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