/* 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.
*/


/* Array/string/dictionary generic operators for PostScript */
#include "memory_.h"
#include "ghost.h"
#include "gsstruct.h"		/* for st_bytes */
#include "oper.h"
#include "dstack.h"		/* for systemdict */
#include "estack.h"		/* for forall */
#include "iddict.h"
#include "iname.h"
#include "ipacked.h"
#include "ivmspace.h"
#include "store.h"

/* This file implements copy, get, put, getinterval, putinterval, */
/* length, and forall, which apply generically to */
/* arrays, strings, and dictionaries.  (Copy also has a special */
/* meaning for copying the top N elements of the stack.) */

/* See the comment in opdef.h for an invariant which allows */
/* more efficient implementation of forall. */

/* Forward references */
static int zcopy_integer(i_ctx_t *);
static int zcopy_interval(i_ctx_t *);
static int copy_interval(i_ctx_t *, os_ptr, uint, os_ptr, client_name_t);

/* <various1> <various2> copy <various> */
/* <obj1> ... <objn> <int> copy <obj1> ... <objn> <obj1> ... <objn> */
/* Note that this implements copy for arrays and strings, */
/* but not for dictionaries (see zcopy_dict in zdict.c). */
int
zcopy(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    int type = r_type(op);

    if (type == t_integer)
        return zcopy_integer(i_ctx_p);
    check_op(2);
    switch (type) {
        case t_array:
        case t_string:
            return zcopy_interval(i_ctx_p);
        case t_dictionary:
            return zcopy_dict(i_ctx_p);
        default:
            return_op_typecheck(op);
    }
}

/* <obj1> ... <objn> <int> copy <obj1> ... <objn> <obj1> ... <objn> */
static int
zcopy_integer(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int count, i;
    int code;

    if ((uint) op->value.intval > (uint)(op - osbot)) {
        /* There might be enough elements in other blocks. */
        check_type(*op, t_integer);
        if (op->value.intval >= (int)ref_stack_count(&o_stack))
            return_error(gs_error_stackunderflow);
        if (op->value.intval < 0)
            return_error(gs_error_rangecheck);
        check_int_ltu(*op, ref_stack_count(&o_stack));
        count = op->value.intval;
    } else if (op1 + (count = op->value.intval) <= ostop) {
        /* Fast case. */
        memcpy((char *)op, (char *)(op - count), count * sizeof(ref));
        push(count - 1);
        return 0;
    }
    /* Do it the slow, general way. */
    code = ref_stack_push(&o_stack, count - 1);
    if (code < 0)
        return code;
    for (i = 0; i < count; i++)
        *ref_stack_index(&o_stack, i) =
            *ref_stack_index(&o_stack, i + count);
    return 0;
}

/* <array1> <array2> copy <subarray2> */
/* <string1> <string2> copy <substring2> */
static int
zcopy_interval(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    int code = copy_interval(i_ctx_p, op, 0, op1, "copy");

    if (code < 0)
        return code;
    r_set_size(op, r_size(op1));
    *op1 = *op;
    pop(1);
    return 0;
}

/* <array|dict|name|packedarray|string> length <int> */
static int
zlength(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    switch (r_type(op)) {
        case t_array:
        case t_string:
        case t_mixedarray:
        case t_shortarray:
            check_read(*op);
            make_int(op, r_size(op));
            return 0;
        case t_dictionary:
            check_dict_read(*op);
            make_int(op, dict_length(op));
            return 0;
        case t_name: {
            ref str;

            name_string_ref(imemory, op, &str);
            make_int(op, r_size(&str));
            return 0;
        }
        case t_astruct:
            if (gs_object_type(imemory, op->value.pstruct) != &st_bytes)
                return_error(gs_error_typecheck);
            check_read(*op);
            make_int(op, gs_object_size(imemory, op->value.pstruct));
            return 0;
        default:
            return_op_typecheck(op);
    }
}

/* <array|packedarray|string> <index> get <obj> */
/* <dict> <key> get <obj> */
static int
zget(i_ctx_t *i_ctx_p)
{
    int code;
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    ref *pvalue;

    switch (r_type(op1)) {
        case t_dictionary:
            check_dict_read(*op1);
            if (dict_find(op1, op, &pvalue) <= 0)
                return_error(gs_error_undefined);
            op[-1] = *pvalue;
            break;
        case t_string:
            check_read(*op1);
            check_int_ltu(*op, r_size(op1));
            make_int(op1, op1->value.bytes[(uint) op->value.intval]);
            break;
        case t_array:
        case t_mixedarray:
        case t_shortarray:
            check_type(*op, t_integer);
            check_read(*op1);
            code = array_get(imemory, op1, op->value.intval, op1);
            if (code < 0)
                return code;
            break;
        case t__invalid:
            return_error(gs_error_stackunderflow);
        default:
            return_error(gs_error_typecheck);
    }
    pop(1);
    return 0;
}

/* <array> <index> <obj> put - */
/* <dict> <key> <value> put - */
/* <string> <index> <int> put - */
static int
zput(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    os_ptr op2 = op1 - 1;
    byte *sdata;
    uint ssize;

    switch (r_type(op2)) {
        case t_dictionary:
            check_dict_write(*op2);
            {
                int code = idict_put(op2, op1, op);

                if (code < 0)
                    return code;	/* error */
            }
            break;
        case t_array:
            check_write(*op2);
            check_int_ltu(*op1, r_size(op2));
            store_check_dest(op2, op);
            {
                ref *eltp = op2->value.refs + (uint) op1->value.intval;

                ref_assign_old(op2, eltp, op, "put");
            }
            break;
        case t_mixedarray:	/* packed arrays are read-only */
        case t_shortarray:
            return_error(gs_error_invalidaccess);
        case t_string:
            sdata = op2->value.bytes;
            ssize = r_size(op2);
str:	    check_write(*op2);
            check_int_ltu(*op1, ssize);
            check_int_leu(*op, 0xff);
            sdata[(uint)op1->value.intval] = (byte)op->value.intval;
            break;
        case t_astruct:
            if (gs_object_type(imemory, op2->value.pstruct) != &st_bytes)
                return_error(gs_error_typecheck);
            sdata = r_ptr(op2, byte);
            ssize = gs_object_size(imemory, op2->value.pstruct);
            goto str;
        default:
            return_op_typecheck(op2);
    }
    pop(3);
    return 0;
}

/* <array> <index> <obj> .forceput - */
/* <dict> <key> <value> .forceput - */
/*
 * This forces a "put" even if the object is not writable, and (if the
 * object is systemdict or the save level is 0) even if the value is in
 * local VM.  It is meant to be used only for replacing the value of
 * FontDirectory in systemdict when switching between local and global VM,
 * and a few similar applications.  After initialization, this operator
 * should no longer be accessible by name.
 */
static int
zforceput(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    os_ptr op2 = op - 2;
    int code;

    switch (r_type(op2)) {
    case t_array:
        check_int_ltu(*op1, r_size(op2));
        if (r_space(op2) > r_space(op)) {
            if (imemory_save_level(iimemory))
                return_error(gs_error_invalidaccess);
        }
        {
            ref *eltp = op2->value.refs + (uint) op1->value.intval;

            ref_assign_old(op2, eltp, op, "put");
        }
        break;
    case t_dictionary:
        if (op2->value.pdict == systemdict->value.pdict ||
            !imemory_save_level(iimemory)
            ) {
            uint space = r_space(op2);

            r_set_space(op2, avm_local);
            code = idict_put(op2, op1, op);
            r_set_space(op2, space);
        } else
            code = idict_put(op2, op1, op);
        if (code < 0)
            return code;
        break;
    default:
        return_error(gs_error_typecheck);
    }
    pop(3);
    return 0;
}

/* <seq:array|packedarray|string> <index> <count> getinterval <subseq> */
static int
zgetinterval(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr op1 = op - 1;
    os_ptr op2 = op1 - 1;
    uint index;
    uint count;

    switch (r_type(op2)) {
        default:
            return_op_typecheck(op2);
        case t_array:
        case t_string:
        case t_mixedarray:
        case t_shortarray:;
    }
    check_read(*op2);
    check_int_leu(*op1, r_size(op2));
    index = op1->value.intval;
    check_int_leu(*op, r_size(op2) - index);
    count = op->value.intval;
    switch (r_type(op2)) {
        case t_array:
            op2->value.refs += index;
            break;
        case t_string:
            op2->value.bytes += index;
            break;
        case t_mixedarray: {
            const ref_packed *packed = op2->value.packed;

            for (; index--;)
                packed = packed_next(packed);
            op2->value.packed = packed;
            break;
        }
        case t_shortarray:
            op2->value.packed += index;
            break;
    }
    r_set_size(op2, count);
    pop(2);
    return 0;
}

/* <array1> <index> <array2|packedarray2> putinterval - */
/* <string1> <index> <string2> putinterval - */
/* <bytestring1> <index> <string2> putinterval - */
static int
zputinterval(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr opindex = op - 1;
    os_ptr opto = opindex - 1;
    int code;

    switch (r_type(opto)) {
        default:
            return_error(gs_error_typecheck);
        case t__invalid:
            if (r_type(op) != t_array && r_type(op) != t_string && r_type(op) != t__invalid)
                return_error(gs_error_typecheck); /* to match Distiller */
            else
                return_error(gs_error_stackunderflow);
        case t_mixedarray:
        case t_shortarray:
            return_error(gs_error_invalidaccess);
        case t_array:
        case t_string:
            check_write(*opto);
            check_int_leu(*opindex, r_size(opto));
            code = copy_interval(i_ctx_p, opto, (uint)(opindex->value.intval),
                                 op, "putinterval");
            break;
        case t_astruct: {
            uint dsize, ssize, index;

            check_write(*opto);
            if (gs_object_type(imemory, opto->value.pstruct) != &st_bytes)
                return_error(gs_error_typecheck);
            dsize = gs_object_size(imemory, opto->value.pstruct);
            check_int_leu(*opindex, dsize);
            index = (uint)opindex->value.intval;
            check_read_type(*op, t_string);
            ssize = r_size(op);
            if (ssize > dsize - index)
                return_error(gs_error_rangecheck);
            memcpy(r_ptr(opto, byte) + index, op->value.const_bytes, ssize);
            code = 0;
            break;
        }
    }
    if (code >= 0)
        pop(3);
    return code;
}

/* <array|packedarray|string> <<element> proc> forall - */
/* <dict> <<key> <value> proc> forall - */
static int
    array_continue(i_ctx_t *),
    dict_continue(i_ctx_t *),
    string_continue(i_ctx_t *),
    packedarray_continue(i_ctx_t *);
static int forall_cleanup(i_ctx_t *);
static int
zforall(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    os_ptr obj = op - 1;
    es_ptr ep = esp;
    es_ptr cproc = ep + 4;

    check_estack(6);
    check_proc(*op);
    switch (r_type(obj)) {
        default:
            return_op_typecheck(obj);
        case t_array:
            check_read(*obj);
            make_op_estack(cproc, array_continue);
            break;
        case t_dictionary:
            check_dict_read(*obj);
            make_int(cproc, dict_first(obj));
            ++cproc;
            make_op_estack(cproc, dict_continue);
            break;
        case t_string:
            check_read(*obj);
            make_op_estack(cproc, string_continue);
            break;
        case t_mixedarray:
        case t_shortarray:
            check_read(*obj);
            make_op_estack(cproc, packedarray_continue);
            break;
    }
    /*
     * Push:
     *   - a mark;
     *   - the composite object;
     *   - the procedure;
     *   - the iteration index (only for dictionaries, done above);
     * and invoke the continuation operator.
     */
    make_mark_estack(ep + 1, es_for, forall_cleanup);
    ep[2] = *obj;
    ep[3] = *op;
    esp = cproc - 1;
    pop(2);
    return (*real_opproc(cproc))(i_ctx_p);
}
/* Continuation operator for arrays */
static int
array_continue(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    es_ptr obj = esp - 1;

    if (r_size(obj)) {		/* continue */
        push(1);
        r_dec_size(obj, 1);
        *op = *obj->value.refs;
        obj->value.refs++;
        esp += 2;
        *esp = obj[1];
        return o_push_estack;
    } else {			/* done */
        esp -= 3;		/* pop mark, object, proc */
        return o_pop_estack;
    }
}
/* Continuation operator for dictionaries */
static int
dict_continue(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    es_ptr obj = esp - 2;
    int index = esp->value.intval;

    push(2);			/* make room for key and value */
    if ((index = dict_next(obj, index, op - 1)) >= 0) {	/* continue */
        esp->value.intval = index;
        esp += 2;
        *esp = obj[1];
        return o_push_estack;
    } else {			/* done */
        pop(2);			/* undo push */
        esp -= 4;		/* pop mark, object, proc, index */
        return o_pop_estack;
    }
}
/* Continuation operator for strings */
static int
string_continue(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    es_ptr obj = esp - 1;

    if (r_size(obj)) {		/* continue */
        push(1);		/* check for result space on stack BEFORE changing string size */
        r_dec_size(obj, 1);	/* Bug 701550 :-O */
        make_int(op, *obj->value.bytes);
        obj->value.bytes++;
        esp += 2;
        *esp = obj[1];
        return o_push_estack;
    } else {			/* done */
        esp -= 3;		/* pop mark, object, proc */
        return o_pop_estack;
    }
}
/* Continuation operator for packed arrays */
static int
packedarray_continue(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    es_ptr obj = esp - 1;

    if (r_size(obj)) {		/* continue */
        const ref_packed *packed = obj->value.packed;

        r_dec_size(obj, 1);
        push(1);
        packed_get(imemory, packed, op);
        obj->value.packed = packed_next(packed);
        esp += 2;
        *esp = obj[1];
        return o_push_estack;
    } else {			/* done */
        esp -= 3;		/* pop mark, object, proc */
        return o_pop_estack;
    }
}
/* Vacuous cleanup procedure */
static int
forall_cleanup(i_ctx_t *i_ctx_p)
{
    return 0;
}

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

const op_def zgeneric_op_defs[] =
{
    {"1copy", zcopy},
    {"2forall", zforall},
    {"3.forceput", zforceput},
    {"2get", zget},
    {"3getinterval", zgetinterval},
    {"1length", zlength},
    {"3put", zput},
    {"3putinterval", zputinterval},
                /* Internal operators */
    {"0%array_continue", array_continue},
    {"0%dict_continue", dict_continue},
    {"0%packedarray_continue", packedarray_continue},
    {"0%string_continue", string_continue},
    op_def_end(0)
};

/* ------ Shared routines ------ */

/* Copy an interval from one operand to another. */
/* This is used by both putinterval and string/array copy. */
/* The destination is known to be an array or string, */
/* and the starting index is known to be less than or equal to */
/* its length; nothing else has been checked. */
static int
copy_interval(i_ctx_t *i_ctx_p /* for ref_assign_old */, os_ptr prto,
              uint index, os_ptr prfrom, client_name_t cname)
{
    int fromtype = r_type(prfrom);
    uint fromsize = r_size(prfrom);

    if (!(fromtype == r_type(prto) ||
          ((fromtype == t_shortarray || fromtype == t_mixedarray) &&
           r_type(prto) == t_array))
        )
        return_op_typecheck(prfrom);
    check_read(*prfrom);
    check_write(*prto);
    if (fromsize > r_size(prto) - index)
        return_error(gs_error_rangecheck);
    switch (fromtype) {
        case t_array:
            {			/* We have to worry about aliasing, */
                /* but refcpy_to_old takes care of it for us. */
                return refcpy_to_old(prto, index, prfrom->value.refs,
                                     fromsize, idmemory, cname);
            }
        case t_string:
            {	/* memmove takes care of aliasing. */
                memmove(prto->value.bytes + index, prfrom->value.bytes,
                        fromsize);
            }
            break;
        case t_mixedarray:
        case t_shortarray:
            {	/* We don't have to worry about aliasing, because */
                /* packed arrays are read-only and hence the destination */
                /* can't be a packed array. */
                uint i;
                const ref_packed *packed = prfrom->value.packed;
                ref *pdest = prto->value.refs + index;
                ref elt;

                for (i = 0; i < fromsize; i++, pdest++) {
                    packed_get(imemory, packed, &elt);
                    ref_assign_old(prto, pdest, &elt, cname);
                    packed = packed_next(packed);
                }
            }
            break;
    }
    return 0;
}