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/*
Crown Copyright (c) 1997
This TenDRA(r) Computer Program is subject to Copyright
owned by the United Kingdom Secretary of State for Defence
acting through the Defence Evaluation and Research Agency
(DERA). It is made available to Recipients with a
royalty-free licence for its use, reproduction, transfer
to other parties and amendment for any purpose not excluding
product development provided that any such use et cetera
shall be deemed to be acceptance of the following conditions:-
(1) Its Recipients shall ensure that this Notice is
reproduced upon any copies or amended versions of it;
(2) Any amended version of it shall be clearly marked to
show both the nature of and the organisation responsible
for the relevant amendment or amendments;
(3) Its onward transfer from a recipient to another
party shall be deemed to be that party's acceptance of
these conditions;
(4) DERA gives no warranty or assurance as to its
quality or suitability for any purpose and DERA accepts
no liability whatsoever in relation to any use to which
it may be put.
*/
#include "implement.h"
#include "interface.h"
#include <cstdio>
#include <cstring>
#include <typeinfo>
using namespace std ;
/*
CHECK FOR EQUAL TYPES
This routine returns true if the types represented by t and s are
equal.
*/
static int is_equal_type ( TYPE_INFO *t, TYPE_INFO *s )
{
if ( t == s ) return ( 1 ) ;
int c = t->code ;
if ( c == s->code ) {
// Type categories match
switch ( c ) {
case RTTI_ptr :
case RTTI_ref :
case RTTI_ptr_mem :
case RTTI_array :
case RTTI_bitfield :
case RTTI_func :
case RTTI_c_func : {
// Examine sub-types
BASE_INFO *bt = t->base ;
BASE_INFO *bs = s->base ;
while ( bt && bs ) {
if ( bt->access != bs->access ) return ( 0 ) ;
if ( bt->virt != bs->virt ) return ( 0 ) ;
t = bt->rtti ;
s = bs->rtti ;
if ( !is_equal_type ( t, s ) ) return ( 0 ) ;
bt = bt->next ;
bs = bs->next ;
}
if ( bt || bs ) return ( 0 ) ;
return ( 1 ) ;
}
case RTTI_class :
case RTTI_union :
case RTTI_enum : {
// Examine type names
if ( strcmp ( t->name, s->name ) == 0 ) return ( 1 ) ;
break ;
}
default : {
// Built-in types have unique representative
break ;
}
}
}
return ( 0 ) ;
}
/*
CHECK FOR A BASE CLASS
This routine returns 1 if the type represented by s is a base class
of the type represented by t and 2 if the two types are actually
equal.
*/
static int is_base_class ( TYPE_INFO *t, TYPE_INFO *s )
{
if ( is_equal_type ( t, s ) ) return ( 2 ) ;
if ( t->code == RTTI_class ) {
for ( BASE_INFO *b = t->base ; b ; b = b->next ) {
// Check base classes
if ( is_base_class ( b->rtti, s ) ) return ( 1 ) ;
}
}
return ( 0 ) ;
}
/*
UNIQUE POINTERS
The following unique pointers are used in do_base_cast.
*/
static void *error_ptr = ( void * ) &error_ptr ;
static void *null_ptr = ( void * ) &null_ptr ;
/*
PERFORM A BASE CLASS CONVERSION
This routine converts the pointer p from the type represented by t
to the type represented by s. The error pointer is returned for
ambiguous conversions while a keeps track of the base class access.
*/
static void *do_base_cast ( void *p, TYPE_INFO *t, TYPE_INFO *s, int &a )
{
void *r = NULL ;
int acc = 0 ;
if ( is_equal_type ( t, s ) ) {
r = p ;
} else {
// Check base classes
for ( BASE_INFO *b = t->base ; b ; b = b->next ) {
int c = b->access ;
void *q = p ;
if ( q != null_ptr ) {
q = ( void * ) ( ( char * ) p + b->off ) ;
if ( b->virt ) q = *( ( void ** ) q ) ;
}
q = do_base_cast ( q, b->rtti, s, c ) ;
if ( q ) {
if ( r == NULL ) {
// First successful conversion
r = q ;
acc = c ;
} else if ( r == q ) {
// Select most accessible successful conversion
if ( c < acc ) acc = c ;
} else {
// Ambiguous conversion
r = error_ptr ;
return ( r ) ;
}
}
}
}
a += acc ;
return ( r ) ;
}
/*
PERFORM AN UNAMBIGUOUS BASE CLASS CONVERSION
This routine is identical to do_base_cast except that it returns the
null pointer for ambiguous or inaccessible conversions.
*/
static void *do_valid_base_cast ( void *p, TYPE_INFO *t, TYPE_INFO *s )
{
int acc = INFO_public ;
p = do_base_cast ( p, t, s, acc ) ;
if ( p == error_ptr || acc != INFO_public ) p = NULL ;
return ( p ) ;
}
/*
PERFORM A DYNAMIC CAST
This routine is used to implement the dynamic cast construct. p gives
a pointer to the virtual function table pointer for the construct
operand and s gives the type information for the target type.
*/
void *__TCPPLUS_dynamic_cast ( VTABLE **p, TYPE_INFO *s )
{
void *r = NULL ;
VTABLE *vptr = *p ;
TYPE_INFO *t = vptr->extra.rtti ;
int c = is_base_class ( t, s ) ;
if ( c ) {
// Perform the base class conversion
r = ( void * ) p ;
r = ( void * ) ( ( ( char * ) r ) + vptr->extra.off ) ;
if ( c == 1 ) r = do_valid_base_cast ( r, t, s ) ;
}
return ( r ) ;
}
/*
PERFORM AN EXCEPTION CATCH CONVERSION
This routine checks whether an exception of type t can be caught
by a handler of type s. If so it applies any necessary conversions
to the exception value p and returns the value. Otherwise the
null pointer is returned. Note that any reference components will
have been removed from s. cn is true if all the qualifiers in
a qualification conversion contain 'const'. dpt keeps track of
the depth of pointer conversions.
*/
void *__TCPPLUS_catch_cast
( void *p, TYPE_INFO *t, TYPE_INFO *s, int cn, int dpt )
{
if ( p ) {
if ( is_equal_type ( t, s ) ) {
// Exact match
return ( p ) ;
}
int c = t->code ;
if ( c == s->code ) {
if ( c == RTTI_ptr || c == RTTI_ref ) {
// Check for pointer conversions
BASE_INFO *bt = t->base ;
BASE_INFO *bs = s->base ;
int at = bt->access ;
int as = bs->access ;
if ( at == as || ( cn && !( at & ~as ) ) ) {
// Qualifiers are alright
t = bt->rtti ;
s = bs->rtti ;
if ( dpt == 0 ) {
if ( s->code == RTTI_void && c == RTTI_ptr ) {
switch ( t->code ) {
case RTTI_func :
case RTTI_c_func : {
// Can't convert function to 'void *'
break ;
}
default : {
// Can convert 't *' to 'void *'
return ( p ) ;
}
}
}
int b = is_base_class ( t, s ) ;
if ( b == 2 ) {
// Exact base class conversion
return ( p ) ;
}
if ( b == 1 ) {
// Base class conversion
void *q = *( ( void ** ) p ) ;
if ( q == NULL ) q = null_ptr ;
void *r = do_valid_base_cast ( q, t, s ) ;
if ( r ) {
static void *buf = NULL ;
if ( q == r ) return ( p ) ;
buf = r ;
return ( ( void * ) &buf ) ;
}
}
}
if ( !( at & INFO_const ) ) cn = 0 ;
p = __TCPPLUS_catch_cast ( p, t, s, cn, dpt + 1 ) ;
return ( p ) ;
}
} else if ( c == RTTI_ptr_mem ) {
// Check for pointer to member conversion
BASE_INFO *bt = t->base ;
BASE_INFO *bs = s->base ;
if ( is_equal_type ( bt->rtti, bs->rtti ) ) {
// Classes match
bt = bt->next ;
bs = bs->next ;
int at = bt->access ;
int as = bs->access ;
if ( at == as || ( cn && !( at & ~as ) ) ) {
// Qualifiers are alright
t = bt->rtti ;
s = bs->rtti ;
if ( !( at & INFO_const ) ) cn = 0 ;
p = __TCPPLUS_catch_cast ( p, t, s, cn, dpt + 1 ) ;
return ( p ) ;
}
}
} else if ( c == RTTI_class ) {
// Check for base class conversions
if ( dpt == 0 ) {
int b = is_base_class ( t, s ) ;
if ( b == 2 ) {
return ( p ) ;
}
if ( b == 1 ) {
p = do_valid_base_cast ( p, t, s ) ;
return ( p ) ;
}
}
}
}
}
return ( NULL ) ;
}
/*
PRINT RUN-TIME TYPE INFORMATION
This routine prints the run-time type information t with access a
and virtual qualifier v at an indentation of i.
*/
static void print_type_info ( TYPE_INFO *t, char *a, char *v, int i )
{
for ( int j = 0 ; j < i ; j++ ) fputc ( ' ', stdout ) ;
printf ( "%s%s%s", a, v, t->name ) ;
BASE_INFO *b = t->base ;
if ( b && t->code == RTTI_class ) {
printf ( " = {\n" ) ;
while ( b ) {
switch ( b->access ) {
case INFO_public : a = "public " ; break ;
case INFO_protected : a = "protected " ; break ;
case INFO_private : a = "private " ; break ;
}
v = const_cast < char * > ( b->virt ? "virtual " : "" ) ;
print_type_info ( b->rtti, a, v, i + 4 ) ;
b = b->next ;
}
for ( int j = 0 ; j < i ; j++ ) fputc ( ' ', stdout ) ;
fputc ( '}', stdout ) ;
}
printf ( " ;\n" ) ;
return ;
}
/*
PRINT RUN-TIME TYPE INFORMATION FOR AN OBJECT
This routine prints the run-time type information for an object given
a pointer to its virtual function table.
*/
void __TCPPLUS_type_info ( VTABLE *p )
{
if ( p ) {
TYPE_INFO *t = p->extra.rtti ;
print_type_info ( t, "", "", 0 ) ;
}
return ;
}
/*
MEMBER FUNCTIONS FOR TYPE_INFO CLASS
These routines give the member functions for the type_info class. They
exploit the layout equivalent of a type_info and a TYPE_INFO.
*/
type_info::type_info ( const type_info &rhs )
{
__code = rhs.__code ;
__name = rhs.__name ;
__base = rhs.__base ;
return ;
}
type_info &type_info::operator= ( const type_info &rhs )
{
__code = rhs.__code ;
__name = rhs.__name ;
__base = rhs.__base ;
return ( *this ) ;
}
type_info::~type_info ()
{
return ;
}
bool type_info::operator== ( const type_info &rhs ) const
{
return ( is_equal_type ( ( TYPE_INFO * ) this, ( TYPE_INFO * ) &rhs ) ) ;
}
bool type_info::operator!= ( const type_info &rhs ) const
{
return ( !( *this == rhs ) ) ;
}
bool type_info::before ( const type_info &rhs ) const
{
return ( strcmp ( __name, rhs.__name ) < 0 ) ;
}
const char *type_info::name () const
{
return ( __name ) ;
}