/* Copyright (C) 2001-2006 Artifex Software, Inc.
   All Rights Reserved.
  
   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied, modified
   or distributed except as expressly authorized under the terms of that
   license.  Refer to licensing information at http://www.artifex.com/
   or contact Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134,
   San Rafael, CA  94903, U.S.A., +1(415)492-9861, for further information.
*/

/* $Id$ */
/* clipsave/cliprestore */
#include "gx.h"
#include "gserrors.h"
#include "gsclipsr.h"
#include "gsstruct.h"
#include "gxclipsr.h"
#include "gxfixed.h"		/* for gxpath.h */
#include "gxpath.h"
#include "gzstate.h"

/* Structure descriptors */
private_st_clip_stack();

/*
 * When we free a clip stack entry, free the associated clip path,
 * and iterate down the list.  We do this iteratively so that we don't
 * take a level of recursion for each node on the list.
 */
private void
rc_free_clip_stack(gs_memory_t * mem, void *vstack, client_name_t cname)
{
    gx_clip_stack_t *stack = (gx_clip_stack_t *)vstack;
    gx_clip_stack_t *next;

    do {
	gx_clip_path *pcpath = stack->clip_path;

	next = stack->next;
	gs_free_object(stack->rc.memory, stack, cname);
	gx_cpath_free(pcpath, "rc_free_clip_stack");
    } while ((stack = next) != 0 && !--(stack->rc.ref_count));
}

/* clipsave */
int
gs_clipsave(gs_state *pgs)
{
    gs_memory_t *mem = pgs->memory;
    gx_clip_path *copy =
	gx_cpath_alloc_shared(pgs->clip_path, mem, "gs_clipsave(clip_path)");
    gx_clip_stack_t *stack =
	gs_alloc_struct(mem, gx_clip_stack_t, &st_clip_stack,
			"gs_clipsave(stack)");

    if (copy == 0 || stack == 0) {
	gs_free_object(mem, stack, "gs_clipsave(stack)");
	gs_free_object(mem, copy, "gs_clipsave(clip_path)");
	return_error(gs_error_VMerror);
    }
    rc_init_free(stack, mem, 1, rc_free_clip_stack);
    stack->clip_path = copy;
    stack->next = pgs->clip_stack;
    pgs->clip_stack = stack;
    return 0;
}

/* cliprestore */
int
gs_cliprestore(gs_state *pgs)
{
    gx_clip_stack_t *stack = pgs->clip_stack;

    if (stack) {
	gx_clip_stack_t *next = stack->next;
	gx_clip_path *pcpath = stack->clip_path;
	int code;

	if (stack->rc.ref_count == 1) {
	    /* Use assign_free rather than assign_preserve. */
	    gs_free_object(stack->rc.memory, stack, "cliprestore");
	    code = gx_cpath_assign_free(pgs->clip_path, pcpath);
	} else {
	    code = gx_cpath_assign_preserve(pgs->clip_path, pcpath);
	    if (code < 0)
		return code;
	    --(stack->rc.ref_count);
	}
	pgs->clip_stack = next;
	return code;
    } else {
	return gx_cpath_assign_preserve(pgs->clip_path, pgs->saved->clip_path);
    }
}