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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.

*/

/*** scope.c --- Scope stack ADT.

 *

 ** Author: Steve Folkes <smf@hermes.mod.uk>

 *

 *** Commentary:

 *

 * This file implements the scope stack manipulation routines.

 *

 *** Change Log:

 * $Log: scope.c,v $

 * Revision 1.1.1.1  1998/01/17  15:57:47  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1994/12/15  09:59:02  smf

 * Brought into line with OSSG C Coding Standards Document, as per

 * "CR94_178.sid+tld-update".

 *

 * Revision 1.1.1.1  1994/07/25  16:04:42  smf

 * Initial import of SID 1.8 non shared files.

 *

**/

/****************************************************************************/

#include "scope.h"

#include "gen-errors.h"

#include "rule.h"

/*--------------------------------------------------------------------------*/

void

scope_stack_init PROTO_N ((stack))

		 PROTO_T (ScopeStackP stack)

{

    stack->head = NIL (ScopeStackFrameP);

}

void

scope_stack_push PROTO_N ((stack, scope))

		 PROTO_T (ScopeStackP stack X

			  NStringP    scope)

{

    ScopeStackFrameP frame = ALLOCATE (ScopeStackFrameT);

    DStringT         dstring;

    dstring_init (&dstring);

    if (frame->head) {

	dstring_append_nstring (&dstring, &(stack->head->scope));

    }

    dstring_append_nstring (&dstring, scope);

    dstring_append_cstring (&dstring, "::");

    dstring_to_nstring (&dstring, &(frame->scope));

    dstring_destroy (&dstring);

    frame->next = stack->head;

    frame->head = NIL (ScopeMapEntryP);

    frame->tail = &(frame->head);

    stack->head = frame;

}

void

scope_stack_pop PROTO_N ((stack))

		PROTO_T (ScopeStackP stack)

{

    ScopeStackFrameP frame = stack->head;

    ScopeMapEntryP   entry;

    ScopeMapEntryP   next;

    ASSERT (frame);

    stack->head = frame->next;

    nstring_destroy (&(frame->scope));

    for (entry = frame->head; entry; entry = next) {

	next = entry->next;

	DEALLOCATE (entry);

    }

    DEALLOCATE (frame);

}

EntryP

scope_stack_add_rule PROTO_N ((stack, table, key, rule, found_ref))

		     PROTO_T (ScopeStackP stack X

			      TableP      table X

			      NStringP    key X

			      RuleP       rule X

			      BoolT      *found_ref)

{

    *found_ref = FALSE;

    if (stack->head) {

	DStringT dstring;

	NStringT nstring;

	EntryP   entry;

	dstring_init (&dstring);

	dstring_append_nstring (&dstring, &(stack->head->scope));

	dstring_append_nstring (&dstring, key);

	dstring_to_nstring (&dstring, &nstring);

	dstring_destroy (&dstring);

	if ((entry = table_get_rule (table, &nstring)) != NIL (EntryP)) {

	    *found_ref = TRUE;

	    nstring_destroy (&nstring);

	    return (entry);

	} else if ((entry = table_add_rule (table, &nstring)) !=

		   NIL (EntryP)) {

	    EntryP         from = table_add_name (table, key);

	    ScopeMapEntryP map  = ALLOCATE (ScopeMapEntryT);

	    (void) scope_stack_check_shadowing (stack, from, rule);

	    map->next            = NIL (ScopeMapEntryP);

	    map->from            = from;

	    map->to              = entry;

	    *(stack->head->tail) = map;

	    stack->head->tail    = &(map->next);

	    return (entry);

	} else {

	    nstring_destroy (&nstring);

	    return (NIL (EntryP));

	}

    } else {

	if (table_get_rule (table, key)) {

	    *found_ref = TRUE;

	}

	return (table_add_rule (table, key));

    }

}

EntryP

scope_stack_add_action PROTO_N ((stack, table, key, rule, found_ref))

		       PROTO_T (ScopeStackP stack X

				TableP      table X

				NStringP    key X

				RuleP       rule X

				BoolT      *found_ref)

{

    *found_ref = FALSE;

    if (stack->head) {

	DStringT dstring;

	NStringT nstring;

	EntryP   entry;

	dstring_init (&dstring);

	dstring_append_nstring (&dstring, &(stack->head->scope));

	dstring_append_nstring (&dstring, key);

	dstring_to_nstring (&dstring, &nstring);

	dstring_destroy (&dstring);

	if ((entry = table_get_action (table, &nstring)) != NIL (EntryP)) {

	    *found_ref = TRUE;

	    nstring_destroy (&nstring);

	    return (entry);

	} else if ((entry = table_add_action (table, &nstring)) !=

		   NIL (EntryP)) {

	    EntryP         from = table_add_name (table, key);

	    ScopeMapEntryP map  = ALLOCATE (ScopeMapEntryT);

	    (void) scope_stack_check_shadowing (stack, from, rule);

	    map->next            = NIL (ScopeMapEntryP);

	    map->from            = from;

	    map->to              = entry;

	    *(stack->head->tail) = map;

	    stack->head->tail    = &(map->next);

	    return (entry);

	} else {

	    nstring_destroy (&nstring);

	    return (NIL (EntryP));

	}

    } else {

	if (table_get_action (table, key)) {

	    *found_ref = TRUE;

	}

	return (table_add_action (table, key));

    }

}

EntryP

scope_stack_add_non_local PROTO_N ((stack, table, key, type, rule))

			  PROTO_T (ScopeStackP stack X

				   TableP      table X

				   NStringP    key X

				   EntryP      type X

				   RuleP       rule)

{

    DStringT dstring;

    NStringT nstring;

    EntryP   entry;

    ASSERT (stack->head);

    dstring_init (&dstring);

    dstring_append_nstring (&dstring, &(stack->head->scope));

    dstring_append_nstring (&dstring, key);

    dstring_to_nstring (&dstring, &nstring);

    dstring_destroy (&dstring);

    if ((entry = table_add_non_local (table, &nstring, type)) !=

	NIL (EntryP)) {

	EntryP         from = table_add_name (table, key);

	ScopeMapEntryP map  = ALLOCATE (ScopeMapEntryT);

	(void) scope_stack_check_shadowing (stack, from, rule);

	map->next            = NIL (ScopeMapEntryP);

	map->from            = from;

	map->to              = entry;

	*(stack->head->tail) = map;

	stack->head->tail    = &(map->next);

	return (entry);

    } else {

	nstring_destroy (&nstring);

	return (NIL (EntryP));

    }

}

EntryP

scope_stack_get_rule PROTO_N ((stack, table, key))

		     PROTO_T (ScopeStackP stack X

			      TableP      table X

			      NStringP    key)

{

    EntryP entry = table_get_entry (table, key);

    if (entry) {

	ScopeStackFrameP frame = stack->head;

	for (; frame; frame = frame->next) {

	    ScopeMapEntryP map = frame->head;

	    for (; map; map = map->next) {

		if (map->from == entry) {

		    if (entry_is_rule (map->to)) {

			return (map->to);

		    } else {

			return (NIL (EntryP));

		    }

		}

	    }

	}

	if (entry_is_rule (entry)) {

	    return (entry);

	}

    }

    return (NIL (EntryP));

}

EntryP

scope_stack_get_action PROTO_N ((stack, table, key))

		       PROTO_T (ScopeStackP stack X

				TableP      table X

				NStringP    key)

{

    EntryP entry = table_get_entry (table, key);

    if (entry) {

	ScopeStackFrameP frame = stack->head;

	for (; frame; frame = frame->next) {

	    ScopeMapEntryP map = frame->head;

	    for (; map; map = map->next) {

		if (map->from == entry) {

		    if (entry_is_action (map->to)) {

			return (map->to);

		    } else {

			return (NIL (EntryP));

		    }

		}

	    }

	}

	if (entry_is_action (entry)) {

	    return (entry);

	}

    }

    return (NIL (EntryP));

}

EntryP

scope_stack_get_non_local PROTO_N ((stack, table, key, scope))

			  PROTO_T (ScopeStackP stack X

				   TableP      table X

				   NStringP    key X

				   NStringP    scope)

{

    EntryP entry = table_get_entry (table, key);

    if (entry) {

	ScopeStackFrameP frame = stack->head;

	for (; frame; frame = frame->next) {

	    ScopeMapEntryP map = frame->head;

	    for (; map; map = map->next) {

		if (map->from == entry) {

		    if (entry_is_non_local (map->to)) {

			nstring_copy (scope, &(frame->scope));

			return (map->to);

		    } else {

			return (NIL (EntryP));

		    }

		}

	    }

	}

    }

    return (NIL (EntryP));

}

BoolT

scope_stack_check_shadowing PROTO_N ((stack, from, rule))

			    PROTO_T (ScopeStackP stack X

				     EntryP      from X

				     RuleP       rule)

{

    ScopeStackFrameP frame = stack->head;

    for (; frame; frame = frame->next) {

	ScopeMapEntryP entry;

	for (entry = frame->head; entry; entry = entry->next) {

	    if (entry->from == from) {

		E_shadows_non_local (entry_key (from), entry_key (entry->to),

				     rule);

		return (TRUE);

	    }

	}

    }

    if (entry_is_rule (from) || entry_is_action (from) ||

	entry_is_basic (from)) {

	E_shadows_global (entry_key (from), rule);

	return (TRUE);

    }

    return (FALSE);

}

/*

 * Local variables(smf):

 * eval: (include::add-path-entry "../os-interface" "../library")

 * eval: (include::add-path-entry "../generated")

 * end:

**/