duktape-1.5.2/src-separate/duk_bi_pointer.c

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/*
 *  Pointer built-ins
 */
 
#include "duk_internal.h"
 
/*
 *  Constructor
 */
 
DUK_INTERNAL duk_ret_t duk_bi_pointer_constructor(duk_context *ctx) {
    /* XXX: this behavior is quite useless now; it would be nice to be able
     * to create pointer values from e.g. numbers or strings.  Numbers are
     * problematic on 64-bit platforms though.  Hex encoded strings?
     */
    if (duk_get_top(ctx) == 0) {
        duk_push_pointer(ctx, NULL);
    } else {
        duk_to_pointer(ctx, 0);
    }
    DUK_ASSERT(duk_is_pointer(ctx, 0));
    duk_set_top(ctx, 1);
 
    if (duk_is_constructor_call(ctx)) {
        duk_push_object_helper(ctx,
                               DUK_HOBJECT_FLAG_EXTENSIBLE |
                               DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_POINTER),
                               DUK_BIDX_POINTER_PROTOTYPE);
 
        /* Pointer object internal value is immutable */
        duk_dup(ctx, 0);
        duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);
    }
    /* Note: unbalanced stack on purpose */
 
    return 1;
}
 
/*
 *  toString(), valueOf()
 */
 
DUK_INTERNAL duk_ret_t duk_bi_pointer_prototype_tostring_shared(duk_context *ctx) {
    duk_tval *tv;
    duk_small_int_t to_string = duk_get_current_magic(ctx);
 
    duk_push_this(ctx);
    tv = duk_require_tval(ctx, -1);
    DUK_ASSERT(tv != NULL);
 
    if (DUK_TVAL_IS_POINTER(tv)) {
        /* nop */
    } else if (DUK_TVAL_IS_OBJECT(tv)) {
        duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
        DUK_ASSERT(h != NULL);
 
        /* Must be a "pointer object", i.e. class "Pointer" */
        if (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_POINTER) {
            goto type_error;
        }
 
        duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_VALUE);
    } else {
        goto type_error;
    }
 
    if (to_string) {
        duk_to_string(ctx, -1);
    }
    return 1;
 
 type_error:
    return DUK_RET_TYPE_ERROR;
}