Binary Little Endianness Generators

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##### Binary Little Endianness Generators

###### Description

The little native endianness generators described in this section are used to emit binary byte streams laid out conforming to the little endianness byte order.

###### Header

    // forwards to <boost/spirit/home/karma/binary.hpp>
    #include <boost/spirit/include/karma_binary.hpp>

Also, see Include Structure.

###### Namespace

Name
`boost::spirit::little_word // alias: boost::spirit::karma::little_word`
`boost::spirit::little_dword // alias: boost::spirit::karma::little_dword`
`boost::spirit::little_qword // alias: boost::spirit::karma::little_qword`

| Note
The generators `little_qword` and `little_qword(qw)` are 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

> `PrimitiveGenerator`

Notation

`w`

  A 16 bit binary value or a Lazy Argument that evaluates to a 16 bit binary value. This value is always interpreted using native endianness.

`dw`

  A 32 bit binary value or a Lazy Argument that evaluates to a 32 bit binary value. This value is always interpreted using native endianness.

`qw`

  A 64 bit binary value or a Lazy Argument that evaluates to a 64 bit binary value. This value is always interpreted using native endianness.

###### Expression Semantics

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

Expression | Description
--- | ---
`little_word` | Output the binary representation of the least significant 16 bits of the mandatory attribute in little endian representation. This generator never fails (unless the underlying output stream reports an error).
`little_dword` | Output the binary representation of the least significant 32 bits of the mandatory attribute in little endian representation. This generator never fails (unless the underlying output stream reports an error).
`little_qword` | Output the binary representation of the least significant 64 bits of the mandatory attribute in little endian representation. This generator never fails (unless the underlying output stream reports an error).
`little_word(w)` | Output the binary representation of the least significant 16 bits of the immediate parameter in little endian representation. This generator never fails (unless the underlying output stream reports an error).
`little_dword(dw)` | Output the binary representation of the least significant 32 bits of the immediate parameter in little endian representation. This generator never fails (unless the underlying output stream reports an error).
`little_qword(qw)` | Output the binary representation of the least significant 64 bits of the immediate parameter in little endian representation. This generator never fails (unless the underlying output stream reports an error).

###### Attributes

Expression | Attribute
--- | ---
`little_word` | `boost::uint_least16_t`, attribute is mandatory (otherwise compilation will fail)
`little_dword` | `boost::uint_least32_t`, attribute is mandatory (otherwise compilation will fail)
`little_qword` | `boost::uint_least64_t`, attribute is mandatory (otherwise compilation will fail)
`little_word(w)` | `unused`
`little_dword(dw)` | `unused`
`little_qword(qw)` | `unused`

###### Complexity

> O(N), where N is the number of bytes emitted by the binary generator

###### Example

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

Some includes:

    #include <boost/spirit/include/karma.hpp>
    #include <boost/spirit/include/support_utree.hpp>
    #include <boost/spirit/include/phoenix_core.hpp>
    #include <boost/spirit/include/phoenix_operator.hpp>
    #include <boost/fusion/include/std_pair.hpp>
    #include <iostream>
    #include <string>

Some using declarations:

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

Basic usage of the little binary generators:

    test_binary_generator("\x01\x02", 2, little_word(0x0201));
    test_binary_generator("\x01\x02\x03\x04", 4, little_dword(0x04030201));
    test_binary_generator("\x01\x02\x03\x04\x05\x06\x07\x08", 8, little_qword(0x0807060504030201LL));

    test_binary_generator_attr("\x01\x02", 2, little_word, 0x0201);
    test_binary_generator_attr("\x01\x02\x03\x04", 4, little_dword, 0x04030201);
    test_binary_generator_attr("\x01\x02\x03\x04\x05\x06\x07\x08", 8, little_qword, 0x0807060504030201LL);