/* Copyright (C) 1989, 2000 Aladdin Enterprises.  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.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: ztype.c,v 1.8 2004/08/04 19:36:13 stefan Exp $ */
/* Type, attribute, and conversion operators */
#include "math_.h"
#include "memory_.h"
#include "string_.h"
#include "gsexit.h"
#include "ghost.h"
#include "oper.h"
#include "imemory.h"		/* for register_ref_root */
#include "idict.h"
#include "iname.h"
#include "stream.h"		/* for iscan.h */
#include "strimpl.h"		/* for sfilter.h for picky compilers */
#include "sfilter.h"		/* ditto */
#include "iscan.h"
#include "iutil.h"
#include "dstack.h"		/* for dict_set_top */
#include "store.h"

/*
 * Some of the procedures in this file are public only so they can be
 * called from the FunctionType 4 interpreter (zfunc4.c).
 */

/* Forward references */
private int access_check(i_ctx_t *, int, bool);
private int convert_to_string(const gs_memory_t *mem, os_ptr, os_ptr);

/*
 * Max and min integer values expressed as reals.
 * Note that these are biased by 1 to allow for truncation.
 * They should be #defines rather than static consts, but
 * several of the SCO Unix compilers apparently can't handle this.
 * On the other hand, the DEC compiler can't handle casts in
 * constant expressions, so we can't use min_long and max_long.
 * What a nuisance!
 */
#define ALT_MIN_LONG (-1L << (arch_sizeof_long * 8 - 1))
#define ALT_MAX_LONG (~(ALT_MIN_LONG))
private const double min_int_real = (ALT_MIN_LONG * 1.0 - 1);
private const double max_int_real = (ALT_MAX_LONG * 1.0 + 1);

#define REAL_CAN_BE_INT(v)\
  ((v) > min_int_real && (v) < max_int_real)

/* Get the pointer to the access flags for a ref. */
#define ACCESS_REF(opp)\
  (r_has_type(opp, t_dictionary) ? dict_access_ref(opp) : opp)

/* <obj> <typenames> .type <name> */
private int
ztype(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref tnref;
    int code = array_get(imemory, op, (long)r_btype(op - 1), &tnref);

    if (code < 0)
	return code;
    if (!r_has_type(&tnref, t_name)) {
	/* Must be either a stack underflow or a t_[a]struct. */
	check_op(2);
	{			/* Get the type name from the structure. */
	    if ((r_has_type(&op[-1], t_struct) || r_has_type(&op[-1], t_astruct))
	    && op[-1].value.pstruct != 0x00) {
		const char *sname =
		    gs_struct_type_name_string(gs_object_type(imemory, op[-1].value.pstruct));
		code = name_ref(imemory, (const byte *)sname, strlen(sname), (ref *) (op - 1), 0);
		if (code < 0)
		    return code;
	    } else
		return_error(e_stackunderflow);
	}
	r_set_attrs(op - 1, a_executable);
    } else {
	ref_assign(op - 1, &tnref);
    }
    pop(1);
    return 0;
}

/* - .typenames <name1|null> ... <nameN|null> */
private int
ztypenames(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    static const char *const tnames[] = { REF_TYPE_NAME_STRINGS };
    int i;

    check_ostack(t_next_index);
    for (i = 0; i < t_next_index; i++) {
	ref *const rtnp = op + 1 + i;

	if (i >= countof(tnames) || tnames[i] == 0)
	    make_null(rtnp);
	else {
	    int code = name_enter_string(imemory, tnames[i], rtnp);

	    if (code < 0)
		return code;
	    r_set_attrs(rtnp, a_executable);
	}
    }
    osp += t_next_index;
    return 0;
}

/* <obj> cvlit <obj> */
private int
zcvlit(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref *aop;

    check_op(1);
    aop = ACCESS_REF(op);
    r_clear_attrs(aop, a_executable);
    return 0;
}

/* <obj> cvx <obj> */
int
zcvx(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref *aop;
    uint opidx;

    check_op(1);
    /*
     * If the object is an internal operator, we can't allow it to
     * exist in executable form anywhere outside the e-stack.
     */
    if (r_has_type(op, t_operator) &&
	((opidx = op_index(op)) == 0 ||
	 op_def_is_internal(op_index_def(opidx)))
	)
	return_error(e_rangecheck);
    aop = ACCESS_REF(op);
    r_set_attrs(aop, a_executable);
    return 0;
}

/* <obj> xcheck <bool> */
private int
zxcheck(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_op(1);
    make_bool(op, (r_has_attr(ACCESS_REF(op), a_executable) ? 1 : 0));
    return 0;
}

/* <obj:array|packedarray|file|string> executeonly <obj> */
private int
zexecuteonly(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_op(1);
    if (r_has_type(op, t_dictionary))
	return_error(e_typecheck);
    return access_check(i_ctx_p, a_execute, true);
}

/* <obj:array|packedarray|dict|file|string> noaccess <obj> */
private int
znoaccess(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_op(1);
    if (r_has_type(op, t_dictionary)) {
	/*
	 * Setting noaccess on a read-only dictionary is an attempt to
	 * change its value, which is forbidden (this is a subtle
	 * point confirmed with Adobe).  Also, don't allow removing
	 * read access to permanent dictionaries.
	 */
	if (dict_is_permanent_on_dstack(op) ||
	    !r_has_attr(dict_access_ref(op), a_write)
	    )
	    return_error(e_invalidaccess);
    }
    return access_check(i_ctx_p, 0, true);
}

/* <obj:array|packedarray|dict|file|string> readonly <obj> */
int
zreadonly(i_ctx_t *i_ctx_p)
{
    return access_check(i_ctx_p, a_readonly, true);
}

/* <array|packedarray|dict|file|string> rcheck <bool> */
private int
zrcheck(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = access_check(i_ctx_p, a_read, false);

    if (code >= 0)
	make_bool(op, code), code = 0;
    return code;
}

/* <array|packedarray|dict|file|string> wcheck <bool> */
private int
zwcheck(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code = access_check(i_ctx_p, a_write, false);

    if (code >= 0)
	make_bool(op, code), code = 0;
    return code;
}

/* <num> cvi <int> */
/* <string> cvi <int> */
int
zcvi(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    float fval;

    switch (r_type(op)) {
	case t_integer:
	    return 0;
	case t_real:
	    fval = op->value.realval;
	    break;
	default:
	    return_op_typecheck(op);
	case t_string:
	    {
		ref str, token;
		int code;

		ref_assign(&str, op);
		code = scan_string_token(i_ctx_p, &str, &token);
		if (code > 0)	/* anything other than a plain token */
		    code = gs_note_error(e_syntaxerror);
		if (code < 0)
		    return code;
		switch (r_type(&token)) {
		    case t_integer:
			*op = token;
			return 0;
		    case t_real:
			fval = token.value.realval;
			break;
		    default:
			return_error(e_typecheck);
		}
	    }
    }
    if (!REAL_CAN_BE_INT(fval))
	return_error(e_rangecheck);
    make_int(op, (long)fval);	/* truncates towards 0 */
    return 0;
}

/* <string> cvn <name> */
private int
zcvn(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_read_type(*op, t_string);
    return name_from_string(imemory, op, op);
}

/* <num> cvr <real> */
/* <string> cvr <real> */
int
zcvr(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    switch (r_type(op)) {
	case t_integer:
	    make_real(op, (float)op->value.intval);
	case t_real:
	    return 0;
	default:
	    return_op_typecheck(op);
	case t_string:
	    {
		ref str, token;
		int code;

		ref_assign(&str, op);
		code = scan_string_token(i_ctx_p, &str, &token);
		if (code > 0)	/* anything other than a plain token */
		    code = gs_note_error(e_syntaxerror);
		if (code < 0)
		    return code;
		switch (r_type(&token)) {
		    case t_integer:
			make_real(op, (float)token.value.intval);
			return 0;
		    case t_real:
			*op = token;
			return 0;
		    default:
			return_error(e_typecheck);
		}
	    }
    }
}

/* <num> <radix_int> <string> cvrs <substring> */
private int
zcvrs(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int radix;

    check_type(op[-1], t_integer);
    if (op[-1].value.intval < 2 || op[-1].value.intval > 36)
	return_error(e_rangecheck);
    radix = op[-1].value.intval;
    check_write_type(*op, t_string);
    if (radix == 10) {
	switch (r_type(op - 2)) {
	    case t_integer:
	    case t_real:
		{
		    int code = convert_to_string(imemory, op - 2, op);

		    if (code < 0)
			return code;
		    pop(2);
		    return 0;
		}
	    case t__invalid:
		return_error(e_stackunderflow);
	    default:
		return_op_typecheck(op - 2);
	}
    } else {
	ulong ival;
	byte digits[sizeof(ulong) * 8];
	byte *endp = &digits[countof(digits)];
	byte *dp = endp;

	switch (r_type(op - 2)) {
	    case t_integer:
		ival = (ulong) op[-2].value.intval;
		break;
	    case t_real:
		{
		    float fval = op[-2].value.realval;

		    if (!REAL_CAN_BE_INT(fval))
			return_error(e_rangecheck);
		    ival = (ulong) (long)fval;
		} break;
	    case t__invalid:
		return_error(e_stackunderflow);
	    default:
		return_op_typecheck(op - 2);
	}
	do {
	    int dit = ival % radix;

	    *--dp = dit + (dit < 10 ? '0' : ('A' - 10));
	    ival /= radix;
	}
	while (ival);
	if (endp - dp > r_size(op))
	    return_error(e_rangecheck);
	memcpy(op->value.bytes, dp, (uint) (endp - dp));
	r_set_size(op, endp - dp);
    }
    op[-2] = *op;
    pop(2);
    return 0;
}

/* <any> <string> cvs <substring> */
private int
zcvs(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code;

    check_op(2);
    check_write_type(*op, t_string);
    code = convert_to_string(imemory, op - 1, op);
    if (code >= 0)
	pop(1);
    return code;
}

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

const op_def ztype_op_defs[] =
{
    {"1cvi", zcvi},
    {"1cvlit", zcvlit},
    {"1cvn", zcvn},
    {"1cvr", zcvr},
    {"3cvrs", zcvrs},
    {"2cvs", zcvs},
    {"1cvx", zcvx},
    {"1executeonly", zexecuteonly},
    {"1noaccess", znoaccess},
    {"1rcheck", zrcheck},
    {"1readonly", zreadonly},
    {"2.type", ztype},
    {"0.typenames", ztypenames},
    {"1wcheck", zwcheck},
    {"1xcheck", zxcheck},
    op_def_end(0)
};

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

/* Test or modify the access of an object. */
/* If modify = true, restrict to the selected access and return 0; */
/* if modify = false, do not change the access, and return 1 */
/* if the object had the access. */
/* Return an error code if the object is not of appropriate type, */
/* or if the object did not have the access already when modify=1. */
private int
access_check(i_ctx_t *i_ctx_p,
	     int access,	/* mask for attrs */
	     bool modify)	/* if true, reduce access */
{
    os_ptr op = osp;
    ref *aop;

    switch (r_type(op)) {
	case t_dictionary:
	    aop = dict_access_ref(op);
	    if (modify) {
		if (!r_has_attrs(aop, access))
		    return_error(e_invalidaccess);
		ref_save(op, aop, "access_check(modify)");
		r_clear_attrs(aop, a_all);
		r_set_attrs(aop, access);
		dict_set_top();
		return 0;
	    }
	    break;
	case t_array:
	case t_file:
	case t_string:
	case t_mixedarray:
	case t_shortarray:
	case t_astruct:
	case t_device:;
	    if (modify) {
		if (!r_has_attrs(op, access))
		    return_error(e_invalidaccess);
		r_clear_attrs(op, a_all);
		r_set_attrs(op, access);
		return 0;
	    }
	    aop = op;
	    break;
	default:
	    return_op_typecheck(op);
    }
    return (r_has_attrs(aop, access) ? 1 : 0);
}

/* Do all the work of cvs.  The destination has been checked, but not */
/* the source.  This is a separate procedure so that */
/* cvrs can use it when the radix is 10. */
private int
convert_to_string(const gs_memory_t *mem, os_ptr op1, os_ptr op)
{
    uint len;
    const byte *pstr = 0;
    int code = obj_cvs(mem, op1, op->value.bytes, r_size(op), &len, &pstr);

    if (code < 0) {
	/*
	 * Some common downloaded error handlers assume that
	 * operator names don't exceed a certain fixed size.
	 * To work around this bit of bad design, we implement
	 * a special hack here: if we got a rangecheck, and
	 * the object is an operator whose name begins with
	 * %, ., or @, we just truncate the name.
	 */
	if (code == e_rangecheck)
	    switch (r_btype(op1)) {
		case t_oparray:
		case t_operator:
		    if (pstr != 0)
			switch (*pstr) {
			    case '%':
			    case '.':
			    case '@':
				len = r_size(op);
				memcpy(op->value.bytes, pstr, len);
				goto ok;
			}
	    }
	return code;
    }
ok:
    *op1 = *op;
    r_set_size(op1, len);
    return 0;
}
