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scully/inc/lexertl/parser/tokeniser/re_tokeniser.hpp

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// tokeniser.hpp
// Copyright (c) 2005-2012 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 "../../size_t.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:
typedef basic_re_token<rules_char_type, char_type> re_token;
typedef basic_re_tokeniser_helper<rules_char_type, char_type, id_type>
tokeniser_helper;
typedef typename tokeniser_helper::char_state char_state;
typedef typename tokeniser_helper::state state;
typedef basic_string_token<char_type> string_token;
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_);
}
// (?# ...)
skipped_ = comment (eos_, ch_, state_);
// skip_ws set
skipped_ |= skip (eos_, ch_, state_);
} while (skipped_);
if (eos_)
{
if (state_._in_string)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
ss_ << "Unexpected end of regex (missing '\"') in rule id " <<
state_._id << '.';
throw runtime_error (ss_.str ());
}
if (state_._paren_count)
{
std::ostringstream ss_;
// Pointless returning index if at end of string
ss_ << "Unexpected end of regex (missing ')') in rule id " <<
state_._id << '.';
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;
token_->_str.insert (typename string_token::range (ch_, ch_));
}
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 <<
" in rule id " << state_._id << '.';
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 && state_._curr - 1 == state_._start)
{
token_->_type = BOL;
}
else
{
token_->_type = CHARSET;
token_->_str.insert (typename string_token::range
(ch_, ch_));
}
break;
case '$':
if (!state_._macro && state_._curr == state_._end)
{
token_->_type = EOL;
}
else
{
token_->_type = CHARSET;
token_->_str.insert (typename string_token::range
(ch_, ch_));
}
break;
case '.':
{
token_->_type = CHARSET;
if (state_._flags & dot_not_newline)
{
token_->_str.insert (typename string_token::range
('\n', '\n'));
}
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 in " <<
"rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
break;
}
default:
token_->_type = CHARSET;
if ((state_._flags & icase) &&
(std::isupper (ch_, state_._locale) ||
std::islower (ch_, state_._locale)))
{
char_type upper_ = std::toupper
(ch_, state_._locale);
char_type lower_ = std::tolower
(ch_, state_._locale);
token_->_str.insert (typename string_token::range
(upper_, upper_));
token_->_str.insert (typename string_token::range
(lower_, lower_));
}
else
{
token_->_str.insert (typename string_token::range
(ch_, ch_));
}
break;
}
}
}
}
private:
static bool comment (bool &eos_, rules_char_type &ch_, state &state_)
{
bool skipped_ = false;
if (!eos_ && !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
ss_ << "Unexpected end of regex (unterminated comment) " <<
"in rule id " << state_._id << '.';
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 (!eos_ && (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
ss_ << "Unexpected end of regex (unterminated " <<
"C style comment) in rule id " <<
state_._id << '.';
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 (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_)
{
state_._flags = state_._flags | dot_not_newline;
}
else
{
state_._flags = state_._flags & ~dot_not_newline;
}
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 << " in rule id " <<
state_._id << '.';
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, false);
tokeniser_helper::charset (state2_, token_);
}
else
{
token_.insert (typename string_token::range (ch_, ch_));
}
}
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
ss_ << "Unexpected end of regex (missing '}') in rule id " <<
state_._id << '.';
throw runtime_error (ss_.str ());
}
else if (*state_._curr == '-')
{
charset_difference (lhs_, state_, token_);
}
else if (*state_._curr == '+')
{
charset_union (lhs_, state_, token_);
}
else if (*state_._curr >= '0' && *state_._curr <= '9')
{
repeat_n (state_, token_);
}
else
{
macro (state_, token_);
}
}
static void charset_difference (re_token *lhs_, state &state_,
re_token *token_)
{
rules_char_type ch_ = 0;
if (lhs_->_type != CHARSET)
{
std::ostringstream ss_;
ss_ << "CHARSET must precede {-} at index " <<
state_.index () - 1 << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
state_.next (ch_);
if (state_.next (ch_))
{
std::ostringstream ss_;
// Pointless returning index if at end of string
ss_ << "Unexpected end of regex (missing '}') in rule id " <<
state_._id << '.';
throw runtime_error (ss_.str ());
}
if (ch_ != '}')
{
std::ostringstream ss_;
ss_ << "Missing '}' at index " << state_.index () - 1 <<
" in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
re_token rhs_;
next (lhs_, state_, &rhs_);
if (rhs_._type != CHARSET)
{
std::ostringstream ss_;
ss_ << "CHARSET must follow {-} at index " <<
state_.index () - 1 << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
lhs_->_str.remove (rhs_._str);
if (lhs_->_str.empty ())
{
std::ostringstream ss_;
ss_ << "Empty charset created by {-} at index " <<
state_.index () - 1 << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
next (lhs_, state_, token_);
}
static void charset_union (re_token *lhs_, state &state_,
re_token *token_)
{
rules_char_type ch_ = 0;
if (lhs_->_type != CHARSET)
{
std::ostringstream ss_;
ss_ << "CHARSET must precede {+} at index " <<
state_.index () - 1 << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
state_.next (ch_);
if (state_.next (ch_))
{
std::ostringstream ss_;
// Pointless returning index if at end of string
ss_ << "Unexpected end of regex (missing '}') in rule id " <<
state_._id << '.';
throw runtime_error (ss_.str ());
}
if (ch_ != '}')
{
std::ostringstream ss_;
ss_ << "Missing '}' at index " << state_.index () - 1 <<
" in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
re_token rhs_;
next (lhs_, state_, &rhs_);
if (rhs_._type != CHARSET)
{
std::ostringstream ss_;
ss_ << "CHARSET must follow {+} at index " <<
state_.index () - 1 << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
lhs_->_str.insert (rhs_._str);
next (lhs_, 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
ss_ << "Unexpected end of regex (missing '}') in rule id " <<
state_._id << '.';
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
ss_ << "Unexpected end of regex (missing '}') in rule id " <<
state_._id << '.';
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 '}' at index " << state_.index () - 1 <<
" in rule id " << state_._id << '.';
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
ss_ << "Unexpected end of regex (missing '}') "
"in rule id " << state_._id << '.';
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 '}' at index " << state_.index () - 1 <<
" in rule id " << state_._id << '.';
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 () << " in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
if (min_max_ && max_ < min_)
{
std::ostringstream ss_;
ss_ << "Max less than min preceding index " <<
state_.index () << " in rule id " << state_._id << '.';
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 <<
" in rule id " << state_._id << '.';
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
ss_ << "Unexpected end of regex " <<
"(missing '}') in rule id " << state_._id << '.';
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 '}' at index " << state_.index () - 1 <<
" in rule id " << state_._id << '.';
throw runtime_error (ss_.str ());
}
token_->_type = MACRO;
}
};
}
}
#endif