ghostscript-7.07/src/gsstate.c

/* Copyright (C) 1989, 2000 artofcode LLC.  All rights reserved.

  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gsstate.c,v 1.11.2.1.2.1 2003/01/17 00:49:03 giles Exp $ */
/* Miscellaneous graphics state operators for Ghostscript library */
#include "gx.h"
#include "memory_.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gzstate.h"
#include "gxcspace.h"		/* here for gscolor2.h */
#include "gsalpha.h"
#include "gscolor2.h"
#include "gscoord.h"		/* for gs_initmatrix */
#include "gscie.h"
#include "gscssub.h"
#include "gxclipsr.h"
#include "gxcmap.h"
#include "gxdevice.h"
#include "gxpcache.h"
#include "gzht.h"
#include "gzline.h"
#include "gspath.h"
#include "gzpath.h"
#include "gzcpath.h"

/* Forward references */
private gs_state *gstate_alloc(P3(gs_memory_t *, client_name_t,
				  const gs_state *));
private gs_state *gstate_clone(P4(gs_state *, gs_memory_t *, client_name_t,
				  gs_state_copy_reason_t));
private void gstate_free_contents(P1(gs_state *));
private int gstate_copy(P4(gs_state *, const gs_state *,
			   gs_state_copy_reason_t, client_name_t));

/*
 * Graphics state storage management is complicated.  There are many
 * different classes of storage associated with a graphics state:
 *
 * (1) The gstate object itself.  This includes some objects physically
 *      embedded within the gstate object, but because of garbage collection
 *      requirements, there are no embedded objects that can be
 *      referenced by non-transient pointers.  We assume that the gstate
 *      stack "owns" its gstates and that we can free the top gstate when
 *      doing a restore.
 *
 * (2) Objects that are referenced directly by the gstate and whose lifetime
 *      is independent of the gstate.  These are garbage collected, not
 *      reference counted, so we don't need to do anything special with them
 *      when manipulating gstates.  Currently this includes:
 *              font, device
 *
 * (3) Objects that are referenced directly by the gstate, may be shared
 *      among gstates, and should disappear when no gstates reference them.
 *      These fall into two groups:
 *
 *   (3a) Objects that are logically connected to individual gstates.
 *      We use reference counting to manage these.  Currently these are:
 *              halftone, dev_ht, cie_render, black_generation,
 *              undercolor_removal, set_transfer.*, cie_joint_caches,
 *		clip_stack, {opacity,shape}.mask
 *      effective_transfer.* may point to some of the same objects as
 *      set_transfer.*, but don't contribute to the reference count.
 *      Similarly, dev_color may point to the dev_ht object.  For
 *      simplicity, we initialize all of these pointers to 0 and then
 *      allocate the object itself when needed.
 *
 *   (3b) Objects whose lifetimes are associated with something else.
 *      Currently these are:
 *              ht_cache, which is associated with the entire gstate
 *                stack, is allocated with the very first graphics state,
 *                and currently is never freed;
 *              pattern_cache, which is associated with the entire
 *                stack, is allocated when first needed, and currently
 *                is never freed;
 *              view_clip, which is associated with the current
 *                save level (effectively, with the gstate sub-stack
 *                back to the save) and is managed specially;
 *		transparency_stack, which is associated with the entire
 *		  stack but only stored in the topmost graphics state.
 *
 * (4) Objects that are referenced directly by exactly one gstate and that
 *      are not referenced (except transiently) from any other object.
 *      These fall into two groups:
 *
 *   (4b) Objects allocated individually, for the given reason:
 *              line_params.dash.pattern (variable-length),
 *              color_space, path, clip_path, effective_clip.path,
 *              ccolor, dev_color
 *                  (may be referenced from image enumerators or elsewhere)
 *
 *   (4b) The "client data" for a gstate.  For the interpreter, this is
 *      the refs associated with the gstate, such as the screen procedures.
 *      Client-supplied procedures manage client data.
 *
 * (5) Objects referenced indirectly from gstate objects of category (4),
 *      including objects that may also be referenced directly by the gstate.
 *      The individual routines that manipulate these are responsible
 *      for doing the right kind of reference counting or whatever.
 *      Currently:
 *              path, clip_path, and (if different from both clip_path
 *                and view_clip) effective_clip.path require
 *                gx_path_assign/free, which uses a reference count;
 *              color_space and ccolor require cs_adjust_color/cspace_count
 *                or cs_adjust_counts, which use a reference count;
 *              dev_color has no references to storage that it owns.
 *      We count on garbage collection or restore to deallocate
 *        sub-objects of halftone.
 *
 * Note that when after a gsave, the existing gstate references the related
 * objects that we allocate at the same time, and the newly allocated gstate
 * references the old related objects.  Similarly, during a grestore, we
 * free the related objects referenced by the current gstate, but after the
 * grestore, we free the saved gstate, not the current one.  However, when
 * we allocate gstates off-stack, the newly allocated gstate does reference
 * the newly allocated component objects.  Note also that setgstate /
 * currentgstate may produce gstates in which different allocators own
 * different sub-objects; this is OK, because restore guarantees that there
 * won't be any dangling pointers (as long as we don't allow pointers from
 * global gstates to local objects).
 */

/*
 * Define these elements of the graphics state that are allocated
 * individually for each state, except for line_params.dash.pattern.
 * Note that effective_clip_shared is not on the list.
 */
typedef struct gs_state_parts_s {
    gx_path *path;
    gx_clip_path *clip_path;
    gx_clip_path *effective_clip_path;
    gs_color_space *color_space;
    gs_client_color *ccolor;
    gx_device_color *dev_color;
} gs_state_parts;

#define GSTATE_ASSIGN_PARTS(pto, pfrom)\
  ((pto)->path = (pfrom)->path, (pto)->clip_path = (pfrom)->clip_path,\
   (pto)->effective_clip_path = (pfrom)->effective_clip_path,\
   (pto)->color_space = (pfrom)->color_space,\
   (pto)->ccolor = (pfrom)->ccolor, (pto)->dev_color = (pfrom)->dev_color)

/* GC descriptors */
extern_st(st_imager_state);
public_st_gs_state();

/* GC procedures for gs_state */
private ENUM_PTRS_WITH(gs_state_enum_ptrs, gs_state *gsvptr)
ENUM_PREFIX(st_imager_state, gs_state_num_ptrs + 2);
#define e1(i,elt) ENUM_PTR(i,gs_state,elt);
gs_state_do_ptrs(e1)
case gs_state_num_ptrs:	/* handle device specially */
ENUM_RETURN(gx_device_enum_ptr(gsvptr->device));
case gs_state_num_ptrs + 1:	/* handle device filter stack specially */
ENUM_RETURN(gsvptr->dfilter_stack);
#undef e1
ENUM_PTRS_END
private RELOC_PTRS_WITH(gs_state_reloc_ptrs, gs_state *gsvptr)
{
    RELOC_PREFIX(st_imager_state);
    {
#define r1(i,elt) RELOC_PTR(gs_state,elt);
	gs_state_do_ptrs(r1)
#undef r1
	gsvptr->device = gx_device_reloc_ptr(gsvptr->device, gcst);
	RELOC_PTR(gs_state, dfilter_stack);
    }
}
RELOC_PTRS_END

/* Copy client data, using the copy_for procedure if available, */
/* the copy procedure otherwise. */
private int
gstate_copy_client_data(gs_state * pgs, void *dto, void *dfrom,
			gs_state_copy_reason_t reason)
{
    return (pgs->client_procs.copy_for != 0 ?
	    (*pgs->client_procs.copy_for) (dto, dfrom, reason) :
	    (*pgs->client_procs.copy) (dto, dfrom));
}

/* ------ Operations on the entire graphics state ------ */

/* Define the initial value of the graphics state. */
private const gs_imager_state gstate_initial = {
    gs_imager_state_initial(1.0)
};

/*
 * Allocate a path for the graphics state.  We use stable memory because
 * some PostScript files have Type 3 fonts whose BuildChar procedure
 * uses the sequence save ... setcachedevice ... restore, and the path
 * built between the setcachedevice and the restore must not be freed.
 * If it weren't for this, we don't think stable memory would be needed.
 */
private gs_memory_t *
gstate_path_memory(gs_memory_t *mem)
{
    return gs_memory_stable(mem);
}

/* Allocate and initialize a graphics state. */
gs_state *
gs_state_alloc(gs_memory_t * mem)
{
    gs_state *pgs = gstate_alloc(mem, "gs_state_alloc", NULL);
    int code;

    if (pgs == 0)
	return 0;
    pgs->saved = 0;
    *(gs_imager_state *)pgs = gstate_initial;

    /*
     * Just enough of the state is initialized at this point
     * that it's OK to call gs_state_free if an allocation fails.
     */

    code = gs_imager_state_initialize((gs_imager_state *) pgs, mem);
    if (code < 0)
	goto fail;

    /* Finish initializing the color rendering state. */

    rc_alloc_struct_1(pgs->halftone, gs_halftone, &st_halftone, mem,
		      goto fail, "gs_state_alloc(halftone)");
    pgs->halftone->type = ht_type_none;
    pgs->ht_cache = gx_ht_alloc_cache(mem,
				      gx_ht_cache_default_tiles(),
				      gx_ht_cache_default_bits());

    /* Initialize other things not covered by initgraphics */

    pgs->path = gx_path_alloc(gstate_path_memory(mem), "gs_state_alloc(path)");
    pgs->clip_path = gx_cpath_alloc(mem, "gs_state_alloc(clip_path)");
    pgs->clip_stack = 0;
    pgs->view_clip = gx_cpath_alloc(mem, "gs_state_alloc(view_clip)");
    pgs->view_clip->rule = 0;	/* no clipping */
    pgs->effective_clip_id = pgs->clip_path->id;
    pgs->effective_view_clip_id = gs_no_id;
    pgs->effective_clip_path = pgs->clip_path;
    pgs->effective_clip_shared = true;
    /* Initialize things so that gx_remap_color won't crash. */
    gs_cspace_init_DeviceGray(pgs->color_space);
    {
	int i;

	for (i = 0; i < countof(pgs->device_color_spaces.indexed); ++i)
	    pgs->device_color_spaces.indexed[i] = 0;
    }
    gx_set_device_color_1(pgs);
    pgs->device = 0;		/* setting device adjusts refcts */
    gs_nulldevice(pgs);
    gs_setalpha(pgs, 1.0);
    gs_settransfer(pgs, gs_identity_transfer);
    gs_setflat(pgs, 1.0);
    gs_setfilladjust(pgs, 0.25, 0.25);
    gs_setlimitclamp(pgs, false);
    gs_setstrokeadjust(pgs, true);
    pgs->font = 0;		/* Not right, but acceptable until the */
    /* PostScript code does the first setfont. */
    pgs->root_font = 0;		/* ditto */
    pgs->in_cachedevice = 0;
    pgs->in_charpath = (gs_char_path_mode) 0;
    pgs->show_gstate = 0;
    pgs->level = 0;
    pgs->dfilter_stack = 0;
    pgs->transparency_group_stack = 0;
    if (gs_initgraphics(pgs) >= 0)
	return pgs;
    /* Something went very wrong. */
fail:
    gs_state_free(pgs);
    return 0;
}

/* Set the client data in a graphics state. */
/* This should only be done to a newly created state. */
void
gs_state_set_client(gs_state * pgs, void *pdata,
		    const gs_state_client_procs * pprocs)
{
    pgs->client_data = pdata;
    pgs->client_procs = *pprocs;
}

/* Get the client data from a graphics state. */
#undef gs_state_client_data	/* gzstate.h makes this a macro */
void *
gs_state_client_data(const gs_state * pgs)
{
    return pgs->client_data;
}

/* Free a graphics state. */
int
gs_state_free(gs_state * pgs)
{
    gstate_free_contents(pgs);
    gs_free_object(pgs->memory, pgs, "gs_state_free");
    return 0;
}

/* Save the graphics state. */
int
gs_gsave(gs_state * pgs)
{
    gs_state *pnew = gstate_clone(pgs, pgs->memory, "gs_gsave",
				  copy_for_gsave);

    if (pnew == 0)
	return_error(gs_error_VMerror);
    /*
     * It isn't clear from the Adobe documentation whether gsave retains
     * the current clip stack or clears it.  The following statement
     * bets on the latter.  If it's the former, this should become
     *	rc_increment(pnew->clip_stack);
     */
    pnew->clip_stack = 0;
    pgs->saved = pnew;
    if (pgs->show_gstate == pgs)
	pgs->show_gstate = pnew->show_gstate = pnew;
    pgs->level++;
    if_debug2('g', "[g]gsave -> 0x%lx, level = %d\n",
	      (ulong) pnew, pgs->level);
    return 0;
}

/*
 * Save the graphics state for a 'save'.
 * We cut the stack below the new gstate, and return the old one.
 * In addition to an ordinary gsave, we create a new view clip path.
 */
int
gs_gsave_for_save(gs_state * pgs, gs_state ** psaved)
{
    int code;
    gx_clip_path *old_cpath = pgs->view_clip;
    gx_clip_path *new_cpath;
    gx_device_color_spaces_t save_spaces;
    int i;

    if (old_cpath) {
	new_cpath =
	    gx_cpath_alloc_shared(old_cpath, pgs->memory,
				  "gs_gsave_for_save(view_clip)");
	if (new_cpath == 0)
	    return_error(gs_error_VMerror);
    } else {
	new_cpath = 0;
    }
    code = gs_gsave(pgs);
    if (code < 0)
	goto fail;
    for (i = 0; i < countof(save_spaces.indexed); ++i) {
	gs_color_space *pcs = pgs->device_color_spaces.indexed[i];

	if (pcs) {
	    pgs->device_color_spaces.indexed[i] = 0;
	    code = gs_setsubstitutecolorspace(pgs, (gs_color_space_index)i,
					      pcs);
	    if (code < 0) {
		/*
		 * Patch the second saved pointer so we won't try to
		 * gsave after the grestore.
		 */
		if (pgs->saved->saved == 0)
		    pgs->saved->saved = pgs;
		gs_grestore(pgs);
		if (pgs->saved == pgs)
		    pgs->saved = 0;
		goto fail;
	    }
	}
    }
    if (pgs->effective_clip_path == pgs->view_clip)
	pgs->effective_clip_path = new_cpath;
    pgs->view_clip = new_cpath;
    /* Cut the stack so we can't grestore past here. */
    *psaved = pgs->saved;
    pgs->saved = 0;
    return code;
fail:
    if (new_cpath)
	gx_cpath_free(new_cpath, "gs_gsave_for_save(view_clip)");
    return code;
}

/* Restore the graphics state. Can fully empty graphics stack */
int	/* return 0 if ok, 1 if stack was empty */
gs_grestore_only(gs_state * pgs)
{
    gs_state *saved = pgs->saved;
    void *pdata = pgs->client_data;
    void *sdata;
    gs_transparency_state_t *tstack = pgs->transparency_stack;

    if_debug2('g', "[g]grestore 0x%lx, level was %d\n",
	      (ulong) saved, pgs->level);
    if (!saved)
	return 1;
    sdata = saved->client_data;
    if (saved->pattern_cache == 0)
	saved->pattern_cache = pgs->pattern_cache;
    /* Swap back the client data pointers. */
    pgs->client_data = sdata;
    saved->client_data = pdata;
    if (pdata != 0 && sdata != 0)
	gstate_copy_client_data(pgs, pdata, sdata, copy_for_grestore);
    gstate_free_contents(pgs);
    *pgs = *saved;
    pgs->transparency_stack = tstack;
    if (pgs->show_gstate == saved)
	pgs->show_gstate = pgs;
    gs_free_object(pgs->memory, saved, "gs_grestore");
    return 0;
}

/* Restore the graphics state per PostScript semantics */
int
gs_grestore(gs_state * pgs)
{
    int code;
    if (!pgs->saved)
	return gs_gsave(pgs);	/* shouldn't ever happen */
    code = gs_grestore_only(pgs);
    if (code < 0)
	return code;

    /* Wraparound: make sure there are always >= 1 saves on stack */
    if (pgs->saved)
	return 0;
    return gs_gsave(pgs);
}

/* Restore the graphics state for a 'restore', splicing the old stack */
/* back on.  Note that we actually do a grestoreall + 2 grestores. */
int
gs_grestoreall_for_restore(gs_state * pgs, gs_state * saved)
{
    int code;
    gx_device_color_spaces_t freed_spaces;

    while (pgs->saved->saved) {
	code = gs_grestore(pgs);
	if (code < 0)
	    return code;
    }
    /* Make sure we don't leave dangling pointers in the caches. */
    gx_ht_clear_cache(pgs->ht_cache);
    if (pgs->pattern_cache)
	(*pgs->pattern_cache->free_all) (pgs->pattern_cache);
    pgs->saved->saved = saved;
    freed_spaces = pgs->device_color_spaces;
    code = gs_grestore(pgs);
    if (code < 0)
	return code;
    gx_device_color_spaces_free(&freed_spaces, pgs->memory,
				"gs_grestoreall_for_restore");
    if (pgs->view_clip) {
	gx_cpath_free(pgs->view_clip, "gs_grestoreall_for_restore");
	pgs->view_clip = 0;
    }
    return gs_grestore(pgs);
}


/* Restore to the bottommost graphics state (at this save level). */
int
gs_grestoreall(gs_state * pgs)
{
    if (!pgs->saved)		/* shouldn't happen */
	return gs_gsave(pgs);
    while (pgs->saved->saved) {
	int code = gs_grestore(pgs);

	if (code < 0)
	    return code;
    }
    return gs_grestore(pgs);
}

/* Allocate and return a new graphics state. */
gs_state *
gs_gstate(gs_state * pgs)
{
    gs_state *copied = gs_state_copy(pgs, pgs->memory);
    int i;

    if (copied == 0)
	return 0;
    /* Don't capture the substituted color spaces. */
    for (i = 0; i < countof(copied->device_color_spaces.indexed); ++i)
	copied->device_color_spaces.indexed[i] = 0;
    return copied;
}
gs_state *
gs_state_copy(gs_state * pgs, gs_memory_t * mem)
{
    gs_state *pnew;
    /* Prevent 'capturing' the view clip path. */
    gx_clip_path *view_clip = pgs->view_clip;

    pgs->view_clip = 0;
    pnew = gstate_clone(pgs, mem, "gs_gstate", copy_for_gstate);
    rc_increment(pnew->clip_stack);
    pgs->view_clip = view_clip;
    if (pnew == 0)
	return 0;
    pnew->saved = 0;
    /*
     * Prevent dangling references from the show_gstate pointer.  If
     * this context is its own show_gstate, set the pointer in the clone
     * to point to the clone; otherwise, set the pointer in the clone to
     * 0, and let gs_setgstate fix it up.
     */
    pnew->show_gstate =
	(pgs->show_gstate == pgs ? pnew : 0);
    return pnew;
}

/* Copy one previously allocated graphics state to another. */
int
gs_copygstate(gs_state * pto, const gs_state * pfrom)
{
    return gstate_copy(pto, pfrom, copy_for_copygstate, "gs_copygstate");
}

/* Copy the current graphics state to a previously allocated one. */
int
gs_currentgstate(gs_state * pto, const gs_state * pgs)
{
    int code =
	gstate_copy(pto, pgs, copy_for_currentgstate, "gs_currentgstate");

    if (code >= 0)
	pto->view_clip = 0;
    return code;
}

/* Restore the current graphics state from a previously allocated one. */
int
gs_setgstate(gs_state * pgs, const gs_state * pfrom)
{
    /*
     * The implementation is the same as currentgstate,
     * except we must preserve the saved pointer, the level,
     * the view clip, and possibly the show_gstate.
     */
    gs_state *saved_show = pgs->show_gstate;
    int level = pgs->level;
    gx_clip_path *view_clip = pgs->view_clip;
    gs_transparency_state_t *tstack = pgs->transparency_stack;
    int code;

    pgs->view_clip = 0;		/* prevent refcount decrementing */
    code = gstate_copy(pgs, pfrom, copy_for_setgstate, "gs_setgstate");
    if (code < 0)
	return code;
    pgs->level = level;
    pgs->view_clip = view_clip;
    pgs->show_gstate =
	(pgs->show_gstate == pfrom ? pgs : saved_show);
    pgs->transparency_stack = tstack;
    return 0;
}

/* Get the allocator pointer of a graphics state. */
/* This is provided only for the interpreter */
/* and for color space implementation. */
gs_memory_t *
gs_state_memory(const gs_state * pgs)
{
    return pgs->memory;
}

/* Get the saved pointer of the graphics state. */
/* This is provided only for Level 2 grestore. */
gs_state *
gs_state_saved(const gs_state * pgs)
{
    return pgs->saved;
}

/* Swap the saved pointer of the graphics state. */
/* This is provided only for save/restore. */
gs_state *
gs_state_swap_saved(gs_state * pgs, gs_state * new_saved)
{
    gs_state *saved = pgs->saved;

    pgs->saved = new_saved;
    return saved;
}

/* Swap the memory pointer of the graphics state. */
/* This is provided only for the interpreter. */
gs_memory_t *
gs_state_swap_memory(gs_state * pgs, gs_memory_t * mem)
{
    gs_memory_t *memory = pgs->memory;

    pgs->memory = mem;
    return memory;
}

/* ------ Operations on components ------ */

/* Reset most of the graphics state */
int
gs_initgraphics(gs_state * pgs)
{
    int code;

    gs_initmatrix(pgs);
    if ((code = gs_newpath(pgs)) < 0 ||
	(code = gs_initclip(pgs)) < 0 ||
	(code = gs_setlinewidth(pgs, 1.0)) < 0 ||
	(code = gs_setlinecap(pgs, gstate_initial.line_params.cap)) < 0 ||
	(code = gs_setlinejoin(pgs, gstate_initial.line_params.join)) < 0 ||
	(code = gs_setcurvejoin(pgs, gstate_initial.line_params.curve_join)) < 0 ||
	(code = gs_setdash(pgs, (float *)0, 0, 0.0)) < 0 ||
	(gs_setdashadapt(pgs, false),
	 (code = gs_setdotlength(pgs, 0.0, false))) < 0 ||
	(code = gs_setdotorientation(pgs)) < 0 ||
	(code = gs_setgray(pgs, 0.0)) < 0 ||
	(code = gs_setmiterlimit(pgs, gstate_initial.line_params.miter_limit)) < 0
	)
	return code;
    gs_init_rop(pgs);
    return 0;
}

/* setfilladjust */
int
gs_setfilladjust(gs_state * pgs, floatp adjust_x, floatp adjust_y)
{
#define CLAMP_TO_HALF(v)\
    ((v) <= 0 ? fixed_0 : (v) >= 0.5 ? fixed_half : float2fixed(v));

    pgs->fill_adjust.x = CLAMP_TO_HALF(adjust_x);
    pgs->fill_adjust.y = CLAMP_TO_HALF(adjust_y);
    return 0;
#undef CLAMP_TO_HALF
}

/* currentfilladjust */
int
gs_currentfilladjust(const gs_state * pgs, gs_point * adjust)
{
    adjust->x = fixed2float(pgs->fill_adjust.x);
    adjust->y = fixed2float(pgs->fill_adjust.y);
    return 0;
}

/* setlimitclamp */
void
gs_setlimitclamp(gs_state * pgs, bool clamp)
{
    pgs->clamp_coordinates = clamp;
}

/* currentlimitclamp */
bool
gs_currentlimitclamp(const gs_state * pgs)
{
    return pgs->clamp_coordinates;
}

/* ------ Internal routines ------ */

/* Free the privately allocated parts of a gstate. */
private void
gstate_free_parts(const gs_state * parts, gs_memory_t * mem, client_name_t cname)
{
    gs_free_object(mem, parts->dev_color, cname);
    gs_free_object(mem, parts->ccolor, cname);
    gs_free_object(mem, parts->color_space, cname);
    if (!parts->effective_clip_shared)
	gx_cpath_free(parts->effective_clip_path, cname);
    gx_cpath_free(parts->clip_path, cname);
    gx_path_free(parts->path, cname);
}

/* Allocate the privately allocated parts of a gstate. */
private int
gstate_alloc_parts(gs_state * parts, const gs_state * shared,
		   gs_memory_t * mem, client_name_t cname)
{
    gs_memory_t *path_mem = gstate_path_memory(mem);

    parts->path =
	(shared ?
	 gx_path_alloc_shared(shared->path, path_mem,
			      "gstate_alloc_parts(path)") :
	 gx_path_alloc(path_mem, "gstate_alloc_parts(path)"));
    parts->clip_path =
	(shared ?
	 gx_cpath_alloc_shared(shared->clip_path, mem,
			       "gstate_alloc_parts(clip_path)") :
	 gx_cpath_alloc(mem, "gstate_alloc_parts(clip_path)"));
    if (!shared || shared->effective_clip_shared) {
	parts->effective_clip_path = parts->clip_path;
	parts->effective_clip_shared = true;
    } else {
	parts->effective_clip_path =
	    gx_cpath_alloc_shared(shared->effective_clip_path, mem,
				  "gstate_alloc_parts(effective_clip_path)");
	parts->effective_clip_shared = false;
    }
    parts->color_space =
	gs_alloc_struct(mem, gs_color_space, &st_color_space, cname);
    parts->ccolor =
	gs_alloc_struct(mem, gs_client_color, &st_client_color, cname);
    parts->dev_color =
	gs_alloc_struct(mem, gx_device_color, &st_device_color, cname);
    if (parts->path == 0 || parts->clip_path == 0 ||
	parts->effective_clip_path == 0 ||
	parts->color_space == 0 || parts->ccolor == 0 ||
	parts->dev_color == 0
	) {
	gstate_free_parts(parts, mem, cname);
	return_error(gs_error_VMerror);
    }
    return 0;
}

/*
 * Allocate a gstate and its contents.
 * If pfrom is not NULL, the path, clip_path, and (if distinct from both
 * clip_path and view_clip) effective_clip_path share the segments of
 * pfrom's corresponding path(s).
 */
private gs_state *
gstate_alloc(gs_memory_t * mem, client_name_t cname, const gs_state * pfrom)
{
    gs_state *pgs =
	gs_alloc_struct(mem, gs_state, &st_gs_state, cname);

    if (pgs == 0)
	return 0;
    if (gstate_alloc_parts(pgs, pfrom, mem, cname) < 0) {
	gs_free_object(mem, pgs, cname);
	return 0;
    }
    pgs->memory = mem;
    return pgs;
}

/* Copy the dash pattern from one gstate to another. */
private int
gstate_copy_dash(gs_state * pto, const gs_state * pfrom)
{
    return gs_setdash(pto, pfrom->line_params.dash.pattern,
		      pfrom->line_params.dash.pattern_size,
		      pfrom->line_params.dash.offset);
}

/* Clone an existing graphics state. */
/* Return 0 if the allocation fails. */
/* If reason is for_gsave, the clone refers to the old contents, */
/* and we switch the old state to refer to the new contents. */
private gs_state *
gstate_clone(gs_state * pfrom, gs_memory_t * mem, client_name_t cname,
	     gs_state_copy_reason_t reason)
{
    gs_state *pgs = gstate_alloc(mem, cname, pfrom);
    gs_state_parts parts;

    if (pgs == 0)
	return 0;
    GSTATE_ASSIGN_PARTS(&parts, pgs);
    *pgs = *pfrom;
    pgs->transparency_stack = 0;
    /* Copy the dash pattern if necessary. */
    if (pgs->line_params.dash.pattern) {
	int code;

	pgs->line_params.dash.pattern = 0;	/* force allocation */
	code = gstate_copy_dash(pgs, pfrom);
	if (code < 0)
	    goto fail;
    }
    if (pgs->client_data != 0) {
	void *pdata = pgs->client_data = (*pgs->client_procs.alloc) (mem);

	if (pdata == 0 ||
	 gstate_copy_client_data(pgs, pdata, pfrom->client_data, reason) < 0
	    )
	    goto fail;
    }
    gs_imager_state_copied((gs_imager_state *)pgs);
    /* Don't do anything to clip_stack. */
    rc_increment(pgs->device);
    *parts.color_space = *pfrom->color_space;
    *parts.ccolor = *pfrom->ccolor;
    *parts.dev_color = *pfrom->dev_color;
    if (reason == copy_for_gsave) {
	float *dfrom = pfrom->line_params.dash.pattern;
	float *dto = pgs->line_params.dash.pattern;

	GSTATE_ASSIGN_PARTS(pfrom, &parts);
	pgs->line_params.dash.pattern = dfrom;
	pfrom->line_params.dash.pattern = dto;
    } else {
	GSTATE_ASSIGN_PARTS(pgs, &parts);
    }
    cs_adjust_counts(pgs, 1);
    return pgs;
  fail:
    gs_free_object(mem, pgs->line_params.dash.pattern, cname);
    GSTATE_ASSIGN_PARTS(pgs, &parts);
    gstate_free_parts(pgs, mem, cname);
    gs_free_object(mem, pgs, cname);
    return 0;
}

/* Release the composite parts of a graphics state, */
/* but not the state itself. */
private void
gstate_free_contents(gs_state * pgs)
{
    gs_memory_t *mem = pgs->memory;
    const char *const cname = "gstate_free_contents";

    rc_decrement(pgs->device, cname);
    rc_decrement(pgs->clip_stack, cname);
    cs_adjust_counts(pgs, -1);
    if (pgs->client_data != 0)
	(*pgs->client_procs.free) (pgs->client_data, mem);
    gs_free_object(mem, pgs->line_params.dash.pattern, cname);
    gstate_free_parts(pgs, mem, cname);
    gs_imager_state_release((gs_imager_state *)pgs);
}

/* Copy one gstate to another. */
private int
gstate_copy(gs_state * pto, const gs_state * pfrom,
	    gs_state_copy_reason_t reason, client_name_t cname)
{
    gs_state_parts parts;
    gx_device_color_spaces_t saved_spaces;

    GSTATE_ASSIGN_PARTS(&parts, pto);
    saved_spaces = pto->device_color_spaces;
    /* Copy the dash pattern if necessary. */
    if (pfrom->line_params.dash.pattern || pto->line_params.dash.pattern) {
	int code = gstate_copy_dash(pto, pfrom);

	if (code < 0)
	    return code;
    }
    /*
     * It's OK to decrement the counts before incrementing them,
     * because anything that is going to survive has a count of
     * at least 2 (pto and somewhere else) initially.
     * Handle references from contents.
     */
    cs_adjust_counts(pto, -1);
    gx_path_assign_preserve(pto->path, pfrom->path);
    gx_cpath_assign_preserve(pto->clip_path, pfrom->clip_path);
    /*
     * effective_clip_shared will be copied, but we need to do the
     * right thing with effective_clip_path.
     */
    if (pfrom->effective_clip_shared) {
	/*
	 * pfrom->effective_clip_path is either pfrom->view_clip or
	 * pfrom->clip_path.
	 */
	parts.effective_clip_path =
	    (pfrom->effective_clip_path == pfrom->view_clip ?
	     pto->view_clip : parts.clip_path);
    } else
	gx_cpath_assign_preserve(pto->effective_clip_path,
				 pfrom->effective_clip_path);
    *parts.color_space = *pfrom->color_space;
    *parts.ccolor = *pfrom->ccolor;
    *parts.dev_color = *pfrom->dev_color;
    cs_adjust_counts(pto, 1);
    /* Handle references from gstate object. */
#define RCCOPY(element)\
    rc_pre_assign(pto->element, pfrom->element, cname)
    RCCOPY(device);
    RCCOPY(clip_stack);
    {
	struct gx_pattern_cache_s *pcache = pto->pattern_cache;
	void *pdata = pto->client_data;
	gs_memory_t *mem = pto->memory;
	gs_state *saved = pto->saved;
	float *pattern = pto->line_params.dash.pattern;

	gs_imager_state_pre_assign((gs_imager_state *)pto,
				   (gs_imager_state *)pfrom);
	*pto = *pfrom;
	pto->client_data = pdata;
	pto->memory = mem;
	pto->saved = saved;
	pto->line_params.dash.pattern = pattern;
	if (pto->pattern_cache == 0)
	    pto->pattern_cache = pcache;
	if (pfrom->client_data != 0) {
	    /* We need to break 'const' here. */
	    gstate_copy_client_data((gs_state *) pfrom, pdata,
				    pfrom->client_data, reason);
	}
    }
    GSTATE_ASSIGN_PARTS(pto, &parts);
    pto->device_color_spaces = saved_spaces;
#undef RCCOPY
    pto->show_gstate =
	(pfrom->show_gstate == pfrom ? pto : 0);
    return 0;
}