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monero/contrib/epee/include/storages/parserse_base_utils.h
moneromooo-monero 21777daf6e
epee: speedup word/number matching 
Number matching semantics are slightly changed: since this is used
as a filter to check whether a number is signed and/or floating
point, we can speed this up further. strto* functions are called
afterwards and will error out where necessary. We now also accept
numbers like .4 which were not accepted before.

The strto* calls on a boost::string_ref will not access unallocated
memory since the parsers always stop at the first bad character,
and the original string is zero terminated.

in arbitrary time measurement units for some arbitrary test case:

match_number2: 235 -> 70
match_word2: 330 -> 108
2019-01-16 19:59:40 +00:00

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// Copyright (c) 2006-2013, Andrey N. Sabelnikov, www.sabelnikov.net
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the Andrey N. Sabelnikov nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
#pragma once
#include <algorithm>
#include <boost/utility/string_ref.hpp>
namespace epee
{
namespace misc_utils
{
namespace parse
{
// 1: digit
// 2: .eE (floating point)
// 4: alpha
// 8: whitespace
// 16: allowed in float but doesn't necessarily mean it's a float
static const constexpr uint8_t lut[256]={
0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 8, 8, 8, 8, 0, 0, // 16
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 32
8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 16, 18, 0, // 48
17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 0, 0, 0, 0, 0, 0, // 64
0, 4, 4, 4, 4, 22, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, // 80
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, // 96
0, 4, 4, 4, 4, 22, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, // 112
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, // 128
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
inline bool isspace(char c)
{
return lut[(uint8_t)c] & 8;
}
inline bool isdigit(char c)
{
return lut[(uint8_t)c] & 1;
}
inline std::string transform_to_escape_sequence(const std::string& src)
{
static const char escaped[] = "\b\f\n\r\t\v\"\\/";
std::string::const_iterator it = std::find_first_of(src.begin(), src.end(), escaped, escaped + sizeof(escaped));
if (it == src.end())
return src;
std::string res;
res.reserve(2 * src.size());
res.assign(src.begin(), it);
for(; it!=src.end(); ++it)
{
switch(*it)
{
case '\b': //Backspace (ascii code 08)
res+="\\b"; break;
case '\f': //Form feed (ascii code 0C)
res+="\\f"; break;
case '\n': //New line
res+="\\n"; break;
case '\r': //Carriage return
res+="\\r"; break;
case '\t': //Tab
res+="\\t"; break;
case '\v': //Vertical tab
res+="\\v"; break;
//case '\'': //Apostrophe or single quote
// res+="\\'"; break;
case '"': //Double quote
res+="\\\""; break;
case '\\': //Backslash caracter
res+="\\\\"; break;
case '/': //Backslash caracter
res+="\\/"; break;
default:
res.push_back(*it);
}
}
return res;
}
/*
\b Backspace (ascii code 08)
\f Form feed (ascii code 0C)
\n New line
\r Carriage return
\t Tab
\v Vertical tab
\' Apostrophe or single quote
\" Double quote
\\ Backslash character
*/
inline void match_string2(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, std::string& val)
{
bool escape_mode = false;
std::string::const_iterator it = star_end_string;
++it;
std::string::const_iterator fi = it;
while (fi != buf_end && *fi != '\\' && *fi != '\"')
++fi;
val.assign(it, fi);
val.reserve(std::distance(star_end_string, buf_end));
it = fi;
for(;it != buf_end;it++)
{
if(escape_mode/*prev_ch == '\\'*/)
{
switch(*it)
{
case 'b': //Backspace (ascii code 08)
val.push_back(0x08);break;
case 'f': //Form feed (ascii code 0C)
val.push_back(0x0C);break;
case 'n': //New line
val.push_back('\n');break;
case 'r': //Carriage return
val.push_back('\r');break;
case 't': //Tab
val.push_back('\t');break;
case 'v': //Vertical tab
val.push_back('\v');break;
case '\'': //Apostrophe or single quote
val.push_back('\'');break;
case '"': //Double quote
val.push_back('"');break;
case '\\': //Backslash character
val.push_back('\\');break;
case '/': //Slash character
val.push_back('/');break;
default:
val.push_back(*it);
LOG_PRINT_L0("Unknown escape sequence :\"\\" << *it << "\"");
}
escape_mode = false;
}else if(*it == '"')
{
star_end_string = it;
return;
}else if(*it == '\\')
{
escape_mode = true;
}
else
{
val.push_back(*it);
}
}
ASSERT_MES_AND_THROW("Failed to match string in json entry: " << std::string(star_end_string, buf_end));
}
inline bool match_string(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, std::string& val)
{
try
{
match_string2(star_end_string, buf_end, val);
return true;
}
catch(...)
{
return false;
}
}
inline void match_number2(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, boost::string_ref& val, bool& is_float_val, bool& is_signed_val)
{
val.clear();
uint8_t float_flag = 0;
is_signed_val = false;
size_t chars = 0;
std::string::const_iterator it = star_end_string;
if (it != buf_end && *it == '-')
{
is_signed_val = true;
++chars;
++it;
}
for(;it != buf_end;it++)
{
const uint8_t flags = lut[(uint8_t)*it];
if (flags & 16)
{
float_flag |= flags;
++chars;
}
else
{
val = boost::string_ref(&*star_end_string, chars);
if(val.size())
{
star_end_string = --it;
is_float_val = !!(float_flag & 2);
return;
}
else
ASSERT_MES_AND_THROW("wrong number in json entry: " << std::string(star_end_string, buf_end));
}
}
ASSERT_MES_AND_THROW("wrong number in json entry: " << std::string(star_end_string, buf_end));
}
inline bool match_number(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, boost::string_ref& val)
{
try
{
bool is_v_float = false;bool is_signed_val = false;
match_number2(star_end_string, buf_end, val, is_v_float, is_signed_val);
return !is_v_float;
}
catch(...)
{
return false;
}
}
inline void match_word2(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, boost::string_ref& val)
{
val.clear();
for(std::string::const_iterator it = star_end_string;it != buf_end;it++)
{
if (!(lut[(uint8_t)*it] & 4))
{
val = boost::string_ref(&*star_end_string, std::distance(star_end_string, it));
if(val.size())
{
star_end_string = --it;
return;
}else
ASSERT_MES_AND_THROW("failed to match word number in json entry: " << std::string(star_end_string, buf_end));
}
}
ASSERT_MES_AND_THROW("failed to match word number in json entry: " << std::string(star_end_string, buf_end));
}
inline bool match_word(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, boost::string_ref& val)
{
try
{
match_word2(star_end_string, buf_end, val);
return true;
}
catch(...)
{
return false;
}
}
inline bool match_word_with_extrasymb(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, std::string& val)
{
val.clear();
for(std::string::const_iterator it = star_end_string;it != buf_end;it++)
{
if(!isalnum(*it) && *it != '-' && *it != '_')
{
val.assign(star_end_string, it);
if(val.size())
{
star_end_string = --it;
return true;
}else
return false;
}
}
return false;
}
inline bool match_word_til_equal_mark(std::string::const_iterator& star_end_string, std::string::const_iterator buf_end, std::string::const_iterator& word_end)
{
word_end = star_end_string;
for(std::string::const_iterator it = star_end_string;it != buf_end;it++)
{
if(isspace(*it))
{
continue;
}else if( *it == '=' )
{
star_end_string = it;
word_end = it;
return true;
}
}
return false;
}
}
}
}
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