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Unsigned Integer Parsers (uint_, etc.)
Description

The uint_parser class is the simplest among the members of the numerics package. The uint_parser can parse unsigned integers of arbitrary length and size. The uint_parser parser can be used to parse ordinary primitive C/C++ integers or even user defined scalars such as bigints (unlimited precision integers) as long as the type follows certain expression requirements (documented below). The uint_parser is a template class. Template parameters fine tune its behavior.

Header
// forwards to <boost/spirit/home/qi/numeric/uint.hpp>
#include <boost/spirit/include/qi_uint.hpp>

Also, see Include Structure.

Namespace

Name

boost::spirit::lit // alias: boost::spirit::qi::lit

boost::spirit::bin // alias: boost::spirit::qi::bin

boost::spirit::oct // alias: boost::spirit::qi::oct

boost::spirit::hex // alias: boost::spirit::qi::hex

boost::spirit::ushort_ // alias: boost::spirit::qi::ushort_

boost::spirit::ulong_ // alias: boost::spirit::qi::ulong_

boost::spirit::uint_ // alias: boost::spirit::qi::uint_

boost::spirit::ulong_long // alias: boost::spirit::qi::ulong_long

[Note] Note

ulong_long is only available on platforms where the preprocessor constant BOOST_HAS_LONG_LONG is defined (i.e. on platforms having native support for unsigned long long (64 bit) unsigned integer types).

[Note] Note

lit is reused by the Character Parsers, and the Numeric Parsers. In general, a char parser is created when you pass in a character, and a numeric parser is created when you use a numeric literal.

Synopsis
template <
    typename T
  , unsigned Radix
  , unsigned MinDigits
  , int MaxDigits>
struct uint_parser;
Template parameters

Parameter

Description

Default

T

The numeric base type of the numeric parser.

none

Radix

The radix base. This can be any base from 2..10 and 16

10

MinDigits

The minimum number of digits allowable.

1

MaxDigits

The maximum number of digits allowable. If this is -1, then the maximum limit becomes unbounded.

-1

Model of

PrimitiveParser

Notation

n

An object of T, the numeric base type.

num

Numeric literal, any unsigned integer value, or a Lazy Argument that evaluates to a unsigned integer value.

Expression Semantics

Semantics of an expression is defined only where it differs from, or is not defined in PrimitiveParser.

Expression

Semantics

ushort_
uint_
ulong_
ulong_long

Parse an unsigned integer using the default radix (10).

lit(num)
ushort_(num)
uint_(num)
ulong_(num)
ulong_long(num)

Match the literal num using the default radix (10). The parser will fail if the parsed value is not equal to the specified value.

bin
oct
hex

Parse an unsigned integer using radix 2 for bin, radix 8 for oct, and radix 16 for hex.

bin(num)
oct(num)
hex(num)

Match the literal num using radix 2 for bin, radix 8 for oct, and radix 16 for hex. The parser will fail if the parsed value is not equal to the specified value.

uint_parser<
    T, Radix, MinDigits, MaxDigits
>()

Parse an unsigned integer of type T using radix Radix, with a minimum of MinDigits and a maximum of MaxDigits.

uint_parser<
    T, Radix, MinDigits, MaxDigits
>()(num)

Match the literal num of type T using radix Radix, with a minimum of MinDigits and a maximum of MaxDigits. The parser will fail if the parsed value is not equal to the specified value.

[Important] Important

All numeric parsers check for overflow conditions based on the type T the corresponding uint_parser<> has been instantiated with. If the parsed number overflows this type the parsing fails. Please be aware that the overflow check is not based on the type of the supplied attribute but solely depends on the template parameter T.

Attributes

Expression

Attribute

lit(num)

unused

ushort_
ushort_(num)

unsigned short

uint_
uint_(num)
bin
bin(num)
oct
oct(num)
hex
hex(num)

unsigned int

ulong_
ulong_(num)

unsigned long

ulong_long
ulong_long(num)

boost::ulong_long_type

uint_parser<
    T, Radix, MinDigits, MaxDigits
>()
uint_parser<
    T, Radix, MinDigits, MaxDigits
>()(num)

T

Complexity

O(N), where N is the number of digits being parsed.

Minimum Expression Requirements for T

For the numeric base type, T, the expression requirements below must be valid:

Expression

Semantics

T()

Default construct.

T(0)

Construct from an int.

n + n

Addition.

n * n

Multiplication.

std::numeric_limits<T>::is_bounded

true or false if T bounded.

std::numeric_limits<T>::digits

Maximum Digits for T, radix digits. Required only if T is bounded.

std::numeric_limits<T>::digits10

Maximum Digits for T, base 10. Required only if T is bounded.

std::numeric_limits<T>::max()

Maximum value for T. Required only if T is bounded.

std::numeric_limits<T>::min()

Minimum value for T. Required only if T is bounded.

Example
[Note] Note

The test harness for the example(s) below is presented in the Basics Examples section.

Some using declarations:

using boost::phoenix::val;
using boost::spirit::qi::lit;
using boost::spirit::qi::uint_;
using boost::spirit::qi::uint_parser;

Basic unsigned integers:

// unsigned int
test_parser("12345", uint_);
test_parser("12345", uint_(12345));
test_parser("12345", uint_(val(12345)));

// literals
test_parser("12345", lit(12345));
test_parser("12345", lit(val(12345)));

Thousand separated number parser:

uint_parser<unsigned, 10, 1, 3> uint3_p;        //  1..3 digits
uint_parser<unsigned, 10, 3, 3> uint3_3_p;      //  exactly 3 digits
test_parser("12,345,678", uint3_p >> *(',' >> uint3_3_p));


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