/* 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.
*/


/* Interpreter implementations of parameter dictionaries */
#include "memory_.h"
#include "string_.h"
#include "ghost.h"
#include "ierrors.h"
#include "oper.h"		/* for check_type */
#include "opcheck.h"
#include "ialloc.h"
#include "idict.h"
#include "imemory.h"		/* for iutil.h */
#include "iname.h"
#include "istack.h"
#include "iparam.h"
#include "iutil.h"		/* for num_params */
#include "ivmspace.h"
#include "store.h"
#include "gsstruct.h"           /* for st_bytes */

/* ================ Utilities ================ */

/* Convert a key to a ref. */
static int
ref_param_key(const iparam_list * plist, gs_param_name pkey, ref * pkref)
{
    if (plist->int_keys) {
        long key;

        if (sscanf(pkey, "%ld", &key) != 1)
            return_error(gs_error_rangecheck);
        make_int(pkref, key);
        return 0;
    } else
        return name_ref(plist->memory, (const byte *)pkey, strlen(pkey), pkref, 0);
}

/* Fill in a gs_param_key_t from a name or int ref. */
static int
ref_to_key(const ref * pref, gs_param_key_t * key, iparam_list *plist)
{
    if (r_has_type(pref, t_name)) {
        ref nref;

        name_string_ref(plist->memory, pref, &nref);
        key->data = nref.value.const_bytes;
        key->size = r_size(&nref);
        key->persistent = false; /* names may be freed */
    } else if (r_has_type(pref, t_integer)) {
        char istr[sizeof(long) * 8 / 3 + 2];
        int len;
        byte *buf;

        gs_sprintf(istr, "%"PRIpsint, pref->value.intval);
        len = strlen(istr);
        /* GC will take care of freeing this: */
        buf = gs_alloc_string(plist->memory, len, "ref_to_key");
        if (!buf)
            return_error(gs_error_VMerror);
        key->data = buf;
        key->size = len;
        key->persistent = true;
    } else
        return_error(gs_error_typecheck);
    return 0;
}

/* ================ Writing parameters to refs ================ */

/* Forward references */
static int array_new_indexed_plist_write(dict_param_list *plist,
                                          ref *parray, const ref *pwanted,
                                          gs_ref_memory_t *imem);

/* ---------------- Generic writing procedures ---------------- */

static param_proc_begin_xmit_collection(ref_param_begin_write_collection);
static param_proc_end_xmit_collection(ref_param_end_write_collection);
static param_proc_xmit_typed(ref_param_write_typed);
static param_proc_next_key(ref_param_get_next_key);
static param_proc_requested(ref_param_requested);
static const gs_param_list_procs ref_write_procs =
{
    ref_param_write_typed,
    ref_param_begin_write_collection,
    ref_param_end_write_collection,
    ref_param_get_next_key,
    NULL,			/* request */
    ref_param_requested
};
static int ref_array_param_requested(const iparam_list *, gs_param_name,
                                      ref *, uint, client_name_t);
static int ref_param_write(iparam_list *, gs_param_name, const ref *);
static int ref_param_write_string_value(ref *, const gs_param_string *,
                                         gs_ref_memory_t *);
static int ref_param_write_name_value(const gs_memory_t *mem, ref *, const gs_param_string *);
static int
ref_param_make_int(ref *pe, const void *pvalue, uint i, gs_ref_memory_t *imem)
{
    make_tav(pe, t_integer, imemory_new_mask(imem), intval,
             ((const gs_param_int_array *)pvalue)->data[i]);
    return 0;
}
static int
ref_param_make_float(ref *pe, const void *pvalue, uint i, gs_ref_memory_t *imem)
{
    make_tav(pe, t_real, imemory_new_mask(imem), realval,
             ((const gs_param_float_array *)pvalue)->data[i]);
    return 0;
}
static int
ref_param_make_string(ref *pe, const void *pvalue, uint i, gs_ref_memory_t *imem)
{
    return ref_param_write_string_value(pe,
                         &((const gs_param_string_array *)pvalue)->data[i],
                                        imem);
}
static int
ref_param_make_name(ref * pe, const void *pvalue, uint i, gs_ref_memory_t *imem)
{
    return ref_param_write_name_value((const gs_memory_t *)imem, pe,
                         &((const gs_param_string_array *)pvalue)->data[i]);
}
static int
ref_param_write_typed_array(gs_param_list * plist, gs_param_name pkey,
                            void *pvalue, uint count,
                            int (*make)(ref *, const void *, uint,
                                        gs_ref_memory_t *))
{
    iparam_list *const iplist = (iparam_list *) plist;
    ref value;
    uint i;
    ref *pe;
    int code;

    if ((code = ref_array_param_requested(iplist, pkey, &value, count,
                                       "ref_param_write_typed_array")) <= 0)
        return code;
    for (i = 0, pe = value.value.refs; i < count; ++i, ++pe)
        if ((code = (*make) (pe, pvalue, i, iplist->ref_memory)) < 0)
            return code;
    return ref_param_write(iplist, pkey, &value);
}
static int
ref_param_begin_write_collection(gs_param_list * plist, gs_param_name pkey,
                                 gs_param_dict * pvalue,
                                 gs_param_collection_type_t coll_type)
{
    iparam_list *const iplist = (iparam_list *) plist;
    gs_ref_memory_t *imem = iplist->ref_memory;
    dict_param_list *dlist = (dict_param_list *)
        gs_alloc_bytes(plist->memory, size_of(dict_param_list),
                       "ref_param_begin_write_collection");
    int code;

    if (dlist == 0)
        return_error(gs_error_VMerror);
    if (coll_type != gs_param_collection_array) {
        ref dref;

        code = dict_alloc(imem, pvalue->size, &dref);
        if (code >= 0) {
            code = dict_param_list_write(dlist, &dref, NULL, imem);
            dlist->int_keys = coll_type == gs_param_collection_dict_int_keys;
        }
    } else {
        ref aref;

        code = gs_alloc_ref_array(imem, &aref, a_all, pvalue->size,
                                  "ref_param_begin_write_collection");
        if (code >= 0)
            code = array_new_indexed_plist_write(dlist, &aref, NULL, imem);
    }
    if (code < 0)
        gs_free_object(plist->memory, dlist, "ref_param_begin_write_collection");
    else
        pvalue->list = (gs_param_list *) dlist;
    return code;
}
static int
ref_param_end_write_collection(gs_param_list * plist, gs_param_name pkey,
                               gs_param_dict * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    int code = ref_param_write(iplist, pkey,
                               &((dict_param_list *) pvalue->list)->dict);

    gs_free_object(plist->memory, pvalue->list, "ref_param_end_write_collection");
    pvalue->list = 0;
    return code;
}
static int
ref_param_write_typed(gs_param_list * plist, gs_param_name pkey,
                      gs_param_typed_value * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    ref value;
    int code = 0;

    switch (pvalue->type) {
        case gs_param_type_null:
            make_null(&value);
            break;
        case gs_param_type_bool:
            make_bool(&value, pvalue->value.b);
            break;
        case gs_param_type_int:
            make_int(&value, pvalue->value.i);
            break;
        case gs_param_type_long:
            make_int(&value, pvalue->value.l);
            break;
        case gs_param_type_float:
            make_real(&value, pvalue->value.f);
            break;
        case gs_param_type_string:
            if (!ref_param_requested(plist, pkey))
                return 0;
            code = ref_param_write_string_value(&value, &pvalue->value.s,
                                                iplist->ref_memory);
            break;
        case gs_param_type_name:
            if (!ref_param_requested(plist, pkey))
                return 0;
            code = ref_param_write_name_value(iplist->memory, &value, &pvalue->value.n);
            break;
        case gs_param_type_int_array:
            return ref_param_write_typed_array(plist, pkey, &pvalue->value.ia,
                                               pvalue->value.ia.size,
                                               ref_param_make_int);
        case gs_param_type_float_array:
            return ref_param_write_typed_array(plist, pkey, &pvalue->value.fa,
                                               pvalue->value.fa.size,
                                               ref_param_make_float);
        case gs_param_type_string_array:
            return ref_param_write_typed_array(plist, pkey, &pvalue->value.sa,
                                               pvalue->value.sa.size,
                                               ref_param_make_string);
        case gs_param_type_name_array:
            return ref_param_write_typed_array(plist, pkey, &pvalue->value.na,
                                               pvalue->value.na.size,
                                               ref_param_make_name);
        case gs_param_type_dict:
        case gs_param_type_dict_int_keys:
        case gs_param_type_array:
            return ref_param_begin_write_collection(plist, pkey,
                                                    &pvalue->value.d,
              (gs_param_collection_type_t)(pvalue->type - gs_param_type_dict));
        default:
            return_error(gs_error_typecheck);
    }
    if (code < 0)
        return code;
    return ref_param_write(iplist, pkey, &value);
}

/* Check whether a given parameter was requested. */
static int
ref_param_requested(const gs_param_list * plist, gs_param_name pkey)
{
    const iparam_list *const ciplist = (const iparam_list *)plist;
    ref kref;
    ref *ignore_value;

    if (!r_has_type(&ciplist->u.w.wanted, t_dictionary))
        return -1;
    if (ref_param_key(ciplist, pkey, &kref) < 0)
        return -1;		/* catch it later */
    return (dict_find(&ciplist->u.w.wanted, &kref, &ignore_value) > 0);
}

/* Check whether an array parameter is wanted, and allocate it if so. */
/* Return <0 on error, 0 if not wanted, 1 if wanted. */
static int
ref_array_param_requested(const iparam_list *iplist, gs_param_name pkey,
                          ref *pvalue, uint size, client_name_t cname)
{
    int code;

    if (!ref_param_requested((const gs_param_list *)iplist, pkey))
        return 0;
    code = gs_alloc_ref_array(iplist->ref_memory, pvalue, a_all, size, cname);
    return (code < 0 ? code : 1);
}

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

/* Prepare to write a string value. */
static int
ref_param_write_string_value(ref * pref, const gs_param_string * pvalue,
                             gs_ref_memory_t *imem)
{
    const byte *pdata = pvalue->data;
    uint n = pvalue->size;

    if (pvalue->persistent)
        make_const_string(pref, a_readonly | avm_foreign, n, pdata);
    else {
        byte *pstr = gs_alloc_string((gs_memory_t *)imem, n,
                                     "ref_param_write_string");

        if (pstr == 0)
            return_error(gs_error_VMerror);
        memcpy(pstr, pdata, n);
        make_string(pref, a_readonly | imemory_space(imem), n, pstr);
    }
    return 0;
}

/* Prepare to write a name value. */
static int
ref_param_write_name_value(const gs_memory_t *mem, ref * pref, const gs_param_string * pvalue)
{
    return name_ref(mem, pvalue->data, pvalue->size, pref,
                    (pvalue->persistent ? 0 : 1));
}

/* Generic routine for writing a ref parameter. */
static int
ref_param_write(iparam_list * plist, gs_param_name pkey, const ref * pvalue)
{
    ref kref;
    int code;

    if (!ref_param_requested((gs_param_list *) plist, pkey))
        return 0;
    code = ref_param_key(plist, pkey, &kref);
    if (code < 0)
        return code;
    return (*plist->u.w.write) (plist, &kref, pvalue);
}

/* ---------------- Implementations ---------------- */

/* Initialize for writing parameters. */
static void
ref_param_write_init(iparam_list * plist, const ref * pwanted,
                     gs_ref_memory_t *imem)
{
    gs_param_list_init((gs_param_list *)plist, &ref_write_procs,
                       (gs_memory_t *)imem);
    plist->ref_memory = imem;
    if (pwanted == 0)
        make_null(&plist->u.w.wanted);
    else
        plist->u.w.wanted = *pwanted;
    plist->results = 0;
    plist->int_keys = false;
}

/* Implementation for getting parameters to a stack. */
static int
stack_param_write(iparam_list * plist, const ref * pkey, const ref * pvalue)
{
    stack_param_list *const splist = (stack_param_list *) plist;
    ref_stack_t *pstack = splist->pstack;
    s_ptr p = pstack->p;

    if (pstack->top - p < 2) {
        int code = ref_stack_push(pstack, 2);

        if (code < 0)
            return code;
        *ref_stack_index(pstack, 1) = *pkey;
        p = pstack->p;
    } else {
        pstack->p = p += 2;
        p[-1] = *pkey;
    }
    *p = *pvalue;
    splist->count++;
    return 0;
}

/* Implementation for enumerating parameters on a stack */
static int			/* ret 0 ok, 1 if EOF, or -ve err */
stack_param_enumerate(iparam_list * plist, gs_param_enumerator_t * penum,
                      gs_param_key_t * key, ref_type * type)
{
    int code;
    stack_param_list *const splist = (stack_param_list *) plist;
    int index = penum->intval;
    ref *stack_element;

    do {
        stack_element =
            ref_stack_index(splist->pstack, index + 1 + splist->skip);
        if (!stack_element)
            return 1;
    } while (index += 2, !r_has_type(stack_element, t_name));
    *type = r_type(stack_element);
    code = ref_to_key(stack_element, key, plist);
    penum->intval = index;
    return code;
}

int
stack_param_list_write(stack_param_list * plist, ref_stack_t * pstack,
                       const ref * pwanted, gs_ref_memory_t *imem)
{
    plist->u.w.write = stack_param_write;
    ref_param_write_init((iparam_list *) plist, pwanted, imem);
    plist->enumerate = stack_param_enumerate;
    plist->pstack = pstack;
    plist->skip = 0;
    plist->count = 0;
    return 0;
}

/* Implementation for getting parameters to a dictionary. */
static int
dict_param_write(iparam_list * plist, const ref * pkey, const ref * pvalue)
{
    int code =
        dict_put(&((dict_param_list *) plist)->dict, pkey, pvalue, NULL);

    return min(code, 0);
}

/* Implementation for enumerating parameters in a dictionary */
static int			/* ret 0 ok, 1 if EOF, or -ve err */
dict_param_enumerate(iparam_list * plist, gs_param_enumerator_t * penum,
                     gs_param_key_t * key, ref_type * type)
{
    ref elt[2];
    int code;
    dict_param_list *const pdlist = (dict_param_list *) plist;
    int index =
    (penum->intval != 0 ? penum->intval : dict_first(&pdlist->dict));

    index = dict_next(&pdlist->dict, index, elt);
    if (index < 0)
        return 1;
    *type = r_type(&elt[1]);
    code = ref_to_key(&elt[0], key, plist);
    penum->intval = index;
    return code;
}

int
dict_param_list_write(dict_param_list *plist, ref *pdict, const ref *pwanted,
                      gs_ref_memory_t *imem)
{
    check_dict_write(*pdict);
    plist->u.w.write = dict_param_write;
    plist->enumerate = dict_param_enumerate;
    ref_param_write_init((iparam_list *) plist, pwanted, imem);
    plist->dict = *pdict;
    return 0;
}

/* Implementation for getting parameters to an indexed array. */
/* Note that this is now internal, since it only handles "new" arrays. */
static int
array_new_indexed_param_write(iparam_list * iplist, const ref * pkey,
                          const ref * pvalue)
{
    const ref *const arr = &((dict_param_list *)iplist)->dict;
    ref *eltp;

    if (!r_has_type(pkey, t_integer))
        return_error(gs_error_typecheck);
    check_int_ltu(*pkey, r_size(arr));
    store_check_dest(arr, pvalue);
    eltp = arr->value.refs + pkey->value.intval;
    /* ref_assign_new(eltp, pvalue); */
    ref_assign(eltp, pvalue);
    r_set_attrs(eltp, imemory_new_mask(iplist->ref_memory));
    return 0;
}
static int
array_new_indexed_plist_write(dict_param_list * plist, ref * parray,
                              const ref * pwanted, gs_ref_memory_t *imem)
{
    check_array(*parray);
    check_write(*parray);
    plist->u.w.write = array_new_indexed_param_write;
    ref_param_write_init((iparam_list *) plist, pwanted, imem);
    plist->dict = *parray;
    plist->int_keys = true;
    return 0;
}

/* ================ Reading refs to parameters ================ */

/* ---------------- Generic reading procedures ---------------- */

static param_proc_begin_xmit_collection(ref_param_begin_read_collection);
static param_proc_end_xmit_collection(ref_param_end_read_collection);
static param_proc_xmit_typed(ref_param_read_typed);

/*static param_proc_next_key(ref_param_get_next_key); already dec'ld above */
static param_proc_get_policy(ref_param_read_get_policy);
static param_proc_signal_error(ref_param_read_signal_error);
static param_proc_commit(ref_param_read_commit);
static const gs_param_list_procs ref_read_procs =
{
    ref_param_read_typed,
    ref_param_begin_read_collection,
    ref_param_end_read_collection,
    ref_param_get_next_key,
    NULL,			/* request */
    NULL,			/* requested */
    ref_param_read_get_policy,
    ref_param_read_signal_error,
    ref_param_read_commit
};
static int ref_param_read(iparam_list *, gs_param_name,
                           iparam_loc *, int);
static int ref_param_read_string_value(gs_memory_t *mem,
                                        const iparam_loc *,
                                        gs_param_string *);
static int ref_param_read_array(iparam_list *, gs_param_name,
                                 iparam_loc *);

#define iparam_note_error(loc, code)\
  gs_note_error(*(loc).presult = code)
#define iparam_check_type(loc, typ)\
  if ( !r_has_type((loc).pvalue, typ) )\
    return iparam_note_error(loc, gs_error_typecheck)
#define iparam_check_read(loc)\
  if ( !r_has_attr((loc).pvalue, a_read) )\
    return iparam_note_error(loc, gs_error_invalidaccess)

static int
ref_param_read_int_array(gs_param_list * plist, gs_param_name pkey,
                         gs_param_int_array * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc;
    int code = ref_param_read_array(iplist, pkey, &loc);
    int *piv;
    uint size;
    long i;

    if (code != 0)
        return code;
    size = r_size(loc.pvalue);
    piv = (int *)gs_alloc_byte_array(plist->memory, size, sizeof(int),
                                     "ref_param_read_int_array");

    if (piv == 0)
        return_error(gs_error_VMerror);
    for (i = 0; i < size; i++) {
        ref elt;

        array_get(plist->memory, loc.pvalue, i, &elt);
        if (!r_has_type(&elt, t_integer)) {
            code = gs_note_error(gs_error_typecheck);
            break;
        }
        piv[i] = (int)elt.value.intval;
    }
    if (code < 0) {
        gs_free_object(plist->memory, piv, "ref_param_read_int_array");
        return (*loc.presult = code);
    }
    pvalue->data = piv;
    pvalue->size = size;
    pvalue->persistent = true;
    return 0;
}
static int
ref_param_read_float_array(gs_param_list * plist, gs_param_name pkey,
                           gs_param_float_array * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc;
    ref aref, elt;
    int code = ref_param_read_array(iplist, pkey, &loc);
    float *pfv;
    uint size;
    long i;

    if (code != 0)
        return code;
    size = r_size(loc.pvalue);
    pfv = (float *)gs_alloc_byte_array(plist->memory, size, sizeof(float),
                                       "ref_param_read_float_array");

    if (pfv == 0)
        return_error(gs_error_VMerror);
    aref = *loc.pvalue;
    loc.pvalue = &elt;
    for (i = 0; code >= 0 && i < size; i++) {
        array_get(plist->memory, &aref, i, &elt);
        code = float_param(&elt, pfv + i);
    }
    if (code < 0) {
        gs_free_object(plist->memory, pfv, "ref_read_float_array_param");
        return (*loc.presult = code);
    }
    pvalue->data = pfv;
    pvalue->size = size;
    pvalue->persistent = true;
    return 0;
}
static int
ref_param_read_string_array(gs_param_list * plist, gs_param_name pkey,
                            gs_param_string_array * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc;
    ref aref;
    int code = ref_param_read_array(iplist, pkey, &loc);
    gs_param_string *psv;
    uint size;
    long i;

    if (code != 0)
        return code;
    size = r_size(loc.pvalue);
    psv = (gs_param_string *)
        gs_alloc_byte_array(plist->memory, size, sizeof(gs_param_string),
                            "ref_param_read_string_array");
    if (psv == 0)
        return_error(gs_error_VMerror);
    aref = *loc.pvalue;
    if (r_has_type(&aref, t_array)) {
        for (i = 0; code >= 0 && i < size; i++) {
            loc.pvalue = aref.value.refs + i;
            code = ref_param_read_string_value(plist->memory, &loc, psv + i);
        }
    } else {
        ref elt;

        loc.pvalue = &elt;
        for (i = 0; code >= 0 && i < size; i++) {
            array_get(plist->memory, &aref, i, &elt);
            code = ref_param_read_string_value(plist->memory, &loc, psv + i);
        }
    }
    if (code < 0) {
        gs_free_object(plist->memory, psv, "ref_param_read_string_array");
        return (*loc.presult = code);
    }
    pvalue->data = psv;
    pvalue->size = size;
    pvalue->persistent = true;
    return 0;
}
static int
ref_param_begin_read_collection(gs_param_list * plist, gs_param_name pkey,
                                gs_param_dict * pvalue,
                                gs_param_collection_type_t coll_type)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc;
    bool int_keys = coll_type != 0;
    int code = ref_param_read(iplist, pkey, &loc, -1);
    dict_param_list *dlist;

    if (code != 0)
        return code;
    dlist = (dict_param_list *)
        gs_alloc_bytes(plist->memory, size_of(dict_param_list),
                       "ref_param_begin_read_collection");
    if (dlist == 0)
        return_error(gs_error_VMerror);
    if (r_has_type(loc.pvalue, t_dictionary)) {
        code = dict_param_list_read(dlist, loc.pvalue, NULL, false,
                                    iplist->ref_memory);
        dlist->int_keys = int_keys;
        if (code >= 0)
            pvalue->size = dict_length(loc.pvalue);
    } else if (int_keys && r_is_array(loc.pvalue)) {
        code = array_indexed_param_list_read(dlist, loc.pvalue, NULL, false,
                                             iplist->ref_memory);
        if (code >= 0)
            pvalue->size = r_size(loc.pvalue);
    } else
        code = gs_note_error(gs_error_typecheck);
    if (code < 0) {
        gs_free_object(plist->memory, dlist, "ref_param_begin_write_collection");
        return iparam_note_error(loc, code);
    }
    pvalue->list = (gs_param_list *) dlist;
    return 0;
}
static int
ref_param_end_read_collection(gs_param_list * plist, gs_param_name pkey,
                              gs_param_dict * pvalue)
{
    iparam_list_release((dict_param_list *) pvalue->list);
    gs_free_object(plist->memory, pvalue->list,
                   "ref_param_end_read_collection");
    return 0;
}
static int
ref_param_read_typed(gs_param_list * plist, gs_param_name pkey,
                     gs_param_typed_value * pvalue)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc;
    ref elt;
    int code = ref_param_read(iplist, pkey, &loc, -1);

    if (code != 0)
        return code;
    switch (r_type(loc.pvalue)) {
        case t_array:
        case t_mixedarray:
        case t_shortarray:
            iparam_check_read(loc);
            if (r_size(loc.pvalue) <= 0) {
                /* 0-length array; can't get type info */
                pvalue->type = gs_param_type_array;
                pvalue->value.d.list = 0;
                pvalue->value.d.size = 0;
                return 0;
            }
            /*
             * We have to guess at the array type.  First we guess based
             * on the type of the first element of the array.  If that
             * fails, we try again with more general types.
             */
            array_get(plist->memory, loc.pvalue, 0, &elt);
            switch (r_type(&elt)) {
                case t_integer:
                    pvalue->type = gs_param_type_int_array;
                    code = ref_param_read_int_array(plist, pkey,
                                                    &pvalue->value.ia);
                    if (code != gs_error_typecheck)
                        return code;
                    /* This might be a float array.  Fall through. */
                    *loc.presult = 0;  /* reset error */
                case t_real:
                    pvalue->type = gs_param_type_float_array;
                    return ref_param_read_float_array(plist, pkey,
                                                      &pvalue->value.fa);
                case t_string:
                    pvalue->type = gs_param_type_string_array;
                    return ref_param_read_string_array(plist, pkey,
                                                       &pvalue->value.sa);
                case t_name:
                    pvalue->type = gs_param_type_name_array;
                    return ref_param_read_string_array(plist, pkey,
                                                       &pvalue->value.na);
                default:
                    break;
            }
            return gs_note_error(gs_error_typecheck);
        case t_boolean:
            pvalue->type = gs_param_type_bool;
            pvalue->value.b = loc.pvalue->value.boolval;
            return 0;
        case t_dictionary:
            code = ref_param_begin_read_collection(plist, pkey,
                            &pvalue->value.d, gs_param_collection_dict_any);
            if (code < 0)
                return code;
            pvalue->type = gs_param_type_dict;

            /* fixup new dict's type & int_keys field if contents have int keys */
            {
                gs_param_enumerator_t enumr;
                gs_param_key_t key;
                ref_type keytype;
                dict_param_list *dlist = (dict_param_list *) pvalue->value.d.list;

                param_init_enumerator(&enumr);
                if (!(*(dlist->enumerate))
                    ((iparam_list *) dlist, &enumr, &key, &keytype)
                    && keytype == t_integer) {
                    dlist->int_keys = 1;
                    pvalue->type = gs_param_type_dict_int_keys;
                }
            }
            return 0;
        case t_integer:
            pvalue->type = gs_param_type_long;
            pvalue->value.l = loc.pvalue->value.intval;
            return 0;
        case t_name:
            pvalue->type = gs_param_type_name;
            return ref_param_read_string_value(plist->memory, &loc, &pvalue->value.n);
        case t_null:
            pvalue->type = gs_param_type_null;
            return 0;
        case t_real:
            pvalue->value.f = loc.pvalue->value.realval;
            pvalue->type = gs_param_type_float;
            return 0;
        case t_string:
        case t_astruct:
            pvalue->type = gs_param_type_string;
            return ref_param_read_string_value(plist->memory, &loc, &pvalue->value.s);
        default:
            break;
    }
    return gs_note_error(gs_error_typecheck);
}

static int
ref_param_read_get_policy(gs_param_list * plist, gs_param_name pkey)
{
    iparam_list *const iplist = (iparam_list *) plist;
    ref *pvalue;

    if (!(r_has_type(&iplist->u.r.policies, t_dictionary) &&
          dict_find_string(&iplist->u.r.policies, pkey, &pvalue) > 0 &&
          r_has_type(pvalue, t_integer))
        )
        return gs_param_policy_ignore;
    return (int)pvalue->value.intval;
}
static int
ref_param_read_signal_error(gs_param_list * plist, gs_param_name pkey, int code)
{
    iparam_list *const iplist = (iparam_list *) plist;
    iparam_loc loc = {0};

    ref_param_read(iplist, pkey, &loc, -1);
    if (loc.presult)
        *loc.presult = code;
    switch (ref_param_read_get_policy(plist, pkey)) {
        case gs_param_policy_ignore:
            return 0;
        case gs_param_policy_consult_user:
            return_error(gs_error_configurationerror);
        default:
            return code;
    }
}
static int
ref_param_read_commit(gs_param_list * plist)
{
    iparam_list *const iplist = (iparam_list *) plist;
    int i;
    int ecode = 0;

    if (!iplist->u.r.require_all)
        return 0;
    /* Check to make sure that all parameters were actually read. */
    for (i = 0; i < iplist->count; ++i)
        if (iplist->results[i] == 0)
            iplist->results[i] = ecode = gs_note_error(gs_error_undefined);
    return ecode;
}
static int
ref_param_get_next_key(gs_param_list * plist, gs_param_enumerator_t * penum,
                       gs_param_key_t * key)
{
    ref_type keytype;		/* result not needed here */
    iparam_list *const pilist = (iparam_list *) plist;

    return (*pilist->enumerate) (pilist, penum, key, &keytype);
}

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

/* Read a string value. */
static int
ref_param_read_string_value(gs_memory_t *mem, const iparam_loc * ploc, gs_param_string * pvalue)
{
    const ref *pref = ploc->pvalue;

    switch (r_type(pref)) {
        case t_name: {
            ref nref;

            name_string_ref(mem, pref, &nref);
            pvalue->data = nref.value.const_bytes;
            pvalue->size = r_size(&nref);
            pvalue->persistent = true;
        }
            break;
        case t_string:
            iparam_check_read(*ploc);
            pvalue->data = pref->value.const_bytes;
            pvalue->size = r_size(pref);
            pvalue->persistent = false;
            break;
        case t_astruct:
            /* Note: technically, instead of the "mem" argument, we
               should be using the plists's ref_memory. However, in a
               simple call to .putdeviceparams, they are identical. */
            iparam_check_read(*ploc);
            if (gs_object_type(mem, pref->value.pstruct) != &st_bytes)
                return iparam_note_error(*ploc, gs_error_typecheck);
            pvalue->data = r_ptr(pref, byte);
            pvalue->size = gs_object_size(mem, pref->value.pstruct);
            pvalue->persistent = false;
            break;
        default:
            return iparam_note_error(*ploc, gs_error_typecheck);
    }
    return 0;
}

/* Read an array (or packed array) parameter. */
static int
ref_param_read_array(iparam_list * plist, gs_param_name pkey, iparam_loc * ploc)
{
    int code = ref_param_read(plist, pkey, ploc, -1);

    if (code != 0)
        return code;
    if (!r_is_array(ploc->pvalue))
        return iparam_note_error(*ploc, gs_error_typecheck);
    iparam_check_read(*ploc);
    return 0;
}

/* Generic routine for reading a ref parameter. */
static int
ref_param_read(iparam_list * plist, gs_param_name pkey, iparam_loc * ploc,
               int type)
{
    iparam_list *const iplist = (iparam_list *) plist;
    ref kref;
    int code = ref_param_key(plist, pkey, &kref);

    if (code < 0)
        return code;
    code = (*plist->u.r.read) (iplist, &kref, ploc);
    if (code != 0)
        return code;
    if (type >= 0)
        iparam_check_type(*ploc, type);
    return 0;
}

/* ---------------- Implementations ---------------- */

/* Implementation for putting parameters from an empty collection. */
static int
empty_param_read(iparam_list * plist, const ref * pkey, iparam_loc * ploc)
{
    return 1;
}

/* Initialize for reading parameters. */
static int
ref_param_read_init(iparam_list * plist, uint count, const ref * ppolicies,
                    bool require_all, gs_ref_memory_t *imem)
{
    gs_param_list_init((gs_param_list *)plist, &ref_read_procs,
                       (gs_memory_t *)imem);
    plist->ref_memory = imem;
    if (ppolicies == 0)
        make_null(&plist->u.r.policies);
    else
        plist->u.r.policies = *ppolicies;
    plist->u.r.require_all = require_all;
    plist->count = count;
    plist->results = (int *)
        gs_alloc_byte_array(plist->memory, count, sizeof(int),
                            "ref_param_read_init");

    if (plist->results == 0)
        return_error(gs_error_VMerror);
    memset(plist->results, 0, count * sizeof(int));

    plist->int_keys = false;
    return 0;
}

/* Implementation for putting parameters from an indexed array. */
static int
array_indexed_param_read(iparam_list * plist, const ref * pkey, iparam_loc * ploc)
{
    ref *const arr = &((dict_param_list *) plist)->dict;

    check_type(*pkey, t_integer);
    if (pkey->value.intval < 0 || pkey->value.intval >= r_size(arr))
        return 1;
    ploc->pvalue = arr->value.refs + pkey->value.intval;
    ploc->presult = &plist->results[pkey->value.intval];
    *ploc->presult = 1;
    return 0;
}
int
array_indexed_param_list_read(dict_param_list * plist, const ref * parray,
                              const ref * ppolicies, bool require_all,
                              gs_ref_memory_t *ref_memory)
{
    iparam_list *const iplist = (iparam_list *) plist;
    int code;

    check_read_type(*parray, t_array);
    plist->u.r.read = array_indexed_param_read;
    plist->dict = *parray;
    code = ref_param_read_init(iplist, r_size(parray), ppolicies,
                               require_all, ref_memory);
    plist->int_keys = true;
    return code;
}

/* Implementation for putting parameters from an array. */
static int
array_param_read(iparam_list * plist, const ref * pkey, iparam_loc * ploc)
{
    ref *bot = ((array_param_list *) plist)->bot;
    ref *ptr = bot;
    ref *top = ((array_param_list *) plist)->top;

    for (; ptr < top; ptr += 2) {
        if (r_has_type(ptr, t_name) && name_eq(ptr, pkey)) {
            ploc->pvalue = ptr + 1;
            ploc->presult = &plist->results[ptr - bot];
            *ploc->presult = 1;
            return 0;
        }
    }
    return 1;
}

/* Implementation for enumerating parameters in an array */
static int			/* ret 0 ok, 1 if EOF, or -ve err */
array_param_enumerate(iparam_list * plist, gs_param_enumerator_t * penum,
                      gs_param_key_t * key, ref_type * type)
{
    int index = penum->intval;
    ref *bot = ((array_param_list *) plist)->bot;
    ref *ptr = bot + index;
    ref *top = ((array_param_list *) plist)->top;

    for (; ptr < top; ptr += 2) {
        index += 2;

        if (r_has_type(ptr, t_name)) {
            int code = ref_to_key(ptr, key, plist);

            *type = r_type(ptr);
            penum->intval = index;
            return code;
        }
    }
    return 1;
}

int
array_param_list_read(array_param_list * plist, ref * bot, uint count,
                      const ref * ppolicies, bool require_all,
                      gs_ref_memory_t *imem)
{
    iparam_list *const iplist = (iparam_list *) plist;

    if (count & 1)
        return_error(gs_error_rangecheck);
    plist->u.r.read = array_param_read;
    plist->enumerate = array_param_enumerate;
    plist->bot = bot;
    plist->top = bot + count;
    return ref_param_read_init(iplist, count, ppolicies, require_all, imem);
}

/* Implementation for putting parameters from a stack. */
static int
stack_param_read(iparam_list * plist, const ref * pkey, iparam_loc * ploc)
{
    stack_param_list *const splist = (stack_param_list *) plist;
    ref_stack_t *pstack = splist->pstack;

    /* This implementation is slow, but it probably doesn't matter. */
    uint index = splist->skip + 1;
    uint count = splist->count;

    for (; count; count--, index += 2) {
        const ref *p = ref_stack_index(pstack, index);

        if (r_has_type(p, t_name) && name_eq(p, pkey)) {
            ploc->pvalue = ref_stack_index(pstack, index - 1);
            ploc->presult = &plist->results[count - 1];
            *ploc->presult = 1;
            return 0;
        }
    }
    return 1;
}
int
stack_param_list_read(stack_param_list * plist, ref_stack_t * pstack,
                      uint skip, const ref * ppolicies, bool require_all,
                      gs_ref_memory_t *imem)
{
    iparam_list *const iplist = (iparam_list *) plist;
    uint count = ref_stack_counttomark(pstack);

    if (count == 0)
        return_error(gs_error_unmatchedmark);
    count -= skip + 1;
    if (count & 1)
        return_error(gs_error_rangecheck);
    plist->u.r.read = stack_param_read;
    plist->enumerate = stack_param_enumerate;
    plist->pstack = pstack;
    plist->skip = skip;
    return ref_param_read_init(iplist, count >> 1, ppolicies, require_all, imem);
}

/* Implementation for putting parameters from a dictionary. */
static int
dict_param_read(iparam_list * plist, const ref * pkey, iparam_loc * ploc)
{
    ref const *spdict = &((dict_param_list *) plist)->dict;
    int code = dict_find(spdict, pkey, &ploc->pvalue);

    if (code != 1)
        return 1;
    ploc->presult =
        &plist->results[dict_value_index(spdict, ploc->pvalue)];
    *ploc->presult = 1;
    return 0;
}
int
dict_param_list_read(dict_param_list * plist, const ref * pdict,
                     const ref * ppolicies, bool require_all,
                     gs_ref_memory_t *imem)
{
    iparam_list *const iplist = (iparam_list *) plist;
    uint count;

    if (pdict == 0) {
        plist->u.r.read = empty_param_read;
        count = 0;
    } else {
        check_dict_read(*pdict);
        plist->u.r.read = dict_param_read;
        plist->dict = *pdict;
        count = dict_max_index(pdict) + 1;
    }
    plist->enumerate = dict_param_enumerate;
    return ref_param_read_init(iplist, count, ppolicies, require_all, imem);
}
