pqxx::string_traits< TYPE > Struct Template Reference

Traits class for use in string conversions. More...

#include <strconv.hxx>

Static Public Member Functions
static zview	to_buf (char *begin, char *end, TYPE const &value)
	Return a string_view representing value, plus terminating zero. More...
static char *	into_buf (char *begin, char *end, TYPE const &value)
	Write value's string representation into buffer at begin. More...
static TYPE	from_string (std::string_view text)
	Parse a string representation of a TYPE value. More...
static std::size_t	size_buffer (TYPE const &value) noexcept
	Estimate how much buffer space is needed to represent value. More...

Static Public Attributes
static constexpr bool	converts_to_string {false}
	Is conversion from TYPE to strings supported? More...
static constexpr bool	converts_from_string {false}
	Is conversion from string_view to TYPE supported? More...

Detailed Description

template<typename TYPE>
struct pqxx::string_traits< TYPE >

Traits class for use in string conversions.

Specialize this template for a type for which you wish to add to_string and from_string support.

String conversions are not meant to work for nulls. Check for null before converting a value of TYPE to a string, or vice versa.

Member Function Documentation

from_string()

template<typename TYPE >

bool pqxx::string_traits< TYPE >::from_string ( std::string_view  text )

static

Parse a string representation of a TYPE value.

Throws conversion_error if value does not meet the expected format for a value of this type.

Warning

A null value has no string representation. Do not parse a null.

References pqxx::text.

Referenced by pqxx::internal::enum_traits< ENUM >::from_string(), and pqxx::from_string().

into_buf()

template<typename TYPE >

static char* pqxx::string_traits< TYPE >::into_buf ( char *  begin, char *  end, TYPE const &  value  )

static

Write value's string representation into buffer at begin.

Referenced by pqxx::internal::enum_traits< ENUM >::into_buf(), and pqxx::placeholders< COUNTER >::next().

size_buffer()

template<typename TYPE >

static std::size_t pqxx::string_traits< TYPE >::size_buffer ( TYPE const &  value )

staticnoexcept

Estimate how much buffer space is needed to represent value.

The estimate may be a little pessimistic, if it saves time.

The estimate includes the terminating zero.

Referenced by pqxx::string_traits< binarystring >::into_buf(), and pqxx::internal::enum_traits< ENUM >::size_buffer().

to_buf()

template<typename TYPE >

static zview pqxx::string_traits< TYPE >::to_buf ( char *  begin, char *  end, TYPE const &  value  )

static

Return a string_view representing value, plus terminating zero.

Produces a string_view containing the PostgreSQL string representation for value.

Warning

A null value has no string representation. Do not pass a null.

Uses the space from begin to end as a buffer, if needed. The returned string may lie somewhere in that buffer, or it may be a compile-time constant, or it may be null if value was a null value. Even if the string is stored in the buffer, its begin() may or may not be the same as begin.

The string_view is guaranteed to be valid as long as the buffer from begin to end remains accessible and unmodified.

Exceptions

pqxx::conversion_overrun

if the provided buffer space may not be enough. For maximum performance, this is a conservative estimate. It may complain about a buffer which is actually large enough for your value, if an exact check gets too expensive.

Referenced by pqxx::internal::enum_traits< ENUM >::to_buf().

Member Data Documentation

converts_from_string

template<typename TYPE >

constexpr bool pqxx::string_traits< TYPE >::converts_from_string {false}

staticconstexpr

Is conversion from string_view to TYPE supported?

When defining your own conversions, specialise this as true to indicate that your string traits support from_string.

converts_to_string

template<typename TYPE >

constexpr bool pqxx::string_traits< TYPE >::converts_to_string {false}

staticconstexpr

Is conversion from TYPE to strings supported?

When defining your own conversions, specialise this as true to indicate that your string traits support the conversions to strings.

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The documentation for this struct was generated from the following files:

• strconv.hxx
• strconv.cxx