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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef INCLUDED_ORCUS_PARSER_BASE_HPP
#define INCLUDED_ORCUS_PARSER_BASE_HPP
#include "env.hpp"
#include "exception.hpp"
#include <string>
#include <cstdlib>
#include <cstddef>
#include <cassert>
#include <functional>
namespace orcus {
class ORCUS_PSR_DLLPUBLIC parser_base
{
protected:
using numeric_parser_type = std::function<const char*(const char*, const char*, double&)>;
const char* const mp_begin;
const char* mp_char;
const char* mp_end;
private:
numeric_parser_type m_func_parse_numeric;
protected:
parser_base(const char* p, size_t n);
void set_numeric_parser(const numeric_parser_type& func)
{
m_func_parse_numeric = func;
}
bool has_char() const
{
assert(mp_char <= mp_end);
return mp_char != mp_end;
}
bool has_next() const
{
assert((mp_char+1) <= mp_end);
return (mp_char+1) != mp_end;
}
void next(size_t inc=1) { mp_char += inc; }
void prev(size_t dec=1);
char cur_char() const { return *mp_char; }
/**
* Peek a character at specified offset from the current position without
* advancing the current position.
*
* @note The caller <strong>must</strong> ensure that the specified offset
* position is a valid position. This method does not check its
* validity.
*
* @param offset offset from the current position to peek at.
*
* @return character at a specified offset position from the current
* position.
*/
char peek_char(std::size_t offset=1) const;
/**
* Peek a segment of contiguous characters of a specified length starting
* from the current position.
*
* @note The caller <strong>must</strong> ensure that the specified
* substring segment is entirely valid. This method does not check
* its validity.
*
* @param length length of the segment to peek.
*
* @return segment of contiguous characters.
*/
std::string_view peek_chars(std::size_t length) const;
/**
* Skip an optional byte order mark at the current position of the stream.
*
* Currently we only check for UTF-8 BOM.
*/
void skip_bom();
void skip(std::string_view chars_to_skip);
/**
* Skip all characters that are 0-32 in ASCII range
*/
void skip_space_and_control();
/**
* Parse and check next characters to see if it matches specified
* character sequence.
*
* @param expected sequence of characters to match against.
*
* @return true if it matches specified character sequence, false
* otherwise.
*/
bool parse_expected(std::string_view expected);
/**
* Try to parse the next characters as double, or return NaN in case of
* failure.
*
* @return double value on success, or NaN on failure.
*/
double parse_double();
/**
* Determine the number of characters remaining <strong>after</strong> the
* current character. For instance, if the current character is on the
* last character in the stream, this method will return 0, whereas if
* it's on the first character, it will return the total length - 1.
*
* @return number of characters remaining after the current character.
*/
size_t remaining_size() const;
/**
* Determine the number of characters available from the current character
* to the end of the buffer. The current character is included.
*
* @return number of characters available including the current character.
*/
size_t available_size() const
{
return std::distance(mp_char, mp_end);
}
/**
* Return the current offset from the beginning of the character stream.
*
* @return current offset from the beginning of the character stream.
*/
std::ptrdiff_t offset() const;
};
}
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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