| // file_input.hpp |
| // Copyright (c) 2008-2009 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 BOOST_LEXER_FILE_INPUT |
| #define BOOST_LEXER_FILE_INPUT |
| |
| #include "char_traits.hpp" |
| // memcpy |
| #include <cstring> |
| #include <fstream> |
| #include "size_t.hpp" |
| #include "state_machine.hpp" |
| |
| namespace boost |
| { |
| namespace lexer |
| { |
| template<typename CharT, typename Traits = char_traits<CharT> > |
| class basic_file_input |
| { |
| public: |
| class iterator |
| { |
| public: |
| #if defined _MSC_VER && _MSC_VER <= 1200 |
| friend basic_file_input; |
| #else |
| friend class basic_file_input; |
| #endif |
| |
| struct data |
| { |
| std::size_t id; |
| std::size_t unique_id; |
| const CharT *start; |
| const CharT *end; |
| std::size_t state; |
| |
| // Construct in end() state. |
| data () : |
| id (0), |
| unique_id (npos), |
| state (npos) |
| { |
| } |
| |
| bool operator == (const data &rhs_) const |
| { |
| return id == rhs_.id && unique_id == rhs_.unique_id && |
| start == rhs_.start && end == rhs_.end && |
| state == rhs_.state; |
| } |
| }; |
| |
| iterator () : |
| _input (0) |
| { |
| } |
| |
| bool operator == (const iterator &rhs_) const |
| { |
| return _data == rhs_._data; |
| } |
| |
| bool operator != (const iterator &rhs_) const |
| { |
| return !(*this == rhs_); |
| } |
| |
| data &operator * () |
| { |
| return _data; |
| } |
| |
| data *operator -> () |
| { |
| return &_data; |
| } |
| |
| // Let compiler generate operator = (). |
| |
| // prefix version |
| iterator &operator ++ () |
| { |
| next_token (); |
| return *this; |
| } |
| |
| // postfix version |
| iterator operator ++ (int) |
| { |
| iterator iter_ = *this; |
| |
| next_token (); |
| return iter_; |
| } |
| |
| void next_token () |
| { |
| const detail::internals &internals_ = |
| _input->_state_machine->data (); |
| |
| _data.start = _data.end; |
| |
| if (internals_._dfa->size () == 1) |
| { |
| _data.id = _input->next (&internals_._lookup->front ()-> |
| front (), internals_._dfa_alphabet.front (), |
| &internals_._dfa->front ()->front (), _data.start, |
| _data.end, _data.unique_id); |
| } |
| else |
| { |
| _data.id = _input->next (internals_, _data.state, _data.start, |
| _data.end, _data.unique_id); |
| } |
| |
| if (_data.id == 0) |
| { |
| _data.start = 0; |
| _data.end = 0; |
| // Ensure current state matches that returned by end(). |
| _data.state = npos; |
| } |
| } |
| |
| private: |
| // Not owner (obviously!) |
| basic_file_input *_input; |
| data _data; |
| }; |
| |
| #if defined _MSC_VER && _MSC_VER <= 1200 |
| friend iterator; |
| #else |
| friend class iterator; |
| #endif |
| |
| // Make it explict that we are NOT taking a copy of state_machine_! |
| basic_file_input (const basic_state_machine<CharT> *state_machine_, |
| std::basic_ifstream<CharT> *is_, |
| const std::streamsize buffer_size_ = 4096, |
| const std::streamsize buffer_increment_ = 1024) : |
| _state_machine (state_machine_), |
| _stream (is_), |
| _buffer_size (buffer_size_), |
| _buffer_increment (buffer_increment_), |
| _buffer (_buffer_size, '!') |
| { |
| _start_buffer = &_buffer.front (); |
| _end_buffer = _start_buffer + _buffer.size (); |
| _start_token = _end_buffer; |
| _end_token = _end_buffer; |
| } |
| |
| iterator begin () |
| { |
| iterator iter_; |
| |
| iter_._input = this; |
| // Over-ride default of 0 (EOF) |
| iter_._data.id = npos; |
| iter_._data.start = 0; |
| iter_._data.end = 0; |
| iter_._data.state = 0; |
| ++iter_; |
| return iter_; |
| } |
| |
| iterator end () |
| { |
| iterator iter_; |
| |
| iter_._input = this; |
| iter_._data.start = 0; |
| iter_._data.end = 0; |
| return iter_; |
| } |
| |
| void flush () |
| { |
| // This temporary is mandatory, otherwise the |
| // pointer calculations won't work! |
| const CharT *temp_ = _end_buffer; |
| |
| _start_token = _end_token = _end_buffer; |
| reload_buffer (temp_, true, _end_token); |
| } |
| |
| private: |
| typedef std::basic_istream<CharT> istream; |
| typedef std::vector<CharT> buffer; |
| |
| const basic_state_machine<CharT> *_state_machine; |
| const std::streamsize _buffer_size; |
| const std::streamsize _buffer_increment; |
| |
| buffer _buffer; |
| CharT *_start_buffer; |
| istream *_stream; |
| const CharT *_start_token; |
| const CharT *_end_token; |
| CharT *_end_buffer; |
| |
| std::size_t next (const detail::internals &internals_, |
| std::size_t &start_state_, const CharT * &start_, const CharT * &end_, |
| std::size_t &unique_id_) |
| { |
| _start_token = _end_token; |
| |
| again: |
| const std::size_t * lookup_ = &internals_._lookup[start_state_]-> |
| front (); |
| std::size_t dfa_alphabet_ = internals_._dfa_alphabet[start_state_]; |
| const std::size_t *dfa_ = &internals_._dfa[start_state_]->front (); |
| const std::size_t *ptr_ = dfa_ + dfa_alphabet_; |
| const CharT *curr_ = _start_token; |
| bool end_state_ = *ptr_ != 0; |
| std::size_t id_ = *(ptr_ + id_index); |
| std::size_t uid_ = *(ptr_ + unique_id_index); |
| const CharT *end_token_ = curr_; |
| |
| for (;;) |
| { |
| if (curr_ >= _end_buffer) |
| { |
| if (!reload_buffer (curr_, end_state_, end_token_)) |
| { |
| // EOF |
| break; |
| } |
| } |
| |
| const std::size_t BOL_state_ = ptr_[bol_index]; |
| const std::size_t EOL_state_ = ptr_[eol_index]; |
| |
| if (BOL_state_ && (_start_token == _start_buffer || |
| *(_start_token - 1) == '\n')) |
| { |
| ptr_ = &dfa_[BOL_state_ * dfa_alphabet_]; |
| } |
| else if (EOL_state_ && *curr_ == '\n') |
| { |
| ptr_ = &dfa_[EOL_state_ * dfa_alphabet_]; |
| } |
| else |
| { |
| const std::size_t state_ = |
| ptr_[lookup_[static_cast<typename Traits::index_type> |
| (*curr_++)]]; |
| |
| if (state_ == 0) |
| { |
| break; |
| } |
| |
| ptr_ = &dfa_[state_ * dfa_alphabet_]; |
| } |
| |
| if (*ptr_) |
| { |
| end_state_ = true; |
| id_ = *(ptr_ + id_index); |
| uid_ = *(ptr_ + unique_id_index); |
| start_state_ = *(ptr_ + state_index); |
| end_token_ = curr_; |
| } |
| } |
| |
| if (_start_token >= _end_buffer) |
| { |
| // No more tokens... |
| unique_id_ = npos; |
| return 0; |
| } |
| |
| const std::size_t EOL_state_ = ptr_[eol_index]; |
| |
| if (EOL_state_ && curr_ == end_) |
| { |
| ptr_ = &dfa_[EOL_state_ * dfa_alphabet_]; |
| |
| if (*ptr_) |
| { |
| end_state_ = true; |
| id_ = *(ptr_ + id_index); |
| uid_ = *(ptr_ + unique_id_index); |
| start_state_ = *(ptr_ + state_index); |
| end_token_ = curr_; |
| } |
| } |
| |
| if (end_state_) |
| { |
| // return longest match |
| _end_token = end_token_; |
| |
| if (id_ == 0) goto again; |
| } |
| else |
| { |
| // No match causes char to be skipped |
| _end_token = _start_token + 1; |
| id_ = npos; |
| uid_ = npos; |
| } |
| |
| start_ = _start_token; |
| end_ = _end_token; |
| unique_id_ = uid_; |
| return id_; |
| } |
| |
| std::size_t next (const std::size_t * const lookup_, |
| const std::size_t dfa_alphabet_, const std::size_t * const dfa_, |
| const CharT * &start_, const CharT * &end_, std::size_t &unique_id_) |
| { |
| _start_token = _end_token; |
| |
| const std::size_t *ptr_ = dfa_ + dfa_alphabet_; |
| const CharT *curr_ = _start_token; |
| bool end_state_ = *ptr_ != 0; |
| std::size_t id_ = *(ptr_ + id_index); |
| std::size_t uid_ = *(ptr_ + unique_id_index); |
| const CharT *end_token_ = curr_; |
| |
| for (;;) |
| { |
| if (curr_ >= _end_buffer) |
| { |
| if (!reload_buffer (curr_, end_state_, end_token_)) |
| { |
| // EOF |
| break; |
| } |
| } |
| |
| const std::size_t BOL_state_ = ptr_[bol_index]; |
| const std::size_t EOL_state_ = ptr_[eol_index]; |
| |
| if (BOL_state_ && (_start_token == _start_buffer || |
| *(_start_token - 1) == '\n')) |
| { |
| ptr_ = &dfa_[BOL_state_ * dfa_alphabet_]; |
| } |
| else if (EOL_state_ && *curr_ == '\n') |
| { |
| ptr_ = &dfa_[EOL_state_ * dfa_alphabet_]; |
| } |
| else |
| { |
| const std::size_t state_ = |
| ptr_[lookup_[static_cast<typename Traits::index_type> |
| (*curr_++)]]; |
| |
| if (state_ == 0) |
| { |
| break; |
| } |
| |
| ptr_ = &dfa_[state_ * dfa_alphabet_]; |
| } |
| |
| if (*ptr_) |
| { |
| end_state_ = true; |
| id_ = *(ptr_ + id_index); |
| uid_ = *(ptr_ + unique_id_index); |
| end_token_ = curr_; |
| } |
| } |
| |
| if (_start_token >= _end_buffer) |
| { |
| // No more tokens... |
| unique_id_ = npos; |
| return 0; |
| } |
| |
| const std::size_t EOL_state_ = ptr_[eol_index]; |
| |
| if (EOL_state_ && curr_ == end_) |
| { |
| ptr_ = &dfa_[EOL_state_ * dfa_alphabet_]; |
| |
| if (*ptr_) |
| { |
| end_state_ = true; |
| id_ = *(ptr_ + id_index); |
| uid_ = *(ptr_ + unique_id_index); |
| end_token_ = curr_; |
| } |
| } |
| |
| if (end_state_) |
| { |
| // return longest match |
| _end_token = end_token_; |
| } |
| else |
| { |
| // No match causes char to be skipped |
| _end_token = _start_token + 1; |
| id_ = npos; |
| uid_ = npos; |
| } |
| |
| start_ = _start_token; |
| end_ = _end_token; |
| unique_id_ = uid_; |
| return id_; |
| } |
| |
| bool reload_buffer (const CharT * &curr_, const bool end_state_, |
| const CharT * &end_token_) |
| { |
| bool success_ = !_stream->eof (); |
| |
| if (success_) |
| { |
| const CharT *old_start_token_ = _start_token; |
| std::size_t old_size_ = _buffer.size (); |
| std::size_t count_ = 0; |
| |
| if (_start_token - 1 == _start_buffer) |
| { |
| // Run out of buffer space, so increase. |
| _buffer.resize (old_size_ + _buffer_increment, '!'); |
| _start_buffer = &_buffer.front (); |
| _start_token = _start_buffer + 1; |
| _stream->read (_start_buffer + old_size_, |
| _buffer_increment); |
| count_ = _stream->gcount (); |
| _end_buffer = _start_buffer + old_size_ + count_; |
| } |
| else if (_start_token < _end_buffer) |
| { |
| const std::size_t len_ = _end_buffer - _start_token; |
| // Some systems have memcpy in namespace std. |
| using namespace std; |
| |
| memcpy (_start_buffer, _start_token - 1, (len_ + 1) * |
| sizeof (CharT)); |
| _stream->read (_start_buffer + len_ + 1, |
| static_cast<std::streamsize> (_buffer.size () - len_ - 1)); |
| count_ = _stream->gcount (); |
| _start_token = _start_buffer + 1; |
| _end_buffer = _start_buffer + len_ + 1 + count_; |
| } |
| else |
| { |
| _stream->read (_start_buffer, static_cast<std::streamsize> |
| (_buffer.size ())); |
| count_ = _stream->gcount (); |
| _start_token = _start_buffer; |
| _end_buffer = _start_buffer + count_; |
| } |
| |
| if (end_state_) |
| { |
| end_token_ = _start_token + |
| (end_token_ - old_start_token_); |
| } |
| |
| curr_ = _start_token + (curr_ - old_start_token_); |
| } |
| |
| return success_; |
| } |
| |
| // Disallow copying of buffer |
| basic_file_input (const basic_file_input &); |
| const basic_file_input &operator = (const basic_file_input &); |
| }; |
| |
| typedef basic_file_input<char> file_input; |
| typedef basic_file_input<wchar_t> wfile_input; |
| } |
| } |
| |
| #endif |