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C++

// tokeniser.hpp
// Copyright (c) 2005-2018 Ben Hanson (http://www.benhanson.net/)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file licence_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef LEXERTL_RE_TOKENISER_HPP
#define LEXERTL_RE_TOKENISER_HPP
#include <cstring>
#include "re_token.hpp"
#include "../../runtime_error.hpp"
#include <sstream>
#include "../../string_token.hpp"
#include "re_tokeniser_helper.hpp"
namespace lexertl
{
namespace detail
{
template<typename rules_char_type, typename char_type, typename id_type>
class basic_re_tokeniser
{
public:
using re_token = basic_re_token<rules_char_type, char_type>;
using tokeniser_helper =
basic_re_tokeniser_helper<rules_char_type, char_type, id_type>;
using char_state = typename tokeniser_helper::char_state;
using state = typename tokeniser_helper::state;
using string_token = basic_string_token<char_type>;
static void next(re_token &lhs_, state &state_, re_token &token_)
{
rules_char_type ch_ = 0;
bool eos_ = state_.next(ch_);
bool skipped_ = false;
token_.clear();
do
{
// string begin/end
while (!eos_ && ch_ == '"')
{
state_._in_string ^= 1;
eos_ = state_.next(ch_);
}
if (eos_) break;
// (?# ...)
skipped_ = comment(eos_, ch_, state_);
if (eos_) break;
// skip_ws set
skipped_ |= skip(eos_, ch_, state_);
} while (!eos_ && skipped_);
if (eos_)
{
if (state_._in_string)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing '\"')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (state_._paren_count)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing ')')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
token_._type = END;
}
else
{
if (ch_ == '\\')
{
// Even if we are in a string, respect escape sequences...
token_._type = CHARSET;
escape(state_, token_._str);
}
else if (state_._in_string)
{
// All other meta characters lose their special meaning
// inside a string.
token_._type = CHARSET;
add_char(ch_, state_, token_._str);
}
else
{
// Not an escape sequence and not inside a string, so
// check for meta characters.
switch (ch_)
{
case '(':
token_._type = OPENPAREN;
++state_._paren_count;
read_options(state_);
break;
case ')':
--state_._paren_count;
if (state_._paren_count < 0)
{
std::ostringstream ss_;
ss_ << "Number of open parenthesis < 0 "
"at index " << state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
token_._type = CLOSEPAREN;
if (!state_._flags_stack.empty())
{
state_._flags = state_._flags_stack.top();
state_._flags_stack.pop();
}
break;
case '?':
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AOPT;
state_.increment();
}
else
{
token_._type = OPT;
}
break;
case '*':
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AZEROORMORE;
state_.increment();
}
else
{
token_._type = ZEROORMORE;
}
break;
case '+':
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AONEORMORE;
state_.increment();
}
else
{
token_._type = ONEORMORE;
}
break;
case '{':
open_curly(lhs_, state_, token_);
break;
case '|':
token_._type = OR;
break;
case '^':
if (!state_._macro_name &&
state_._curr - 1 == state_._start)
{
token_._type = BOL;
}
else
{
token_._type = CHARSET;
token_._str.insert(range(ch_, ch_));
}
break;
case '$':
if (!state_._macro_name && state_._curr == state_._end)
{
token_._type = EOL;
}
else
{
token_._type = CHARSET;
token_._str.insert(range(ch_, ch_));
}
break;
case '.':
{
token_._type = CHARSET;
if (state_._flags & dot_not_newline)
{
token_._str.insert(range('\n', '\n'));
}
else if (state_._flags & dot_not_cr_lf)
{
token_._str.insert(range('\n', '\n'));
token_._str.insert(range('\r', '\r'));
}
token_._str.negate();
break;
}
case '[':
{
token_._type = CHARSET;
tokeniser_helper::charset(state_, token_._str);
break;
}
case '/':
{
std::ostringstream ss_;
ss_ << "Lookahead ('/') is not supported yet";
state_.error(ss_);
throw runtime_error(ss_.str());
break;
}
default:
token_._type = CHARSET;
add_char(ch_, state_, token_._str);
break;
}
}
}
}
private:
using range = typename string_token::range;
static bool comment(bool &eos_, rules_char_type &ch_, state &state_)
{
bool skipped_ = false;
if (!state_._in_string && ch_ == '(' && !state_.eos() &&
*state_._curr == '?' && state_._curr + 1 < state_._end &&
*(state_._curr + 1) == '#')
{
std::size_t paren_count_ = 1;
state_.increment();
state_.increment();
do
{
eos_ = state_.next(ch_);
if (ch_ == '(')
{
++paren_count_;
}
else if (ch_ == ')')
{
--paren_count_;
}
} while (!eos_ && !(ch_ == ')' && paren_count_ == 0));
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (unterminated comment)";
state_.error(ss_);
throw runtime_error(ss_.str());
}
else
{
eos_ = state_.next(ch_);
}
skipped_ = true;
}
return skipped_;
}
static bool skip(bool &eos_, rules_char_type &ch_, state &state_)
{
bool skipped_ = false;
if ((state_._flags & skip_ws) && !state_._in_string)
{
bool c_comment_ = false;
bool skip_ws_ = false;
do
{
c_comment_ = ch_ == '/' && !state_.eos() &&
*state_._curr == '*';
skip_ws_ = !c_comment_ && (ch_ == ' ' || ch_ == '\t' ||
ch_ == '\n' || ch_ == '\r' || ch_ == '\f' || ch_ == '\v');
if (c_comment_)
{
state_.increment();
eos_ = state_.next(ch_);
while (!eos_ && !(ch_ == '*' && !state_.eos() &&
*state_._curr == '/'))
{
eos_ = state_.next(ch_);
}
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (unterminated C style comment)";
state_.error(ss_);
throw runtime_error(ss_.str());
}
else
{
state_.increment();
eos_ = state_.next(ch_);
}
skipped_ = true;
}
else if (skip_ws_)
{
eos_ = state_.next(ch_);
skipped_ = true;
}
} while (!eos_ && (c_comment_ || skip_ws_));
}
return skipped_;
}
static void read_options(state &state_)
{
if (!state_.eos() && *state_._curr == '?')
{
rules_char_type ch_ = 0;
bool eos_ = false;
bool negate_ = false;
state_.increment();
eos_ = state_.next(ch_);
state_._flags_stack.push(state_._flags);
while (!eos_ && ch_ != ':')
{
switch (ch_)
{
case '-':
negate_ ^= 1;
break;
case 'i':
if (negate_)
{
state_._flags = state_._flags & ~icase;
}
else
{
state_._flags = state_._flags | icase;
}
negate_ = false;
break;
case 's':
if (negate_)
{
#ifdef _WIN32
state_._flags = state_._flags | dot_not_cr_lf;
#else
state_._flags = state_._flags | dot_not_newline;
#endif
}
else
{
#ifdef _WIN32
state_._flags = state_._flags & ~dot_not_cr_lf;
#else
state_._flags = state_._flags & ~dot_not_newline;
#endif
}
negate_ = false;
break;
case 'x':
if (negate_)
{
state_._flags = state_._flags & ~skip_ws;
}
else
{
state_._flags = state_._flags | skip_ws;
}
negate_ = false;
break;
default:
{
std::ostringstream ss_;
ss_ << "Unknown option at index " <<
state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
}
eos_ = state_.next(ch_);
}
// End of string handler will handle early termination
}
else if (!state_._flags_stack.empty())
{
state_._flags_stack.push(state_._flags);
}
}
static void escape(state &state_, string_token &token_)
{
char_type ch_ = 0;
std::size_t str_len_ = 0;
const char *str_ = tokeniser_helper::escape_sequence(state_,
ch_, str_len_);
if (str_)
{
char_state state2_(str_ + 1, str_ + str_len_, state_._id,
state_._flags, state_._locale, 0);
tokeniser_helper::charset(state2_, token_);
}
else
{
add_char(ch_, state_, token_);
}
}
static void add_char(const char_type ch_, const state &state_,
string_token &token_)
{
range range_(ch_, ch_);
token_.insert(range_);
if (state_._flags & icase)
{
string_token folded_;
tokeniser_helper::fold(range_, state_._locale,
folded_, typename tokeniser_helper::template
size<sizeof(char_type)>());
if (!folded_.empty())
{
token_.insert(folded_);
}
}
}
static void open_curly(re_token &lhs_, state &state_,
re_token &token_)
{
if (state_.eos())
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
else if (*state_._curr == '-' || *state_._curr == '+')
{
rules_char_type ch_ = 0;
if (lhs_._type != CHARSET)
{
std::ostringstream ss_;
ss_ << "CHARSET must precede {" <<
state_._curr << "} at index " <<
state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
state_.next(ch_);
token_._type = DIFF;
token_._extra = ch_;
if (state_.next(ch_))
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (ch_ != '}')
{
std::ostringstream ss_;
ss_ << "Missing '}' at index " << state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
}
else if (*state_._curr >= '0' && *state_._curr <= '9')
{
repeat_n(state_, token_);
}
else
{
macro(state_, token_);
}
}
// SYNTAX:
// {n[,[n]]}
// SEMANTIC RULES:
// {0} - INVALID (throw exception)
// {0,} = *
// {0,0} - INVALID (throw exception)
// {0,1} = ?
// {1,} = +
// {min,max} where min == max - {min}
// {min,max} where max < min - INVALID (throw exception)
static void repeat_n(state &state_, re_token &token_)
{
rules_char_type ch_ = 0;
bool eos_ = state_.next(ch_);
std::size_t min_ = 0;
std::size_t max_ = 0;
while (!eos_ && ch_ >= '0' && ch_ <= '9')
{
min_ *= 10;
min_ += ch_ - '0';
token_._extra += ch_;
eos_ = state_.next(ch_);
}
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing repeat terminator '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
bool min_max_ = false;
bool repeatn_ = true;
if (ch_ == ',')
{
token_._extra += ch_;
eos_ = state_.next(ch_);
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing repeat terminator '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (ch_ == '}')
{
// Small optimisation: Check for '*' equivalency.
if (min_ == 0)
{
token_._type = ZEROORMORE;
repeatn_ = false;
}
// Small optimisation: Check for '+' equivalency.
else if (min_ == 1)
{
token_._type = ONEORMORE;
repeatn_ = false;
}
}
else
{
if (ch_ < '0' || ch_ > '9')
{
std::ostringstream ss_;
ss_ << "Missing repeat terminator '}' at index " <<
state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
min_max_ = true;
do
{
max_ *= 10;
max_ += ch_ - '0';
token_._extra += ch_;
eos_ = state_.next(ch_);
} while (!eos_ && ch_ >= '0' && ch_ <= '9');
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing repeat terminator '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
// Small optimisation: Check for '?' equivalency.
if (min_ == 0 && max_ == 1)
{
token_._type = OPT;
repeatn_ = false;
}
// Small optimisation: if min == max, then min.
else if (min_ == max_)
{
token_._extra.erase(token_._extra.find(','));
min_max_ = false;
max_ = 0;
}
}
}
if (ch_ != '}')
{
std::ostringstream ss_;
ss_ << "Missing repeat terminator '}' at index " <<
state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (repeatn_)
{
// SEMANTIC VALIDATION follows:
// NOTE: {0,} has already become *
// therefore we don't check for a comma.
if (min_ == 0 && max_ == 0)
{
std::ostringstream ss_;
ss_ << "Cannot have exactly zero repeats preceding index " <<
state_.index();
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (min_max_ && max_ < min_)
{
std::ostringstream ss_;
ss_ << "Max less than min preceding index " <<
state_.index();
state_.error(ss_);
throw runtime_error(ss_.str());
}
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AREPEATN;
state_.increment();
}
else
{
token_._type = REPEATN;
}
}
else if (token_._type == ZEROORMORE)
{
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AZEROORMORE;
state_.increment();
}
}
else if (token_._type == ONEORMORE)
{
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AONEORMORE;
state_.increment();
}
}
else if (token_._type == OPT)
{
if (!state_.eos() && *state_._curr == '?')
{
token_._type = AOPT;
state_.increment();
}
}
}
static void macro(state &state_, re_token &token_)
{
rules_char_type ch_ = 0;
bool eos_ = false;
state_.next(ch_);
if (ch_ != '_' && !(ch_ >= 'A' && ch_ <= 'Z') &&
!(ch_ >= 'a' && ch_ <= 'z'))
{
std::ostringstream ss_;
ss_ << "Invalid MACRO name at index " << state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
do
{
token_._extra += ch_;
eos_ = state_.next(ch_);
if (eos_)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
state_.unexpected_end(ss_);
ss_ << " (missing MACRO name terminator '}')";
state_.error(ss_);
throw runtime_error(ss_.str());
}
} while (ch_ == '_' || ch_ == '-' || (ch_ >= 'A' && ch_ <= 'Z') ||
(ch_ >= 'a' && ch_ <= 'z') || (ch_ >= '0' && ch_ <= '9'));
if (ch_ != '}')
{
std::ostringstream ss_;
ss_ << "Missing MACRO name terminator '}' at index " <<
state_.index() - 1;
state_.error(ss_);
throw runtime_error(ss_.str());
}
token_._type = MACRO;
}
};
}
}
#endif