Binary Little Endianness Parser

Description

Binary little endian parsers are designed to parse binary byte streams that are laid out in little endian.

Header

// forwards to <boost/spirit/home/qi/binary.hpp>
#include <boost/spirit/include/qi_binary.hpp>

Also, see Include Structure.

Namespace

Name
`boost::spirit::little_word // alias: boost::spirit::qi::little_word`
`boost::spirit::little_dword // alias: boost::spirit::qi::little_dword`
`boost::spirit::little_qword // alias: boost::spirit::qi::little_qword`
`boost::spirit::little_bin_float // alias: boost::spirit::qi::little_bin_float`
`boost::spirit::little_bin_double // alias: boost::spirit::qi::little_bin_double`

	Note
	`little_qword` 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) integer types).

Model of

PrimitiveParser

Notation

w: A 16 bit binary value or a Lazy Argument that evaluates to a 16 bit binary value. This value is always in native endian.
dw: A 32 bit binary value or a Lazy Argument that evaluates to a 32 bit binary value. This value is always in native endian.
qw: A 64 bit binary value or a Lazy Argument that evaluates to a 64 bit binary value. This value is always in native endian.
f: A float binary value or a Lazy Argument that evaluates to a float binary value. This value is always in native endian.
d: A double binary value or a Lazy Argument that evaluates to a double binary value. This value is always in native endian.

Expression Semantics

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

Expression	Description
`little_word`	Matches any 16 bit little endian binary.
`little_dword`	Matches any 32 bit little endian binary.
`little_qword`	Matches any 64 bit little endian binary.
`little_bin_float`	Matches any float little endian binary.
`little_bin_double`	Matches any double little endian binary.
`little_word(w)`	Matches an exact 16 bit little endian binary.
`little_dword(dw)`	Matches an exact 32 bit little endian binary.
`little_qword(qw)`	Matches an exact 32 bit little endian binary.
`little_bin_float(f)`	Matches an exact float little endian binary.
`little_bin_double(d)`	Matches an exact double little endian binary.

Attributes

Expression	Attribute
`little_word`	`boost::uint_least16_t`
`little_dword`	`boost::uint_least32_t`
`little_qword`	`boost::uint_least64_t`
`little_bin_float`	`float`
`little_bin_double`	`double`
`little_word(w)`	`unused`
`little_dword(dw)`	`unused`
`little_qword(qw)`	`unused`
`little_bin_float(f)`	`unused`
`little_bin_double(d)`	`unused`

Complexity

O(N), where N is the number of bytes parsed

Example

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

Using declarations and variables:

using boost::spirit::qi::little_word;
using boost::spirit::qi::little_dword;
using boost::spirit::qi::little_qword;

boost::uint16_t us;
boost::uint32_t ui;
boost::uint64_t ul;

Basic usage of the little endian binary parsers:

test_parser_attr("\x01\x02", little_word, us); assert(us == 0x0201);
test_parser_attr("\x01\x02\x03\x04", little_dword, ui); assert(ui == 0x04030201);
test_parser_attr("\x01\x02\x03\x04\x05\x06\x07\x08", little_qword, ul);
assert(ul == 0x0807060504030201LL);

test_parser("\x01\x02", little_word(0x0201));
test_parser("\x01\x02\x03\x04", little_dword(0x04030201));
test_parser("\x01\x02\x03\x04\x05\x06\x07\x08",
    little_qword(0x0807060504030201LL));