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/*
Copyright (C) 2011-2014, Parrot Foundation.
=head1 NAME
src/pmc/ptr.pmc - Ptr PMC
=head1 DESCRIPTION
C<Ptr> is a bare bones PMC for representing the base type for pointers. It is
intended that additional functionality be added via subclassing. Any
functionality added to this PMC not critical to its operation as a pointer
representation is deprecated in advance and subject to removal without notice.
=head2 Fat versus Thin
C<Ptr> can be implemented with two separate representations - C<fat>, which
makes use of the conventional PMC attributes structure and C<thin> which is
more efficient and stores the pointer directly, avoiding memory allocation and
pointer dereference costs at the expense of extensibility.
The distinction is managed via a set of macros - C<PTR_FAT_TEST>,
C<PTR_FAT_SET>, and C<PTR_FAT_CLEAR>. Internally, these use the
C<private1> flag, and this flag is therefore unavailable for subclass use.
=cut
*/
BEGIN_PMC_HEADER_PREAMBLE
#define PTR_FAT_TEST(i, s) PObj_flag_TEST(private1, (s))
#define PTR_FAT_SET(i, s) PObj_flag_SET(private1, (s))
#define PTR_FAT_CLEAR(i, s) PObj_flag_CLEAR(private1, (s))
END_PMC_HEADER_PREAMBLE
#include "parrot/string_funcs.h"
/* HEADERIZER HFILE: none */
/* HEADERIZER BEGIN: static */
/* HEADERIZER END: static */
/*
=head2 Vtable Functions
=over 4
=cut
*/
pmclass Ptr manual_attrs {
ATTR void *ptr;
/*
=item C<void init()>
If C<fat> and attributes have not yet been otherwise allocated, will allocate
room for the representation.
Unless otherwise initialized, Parrot will have zeroed this and the pointer
value will be C<NULL>.
=item C<init_int(INTVAL i)>
C<init> with a value from an C<INTVAL>.
=item C<init_pmc(PMC *p)>
C<init> with a value from an existing pointer-ish PMC.
=cut
*/
VTABLE void init() :manual_wb {
if (PTR_FAT_TEST(INTERP, SELF) && !PMC_data(SELF)) {
PMC_data(SELF) = (void *)mem_gc_allocate_zeroed_typed(INTERP, Parrot_Ptr_attributes);
PObj_custom_destroy_SET(SELF);
PARROT_GC_WRITE_BARRIER(INTERP, SELF);
}
}
VTABLE void init_int(INTVAL i) :manual_wb {
void *ptr = (void *)i;
SELF.init();
STATICSELF.set_pointer(ptr);
}
VTABLE void init_pmc(PMC *p) :manual_wb {
void *ptr = VTABLE_get_pointer(INTERP, p);
SELF.init();
STATICSELF.set_pointer(ptr);
}
/*
=item C<void *get_pointer()>
=item C<void set_pointer(void *ptr)>
Get and set the pointer value.
=cut
*/
VTABLE void *get_pointer() :manual_wb {
void *ptr;
if (PTR_FAT_TEST(INTERP, SELF))
GET_ATTR_ptr(INTERP, SELF, ptr);
else
ptr = PMC_data(SELF);
/* We are returning raw pointer. Someone can write into it */
PARROT_GC_WRITE_BARRIER(INTERP, SELF);
return ptr;
}
VTABLE void set_pointer(void *ptr) {
if (PTR_FAT_TEST(INTERP, SELF))
SET_ATTR_ptr(INTERP, SELF, ptr);
else
PMC_data(SELF) = ptr;
}
/*
=item C<INTVAL get_bool()>
Boolean value of the pointer. Non-C<NULL> is true, following in the C tradition.
=cut
*/
VTABLE INTVAL get_bool() :no_wb {
return STATICSELF.get_pointer() != NULL;
}
/*
=item C<void destroy()>
Manage attribute deallocation for C<fat> representation.
=cut
*/
VTABLE void destroy() :no_wb {
if (PTR_FAT_TEST(INTERP, SELF) && PMC_data(SELF))
mem_gc_free(INTERP, PMC_data(SELF));
}
/*
=item C<INTVAL get_integer()>
Implement C<PtrBuf> interface. Specifies length of the buffer.
In this case, always returns C<0>, indicating undetermined length.
=cut
*/
VTABLE INTVAL get_integer() :no_wb {
UNUSED(INTERP)
UNUSED(SELF)
return 0;
}
/*
=back
=head2 Methods
=over 4
=item C<as_string(string encodingname)>
Create a string from the buffer, assumed to be a C string, with the encoding
specified. If the encoding is omitted or null, use platform encoding.
=cut
*/
METHOD as_string(STRING *encodingname :optional) :no_wb {
const char * content = (const char *)SELF.get_pointer();
STRING *result = Parrot_str_new_from_cstring(INTERP, content, encodingname);
RETURN(STRING result);
}
}
/*
=back
=cut
*/
/*
* Local variables:
* c-file-style: "parrot"
* End:
* vim: expandtab shiftwidth=4 cinoptions='\:2=2' :
*/