size-trait.hpp File Reference

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Description

Metaprogramming definitions to deal with dependency on implementation size and layout.

Sometimes we need to build our code based on very specific assumptions regarding the implementation data layout of library classes we rely on. Typically such happens when we're forced to work around limitations the library provider never intended to be relevant for any client. Which places us into the very unfortunate situation either to abandon some design concept we prefer to use for some other relevant reason, or to do something very evil and nasty (namely to rely on magic numbers, which may break silently when the library provider changes implementation).

While this situation can not be solved in principle, at least we may concentrate all these nasty dependencies in a single location. Moreover, we can deal with this situation by constructing our magic numbers at least in a systematic way, which allows us to intersperse static assertions to trigger an alarm when adjustments need to be made.

typical example

A prominent example is boost::format, which causes a lot of code size bloat when used liberally. For that reason, we built a front-end to encapsulate the boost implementation, so any typed flavour of any call needs to be instantiated only once per application. This allows us to use type safe formatting in error messages, but unfortunately forces us to rely on the precise size of the boost::format implementation.

Definition in file size-trait.hpp.

#include <vector>
#include <string>

Classes
struct	SizeTrait::BasicAltstringbuf
struct	SizeTrait::BasicStringbuf
struct	SizeTrait::BoostFormat
struct	SizeTrait::CompatAllocator
struct	SizeTrait::Locale
struct	SizeTrait::Optional< T >
class	SizeTrait
	A collection of constants to describe the expected size of some known classes, without needing to include the respective headers. More...

Namespaces
	lib
	Implementation namespace for support and library code.

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Class Documentation

lib::meta::SizeTrait::BoostFormat

struct lib::meta::SizeTrait::BoostFormat

Class Members
Vector	items_
BVector	bound_
int	style_
int	cur_arg_
int	num_args_
bool	dumped_
string	prefix_
unsigned char	exceptions
BasicAltstringbuf	buf_
Optional< Locale >	loc_

Collaboration diagram for SizeTrait::BoostFormat:

lib::meta::SizeTrait::Locale

struct lib::meta::SizeTrait::Locale

Class Members
void *	_M_impl

Collaboration diagram for SizeTrait::Locale:

lib::meta::SizeTrait::Optional

struct lib::meta::SizeTrait::Optional

Class Members
bool	m_initialized_
T	m_storage_

Inheritance diagram for SizeTrait::Optional< T >:

Collaboration diagram for SizeTrait::Optional< T >: