path: root/psi/zdict.c

/* 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.
*/


/* Dictionary operators */
#include "ghost.h"
#include "oper.h"
#include "iddict.h"
#include "dstack.h"
#include "ilevel.h"		/* for [count]dictstack */
#include "iname.h"		/* for dict_find_name */
#include "ipacked.h"		/* for inline dict lookup */
#include "ivmspace.h"
#include "store.h"
#include "iscan.h"              /* for SCAN_PDF_RULES */

/* <int> dict <dict> */
int
zdict(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_type(*op, t_integer);
    if (op->value.intval < 0)
        return_error(gs_error_rangecheck);
    return dict_create((uint) op->value.intval, op);
}

/* <dict> maxlength <int> */
static int
zmaxlength(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_type(*op, t_dictionary);
    check_dict_read(*op);
    make_int(op, dict_maxlength(op));
    return 0;
}

/* <dict> begin - */
int
zbegin(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_type(*op, t_dictionary);
    check_dict_read(*op);
    if ( dsp == dstop ) {
        int code = ref_stack_extend(&d_stack, 1);

        if ( code < 0 ) {
            if (code == gs_error_dictstackoverflow) {
                /* Adobe doesn't restore the operand that caused stack */
                /* overflow. We do the same to match CET 20-02-02      */
                pop(1);
            }
            return code;
        }
    }
    ++dsp;
    ref_assign(dsp, op);
    dict_set_top();
    pop(1);
    return 0;
}

/* - end - */
int
zend(i_ctx_t *i_ctx_p)
{
    if (ref_stack_count_inline(&d_stack) == min_dstack_size) {
        /* We would underflow the d-stack. */
        return_error(gs_error_dictstackunderflow);
    }
    while (dsp == dsbot) {
        /* We would underflow the current block. */
        ref_stack_pop_block(&d_stack);
    }
    dsp--;
    dict_set_top();
    return 0;
}

/* <key> <value> def - */
/*
 * We make this into a separate procedure because
 * the interpreter will almost always call it directly.
 */
int
zop_def(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    ref *pvslot;

    /* The following combines a check_op(2) with a type check. */
    switch (r_type(op1)) {
        case t_name: {
            /* We can use the fast single-probe lookup here. */
            uint nidx = name_index(imemory, op1);
            uint htemp;

            if_dict_find_name_by_index_top(nidx, htemp, pvslot) {
                if (dtop_can_store(op))
                    goto ra;
            }
            break;		/* handle all slower cases */
            }
        case t_null:
            return_error(gs_error_typecheck);
        case t__invalid:
            return_error(gs_error_stackunderflow);
    }
    /*
     * Combine the check for a writable top dictionary with
     * the global/local store check.  See dstack.h for details.
     */
    if (!dtop_can_store(op)) {
        check_dict_write(*dsp);
        /*
         * If the dictionary is writable, the problem must be
         * an invalid store.
         */
        return_error(gs_error_invalidaccess);
    }
    /*
     * Save a level of procedure call in the common (redefinition)
     * case.  With the current interfaces, we pay a double lookup
     * in the uncommon case.
     */
    if (dict_find(dsp, op1, &pvslot) <= 0)
        return idict_put(dsp, op1, op);
ra:
    if ((pvslot->tas.type_attrs & (&i_ctx_p->memory)->test_mask) == 0)
        alloc_save_change(idmemory, &dsp->value.pdict->values, (ref_packed *)pvslot, "dict_put(value)");
    ref_assign_new_inline(pvslot,op);

    return 0;
}
int
zdef(i_ctx_t *i_ctx_p)
{
    int code = zop_def(i_ctx_p);

    if (code >= 0) {
        pop(2);
    }
    return code;
}

/* <key> load <value> */
static int
zload(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref *pvalue;

    switch (r_type(op)) {
        case t_name:
            /* Use the fast lookup. */
            if ((pvalue = dict_find_name(op)) == 0)
                return_error(gs_error_undefined);
            ref_assign(op, pvalue);
            return 0;
        case t_null:
            return_error(gs_error_typecheck);
        case t__invalid:
            return_error(gs_error_stackunderflow);
        default: {
                /* Use an explicit loop. */
                uint size = ref_stack_count(&d_stack);
                uint i;

                for (i = 0; i < size; i++) {
                    ref *dp = ref_stack_index(&d_stack, i);

                    check_dict_read(*dp);
                    if (dict_find(dp, op, &pvalue) > 0) {
                        ref_assign(op, pvalue);
                        return 0;
                    }
                }
                return_error(gs_error_undefined);
            }
    }
}

/* get - implemented in zgeneric.c */

/* put - implemented in zgeneric.c */

/* <dict> <key> .undef - */
/* <dict> <key> undef - */
static int
zundef(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_write(*op1);
    code = idict_undef(op1, op);
    if (code < 0 && code != gs_error_undefined) /* ignore undefined error */
        return code;
    pop(2);
    return 0;
}

/* <dict> <key> known <bool> */
static int
zknown(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    register os_ptr op1 = op - 1;
    ref *pvalue;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_read(*op1);
    code = dict_find(op1, op, &pvalue);
    switch (code) {
    case gs_error_dictfull:
        code = 0;
    case 0: case 1:
        break;
    default:
        return code;
    }
    make_bool(op1, code);
    pop(1);
    return 0;
}

/* <key> where <dict> true */
/* <key> where false */
int
zwhere(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref_stack_enum_t rsenum;

    check_op(1);
    ref_stack_enum_begin(&rsenum, &d_stack);
    do {
        const ref *const bot = rsenum.ptr;
        const ref *pdref = bot + rsenum.size;
        ref *pvalue;
        int code;

        while (pdref-- > bot) {
            check_dict_read(*pdref);
            code = dict_find(pdref, op, &pvalue);
            if (code < 0 && code != gs_error_dictfull)
                return code;
            if (code > 0) {
                push(1);
                ref_assign(op - 1, pdref);
                make_true(op);
                return 0;
            }
        }
    } while (ref_stack_enum_next(&rsenum));
    make_false(op);
    return 0;
}

/* copy for dictionaries -- called from zcopy in zgeneric.c. */
/* Only the type of *op has been checked. */
int
zcopy_dict(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_read(*op1);
    check_dict_write(*op);
    if (!imemory->gs_lib_ctx->dict_auto_expand &&
        (dict_length(op) != 0 || dict_maxlength(op) < dict_length(op1))
        )
        return_error(gs_error_rangecheck);
    code = idict_copy(op1, op);
    if (code < 0)
        return code;
    /*
     * In Level 1 systems, we must copy the access attributes too.
     * The only possible effect this can have is to make the
     * copy read-only if the original dictionary is read-only.
     */
    if (!level2_enabled)
        r_copy_attrs(dict_access_ref(op), a_write, dict_access_ref(op1));
    ref_assign(op1, op);
    pop(1);
    return 0;
}

/* - currentdict <dict> */
static int
zcurrentdict(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    push(1);
    ref_assign(op, dsp);
    return 0;
}

/* - countdictstack <int> */
static int
zcountdictstack(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    uint count = ref_stack_count(&d_stack);

    push(1);
    if (!level2_enabled)
        count--;		/* see dstack.h */
    make_int(op, count);
    return 0;
}

/* <array> dictstack <subarray> */
static int
zdictstack(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    uint count = ref_stack_count(&d_stack);

    if (!level2_enabled)
        count--;		/* see dstack.h */
    if (!r_is_array(op))
        return_op_typecheck(op);
    if (r_size(op) < count)
        return_error(gs_error_rangecheck);
    if (!r_has_type_attrs(op, t_array, a_write))
        return_error(gs_error_invalidaccess);
    return ref_stack_store(&d_stack, op, count, 0, 0, true, idmemory,
                           "dictstack");
}

/* - cleardictstack - */
static int
zcleardictstack(i_ctx_t *i_ctx_p)
{
    while (zend(i_ctx_p) >= 0)
        DO_NOTHING;
    return 0;
}

/* ------ Extensions ------ */

/* -mark- <key0> <value0> <key1> <value1> ... .dicttomark <dict> */
/* This is the Level 2 >> operator. */
static int
zdicttomark(i_ctx_t *i_ctx_p)
{
    uint count2 = ref_stack_counttomark(&o_stack);
    ref rdict;
    int code;
    uint idx;

    if (count2 == 0)
        return_error(gs_error_unmatchedmark);
    count2--;
    if ((count2 & 1) != 0)
        return_error(gs_error_rangecheck);
    code = dict_create(count2 >> 1, &rdict);
    if (code < 0)
        return code;
    if ((i_ctx_p->scanner_options & SCAN_PDF_RULES) != 0) {
       for (idx = count2; idx > 0; idx -= 2) {
           code = idict_put(&rdict,
                            ref_stack_index(&o_stack, idx - 1),
                            ref_stack_index(&o_stack, idx - 2));
           if (code < 0) {         /* There's no way to free the dictionary -- too bad. */
               return code;
           }
       }
    }
    else {
       /* << /a 1 /a 2 >> => << /a 1 >>, i.e., */
       /* we must enter the keys in top-to-bottom order. */
       for (idx = 0; idx < count2; idx += 2) {
           code = idict_put(&rdict,
                            ref_stack_index(&o_stack, idx + 1),
                            ref_stack_index(&o_stack, idx));
           if (code < 0) {         /* There's no way to free the dictionary -- too bad. */
               return code;
           }
       }
    }
    ref_stack_pop(&o_stack, count2);
    ref_assign(osp, &rdict);
    return code;
}

/* <dict1> <dict2> .forcecopynew <dict2> */
/*
 * This operator is a special-purpose accelerator for use by 'restore' (see
 * gs_dps1.ps).  Note that this operator does *not* require that dict2 be
 * writable.  Hence it is in the same category of "dangerous" operators as
 * .forceput and .forceundef.
 */
static int
zforcecopynew(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_read(*op1);
    check_type(*op, t_dictionary);
    /*check_dict_write(*op);*/	/* see above */
    /* This is only recognized in Level 2 mode. */
    if (!imemory->gs_lib_ctx->dict_auto_expand)
        return_error(gs_error_undefined);
    code = idict_copy_new(op1, op);
    if (code < 0)
        return code;
    ref_assign(op1, op);
    pop(1);
    return 0;
}

/* <dict> <key> .forceundef - */
/*
 * This forces an "undef" even if the dictionary is not writable.
 * Like .forceput, it is meant to be used only in a few special situations,
 * and should not be accessible by name after initialization.
 */
static int
zforceundef(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    check_type(op[-1], t_dictionary);
    /* Don't check_dict_write */
    idict_undef(op - 1, op);	/* ignore undefined error */
    pop(2);
    return 0;
}

/* <dict> <key> .knownget <value> true */
/* <dict> <key> .knownget false */
static int
zknownget(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    register os_ptr op1 = op - 1;
    ref *pvalue;

    check_type(*op1, t_dictionary);
    check_dict_read(*op1);
    if (dict_find(op1, op, &pvalue) <= 0) {
        make_false(op1);
        pop(1);
    } else {
        ref_assign(op1, pvalue);
        make_true(op);
    }
    return 0;
}

/* <dict> <key> .knownundef <bool> */
static int
zknownundef(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_write(*op1);
    code = idict_undef(op1, op);
    make_bool(op1, code == 0);
    pop(1);
    return 0;
}

/* <dict> <int> .setmaxlength - */
static int
zsetmaxlength(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    uint new_size;
    int code;

    check_type(*op1, t_dictionary);
    check_dict_write(*op1);
    check_type(*op, t_integer);
    if (op->value.intval < 0)
        return_error(gs_error_rangecheck);
    new_size = (uint) op->value.intval;
    if (dict_length(op - 1) > new_size)
        return_error(gs_error_dictfull);
    code = idict_resize(op - 1, new_size);
    if (code >= 0)
        pop(2);
    return code;
}

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

/* We need to split the table because of the 16-element limit. */
const op_def zdict1_op_defs[] = {
    {"0cleardictstack", zcleardictstack},
    {"1begin", zbegin},
    {"0countdictstack", zcountdictstack},
    {"0currentdict", zcurrentdict},
    {"2def", zdef},
    {"1dict", zdict},
    {"0dictstack", zdictstack},
    {"0end", zend},
    {"2known", zknown},
    {"1load", zload},
    {"1maxlength", zmaxlength},
    {"2.undef", zundef},	/* we need this even in Level 1 */
    {"1where", zwhere},
    op_def_end(0)
};
const op_def zdict2_op_defs[] = {
                /* Extensions */
    {"1.dicttomark", zdicttomark},
    {"2.forcecopynew", zforcecopynew},
    {"2.forceundef", zforceundef},
    {"2.knownget", zknownget},
    {"1.knownundef", zknownundef},
    {"2.setmaxlength", zsetmaxlength},
        /*
         * In Level 2, >> is a synonym for .dicttomark, and undef for
         * .undef.  By giving the former their own entries, they will not be
         * "eq" to .dicttomark and .undef, but that doesn't matter, since
         * we're doing this only for the sake of Adobe- compatible error
         * stacks.
         */
    op_def_begin_level2(),
    {"1>>", zdicttomark},
    {"2undef", zundef},
    op_def_end(0)
};