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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 "config.h"

#include "c_types.h"

#include "error.h"

#include "xalloc.h"

/*

    CHECK FOR CORRECT HEADERS

    The functions defined in this file give the implementations of various

    support functions used by the c_class implementation.  They should

    therefore be compiled with the c_class implementation rather than the

    specification.

*/

#if c_class_SPECIFICATION

FAIL_COMPILER ( Implementation functions compiled with token specifications )

#endif

/*

    FREE OBJECTS

    These variables indicate the free c_classes.  There is an array

    containing lists of small blocks, plus a single larger block.

*/

#define SMALL_BLOCK		24

#define ALLOC_BLOCK		2048

#if ( c_class_GEN_MAX > SMALL_BLOCK )

FAIL_COMPILER ( Free block array is too small )

#endif

static c_class *free_c_classes = NULL ;

static unsigned free_c_classes_left = 0 ;

unsigned total_c_classes = 0 ;

static c_class *free_c_class_array [ SMALL_BLOCK ] = {

    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,

    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL

} ;

/*

    GENERATE A NEW OBJECT BLOCK

    This routine generates a new block of c_classes of size sz.  Small

    blocks are allocated from the c_class array, others from the main

    c_class list.

*/

c_class *gen_c_class

    PROTO_N ( ( sz ) )

    PROTO_T ( unsigned sz )

{

    c_class *p ;

    unsigned n = sz ;

    if ( n < SMALL_BLOCK ) {

	/* Allocate from small block array */

	if ( n == 0 ) return ( NULL ) ;

	p = free_c_class_array [n] ;

	if ( p ) {

	    free_c_class_array [n] = TAIL_list ( p ) ;

	    return ( p ) ;

	}

    }

    if ( n > free_c_classes_left ) {

	/* Allocate new blocks */

	unsigned m = ALLOC_BLOCK ;

	if ( n > m ) m = n ;

	free_c_classes = xmalloc_nof ( c_class, m ) ;

	free_c_classes_left = m ;

    }

    p = free_c_classes ;

    free_c_classes += n ;

    free_c_classes_left -= n ;

    return ( p ) ;

}

/*

    MARK AN OBJECT AS FREE

    This routine is used in the object destruction routines to mark an

    object as having been freed.  This only has any effect in conjunction

    with the debugging routine below.

*/

#ifdef RUNTIME

#define clean_c_class( P, Z )\

    {\

	ASSERT ( TYPEID ( P ) != TYPEID_free ) ;\

	TYPEID ( P ) = TYPEID_free ;\

	total_c_classes -= ( Z ) ;\

    }

#else

#define clean_c_class( P, Z )	/* empty */

#endif

/*

    GENERATE A NEW OBJECT BLOCK (DEBUG VERSION)

    This routine is identical to gen_c_class except that it includes the

    run-time type information t in the allocated block.

*/

#ifdef RUNTIME

c_class *debug_c_class

    PROTO_N ( ( sz, t ) )

    PROTO_T ( unsigned sz X unsigned t )

{

    c_class *p ;

    unsigned n = sz ;

    total_c_classes += n ;

    if ( n < SMALL_BLOCK ) {

	/* Allocate from small block array */

	if ( n == 0 ) return ( NULL ) ;

	p = free_c_class_array [n] ;

	if ( p ) {

	    free_c_class_array [n] = TAIL_list ( p ) ;

	    ASSERT ( TYPEID ( p ) == TYPEID_free ) ;

	    TYPEID ( p ) = t ;

	    return ( p ) ;

	}

    }

    n += 1 ;

    if ( n > free_c_classes_left ) {

	/* Allocate new blocks */

	unsigned m = ALLOC_BLOCK ;

	if ( n > m ) m = n ;

	free_c_classes = xmalloc_nof ( c_class, m ) ;

	free_c_classes_left = m ;

    }

    p = free_c_classes + 1 ;

    TYPEID ( p ) = t ;

    free_c_classes += n ;

    free_c_classes_left -= n ;

    return ( p ) ;

}

#endif /* RUNTIME */

/*

    DESTROY AN OBJECT BLOCK

    This routine destroys the block of c_classes p of size sz.

*/

void destroy_c_class

    PROTO_N ( ( p, sz ) )

    PROTO_T ( c_class *p X unsigned sz )

{

    if ( p ) {

	unsigned n = sz ;

	c_class **r = free_c_class_array ;

	if ( n < SMALL_BLOCK ) r += n ;

	clean_c_class ( p, n ) ;

	TAIL_list ( p ) = *r ;

	*r = p ;

    }

    return ;

}

/*

    DUMMY OBJECT BLOCK DESTRUCTOR

    This routine is a dummy destructor which does nothing.

*/

void dummy_destroy_c_class

    PROTO_N ( ( p, sz ) )

    PROTO_T ( c_class *p X unsigned sz )

{

    UNUSED ( p ) ;

    UNUSED ( sz ) ;

    return ;

}

/*

    DESTROY A LIST OF OBJECT BLOCKS

    This routine destroys the list p of blocks of c_classes of size sz.

    The list is added to the appropriate entry of the free c_class array.

*/

void destroy_c_class_list

    PROTO_N ( ( p, sz ) )

    PROTO_T ( c_class *p X unsigned sz )

{

    if ( p ) {

	c_class *q = p ;

	unsigned n = sz + 1 ;

	c_class **r = free_c_class_array ;

	if ( n < SMALL_BLOCK ) r += n ;

	while ( TAIL_list ( p ) ) {

	    clean_c_class ( p, n ) ;

	    p = TAIL_list ( p ) ;

	}

	clean_c_class ( p, n ) ;

	TAIL_list ( p ) = *r ;

	*r = q ;

    }

    return ;

}

/*

    FIND THE LENGTH OF A LIST

    This routine calculates the length of the list p.

*/

unsigned length_c_class_list

    PROTO_N ( ( p ) )

    PROTO_T ( c_class *p )

{

    unsigned n = 0 ;

    c_class *q = p ;

    while ( q ) {

	n++ ;

	q = TAIL_list ( q ) ;

    }

    return ( n ) ;

}

/*

    REVERSE A LIST

    This routine reverses the order of the list p.

*/

c_class *reverse_c_class_list

    PROTO_N ( ( p ) )

    PROTO_T ( c_class *p )

{

    c_class *r = NULL ;

    c_class *q = p ;

    while ( q ) {

	c_class *nq = TAIL_list ( q ) ;

	TAIL_list ( q ) = r ;

	r = q ;

	q = nq ;

    }

    return ( r ) ;

}

/*

    APPEND TWO LISTS

    This routine appends the lists of c_class blocks p and q.

*/

c_class *append_c_class_list

    PROTO_N ( ( p, q ) )

    PROTO_T ( c_class *p X c_class *q )

{

    c_class *r = p ;

    if ( r == NULL ) return ( q ) ;

    while ( TAIL_list ( r ) ) r = TAIL_list ( r ) ;

    TAIL_list ( r ) = q ;

    return ( p ) ;

}

/*

    FIND THE LAST MEMBER OF A LIST

    This routine returns the last member of the list of c_class blocks p.

*/

c_class *end_c_class_list

    PROTO_N ( ( p ) )

    PROTO_T ( c_class *p )

{

    c_class *r = p ;

    if ( r == NULL ) return ( NULL ) ;

    while ( TAIL_list ( r ) ) r = TAIL_list ( r ) ;

    return ( r ) ;

}

/*

    GENERIC EMPTY VECTOR

    This c_class represents the generic empty vector.  It is only defined

    if vector operations have been enabled.  Note that the element field

    of a vector is not be NULL, even if the vector is empty.

*/

#ifdef VEC

static c_class dummy_elem ;

c_class_VEC empty_c_class_vec = { 0, { &dummy_elem, &dummy_elem } } ;

#endif

#ifdef c_class_IO_ROUTINES

/*

    ALIASING VARIABLES

    These variables give respectively the current alias number and the

    list of all aliases.

*/

unsigned crt_c_class_alias = 0 ;

static c_class *crt_alias_list = NULL ;

/*

    SET AN ALIAS

    This routine sets up an alias of p to n.

*/

void set_c_class_alias

    PROTO_N ( ( p, n ) )

    PROTO_T ( c_class *p X unsigned n )

{

    c_class *q = GEN_c_class ( 2, TYPEID_list ) ;

    TAIL_list ( q ) = crt_alias_list ;

    HEAD_list ( q )->ag_ptr = p ;

    ASSERT ( p != NULL ) ;

    p->ag_tag = n ;

    crt_alias_list = q ;

    return ;

}

/*

    FIND AN ALIAS

    This routine searches for alias number n.

*/

c_class *find_c_class_alias

    PROTO_N ( ( n ) )

    PROTO_T ( unsigned n )

{

    c_class *p = crt_alias_list ;

    while ( p ) {

	c_class *q = HEAD_list ( p )->ag_ptr ;

	if ( q->ag_tag == n ) return ( q ) ;

	p = TAIL_list ( p ) ;

    }

    error ( ERROR_INTERNAL, "Can't find alias %u", n ) ;

    return ( NULL ) ;

}

/*

    CLEAR ALL ALIASES

    This routine clears all aliases.  Each alias in the list is reset to

    zero, and the list itself is freed.

*/

void clear_c_class_alias

    PROTO_Z ()

{

    c_class *p = crt_alias_list ;

    c_class *q = NULL ;

    while ( p ) {

	HEAD_list ( p )->ag_ptr->ag_tag = 0 ;

	q = p ;

	p = TAIL_list ( p ) ;

    }

    if ( q ) {

	TAIL_list ( q ) = free_c_class_array [2] ;

	free_c_class_array [2] = crt_alias_list ;

    }

    crt_c_class_alias = 0 ;

    crt_alias_list = NULL ;

    return ;

}

#endif /* c_class_IO_ROUTINES */

/*

    ASSERTION ROUTINES

    These routine implement the assertion checks.

*/

#ifdef ASSERTS

#define assert_c_class	assertion

#include "assert_def.h"

#endif