Provided by: libffi-platypus-type-enum-perl_0.06-2_all 
NAME
FFI::Platypus::Type::Enum - Custom platypus type for dealing with C enumerated types
VERSION
version 0.06
SYNOPSIS
C:
enum {
DEFAULT,
BETTER,
BEST = 12
} foo_t;
foo_t
f(foo_t arg)
{
return foo_t;
}
Perl with strings:
use FFI::Platypus 1.00;
my $ffi = FFI::Platypus->new( api => 1 );
$ffi->load_custom_type('::Enum', 'foo_t',
'default',
'better',
['best' => 12],
);
$ffi->attach( f => ['foo_t'] => 'foo_t' );
f("default") eq 'default'; # true
f("default") eq 'better'; # false
print f("default"), "\n"; # default
print f("better"), "\n"; # better
print f("best"), "\n"; # best
Perl with constants:
use FFI::Platypus 1.00;
my $ffi = FFI::Platypus->new( api => 1 );
$ffi->load_custom_type('::Enum', 'foo_t',
{ rev => 'int', package => 'Foo', prefix => 'FOO_' },
'default',
'better',
['best' => 12],
);
$ffi->attach( f => ['foo_t'] => 'foo_t' );
f(Foo::FOO_DEFAULT) == Foo::FOO_DEFAULT; # true
f(Foo::FOO_DEFAULT) == Foo::FOO_BETTER; # false
DESCRIPTION
This type plugin is a helper for making enumerated types. It makes the most sense to use
this when you have an enumerated type with a small number of possible values. For a large
set of enumerated values or constants, see FFI::Platypus::Constant.
This type plugin has two modes:
string
In string mode, string representations of the enum values are converted into the
integer enum values when passed into C, and the enums are converted back into strings
when coming from C back into Perl. You can also pass in the integer values.
constant
In constant mode, constants are defined in the specified package, and with the
optional prefix. The string representation or integer constants can be passed into C,
but the integer constants are returned from C back into Perl.
In both modes, if you attempt to pass in a value that isn't one of the possible enum
values, an exception will be thrown.
OPTIONS
The general form of the custom type load is:
$ffi->load_custom_type('::Enum', $name, \%options, @values);
$ffi->load_custom_type('::Enum', $name, @values);
The enumerated values are specified as a list of strings and array references.
string
$ffi->load_custom_type('::Enum', $name, $string1, $string2, ... );
For strings the constant value starts at zero (0) and increases by one for each
possible value.
array reference
$ffi->load_custom_type('::Enum', $name, [ $value_name, $value, %options ]);
$ffi->load_custom_type('::Enum', $name, [ $value_name, %options ]);
You can use an array reference to include an explicit integer value, rather than using
the implicit incremented value. You can also use the array reference for value
options. If the value isn't included (that is if there are an odd number of values in
the array reference), then the implicit incremented value will be used.
Value options:
alias
$ffi->load_custom_type('::Enum, $name, [ $value_name, $value, alias => \@aliases ]);
$ffi->load_custom_type('::Enum, $name, [ $value_name, alias => \@aliases ]);
The "alias" option lets you specify value aliases. For example, suppose you have
an enum definition like:
enum {
FOO,
BAR,
BAZ=BAR,
ABC,
XYZ
} foo_t;
The Perl definition would be:
$ffi->load_custom_type('::Enum', 'foo_t',
'foo',
['bar', alias => ['baz']],
'abc',
'xyz',
);
Type options may be passed in as a hash reference after the type name.
Type options:
maps
my @maps;
$ffi->load_custom_type('::Enum', $name, { maps => \@maps }, ... );
my($str,$int,$type) = @maps;
If set to an empty array reference, this will be filled with the string, integer and
native type for the enum.
package
$ffi->load_custom_type('::Enum', $name, { package => $package }, ... );
$ffi->load_custom_type('::Enum', $name, { package => \@package }, ... ); # version 0.05
This option specifies the Perl package where constants will be defined. If not
specified, then no constants will be generated. Unless otherwise specified (see
'casing' below), the constants will be the upper case of the value names as per the
usual convention.
[version 0.05]
As of version 0.05, you can specify multiple packages to create the constants via an
array reference.
prefix
$ffi->load_custom_type('::Enum', $name, { prefix => $prefix }, ... );
This specifies an optional prefix to give each constant. If not specified, then no
prefix will be used.
rev
$ffi->load_custom_type('::Enum', $name, { rev => 'int' }, ... );
$ffi->load_custom_type('::Enum', $name, { rev => 'str' }, ... );
$ffi->load_custom_type('::Enum', $name, { rev => 'dualvar' }, ... ); # version 0.05
This specifies what should be returned for C functions that return the enumerated
type. For strings, use "str", and for integer constants use "int".
("rev" is short for "reverse")
[version 0.05]
As of version 0.05, dualvar can be specified to return a string/integer dualvar.
type
$ffi->load_custom_type('::Enum', $name, { type => $type }, ... );
This specifies the integer type that should be used for the enumerated type. The
default is to use "enum" for types that only have positive possible values and "senum"
for types that have possible negative values. (Note that on some platforms these two
types may actually be the same).
You can also use other integer types, which is useful if the enum is only used to
define constants, and the values are stored in a type smaller than the default for
"enum" or "senum". For example:
C:
enum {
DEFAULT,
BETTER,
BEST = 12
} foo_enum;
typedef uint8_t foo_t;
/*
* you are expected to use the constants from foo_enum,
* but the signature actually uses a uint8_t
*/
void f(foo_t);
Perl:
$ffi->load_custom_type('::Enum', 'foo_t',
{ type => 'uint8' },
'default',
'better',
[best => 12],
);
$ffi->attach( f => [ 'foo_t' ] => 'void' );
casing
[version 0.06]
$ffi->load_custom_type('::Enum', $name, { casing => 'upper' }, ... );
$ffi->load_custom_type('::Enum', $name, { casing => 'keep' }, ... );
When in constant mode, all constant names are by default generated in uppercase as is
conventional. However, some libraries will on occasion define constant names in mixed
case. For these cases, the "casing" option, added in version 0.06, can be set to
"keep" to prevent the names from being modified. The only other allowed value is
"upper", which is the default.
SEE ALSO
FFI::Platypus
FFI::C
AUTHOR
Author: Graham Ollis <plicease@cpan.org>
Contributors:
José Joaquín Atria (JJATRIA)
COPYRIGHT AND LICENSE
This software is copyright (c) 2020 by Graham Ollis.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.