/*
 * call-seq: from_state(opts)
 *
 * Creates a State object from _opts_, which ought to be Hash to create a
 * new State instance configured by _opts_, something else to create an
 * unconfigured instance. If _opts_ is a State object, it is just returned.
 */
static VALUE cState_from_state_s(VALUE self, VALUE opts)
{
    if (rb_obj_is_kind_of(opts, self)) {
        return opts;
    } else if (rb_obj_is_kind_of(opts, rb_cHash)) {
        return rb_funcall(self, i_new, 1, opts);
    } else {
        return rb_funcall(self, i_new, 0);
    }
}

/*
 * call-seq: new(opts = {})
 *
 * Instantiates a new State object, configured by _opts_.
 *
 * _opts_ can have the following keys:
 *
 * * *indent*: a string used to indent levels (default: ''),
 * * *space*: a string that is put after, a : or , delimiter (default: ''),
 * * *space_before*: a string that is put before a : pair delimiter (default: ''),
 * * *object_nl*: a string that is put at the end of a JSON object (default: ''), 
 * * *array_nl*: a string that is put at the end of a JSON array (default: ''),
 * * *check_circular*: true if checking for circular data structures
 *   should be done, false (the default) otherwise.
 * * *allow_nan*: true if NaN, Infinity, and -Infinity should be
 *   generated, otherwise an exception is thrown, if these values are
 *   encountered. This options defaults to false.
 */
static VALUE cState_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE opts;
    GET_STATE(self);

    rb_scan_args(argc, argv, "01", &opts);
    state->indent = rb_str_new2("");
    state->space = rb_str_new2("");
    state->space_before = rb_str_new2("");
    state->array_nl = rb_str_new2("");
    state->object_nl = rb_str_new2("");
    if (NIL_P(opts)) {
        state->check_circular = 1;
        state->allow_nan = 0;
        state->max_nesting = 19;
    } else {
        cState_configure(self, opts);
    }
    state->seen = rb_hash_new();
    state->memo = Qnil;
    state->depth = INT2FIX(0);
    return self;
}

/*
 * call-seq: allow_nan?
 *
 * Returns true, if NaN, Infinity, and -Infinity should be generated, otherwise
 * returns false.
 */
static VALUE cState_allow_nan_p(VALUE self)
{
    GET_STATE(self);
    return state->allow_nan ? Qtrue : Qfalse;
}

/*
 * call-seq: array_nl()
 *
 * This string is put at the end of a line that holds a JSON array.
 */
static VALUE cState_array_nl(VALUE self)
{
    GET_STATE(self);
    return state->array_nl;
}

/*
 * call-seq: array_nl=(array_nl)
 *
 * This string is put at the end of a line that holds a JSON array.
 */
static VALUE cState_array_nl_set(VALUE self, VALUE array_nl)
{
    GET_STATE(self);
    Check_Type(array_nl, T_STRING);
    return state->array_nl = array_nl;
}

/*
 * call-seq: check_circular?
 *
 * Returns true, if circular data structures should be checked,
 * otherwise returns false.
 */
static VALUE cState_check_circular_p(VALUE self)
{
    GET_STATE(self);
    return state->check_circular ? Qtrue : Qfalse;
}

/*
 * call-seq: forget(object)
 *
 * Forget _object_ for this generating run.
 */
static VALUE cState_forget(VALUE self, VALUE object)
{
    GET_STATE(self);
    return rb_hash_delete(state->seen, rb_obj_id(object));
}

/*
 * call-seq: indent()
 *
 * This string is used to indent levels in the JSON text.
 */
static VALUE cState_indent(VALUE self)
{
    GET_STATE(self);
    return state->indent;
}

/*
 * call-seq: indent=(indent)
 *
 * This string is used to indent levels in the JSON text.
 */
static VALUE cState_indent_set(VALUE self, VALUE indent)
{
    GET_STATE(self);
    Check_Type(indent, T_STRING);
    return state->indent = indent;
}

/*
 * call-seq: max_nesting
 *
 * This integer returns the maximum level of data structure nesting in
 * the generated JSON, max_nesting = 0 if no maximum is checked.
 */
static VALUE cState_max_nesting(VALUE self)
{
    GET_STATE(self);
    return LONG2FIX(state->max_nesting);
}

/*
 * call-seq: max_nesting=(depth)
 *
 * This sets the maximum level of data structure nesting in the generated JSON
 * to the integer depth, max_nesting = 0 if no maximum should be checked.
 */
static VALUE cState_max_nesting_set(VALUE self, VALUE depth)
{
    GET_STATE(self);
    Check_Type(depth, T_FIXNUM);
    state->max_nesting = FIX2LONG(depth);
    return Qnil;
}

/*
 * call-seq: object_nl()
 *
 * This string is put at the end of a line that holds a JSON object (or
 * Hash).
 */
static VALUE cState_object_nl(VALUE self)
{
    GET_STATE(self);
    return state->object_nl;
}

/*
 * call-seq: object_nl=(object_nl)
 *
 * This string is put at the end of a line that holds a JSON object (or
 * Hash).
 */
static VALUE cState_object_nl_set(VALUE self, VALUE object_nl)
{
    GET_STATE(self);
    Check_Type(object_nl, T_STRING);
    return state->object_nl = object_nl;
}

/*
 * call-seq: remember(object)
 *
 * Remember _object_, to find out if it was already encountered (if a cyclic
 * data structure is rendered). 
 */
static VALUE cState_remember(VALUE self, VALUE object)
{
    GET_STATE(self);
    return rb_hash_aset(state->seen, rb_obj_id(object), Qtrue);
}

/*
 * call-seq: seen?(object)
 *
 * Returns _true_, if _object_ was already seen during this generating run. 
 */
static VALUE cState_seen_p(VALUE self, VALUE object)
{
    GET_STATE(self);
    return rb_hash_aref(state->seen, rb_obj_id(object));
}

/*
 * call-seq: space()
 *
 * This string is used to insert a space between the tokens in a JSON
 * string.
 */
static VALUE cState_space(VALUE self)
{
    GET_STATE(self);
    return state->space;
}

/*
 * call-seq: space=(space)
 *
 * This string is used to insert a space between the tokens in a JSON
 * string.
 */
static VALUE cState_space_set(VALUE self, VALUE space)
{
    GET_STATE(self);
    Check_Type(space, T_STRING);
    return state->space = space;
}

/*
 * call-seq: space_before()
 *
 * This string is used to insert a space before the ':' in JSON objects.
 */
static VALUE cState_space_before(VALUE self)
{
    GET_STATE(self);
    return state->space_before;
}

/*
 * call-seq: space_before=(space_before)
 *
 * This string is used to insert a space before the ':' in JSON objects.
 */
static VALUE cState_space_before_set(VALUE self, VALUE space_before)
{
    GET_STATE(self);
    Check_Type(space_before, T_STRING);
    return state->space_before = space_before;
}

/*
 * call-seq: to_h
 *
 * Returns the configuration instance variables as a hash, that can be
 * passed to the configure method.
 */
static VALUE cState_to_h(VALUE self)
{
    VALUE result = rb_hash_new();
    GET_STATE(self);
    rb_hash_aset(result, ID2SYM(i_indent), state->indent);
    rb_hash_aset(result, ID2SYM(i_space), state->space);
    rb_hash_aset(result, ID2SYM(i_space_before), state->space_before);
    rb_hash_aset(result, ID2SYM(i_object_nl), state->object_nl);
    rb_hash_aset(result, ID2SYM(i_array_nl), state->array_nl);
    rb_hash_aset(result, ID2SYM(i_check_circular), state->check_circular ? Qtrue : Qfalse);
    rb_hash_aset(result, ID2SYM(i_allow_nan), state->allow_nan ? Qtrue : Qfalse);
    rb_hash_aset(result, ID2SYM(i_max_nesting), LONG2FIX(state->max_nesting));
    return result;
}