ext-boost/boost/date_time/format_date_parser.hpp

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#ifndef DATE_TIME_FORMAT_DATE_PARSER_HPP__
#define DATE_TIME_FORMAT_DATE_PARSER_HPP__
/* Copyright (c) 2004-2005 CrystalClear Software, Inc.
* Use, modification and distribution is subject to the
* Boost Software License, Version 1.0. (See accompanying
* file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
* Author: Jeff Garland, Bart Garst
* $Date$
*/
#include "boost/lexical_cast.hpp"
#include "boost/date_time/string_parse_tree.hpp"
#include "boost/date_time/strings_from_facet.hpp"
#include "boost/date_time/special_values_parser.hpp"
#include <string>
#include <vector>
#include <sstream>
#include <iterator>
#ifndef BOOST_NO_STDC_NAMESPACE
# include <cctype>
#else
# include <ctype.h>
#endif
#ifdef BOOST_NO_STDC_NAMESPACE
namespace std {
using ::isspace;
using ::isdigit;
}
#endif
namespace boost { namespace date_time {
//! Helper function for parsing fixed length strings into integers
/*! Will consume 'length' number of characters from stream. Consumed
* character are transfered to parse_match_result struct.
* Returns '-1' if no number can be parsed or incorrect number of
* digits in stream. */
template<typename int_type, typename charT>
inline
int_type
fixed_string_to_int(std::istreambuf_iterator<charT>& itr,
std::istreambuf_iterator<charT>& stream_end,
parse_match_result<charT>& mr,
unsigned int length,
const charT& fill_char)
{
//typedef std::basic_string<charT> string_type;
unsigned int j = 0;
//string_type s;
while (j < length && itr != stream_end &&
(std::isdigit(*itr) || *itr == fill_char)) {
if(*itr == fill_char) {
/* Since a fill_char can be anything, we convert it to a zero.
* lexical_cast will behave predictably when zero is used as fill. */
mr.cache += ('0');
}
else {
mr.cache += (*itr);
}
itr++;
j++;
}
int_type i = static_cast<int_type>(-1);
// mr.cache will hold leading zeros. size() tells us when input is too short.
if(mr.cache.size() < length) {
return i;
}
try {
i = boost::lexical_cast<int_type>(mr.cache);
}catch(bad_lexical_cast&){
// we want to return -1 if the cast fails so nothing to do here
}
return i;
}
//! Helper function for parsing fixed length strings into integers
/*! Will consume 'length' number of characters from stream. Consumed
* character are transfered to parse_match_result struct.
* Returns '-1' if no number can be parsed or incorrect number of
* digits in stream. */
template<typename int_type, typename charT>
inline
int_type
fixed_string_to_int(std::istreambuf_iterator<charT>& itr,
std::istreambuf_iterator<charT>& stream_end,
parse_match_result<charT>& mr,
unsigned int length)
{
return fixed_string_to_int<int_type, charT>(itr, stream_end, mr, length, '0');
}
//! Helper function for parsing varied length strings into integers
/*! Will consume 'max_length' characters from stream only if those
* characters are digits. Returns '-1' if no number can be parsed.
* Will not parse a number preceeded by a '+' or '-'. */
template<typename int_type, typename charT>
inline
int_type
var_string_to_int(std::istreambuf_iterator<charT>& itr,
const std::istreambuf_iterator<charT>& stream_end,
unsigned int max_length)
{
typedef std::basic_string<charT> string_type;
unsigned int j = 0;
string_type s;
while (itr != stream_end && (j < max_length) && std::isdigit(*itr)) {
s += (*itr);
++itr;
++j;
}
int_type i = static_cast<int_type>(-1);
if(!s.empty()) {
i = boost::lexical_cast<int_type>(s);
}
return i;
}
//! Class with generic date parsing using a format string
/*! The following is the set of recognized format specifiers
- %a - Short weekday name
- %A - Long weekday name
- %b - Abbreviated month name
- %B - Full month name
- %d - Day of the month as decimal 01 to 31
- %j - Day of year as decimal from 001 to 366
- %m - Month name as a decimal 01 to 12
- %U - Week number 00 to 53 with first Sunday as the first day of week 1?
- %w - Weekday as decimal number 0 to 6 where Sunday == 0
- %W - Week number 00 to 53 where Monday is first day of week 1
- %x - facet default date representation
- %y - Year without the century - eg: 04 for 2004
- %Y - Year with century
The weekday specifiers (%a and %A) do not add to the date construction,
but they provide a way to skip over the weekday names for formats that
provide them.
todo -- Another interesting feature that this approach could provide is
an option to fill in any missing fields with the current values
from the clock. So if you have %m-%d the parser would detect
the missing year value and fill it in using the clock.
todo -- What to do with the %x. %x in the classic facet is just bad...
*/
template<class date_type, typename charT>
class format_date_parser
{
public:
typedef std::basic_string<charT> string_type;
typedef std::basic_istringstream<charT> stringstream_type;
typedef std::istreambuf_iterator<charT> stream_itr_type;
typedef typename string_type::const_iterator const_itr;
typedef typename date_type::year_type year_type;
typedef typename date_type::month_type month_type;
typedef typename date_type::day_type day_type;
typedef typename date_type::duration_type duration_type;
typedef typename date_type::day_of_week_type day_of_week_type;
typedef typename date_type::day_of_year_type day_of_year_type;
typedef string_parse_tree<charT> parse_tree_type;
typedef typename parse_tree_type::parse_match_result_type match_results;
typedef std::vector<std::basic_string<charT> > input_collection_type;
// TODO sv_parser uses its default constructor - write the others
format_date_parser(const string_type& format_str,
const input_collection_type& month_short_names,
const input_collection_type& month_long_names,
const input_collection_type& weekday_short_names,
const input_collection_type& weekday_long_names) :
m_format(format_str),
m_month_short_names(month_short_names, 1),
m_month_long_names(month_long_names, 1),
m_weekday_short_names(weekday_short_names),
m_weekday_long_names(weekday_long_names)
{}
format_date_parser(const string_type& format_str,
const std::locale& locale) :
m_format(format_str),
m_month_short_names(gather_month_strings<charT>(locale), 1),
m_month_long_names(gather_month_strings<charT>(locale, false), 1),
m_weekday_short_names(gather_weekday_strings<charT>(locale)),
m_weekday_long_names(gather_weekday_strings<charT>(locale, false))
{}
format_date_parser(const format_date_parser<date_type,charT>& fdp)
{
this->m_format = fdp.m_format;
this->m_month_short_names = fdp.m_month_short_names;
this->m_month_long_names = fdp.m_month_long_names;
this->m_weekday_short_names = fdp.m_weekday_short_names;
this->m_weekday_long_names = fdp.m_weekday_long_names;
}
string_type format() const
{
return m_format;
}
void format(string_type format_str)
{
m_format = format_str;
}
void short_month_names(const input_collection_type& month_names)
{
m_month_short_names = parse_tree_type(month_names, 1);
}
void long_month_names(const input_collection_type& month_names)
{
m_month_long_names = parse_tree_type(month_names, 1);
}
void short_weekday_names(const input_collection_type& weekday_names)
{
m_weekday_short_names = parse_tree_type(weekday_names);
}
void long_weekday_names(const input_collection_type& weekday_names)
{
m_weekday_long_names = parse_tree_type(weekday_names);
}
date_type
parse_date(const string_type& value,
const string_type& format_str,
const special_values_parser<date_type,charT>& sv_parser) const
{
stringstream_type ss(value);
stream_itr_type sitr(ss);
stream_itr_type stream_end;
return parse_date(sitr, stream_end, format_str, sv_parser);
}
date_type
parse_date(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
const special_values_parser<date_type,charT>& sv_parser) const
{
return parse_date(sitr, stream_end, m_format, sv_parser);
}
/*! Of all the objects that the format_date_parser can parse, only a
* date can be a special value. Therefore, only parse_date checks
* for special_values. */
date_type
parse_date(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str,
const special_values_parser<date_type,charT>& sv_parser) const
{
bool use_current_char = false;
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
short year(0), month(0), day(0), day_of_year(0);// wkday(0);
/* Initialized the following to their minimum values. These intermediate
* objects are used so we get specific exceptions when part of the input
* is unparsable.
* Ex: "205-Jan-15" will throw a bad_year, "2005-Jsn-15"- bad_month, etc.*/
year_type t_year(1400);
month_type t_month(1);
day_type t_day(1);
day_of_week_type wkday(0);
const_itr itr(format_str.begin());
while (itr != format_str.end() && (sitr != stream_end)) {
if (*itr == '%') {
if ( ++itr == format_str.end())
break;
if (*itr != '%') {
switch(*itr) {
case 'a':
{
//this value is just throw away. It could be used for
//error checking potentially, but it isn't helpful in
//actually constructing the date - we just need to get it
//out of the stream
match_results mr = m_weekday_short_names.match(sitr, stream_end);
if(mr.current_match == match_results::PARSE_ERROR) {
// check special_values
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
wkday = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'A':
{
//this value is just throw away. It could be used for
//error checking potentially, but it isn't helpful in
//actually constructing the date - we just need to get it
//out of the stream
match_results mr = m_weekday_long_names.match(sitr, stream_end);
if(mr.current_match == match_results::PARSE_ERROR) {
// check special_values
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
wkday = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'b':
{
match_results mr = m_month_short_names.match(sitr, stream_end);
if(mr.current_match == match_results::PARSE_ERROR) {
// check special_values
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_month = month_type(mr.current_match);
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'B':
{
match_results mr = m_month_long_names.match(sitr, stream_end);
if(mr.current_match == match_results::PARSE_ERROR) {
// check special_values
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_month = month_type(mr.current_match);
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'd':
{
match_results mr;
day = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
if(day == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_day = day_type(day);
break;
}
case 'e':
{
match_results mr;
day = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2, ' ');
if(day == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_day = day_type(day);
break;
}
case 'j':
{
match_results mr;
day_of_year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 3);
if(day_of_year == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
// these next two lines are so we get an exception with bad input
day_of_year_type t_day_of_year(1);
t_day_of_year = day_of_year_type(day_of_year);
break;
}
case 'm':
{
match_results mr;
month = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
if(month == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_month = month_type(month);
break;
}
case 'Y':
{
match_results mr;
year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 4);
if(year == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
t_year = year_type(year);
break;
}
case 'y':
{
match_results mr;
year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
if(year == -1) {
if(sv_parser.match(sitr, stream_end, mr)) {
return date_type(static_cast<special_values>(mr.current_match));
}
}
year += 2000; //make 2 digit years in this century
t_year = year_type(year);
break;
}
default:
{} //ignore those we don't understand
}//switch
}
else { // itr == '%', second consecutive
sitr++;
}
itr++; //advance past format specifier
}
else { //skip past chars in format and in buffer
itr++;
if (use_current_char) {
use_current_char = false;
}
else {
sitr++;
}
}
}
if (day_of_year > 0) {
date_type d(static_cast<unsigned short>(year-1),12,31); //end of prior year
return d + duration_type(day_of_year);
}
return date_type(t_year, t_month, t_day); // exceptions were thrown earlier
// if input was no good
}
//! Throws bad_month if unable to parse
month_type
parse_month(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str) const
{
match_results mr;
return parse_month(sitr, stream_end, format_str, mr);
}
//! Throws bad_month if unable to parse
month_type
parse_month(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str,
match_results& mr) const
{
bool use_current_char = false;
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
short month(0);
const_itr itr(format_str.begin());
while (itr != format_str.end() && (sitr != stream_end)) {
if (*itr == '%') {
if ( ++itr == format_str.end())
break;
if (*itr != '%') {
switch(*itr) {
case 'b':
{
mr = m_month_short_names.match(sitr, stream_end);
month = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'B':
{
mr = m_month_long_names.match(sitr, stream_end);
month = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'm':
{
month = var_string_to_int<short, charT>(sitr, stream_end, 2);
// var_string_to_int returns -1 if parse failed. That will
// cause a bad_month exception to be thrown so we do nothing here
break;
}
default:
{} //ignore those we don't understand
}//switch
}
else { // itr == '%', second consecutive
sitr++;
}
itr++; //advance past format specifier
}
else { //skip past chars in format and in buffer
itr++;
if (use_current_char) {
use_current_char = false;
}
else {
sitr++;
}
}
}
return month_type(month); // throws bad_month exception when values are zero
}
//! Expects 1 or 2 digits 1-31. Throws bad_day_of_month if unable to parse
day_type
parse_var_day_of_month(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end) const
{
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
return day_type(var_string_to_int<short, charT>(sitr, stream_end, 2));
}
//! Expects 2 digits 01-31. Throws bad_day_of_month if unable to parse
day_type
parse_day_of_month(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end) const
{
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
//return day_type(var_string_to_int<short, charT>(sitr, stream_end, 2));
match_results mr;
return day_type(fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2));
}
day_of_week_type
parse_weekday(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str) const
{
match_results mr;
return parse_weekday(sitr, stream_end, format_str, mr);
}
day_of_week_type
parse_weekday(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str,
match_results& mr) const
{
bool use_current_char = false;
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
short wkday(0);
const_itr itr(format_str.begin());
while (itr != format_str.end() && (sitr != stream_end)) {
if (*itr == '%') {
if ( ++itr == format_str.end())
break;
if (*itr != '%') {
switch(*itr) {
case 'a':
{
//this value is just throw away. It could be used for
//error checking potentially, but it isn't helpful in
//actually constructing the date - we just need to get it
//out of the stream
mr = m_weekday_short_names.match(sitr, stream_end);
wkday = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'A':
{
//this value is just throw away. It could be used for
//error checking potentially, but it isn't helpful in
//actually constructing the date - we just need to get it
//out of the stream
mr = m_weekday_long_names.match(sitr, stream_end);
wkday = mr.current_match;
if (mr.has_remaining()) {
use_current_char = true;
}
break;
}
case 'w':
{
// weekday as number 0-6, Sunday == 0
wkday = var_string_to_int<short, charT>(sitr, stream_end, 2);
break;
}
default:
{} //ignore those we don't understand
}//switch
}
else { // itr == '%', second consecutive
sitr++;
}
itr++; //advance past format specifier
}
else { //skip past chars in format and in buffer
itr++;
if (use_current_char) {
use_current_char = false;
}
else {
sitr++;
}
}
}
return day_of_week_type(wkday); // throws bad_day_of_month exception
// when values are zero
}
//! throws bad_year if unable to parse
year_type
parse_year(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str) const
{
match_results mr;
return parse_year(sitr, stream_end, format_str, mr);
}
//! throws bad_year if unable to parse
year_type
parse_year(std::istreambuf_iterator<charT>& sitr,
std::istreambuf_iterator<charT>& stream_end,
string_type format_str,
match_results& mr) const
{
// skip leading whitespace
while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; }
unsigned short year(0);
const_itr itr(format_str.begin());
while (itr != format_str.end() && (sitr != stream_end)) {
if (*itr == '%') {
if ( ++itr == format_str.end())
break;
if (*itr != '%') {
//match_results mr;
switch(*itr) {
case 'Y':
{
// year from 4 digit string
year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 4);
break;
}
case 'y':
{
// year from 2 digit string (no century)
year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
year += 2000; //make 2 digit years in this century
break;
}
default:
{} //ignore those we don't understand
}//switch
}
else { // itr == '%', second consecutive
sitr++;
}
itr++; //advance past format specifier
}
else { //skip past chars in format and in buffer
itr++;
sitr++;
}
}
return year_type(year); // throws bad_year exception when values are zero
}
private:
string_type m_format;
parse_tree_type m_month_short_names;
parse_tree_type m_month_long_names;
parse_tree_type m_weekday_short_names;
parse_tree_type m_weekday_long_names;
};
} } //namespace
#endif