/* Copyright (C) 1997, 1998 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
  
  Aladdin Enterprises supports the work of the GNU Project, but is not
  affiliated with the Free Software Foundation or the GNU Project.  GNU
  Ghostscript, as distributed by Aladdin Enterprises, does not require any
  GNU software to build or run it.
*/

/*$Id: zfunc.c $ */
/* Generic PostScript language interface to Functions */
#include "memory_.h"
#include "ghost.h"
#include "oper.h"
#include "gsfunc.h"
#include "gsstruct.h"
#include "ialloc.h"
#include "idict.h"
#include "idparam.h"
#include "ifunc.h"
#include "store.h"

/* Define the maximum depth of nesting of subsidiary functions. */
#define MAX_SUB_FUNCTION_DEPTH 3

/* Define the table of build procedures. */
build_function_proc((*build_function_procs[5])) = {
    build_function_undefined, build_function_undefined, build_function_undefined,
    build_function_undefined, build_function_undefined
};

int
build_function_undefined(const_os_ptr op, const gs_function_params_t * mnDR,
			 int depth, gs_function_t ** ppfn)
{
    return_error(e_rangecheck);
}

/* GC descriptors */
gs_private_st_ptr(st_function_ptr, gs_function_t *, "gs_function_t *",
		  function_ptr_enum_ptrs, function_ptr_reloc_ptrs);
gs_private_st_element(st_function_ptr_element, gs_function_t *,
		      "gs_function_t *[]", function_ptr_element_enum_ptrs,
		      function_ptr_element_reloc_ptrs, st_function_ptr);

/* ------ Operators ------ */

private int zexecfunction(P1(os_ptr op));

/* <dict> .buildfunction <function_struct> */
private int
zbuildfunction(os_ptr op)
{
    gs_function_t *pfn;
    ref cref;			/* closure */
    int code;

    code = ialloc_ref_array(&cref, a_executable | a_execute, 2,
			    ".buildfunction");
    if (code < 0)
	return code;
    code = fn_build_function(op, &pfn);
    if (code < 0) {
	ifree_ref_array(&cref, ".buildfunction");
	return code;
    }
    make_istruct_new(cref.value.refs, a_executable | a_execute, pfn);
    make_oper_new(cref.value.refs + 1, 0, zexecfunction);
    ref_assign(op, &cref);
    return 0;
}

/* <in1> ... <function_struct> %execfunction <out1> ... */
private int
zexecfunction(os_ptr op)
{	/*
	 * Since this operator's name begins with %, the name is not defined
	 * in systemdict.  The only place this operator can ever appear is
	 * in the execute-only closure created by .buildfunction.
	 * Therefore, in principle it is unnecessary to check the argument.
	 * However, we do a little checking anyway just on general
	 * principles.  Note that since the argument may be an instance of
	 * any subclass of gs_function_t, we currently have no way to check
	 * its type.
	 */
    if (!r_is_struct(op) ||
	r_has_masked_attrs(op, a_executable | a_execute, a_all)
	)
	return_error(e_typecheck);
    {
	gs_function_t *pfn = (gs_function_t *) op->value.pstruct;
	int m = pfn->params.m, n = pfn->params.n;
	int diff = n - (m + 1);

	if (diff > 0)
	    check_ostack(diff);
	{
	    float *in = (float *)ialloc_byte_array(m, sizeof(float),
						   "%execfunction(in)");
	    float *out = (float *)ialloc_byte_array(n, sizeof(float),
						    "%execfunction(out)");
	    int code;

	    if (in == 0 || out == 0)
		code = gs_note_error(e_VMerror);
	    else if ((code = float_params(op - 1, m, in)) < 0 ||
		     (code = gs_function_evaluate(pfn, in, out)) < 0
		)
		DO_NOTHING;
	    else {
		if (diff > 0)
		    push(diff);	/* can't fail */
		else if (diff < 0) {
		    pop(-diff);
		    op = osp;
		}
		code = make_floats(op + 1 - n, out, n);
	    }
	    ifree_object(out, "%execfunction(out)");
	    ifree_object(in, "%execfunction(in)");
	    return code;
	}
    }
}

/* ------ Procedures ------ */

/* Build a function structure from a PostScript dictionary. */
int
fn_build_sub_function(const ref * op, gs_function_t ** ppfn, int depth)
{
    int code, type;
    gs_function_params_t params;

    if (depth > MAX_SUB_FUNCTION_DEPTH)
	return_error(e_limitcheck);
    check_type(*op, t_dictionary);
    code = dict_int_param(op, "FunctionType", 0,
			  countof(build_function_procs) - 1, -1, &type);
    if (code < 0)
	return code;
    /* Collect parameters common to all function types. */
    params.Domain = 0;
    params.Range = 0;
    code = fn_build_float_array(op, "Domain", true, true, &params.Domain);
    if (code < 0)
	goto fail;
    params.m = code >> 1;
    code = fn_build_float_array(op, "Range", false, true, &params.Range);
    if (code < 0)
	goto fail;
    params.n = code >> 1;
    /* Finish building the function. */
    /* If this fails, it will free all the parameters. */
    return (*build_function_procs[type]) (op, &params, depth + 1, ppfn);
fail:
    ifree_object((void *)params.Range, "Range");	/* break const */
    ifree_object((void *)params.Domain, "Domain");	/* break const */
    return code;
}

/* Allocate an array of function objects. */
int
ialloc_function_array(uint count, gs_function_t *** pFunctions)
{
    gs_function_t **ptr;

    if (count == 0)
	return_error(e_rangecheck);
    ptr = ialloc_struct_array(count, gs_function_t *,
			      &st_function_ptr_element, "Functions");
    if (ptr == 0)
	return_error(e_VMerror);
    memset(ptr, 0, sizeof(*ptr) * count);
    *pFunctions = ptr;
    return 0;
}

/*
 * Collect a heap-allocated array of floats.  If the key is missing, set
 * *pparray = 0 and return 0; otherwise set *pparray and return the number
 * of elements.  Note that 0-length arrays are acceptable, so if the value
 * returned is 0, the caller must check whether *pparray == 0.
 */
int
fn_build_float_array(const ref * op, const char *kstr, bool required,
		     bool even, const float **pparray)
{
    ref *par;
    int code;

    *pparray = 0;
    if (dict_find_string(op, kstr, &par) <= 0)
	return (required ? gs_note_error(e_rangecheck) : 0);
    if (!r_is_array(par))
	return_error(e_typecheck);
    {
	uint size = r_size(par);
	float *ptr = (float *)ialloc_byte_array(size, sizeof(float), kstr);

	if (ptr == 0)
	    return_error(e_VMerror);
	code = dict_float_array_param(op, kstr, size, ptr, NULL);
	if (code < 0 || (even && (code & 1) != 0)) {
	    ifree_object(ptr, kstr);
	    return(code < 0 ? code : gs_note_error(e_rangecheck));
	}
	*pparray = ptr;
    }
    return code;
}

/* ------ Initialization procedure ------ */

const op_def zfunc_op_defs[] =
{
    {"1.buildfunction", zbuildfunction},
    {"1%execfunction", zexecfunction},
    op_def_end(0)
};
