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ifengine/object.c
Scott Duensing c4e3fb7939 Initial commit.
2018-09-08 19:51:49 -05:00

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/* $Id: object.c,v 1.2 2000/05/25 22:28:56 jholder Exp $
* --------------------------------------------------------------------
* see doc/License.txt for License Information
* --------------------------------------------------------------------
*
* File name: $Id: object.c,v 1.2 2000/05/25 22:28:56 jholder Exp $
*
* Description:
*
* Modification history:
* $Log: object.c,v $
* Revision 1.2 2000/05/25 22:28:56 jholder
* changes routine names to reflect zmachine opcode names per spec 1.0
*
* Revision 1.1.1.1 2000/05/10 14:21:34 jholder
*
* imported
*
*
* --------------------------------------------------------------------
*/
/*
* object.c
*
* Object manipulation routines.
*
*/
#include "ztypes.h"
#define PARENT 0
#define NEXT 1
#define CHILD 2
static zword_t read_object( zword_t objp, int field );
static void write_object( zword_t objp, int field, zword_t value );
/*
* get_object_address
*
* Calculate the address of an object in the data area.
*
*/
zword_t get_object_address( zword_t obj )
{
int offset;
/* Address calculation is object table base + size of default properties area +
* object number-1 * object size */
if ( h_type < V4 )
offset = h_objects_offset + ( ( P3_MAX_PROPERTIES - 1 ) * 2 ) + ( ( obj - 1 ) * O3_SIZE );
else
offset = h_objects_offset + ( ( P4_MAX_PROPERTIES - 1 ) * 2 ) + ( ( obj - 1 ) * O4_SIZE );
return ( ( zword_t ) offset );
} /* get_object_address */
/*
* z_insert_obj
*
* Insert object 1 as the child of object 2 after first removing it from its
* previous parent. The object is inserted at the front of the child object
* chain.
*
*/
void z_insert_obj( zword_t obj1, zword_t obj2 )
{
zword_t obj1p, obj2p, child2;
#ifdef STRICTZ
if ( obj1 == 0 )
{
report_strictz_error( STRZERR_MOVE_OBJECT, "@insert_obj called moving object 0" );
}
if ( obj2 == 0 )
{
report_strictz_error( STRZERR_MOVE_OBJECT_2, "@insert_obj called moving into object 0" );
}
#endif
/* Get addresses of both objects */
obj1p = get_object_address( obj1 );
obj2p = get_object_address( obj2 );
/* Remove object 1 from current parent */
z_remove_obj( obj1 );
/* Make object 2 object 1's parent */
write_object( obj1p, PARENT, obj2 );
/* Get current first child of object 2 */
child2 = read_object( obj2p, CHILD );
/* Make object 1 first child of object 2 */
write_object( obj2p, CHILD, obj1 );
/* If object 2 had children then link them into the next child field of object 1 */
if ( child2 )
write_object( obj1p, NEXT, child2 );
} /* z_insert_obj */
/*
* z_remove_obj
*
* Remove an object by unlinking from the its parent object and from its
* siblings.
*
*/
void z_remove_obj( zword_t obj )
{
zword_t objp, parentp, childp, parent, child;
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_REMOVE_OBJECT, "@remove_obj called with object 0" );
}
#endif
/* Get address of object to be removed */
objp = get_object_address( obj );
/* Get parent of object, and return if no parent */
if ( ( parent = read_object( objp, PARENT ) ) == 0 )
return;
/* Get address of parent object */
parentp = get_object_address( parent );
/* Find first child of parent */
child = read_object( parentp, CHILD );
/* If object is first child then just make the parent child pointer
* equal to the next child */
if ( child == obj )
write_object( parentp, CHILD, read_object( objp, NEXT ) );
else
{
/* Walk down the child chain looking for this object */
do
{
childp = get_object_address( child );
child = read_object( childp, NEXT );
}
while ( child != obj );
/* Set the next pointer thre previous child to the next pointer
* of the current object child pointer */
write_object( childp, NEXT, read_object( objp, NEXT ) );
}
/* Set the parent and next child pointers to NULL */
write_object( objp, PARENT, 0 );
write_object( objp, NEXT, 0 );
} /* z_remove_obj */
/*
* z_get_parent
*
* Load the parent object pointer of an object
*
*/
void z_get_parent( zword_t obj )
{
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_GET_PARENT, "@get_parent called with object 0" );
store_operand( 0 );
return;
}
#endif
store_operand( read_object( get_object_address( obj ), PARENT ) );
} /* z_get_parent */
/*
* z_get_child
*
* Load the child object pointer of an object and jump if the child pointer is
* not NULL.
*
*/
void z_get_child( zword_t obj )
{
zword_t child;
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_GET_CHILD, "@get_child called with object 0" );
store_operand( 0 );
conditional_jump( FALSE );
return;
}
#endif
child = read_object( get_object_address( obj ), CHILD );
store_operand( child );
conditional_jump( child != 0 );
} /* z_get_child */
/*
* z_get_sibling
*
* Load the next child object pointer of an object and jump if the next child
* pointer is not NULL.
*
*/
void z_get_sibling( zword_t obj )
{
zword_t next;
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_GET_SIBLING, "@get_sibling called with object 0" );
store_operand( 0 );
conditional_jump( FALSE );
return;
}
#endif
next = read_object( get_object_address( obj ), NEXT );
store_operand( next );
conditional_jump( next != 0 );
} /* z_get_sibling */
/*
* z_jin
*
* Jump if object 2 is the parent of object 1
*
*/
void z_jin( zword_t obj1, zword_t obj2 )
{
#ifdef STRICTZ
if ( obj1 == 0 )
{
report_strictz_error( STRZERR_JIN, "@jin called with object 0" );
conditional_jump( 0 == obj2 );
return;
}
#endif
conditional_jump( read_object( get_object_address( obj1 ), PARENT ) == obj2 );
} /* z_jin */
/*
* z_test_attr
*
* Test if an attribute bit is set.
*
*/
void z_test_attr( zword_t obj, zword_t bit )
{
zword_t objp;
zbyte_t value;
assert( O3_ATTRIBUTES == O4_ATTRIBUTES );
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_TEST_ATTR, "@test_attr called with object 0" );
conditional_jump( FALSE );
return;
}
#endif
/* Get attribute address */
objp = get_object_address( obj ) + ( bit >> 3 );
/* Load attribute byte */
value = get_byte( objp );
/* Test attribute */
conditional_jump( ( value >> ( 7 - ( bit & 7 ) ) ) & 1 );
} /* z_test_attr */
/*
* z_set_attr
*
* Set an attribute bit.
*
*/
void z_set_attr( zword_t obj, zword_t bit )
{
zword_t objp;
zbyte_t value;
assert( O3_ATTRIBUTES == O4_ATTRIBUTES );
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_SET_ATTR, "@set_attr called with object 0" );
return;
}
#endif
/* Get attribute address */
objp = get_object_address( obj ) + ( bit >> 3 );
/* Load attribute byte */
value = get_byte( objp );
/* Set attribute bit */
value |= ( zbyte_t ) ( 1 << ( 7 - ( bit & 7 ) ) );
/* Store attribute byte */
set_byte( objp, value );
} /* z_set_attr */
/*
* z_clear_attr
*
* Clear an attribute bit
*
*/
void z_clear_attr( zword_t obj, zword_t bit )
{
zword_t objp;
zbyte_t value;
assert( O3_ATTRIBUTES == O4_ATTRIBUTES );
#ifdef STRICTZ
if ( obj == 0 )
{
report_strictz_error( STRZERR_CLEAR_ATTR, "@clear_attr called with object 0" );
return;
}
#endif
/* Get attribute address */
objp = get_object_address( obj ) + ( bit >> 3 );
/* Load attribute byte */
value = get_byte( objp );
/* Clear attribute bit */
value &= ( zbyte_t ) ~ ( 1 << ( 7 - ( bit & 7 ) ) );
/* Store attribute byte */
set_byte( objp, value );
} /* z_clear_attr */
static zword_t read_object( zword_t objp, int field )
{
zword_t value;
if ( h_type < V4 )
{
if ( field == PARENT )
value = ( zword_t ) get_byte( PARENT3( objp ) );
else if ( field == NEXT )
value = ( zword_t ) get_byte( NEXT3( objp ) );
else
value = ( zword_t ) get_byte( CHILD3( objp ) );
}
else
{
if ( field == PARENT )
value = get_word( PARENT4( objp ) );
else if ( field == NEXT )
value = get_word( NEXT4( objp ) );
else
value = get_word( CHILD4( objp ) );
}
return ( value );
} /* read_object */
static void write_object( zword_t objp, int field, zword_t value )
{
if ( h_type < V4 )
{
if ( field == PARENT )
set_byte( PARENT3( objp ), value );
else if ( field == NEXT )
set_byte( NEXT3( objp ), value );
else
set_byte( CHILD3( objp ), value );
}
else
{
if ( field == PARENT )
set_word( PARENT4( objp ), value );
else if ( field == NEXT )
set_word( NEXT4( objp ), value );
else
set_word( CHILD4( objp ), value );
}
} /* write_object */
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