|
|
/*
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 StringUtils.h
* @author Balajiganapathi S <balajiganapathi.s@gmail.com>
* @date 2017
*
* String routines
*/
#include "StringUtils.h"
#include <algorithm>
#include <string>
#include <vector>
using namespace std;
using namespace dev;
bool dev::stringWithinDistance(string const& _str1, string const& _str2, size_t _maxDistance)
{
if (_str1 == _str2)
return true;
size_t n1 = _str1.size();
size_t n2 = _str2.size();
size_t distance = stringDistance(_str1, _str2);
// if distance is not greater than _maxDistance, and distance is strictly less than length of both names, they can be considered similar
// this is to avoid irrelevant suggestions
return distance <= _maxDistance && distance < n1 && distance < n2;
}
size_t dev::stringDistance(string const& _str1, string const& _str2)
{
size_t n1 = _str1.size();
size_t n2 = _str2.size();
// Optimize by storing only last 2 rows and current row. So first index is considered modulo 3
// This is a two-dimensional array of size 3 x (n2 + 1).
vector<size_t> dp(3 * (n2 + 1));
// In this dp formulation of Damerau–Levenshtein distance we are assuming that the strings are 1-based to make base case storage easier.
// So index accesser to _name1 and _name2 have to be adjusted accordingly
for (size_t i1 = 0; i1 <= n1; ++i1)
for (size_t i2 = 0; i2 <= n2; ++i2)
{
size_t x = 0;
if (min(i1, i2) == 0) // base case
x = max(i1, i2);
else
{
size_t left = dp[(i1 - 1) % 3 + i2 * 3];
size_t up = dp[(i1 % 3) + (i2 - 1) * 3];
size_t upleft = dp[((i1 - 1) % 3) + (i2 - 1) * 3];
// deletion and insertion
x = min(left + 1, up + 1);
if (_str1[i1-1] == _str2[i2-1])
// same chars, can skip
x = min(x, upleft);
else
// different chars so try substitution
x = min(x, upleft + 1);
// transposing
if (i1 > 1 && i2 > 1 && _str1[i1 - 1] == _str2[i2 - 2] && _str1[i1 - 2] == _str2[i2 - 1])
x = min(x, dp[((i1 - 2) % 3) + (i2 - 2) * 3] + 1);
}
dp[(i1 % 3) + i2 * 3] = x;
}
return dp[(n1 % 3) + n2 * 3];
}
string dev::quotedAlternativesList(vector<string> const& suggestions)
{
if (suggestions.empty())
return "";
if (suggestions.size() == 1)
return "\"" + suggestions.front() + "\"";
string choices = "\"" + suggestions.front() + "\"";
for (size_t i = 1; i + 1 < suggestions.size(); ++i)
choices += ", \"" + suggestions[i] + "\"";
choices += " or \"" + suggestions.back() + "\"";
return choices;
}
|
