b   c   d   e   f   g   h   i   j   k   l   m   n   o
  59
  60      41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 }; // 112-123
  61 //    p   q   r   s   t   u   v   w   x   y   z
  62
  63
  64 template <typename C>
  65 static void ThreeByteToFourByte(const sal_Int8* pBuffer, const sal_Int32 nStart, const sal_Int32 nFullLen, C* aCharBuffer)
  66 {
  67     const sal_Int32 nLen(std::min(nFullLen - nStart, sal_Int32(3)));
  68     assert(nLen > 0); // We are never expected to leave the output buffer uninitialized
  69
  70     sal_Int32 nBinaer;
  71     switch (nLen)
  72     {
  73         case 1:
  74         {
  75             nBinaer = static_cast<sal_uInt8>(pBuffer[nStart + 0]) << 16;
  76         }
  77         break;
  78         case 2:
  79         {
  80             nBinaer = (static_cast<sal_uInt8>(pBuffer[nStart + 0]) << 16) +
  81                     (static_cast<sal_uInt8>(pBuffer[nStart + 1]) <<  8);
  82         }
  83         break;
  84         default:
  85         {
  86             nBinaer = (static_cast<sal_uInt8>(pBuffer[nStart + 0]) << 16) +
  87                     (static_cast<sal_uInt8>(pBuffer[nStart + 1]) <<  8) +
  88                     static_cast<sal_uInt8>(pBuffer[nStart + 2]);
  89         }
  90         break;
  91     }
  92
  93     aCharBuffer[2] = aCharBuffer[3] = '=';
  94
  95     sal_uInt8 nIndex (static_cast<sal_uInt8>((nBinaer & 0xFC0000) >> 18));
  96     aCharBuffer[0] = aBase64EncodeTable [nIndex];
  97
  98     nIndex = static_cast<sal_uInt8>((nBinaer & 0x3F000) >> 12);
  99     aCharBuffer[1] = aBase64EncodeTable [nIndex];
 100     if (nLen > 1)
 101     {
 102         nIndex = static_cast<sal_uInt8>((nBinaer & 0xFC0) >> 6);
 103         aCharBuffer[2] = aBase64EncodeTable [nIndex];
 104         if (nLen > 2)
 105         {
 106             nIndex = static_cast<sal_uInt8>((nBinaer & 0x3F));
 107             aCharBuffer[3] = aBase64EncodeTable [nIndex];
 108         }
 109     }
 110 }
 111
 112 template <typename Buffer>
 113 static void base64encode(Buffer& aStrBuffer, const uno::Sequence<sal_Int8>& aPass)
 114 {
 115     sal_Int32 i(0);
 116     sal_Int32 nBufferLength(aPass.getLength());
 117     aStrBuffer.ensureCapacity(aStrBuffer.getLength() + (nBufferLength * 4 + 2) / 3);
 118     const sal_Int8* pBuffer = aPass.getConstArray();
 119     while (i < nBufferLength)
 120     {
 121         ThreeByteToFourByte(pBuffer, i, nBufferLength, aStrBuffer.appendUninitialized(4));
 122         i += 3;
 123     }
 124 }
 125
 126 void Base64::encode(OStringBuffer& aStrBuffer, const uno::Sequence<sal_Int8>& aPass)
 127 {
 128     base64encode(aStrBuffer, aPass);
 129 }
 130
 131 void Base64::encode(OUStringBuffer& aStrBuffer, const uno::Sequence<sal_Int8>& aPass)
 132 {
 133     base64encode(aStrBuffer, aPass);
 134 }
 135
 136 void Base64::decode(uno::Sequence<sal_Int8>& aBuffer, std::u16string_view sBuffer)
 137 {
 138     std::size_t nCharsDecoded = decodeSomeChars( aBuffer, sBuffer );
 139     OSL_ENSURE( nCharsDecoded == sBuffer.size(), "some bytes left in base64 decoding!" );
 140 }
 141
 142 std::size_t Base64::decodeSomeChars(uno::Sequence<sal_Int8>& rOutBuffer, std::u16string_view rInBuffer)
 143 {
 144     std::size_t nInBufferLen = rInBuffer.size();
 145     std::size_t nMinOutBufferLen = (nInBufferLen / 4) * 3;
 146     if( o3tl::make_unsigned(rOutBuffer.getLength()) < nMinOutBufferLen )
 147         rOutBuffer.realloc( nMinOutBufferLen );
 148
 149     const sal_Unicode *pInBuffer = rInBuffer.data();
 150     sal_Int8 *pOutBuffer = rOutBuffer.getArray();
 151     sal_Int8 *pOutBufferStart = pOutBuffer;
 152     std::size_t nCharsDecoded = 0;
 153
 154     sal_uInt8 aDecodeBuffer[4];
 155     sal_Int32 nBytesToDecode = 0;
 156     sal_Int32 nBytesGotFromDecoding = 3;
 157     std::size_t nInBufferPos= 0;
 158     while( nInBufferPos < nInBufferLen )
 159     {
 160         sal_Unicode cChar = *pInBuffer;
 161         if( cChar >= '+' && cChar <= 'z' )
 162         {
 163             sal_uInt8 nByte = aBase64DecodeTable[cChar-'+'];
 164             if( nByte != 255 )
 165             {
 166                 // We have found a valid character!
 167                 aDecodeBuffer[nBytesToDecode++] = nByte;
 168
 169                 // One '=' character at the end means 2 out bytes
 170                 // Two '=' characters at the end mean 1 out bytes
 171                 if( '=' == cChar && nBytesToDecode > 2 )
 172                     nBytesGotFromDecoding--;
 173                 if( 4 == nBytesToDecode )
 174                 {
 175                     // Four characters found, so we may convert now!
 176                     sal_uInt32 nOut = (aDecodeBuffer[0] << 18) +
 177                                       (aDecodeBuffer[1] << 12) +
 178                                       (aDecodeBuffer[2] << 6) +
 179                                        aDecodeBuffer[3];
 180
 181                     *pOutBuffer++  = static_cast<sal_Int8>((nOut & 0xff0000) >> 16);
 182                     if( nBytesGotFromDecoding > 1 )
 183                         *pOutBuffer++  = static_cast<sal_Int8>((nOut & 0xff00) >> 8);
 184                     if( nBytesGotFromDecoding > 2 )
 185                         *pOutBuffer++  = static_cast<sal_Int8>(nOut & 0xff);
 186                     nCharsDecoded = nInBufferPos + 1;
 187                     nBytesToDecode = 0;
 188                     nBytesGotFromDecoding = 3;
 189                 }
 190             }
 191             else
 192             {
 193                 nCharsDecoded++;
 194             }
 195         }
 196         else
 197         {
 198             nCharsDecoded++;
 199         }
 200
 201         nInBufferPos++;
 202         pInBuffer++;
 203     }
 204     if( (pOutBuffer - pOutBufferStart) != rOutBuffer.getLength() )
 205         rOutBuffer.realloc( pOutBuffer - pOutBufferStart );
 206
 207     return nCharsDecoded;
 208 }
 209
 210 }
 211
 212 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */