/* Copyright (C) 2001-2019 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.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* 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"
#include "gsstate.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 */
static int access_check(i_ctx_t *, int, bool);
static 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_INT (((ps_int)-1) << ((sizeof(ps_int) * 8) - 1))
#define ALT_MAX_INT (~(ALT_MIN_INT))
static const double min_int_real = (ALT_MIN_INT * 1.0 - 1);
static const double max_int_real = (ALT_MAX_INT * 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> */
static 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));
            int code = name_ref(imemory, (const byte *)sname, strlen(sname),
                                (ref *) (op - 1), 0);

            if (code < 0)
                return code;
            } else
                return_error(gs_error_stackunderflow);
        }
        r_set_attrs(op - 1, a_executable);
    } else {
        ref_assign(op - 1, &tnref);
    }
    pop(1);
    return 0;
}

/* - .typenames <name1|null> ... <nameN|null> */
static 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> */
static 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(gs_error_rangecheck);
    aop = ACCESS_REF(op);
    r_set_attrs(aop, a_executable);
    return 0;
}

/* <obj> xcheck <bool> */
static 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> */
static int
zexecuteonly(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref_type rtype = r_type(op);

    check_op(1);
    if (rtype == t_dictionary || rtype == t_astruct || rtype == t_device)
        return_error(gs_error_typecheck);
    return access_check(i_ctx_p, a_execute, true);
}

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

    check_op(1);
    if (r_has_type(op, t_dictionary)) {
        ref *aop = dict_access_ref(op);

        /* CPSI throws invalidaccess when seting noaccess to a readonly dictionary (CET 13-13-6) : */
        if (!r_has_attrs(aop, a_write)) {
            if (!r_has_attrs(aop, a_read) && !r_has_attrs(aop, a_execute)) {
                /* Already noaccess - do nothing (CET 24-09-1). */
                return 0;
            }
            return_error(gs_error_invalidaccess);
        }

        /* Don't allow removing read access to permanent dictionaries. */
        if (dict_is_permanent_on_dstack(op))
            return_error(gs_error_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> */
static 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> */
static 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 = gs_scan_string_token(i_ctx_p, &str, &token);
                if (code > 0)   /* anything other than a plain token */
                    code = gs_note_error(gs_error_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(gs_error_typecheck);
                }
            }
    }
    if (!REAL_CAN_BE_INT(fval))
        return_error(gs_error_rangecheck);
    make_int(op, (long)fval);   /* truncates towards 0 */
    return 0;
}

/* <string> cvn <name> */
static 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:
        {
            /* Strictly speaking assigning one element of union
             * to another, overlapping element of a different size is
             * undefined behavior, hence assign to an intermediate variable
             */
            float fl = (float)op->value.intval;
            make_real(op, fl);
        }
        case t_real:
            return 0;
        default:
            return_op_typecheck(op);
        case t_string:
            {
                ref str, token;
                int code;

                ref_assign(&str, op);
                code = gs_scan_string_token(i_ctx_p, &str, &token);
                if (code > 0)   /* anything other than a plain token */
                    code = gs_note_error(gs_error_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(gs_error_typecheck);
                }
            }
    }
}

/* <num> <radix_int> <string> cvrs <substring> */
static 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(gs_error_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(gs_error_stackunderflow);
            default:
                return_error(gs_error_rangecheck); /* CET 24-05 wants rangecheck */
        }
    } else {
        ps_uint ival;
        byte digits[sizeof(ulong) * 8];
        byte *endp = &digits[countof(digits)];
        byte *dp = endp;

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

                    if (!REAL_CAN_BE_INT(fval))
                        return_error(gs_error_rangecheck);
                    ival = (ulong) (long)fval;
                } break;
            case t__invalid:
                return_error(gs_error_stackunderflow);
            default:
                return_error(gs_error_rangecheck); /* CET 24-05 wants rangecheck */
        }
        if (gs_currentcpsimode(imemory)) {
            uint val = (uint)ival;
            do {
                int dit = val % radix;

                *--dp = dit + (dit < 10 ? '0' : ('A' - 10));
                val /= radix;
            }
            while (val);

        } else {
            do {
                int dit = ival % radix;

                *--dp = dit + (dit < 10 ? '0' : ('A' - 10));
                ival /= radix;
            }
            while (ival);
        }
        if (endp - dp > r_size(op))
            return_error(gs_error_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> */
static int
zcvs(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int code;

    check_write_type(*op, t_string);
    check_op(2);
    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. */
static 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(gs_error_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(gs_error_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. */
static 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 == gs_error_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;
}
