comphelper/source/xml/xmltools.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
  10 #include <comphelper/xmltools.hxx>
  11 #include <rtl/random.h>
  12 #include <boost/static_assert.hpp>
  13 #include <vector>
  14
  15 using namespace com::sun::star;
  16
  17 namespace
  18 {
  19     //Will be inside an xml comment, so can't use '-' in case '--' appears in
  20     //output, etc. Despite what *is* legal in an xml comment, just using the
  21     //base-64 subset to avoid pain with simplistic third-party parsers
  22     static const sal_uInt8 aChaffEncoder[] =
  23     {
  24         'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
  25         'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
  26         'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
  27         'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
  28         'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
  29         'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
  30         'M', 'c', 's', '8', 'N', 'd', 't', '9',
  31         'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
  32
  33         'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
  34         'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
  35         'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
  36         'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
  37         'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
  38         'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
  39         'M', 'c', 's', '8', 'N', 'd', 't', '9',
  40         'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
  41
  42         'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
  43         'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
  44         'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
  45         'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
  46         'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
  47         'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
  48         'M', 'c', 's', '8', 'N', 'd', 't', '9',
  49         'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
  50
  51         'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
  52         'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
  53         'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
  54         'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
  55         'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
  56         'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
  57         'M', 'c', 's', '8', 'N', 'd', 't', '9',
  58         'O', 'e', 'u', '+', 'P', 'f', 'v', '/'
  59     };
  60
  61     void encodeChaff(std::vector<sal_uInt8> &rChaff)
  62     {
  63         BOOST_STATIC_ASSERT(sizeof(aChaffEncoder) == 256);
  64
  65         for (std::vector<sal_uInt8>::iterator aI = rChaff.begin(), aEnd = rChaff.end();
  66             aI != aEnd; ++aI)
  67         {
  68             *aI = aChaffEncoder[*aI];
  69         }
  70     }
  71 }
  72
  73 namespace comphelper
  74 {
  75     namespace xml
  76     {
  77         OString makeXMLChaff()
  78         {
  79             rtlRandomPool pool = rtl_random_createPool();
  80
  81             sal_Int8 n;
  82             rtl_random_getBytes(pool, &n, 1);
  83
  84             //1024 minus max -127/plus max 128
  85             sal_Int32 nLength = 1024+n;
  86             std::vector<sal_uInt8> aChaff(nLength);
  87             rtl_random_getBytes(pool, &aChaff[0], nLength);
  88
  89             rtl_random_destroyPool(pool);
  90
  91             encodeChaff(aChaff);
  92
  93             return OString(reinterpret_cast<const sal_Char*>(&aChaff[0]), nLength);
  94         }
  95     }
  96 }
  97 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */