/* Copyright (C) 2001-2023 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 the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* 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 and the associated clip path.
 */
static 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;

    if (stack->rc.ref_count <= 1 ) {
        gx_clip_path *pcpath = stack->clip_path;

        gs_free_object(stack->rc.memory, stack, cname);
        gx_cpath_free(pcpath, "rc_free_clip_stack");
    }
}

/* clipsave */
int
gs_clipsave(gs_gstate *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_gstate *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);
    }
}