libpqxx
The C++ client library for PostgreSQL
 
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pqxx::string_traits< binarystring > Struct Reference

String conversion traits for binarystring. More...

Static Public Member Functions

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

Static Public Attributes

static constexpr bool converts_to_string
 Is conversion from TYPE to strings supported?
 
static constexpr bool converts_from_string
 Is conversion from string_view to TYPE supported?
 

Detailed Description

String conversion traits for binarystring.

Defines the conversions between a binarystring and its PostgreSQL textual format, for communication with the database.

These conversions rely on the "hex" format which was introduced in PostgreSQL 9.0. Both your libpq and the server must be recent enough to speak this format.

Member Function Documentation

◆ from_string()

static binarystring pqxx::string_traits< binarystring >::from_string ( std::string_view text)
inlinestaticnodiscard

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.

◆ size_buffer()

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

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.

◆ to_buf()

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

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_overrunif 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.

Member Data Documentation

◆ converts_from_string

bool pqxx::string_traits< binarystring >::converts_from_string
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

bool pqxx::string_traits< binarystring >::converts_to_string
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.


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