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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file UTF8.cpp
* @author Alex Beregszaszi
* @date 2016
*
* UTF-8 related helpers
*/
#include "UTF8.h"
namespace dev
{
namespace
{
/// Validate byte sequence against Unicode chapter 3 Table 3-7.
bool isWellFormed(unsigned char byte1, unsigned char byte2)
{
switch (byte1)
{
case 0xc0 ... 0xc1:
return false;
case 0xc2 ... 0xdf:
break;
case 0xe0:
if (byte2 < 0xa0)
return false;
break;
case 0xe1 ... 0xec:
break;
case 0xed:
if (byte2 > 0x9f)
return false;
break;
case 0xee ... 0xef:
break;
case 0xf0:
if (byte2 < 0x90)
return false;
break;
case 0xf1 ... 0xf3:
break;
case 0xf4:
if (byte2 > 0x8f)
return false;
break;
case 0xf5 ... 0xf7:
default:
/// Technically anything below 0xc0 or above 0xf7 is
/// not possible to encode using Table 3-6 anyway.
return false;
}
return true;
}
bool validateUTF8(const unsigned char *_input, size_t _length, size_t& _invalidPosition)
{
bool valid = true;
size_t i = 0;
for (; i < _length; i++)
{
// Check for Unicode Chapter 3 Table 3-6 conformity.
if (_input[i] < 0x80)
continue;
size_t count = 0;
switch ((unsigned char)_input[i])
{
case 0xc0 ... 0xdf:
count = 1;
break;
case 0xe0 ... 0xef:
count = 2;
break;
case 0xf0 ... 0xf7:
count = 3;
break;
default:
break;
}
if (count == 0)
{
valid = false;
break;
}
if ((i + count) >= _length)
{
valid = false;
break;
}
for (size_t j = 0; j < count; j++)
{
i++;
if ((_input[i] & 0xc0) != 0x80)
{
valid = false;
break;
}
// Check for Unicode Chapter 3 Table 3-7 conformity.
if ((j == 0) && !isWellFormed(_input[i - 1], _input[i]))
{
valid = false;
break;
}
}
}
if (valid)
return true;
_invalidPosition = i;
return false;
}
}
bool validateUTF8(std::string const& _input, size_t& _invalidPosition)
{
return validateUTF8(reinterpret_cast<unsigned char const*>(_input.c_str()), _input.length(), _invalidPosition);
}
}
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