/* dump_object.c
 * Copyright (c) 2012, 2017, Peter Ohler
 * All rights reserved.
 */

#include "code.h"
#include "dump.h"
#include "rails.h"

// Workaround in case INFINITY is not defined in math.h or if the OS is CentOS
#define OJ_INFINITY (1.0/0.0)

bool	oj_use_hash_alt = false;
bool	oj_use_array_alt = false;

static bool	use_struct_alt = false;
static bool	use_exception_alt = false;
static bool	use_bignum_alt = false;

static void
raise_json_err(const char *msg, const char *err_classname) {
    rb_raise(oj_get_json_err_class(err_classname), "%s", msg);
}

static void
dump_obj_classname(const char *classname, int depth, Out out) {
    int		d2 = depth + 1;
    size_t	len = strlen(classname);
    size_t	sep_len = out->opts->dump_opts.before_size + out->opts->dump_opts.after_size + 2;
    size_t	size = d2 * out->indent + 10 + len + out->opts->create_id_len + sep_len;

    assure_size(out, size);
    *out->cur++ = '{';
    fill_indent(out, d2);
    *out->cur++ = '"';
    memcpy(out->cur, out->opts->create_id, out->opts->create_id_len);
    out->cur += out->opts->create_id_len;
    *out->cur++ = '"';
    if (0 < out->opts->dump_opts.before_size) {
	strcpy(out->cur, out->opts->dump_opts.before_sep);
	out->cur += out->opts->dump_opts.before_size;
    }
    *out->cur++ = ':';
    if (0 < out->opts->dump_opts.after_size) {
	strcpy(out->cur, out->opts->dump_opts.after_sep);
	out->cur += out->opts->dump_opts.after_size;
    }
    *out->cur++ = '"';
    memcpy(out->cur, classname, len);
    out->cur += len;
    *out->cur++ = '"';
}

static void
dump_values_array(VALUE *values, int depth, Out out) {
    size_t	size;
    int		d2 = depth + 1;

    assure_size(out, d2 * out->indent + 3);
    *out->cur++ = '[';
    if (Qundef == *values) {
	*out->cur++ = ']';
    } else {
	if (out->opts->dump_opts.use) {
	    size = d2 * out->opts->dump_opts.indent_size + out->opts->dump_opts.array_size + 2;
	} else {
	    size = d2 * out->indent + 3;
	}
	if (out->opts->dump_opts.use) {
	    size += out->opts->dump_opts.array_size;
	    size += out->opts->dump_opts.indent_size;
	}
	for (; Qundef != *values; values++) {
	    assure_size(out, size);
	    if (out->opts->dump_opts.use) {
		if (0 < out->opts->dump_opts.array_size) {
		    strcpy(out->cur, out->opts->dump_opts.array_nl);
		    out->cur += out->opts->dump_opts.array_size;
		}
		if (0 < out->opts->dump_opts.indent_size) {
		    int	i;
		    for (i = d2; 0 < i; i--) {
			strcpy(out->cur, out->opts->dump_opts.indent_str);
			out->cur += out->opts->dump_opts.indent_size;
		    }
		}
	    } else {
		fill_indent(out, d2);
	    }
	    oj_dump_compat_val(*values, d2, out, true);
	    if (Qundef != *(values + 1)) {
		*out->cur++ = ',';
	    }
	}
	assure_size(out, size);
	if (out->opts->dump_opts.use) {
	    if (0 < out->opts->dump_opts.array_size) {
		strcpy(out->cur, out->opts->dump_opts.array_nl);
		out->cur += out->opts->dump_opts.array_size;
	    }
	    if (0 < out->opts->dump_opts.indent_size) {
		int	i;

		for (i = depth; 0 < i; i--) {
		    strcpy(out->cur, out->opts->dump_opts.indent_str);
		    out->cur += out->opts->dump_opts.indent_size;
		}
	    }
	} else {
	    fill_indent(out, depth);
	}
	*out->cur++ = ']';
    }
}

static void
dump_to_json(VALUE obj, Out out) {
    volatile VALUE	rs;
    const char		*s;
    int			len;

#if HAS_METHOD_ARITY
    if (0 == rb_obj_method_arity(obj, oj_to_json_id)) {
	rs = rb_funcall(obj, oj_to_json_id, 0);
    } else {
	rs = rb_funcall2(obj, oj_to_json_id, out->argc, out->argv);
    }
#else
    rs = rb_funcall2(obj, oj_to_json_id, out->argc, out->argv);
#endif

    s = rb_string_value_ptr((VALUE*)&rs);
    len = (int)RSTRING_LEN(rs);

    assure_size(out, len + 1);
    memcpy(out->cur, s, len);
    out->cur += len;
    *out->cur = '\0';
}

static void
dump_array(VALUE a, int depth, Out out, bool as_ok) {
    size_t	size;
    int		i, cnt;
    int		d2 = depth + 1;
    long	id = oj_check_circular(a, out);

    if (0 > id) {
	raise_json_err("Too deeply nested", "NestingError");
	return;
    }
    if (as_ok && !oj_use_hash_alt && rb_obj_class(a) != rb_cArray && rb_respond_to(a, oj_to_json_id)) {
	dump_to_json(a, out);
	return;
    }	
    cnt = (int)RARRAY_LEN(a);
    *out->cur++ = '[';
    assure_size(out, 2);
    if (0 == cnt) {
	*out->cur++ = ']';
    } else {
	if (out->opts->dump_opts.use) {
	    size = d2 * out->opts->dump_opts.indent_size + out->opts->dump_opts.array_size + 1;
	} else {
	    size = d2 * out->indent + 2;
	}
	cnt--;
	for (i = 0; i <= cnt; i++) {
	    assure_size(out, size);
	    if (out->opts->dump_opts.use) {
		if (0 < out->opts->dump_opts.array_size) {
		    strcpy(out->cur, out->opts->dump_opts.array_nl);
		    out->cur += out->opts->dump_opts.array_size;
		}
		if (0 < out->opts->dump_opts.indent_size) {
		    int	i;
		    for (i = d2; 0 < i; i--) {
			strcpy(out->cur, out->opts->dump_opts.indent_str);
			out->cur += out->opts->dump_opts.indent_size;
		    }
		}
	    } else {
		fill_indent(out, d2);
	    }
	    oj_dump_compat_val(rb_ary_entry(a, i), d2, out, true);
	    if (i < cnt) {
		*out->cur++ = ',';
	    }
	}
	size = depth * out->indent + 1;
	assure_size(out, size);
	if (out->opts->dump_opts.use) {
	    if (0 < out->opts->dump_opts.array_size) {
		strcpy(out->cur, out->opts->dump_opts.array_nl);
		out->cur += out->opts->dump_opts.array_size;
	    }
	    if (0 < out->opts->dump_opts.indent_size) {
		int	i;

		for (i = depth; 0 < i; i--) {
		    strcpy(out->cur, out->opts->dump_opts.indent_str);
		    out->cur += out->opts->dump_opts.indent_size;
		}
	    }
	} else {
	    fill_indent(out, depth);
	}
	*out->cur++ = ']';
    }
    *out->cur = '\0';
}

static ID	_dump_id = 0;

static void
bigdecimal_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "b", 1, Qnil },
	{ NULL, 0, Qnil },
    };

    if (0 == _dump_id) {
	_dump_id = rb_intern("_dump");
    }
    attrs[0].value = rb_funcall(obj, _dump_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static ID	real_id = 0;
static ID	imag_id = 0;

static void
complex_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "r", 1, Qnil },
	{ "i", 1, Qnil },
	{ NULL, 0, Qnil },
    };

    if (0 == real_id) {
	real_id = rb_intern("real");
	imag_id = rb_intern("imag");
    }
    attrs[0].value = rb_funcall(obj, real_id, 0);
    attrs[1].value = rb_funcall(obj, imag_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static ID	year_id = 0;
static ID	month_id = 0;
static ID	day_id = 0;
static ID	start_id = 0;

static void
date_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "y", 1, Qnil },
	{ "m", 1, Qnil },
	{ "d", 1, Qnil },
	{ "sg", 2, Qnil },
	{ NULL, 0, Qnil },
    };
    if (0 == year_id) {
	year_id = rb_intern("year");
	month_id = rb_intern("month");
	day_id = rb_intern("day");
	start_id = rb_intern("start");
    }
    attrs[0].value = rb_funcall(obj, year_id, 0);
    attrs[1].value = rb_funcall(obj, month_id, 0);
    attrs[2].value = rb_funcall(obj, day_id, 0);
    attrs[3].value = rb_funcall(obj, start_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static ID	hour_id = 0;
static ID	min_id = 0;
static ID	sec_id = 0;
static ID	offset_id = 0;

static void
datetime_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "y", 1, Qnil },
	{ "m", 1, Qnil },
	{ "d", 1, Qnil },
	{ "H", 1, Qnil },
	{ "M", 1, Qnil },
	{ "S", 1, Qnil },
	{ "of", 2, Qnil },
	{ "sg", 2, Qnil },
	{ NULL, 0, Qnil },
    };
    if (0 == hour_id) {
	year_id = rb_intern("year");
	month_id = rb_intern("month");
	day_id = rb_intern("day");
	hour_id = rb_intern("hour");
	min_id = rb_intern("min");
	sec_id = rb_intern("sec");
	offset_id = rb_intern("offset");
	start_id = rb_intern("start");
    }
    attrs[0].value = rb_funcall(obj, year_id, 0);
    attrs[1].value = rb_funcall(obj, month_id, 0);
    attrs[2].value = rb_funcall(obj, day_id, 0);
    attrs[3].value = rb_funcall(obj, hour_id, 0);
    attrs[4].value = rb_funcall(obj, min_id, 0);
    attrs[5].value = rb_funcall(obj, sec_id, 0);
    attrs[6].value = rb_funcall(rb_funcall(obj, offset_id, 0), oj_to_s_id, 0);
    attrs[7].value = rb_funcall(obj, start_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static ID	message_id = 0;
static ID	backtrace_id = 0;

static void
exception_alt(VALUE obj, int depth, Out out) {
    int		d3 = depth + 2;
    size_t	size = d3 * out->indent + 2;
    size_t	sep_len = out->opts->dump_opts.before_size + out->opts->dump_opts.after_size + 2;

    if (0 == message_id) {
	message_id = rb_intern("message");
	backtrace_id = rb_intern("backtrace");
    }
    dump_obj_classname(rb_class2name(rb_obj_class(obj)), depth, out);

    assure_size(out, size + sep_len + 6);
    *out->cur++ = ',';
    fill_indent(out, d3);
    *out->cur++ = '"';
    *out->cur++ = 'm';
    *out->cur++ = '"';
    if (0 < out->opts->dump_opts.before_size) {
	strcpy(out->cur, out->opts->dump_opts.before_sep);
	out->cur += out->opts->dump_opts.before_size;
    }
    *out->cur++ = ':';
    if (0 < out->opts->dump_opts.after_size) {
	strcpy(out->cur, out->opts->dump_opts.after_sep);
	out->cur += out->opts->dump_opts.after_size;
    }
    oj_dump_str(rb_funcall(obj, message_id, 0), 0, out, false);
    assure_size(out, size + sep_len + 6);
    *out->cur++ = ',';
    fill_indent(out, d3);
    *out->cur++ = '"';
    *out->cur++ = 'b';
    *out->cur++ = '"';
    if (0 < out->opts->dump_opts.before_size) {
	strcpy(out->cur, out->opts->dump_opts.before_sep);
	out->cur += out->opts->dump_opts.before_size;
    }
    *out->cur++ = ':';
    if (0 < out->opts->dump_opts.after_size) {
	strcpy(out->cur, out->opts->dump_opts.after_sep);
	out->cur += out->opts->dump_opts.after_size;
    }
    dump_array(rb_funcall(obj, backtrace_id, 0), depth, out, false);
    fill_indent(out, depth);
    *out->cur++ = '}';
    *out->cur = '\0';
}

static ID	table_id = 0;

static void
openstruct_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "t", 1, Qnil },
	{ NULL, 0, Qnil },
    };
    if (0 == table_id) {
	table_id = rb_intern("table");
    }
    attrs[0].value = rb_funcall(obj, table_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static void
range_alt(VALUE obj, int depth, Out out) {
    int		d3 = depth + 2;
    size_t	size = d3 * out->indent + 2;
    size_t	sep_len = out->opts->dump_opts.before_size + out->opts->dump_opts.after_size + 2;
    VALUE	args[] = { Qundef, Qundef, Qundef, Qundef };

    dump_obj_classname(rb_class2name(rb_obj_class(obj)), depth, out);

    assure_size(out, size + sep_len + 6);
    *out->cur++ = ',';
    fill_indent(out, d3);
    *out->cur++ = '"';
    *out->cur++ = 'a';
    *out->cur++ = '"';
    if (0 < out->opts->dump_opts.before_size) {
	strcpy(out->cur, out->opts->dump_opts.before_sep);
	out->cur += out->opts->dump_opts.before_size;
    }
    *out->cur++ = ':';
    if (0 < out->opts->dump_opts.after_size) {
	strcpy(out->cur, out->opts->dump_opts.after_sep);
	out->cur += out->opts->dump_opts.after_size;
    }
    args[0] = rb_funcall(obj, oj_begin_id, 0);
    args[1] = rb_funcall(obj, oj_end_id, 0);
    args[2] = rb_funcall(obj, oj_exclude_end_id, 0);
    dump_values_array(args, depth, out);
    fill_indent(out, depth);
    *out->cur++ = '}';
    *out->cur = '\0';
}

static ID	numerator_id = 0;
static ID	denominator_id = 0;

static void
rational_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "n", 1, Qnil },
	{ "d", 1, Qnil },
	{ NULL, 0, Qnil },
    };
    if (0 == numerator_id) {
	numerator_id = rb_intern("numerator");
	denominator_id = rb_intern("denominator");
    }
    attrs[0].value = rb_funcall(obj, numerator_id, 0);
    attrs[1].value = rb_funcall(obj, denominator_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static ID	options_id = 0;
static ID	source_id = 0;

static void
regexp_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "o", 1, Qnil },
	{ "s", 1, Qnil },
	{ NULL, 0, Qnil },
    };
    if (0 == options_id) {
	options_id = rb_intern("options");
	source_id = rb_intern("source");
    }
    attrs[0].value = rb_funcall(obj, options_id, 0);
    attrs[1].value = rb_funcall(obj, source_id, 0);

    oj_code_attrs(obj, attrs, depth, out, true);
}

static void
time_alt(VALUE obj, int depth, Out out) {
    struct _Attr	attrs[] = {
	{ "s", 1, Qundef, 0, Qundef },
	{ "n", 1, Qundef, 0, Qundef },
	{ NULL, 0, Qnil },
    };
    struct timespec	ts = rb_time_timespec(obj);

    attrs[0].num = ts.tv_sec;
    attrs[1].num = ts.tv_nsec;

    oj_code_attrs(obj, attrs, depth, out, true);
}

struct _Code	oj_compat_codes[] = {
    { "BigDecimal", Qnil, bigdecimal_alt, NULL, false },
    { "Complex", Qnil, complex_alt, NULL, false },
    { "Date", Qnil, date_alt, false },
    { "DateTime", Qnil, datetime_alt, NULL, false },
    { "OpenStruct", Qnil, openstruct_alt, NULL, false },
    { "Range", Qnil, range_alt, NULL, false },
    { "Rational", Qnil, rational_alt, NULL, false },
    { "Regexp", Qnil, regexp_alt, NULL, false },
    { "Time", Qnil, time_alt, NULL, false },
    // TBD the rest of the library classes
    { NULL, Qundef, NULL, NULL, false },
};

VALUE
oj_add_to_json(int argc, VALUE *argv, VALUE self) {
    Code	a;

    if (0 == argc) {
	for (a = oj_compat_codes; NULL != a->name; a++) {
	    if (Qnil == a->clas || Qundef == a->clas) {
		a->clas = rb_const_get_at(rb_cObject, rb_intern(a->name));
	    }
	    a->active = true;
	}
	use_struct_alt = true;
	use_exception_alt = true;
	use_bignum_alt = true;
	oj_use_hash_alt = true;
	oj_use_array_alt = true;
    } else {
	for (; 0 < argc; argc--, argv++) {
	    if (rb_cStruct == *argv) {
		use_struct_alt = true;
		continue;
	    }
	    if (rb_eException == *argv) {
		use_exception_alt = true;
		continue;
	    }
	    if (rb_cInteger == *argv) {
		use_bignum_alt = true;
		continue;
	    }
	    if (rb_cHash == *argv) {
		oj_use_hash_alt = true;
		continue;
	    }
	    if (rb_cArray == *argv) {
		oj_use_array_alt = true;
		continue;
	    }
	    for (a = oj_compat_codes; NULL != a->name; a++) {
		if (Qnil == a->clas || Qundef == a->clas) {
		    a->clas = rb_const_get_at(rb_cObject, rb_intern(a->name));
		}
		if (*argv == a->clas) {
		    a->active = true;
		    break;
		}
	    }
	}
    }
    return Qnil;
}

VALUE
oj_remove_to_json(int argc, VALUE *argv, VALUE self) {
    if (0 == argc) {
	oj_code_set_active(oj_compat_codes, Qnil, false);
	use_struct_alt = false;
	use_exception_alt = false;
	use_bignum_alt = false;
	oj_use_hash_alt = false;
	oj_use_array_alt = false;
    } else {
	for (; 0 < argc; argc--, argv++) {
	    if (rb_cStruct == *argv) {
		use_struct_alt = false;
		continue;
	    }
	    if (rb_eException == *argv) {
		use_exception_alt = false;
		continue;
	    }
	    if (rb_cInteger == *argv) {
		use_bignum_alt = false;
		continue;
	    }
	    if (rb_cHash == *argv) {
		oj_use_hash_alt = false;
		continue;
	    }
	    if (rb_cArray == *argv) {
		oj_use_array_alt = false;
		continue;
	    }
	    oj_code_set_active(oj_compat_codes, *argv, false);
	}
    }
    return Qnil;
}

// The JSON gem is inconsistent with handling of infinity. Using
// JSON.dump(0.1/0) returns the string Infinity but (0.1/0).to_json raise and
// exception. Worse, for BigDecimals a quoted "Infinity" is returned.
static void
dump_float(VALUE obj, int depth, Out out, bool as_ok) {
    char	buf[64];
    char	*b;
    double	d = rb_num2dbl(obj);
    int		cnt = 0;

    if (0.0 == d) {
	b = buf;
	*b++ = '0';
	*b++ = '.';
	*b++ = '0';
	*b++ = '\0';
	cnt = 3;
    } else if (OJ_INFINITY == d) {
	if (WordNan == out->opts->dump_opts.nan_dump) {
	    strcpy(buf, "Infinity");
	} else {
	    raise_json_err("Infinity not allowed in JSON.", "GeneratorError");
	}
    } else if (-OJ_INFINITY == d) {
	if (WordNan == out->opts->dump_opts.nan_dump) {
	    strcpy(buf, "-Infinity");
	} else {
	    raise_json_err("-Infinity not allowed in JSON.", "GeneratorError");
	}
    } else if (isnan(d)) {
	if (WordNan == out->opts->dump_opts.nan_dump) {
	    strcpy(buf, "NaN");
	} else {
	    raise_json_err("NaN not allowed in JSON.", "GeneratorError");
	}
    } else if (d == (double)(long long int)d) {
	cnt = snprintf(buf, sizeof(buf), "%.1f", d);
    } else if (oj_rails_float_opt) {
	cnt = oj_dump_float_printf(buf, sizeof(buf), obj, d, "%0.16g");
    } else {
	volatile VALUE	rstr = rb_funcall(obj, oj_to_s_id, 0);

	strcpy(buf, rb_string_value_ptr((VALUE*)&rstr));
	cnt = (int)RSTRING_LEN(rstr);
    }
    assure_size(out, cnt);
    for (b = buf; '\0' != *b; b++) {
	*out->cur++ = *b;
    }
    *out->cur = '\0';
}

static int
hash_cb(VALUE key, VALUE value, Out out) {
    int	depth = out->depth;

    if (out->omit_nil && Qnil == value) {
	return ST_CONTINUE;
    }
    if (!out->opts->dump_opts.use) {
	assure_size(out, depth * out->indent + 1);
	fill_indent(out, depth);
    } else {
	assure_size(out, depth * out->opts->dump_opts.indent_size + out->opts->dump_opts.hash_size + 1);
	if (0 < out->opts->dump_opts.hash_size) {
	    strcpy(out->cur, out->opts->dump_opts.hash_nl);
	    out->cur += out->opts->dump_opts.hash_size;
	}
	if (0 < out->opts->dump_opts.indent_size) {
	    int	i;
	    for (i = depth; 0 < i; i--) {
		strcpy(out->cur, out->opts->dump_opts.indent_str);
		out->cur += out->opts->dump_opts.indent_size;
	    }
	}
    }
    switch (rb_type(key)) {
    case T_STRING:
	oj_dump_str(key, 0, out, false);
	break;
    case T_SYMBOL:
	oj_dump_sym(key, 0, out, false);
	break;
    default:
	/*rb_raise(rb_eTypeError, "In :compat mode all Hash keys must be Strings or Symbols, not %s.\n", rb_class2name(rb_obj_class(key)));*/
	oj_dump_str(rb_funcall(key, oj_to_s_id, 0), 0, out, false);
	break;
    }
    if (!out->opts->dump_opts.use) {
	*out->cur++ = ':';
    } else {
	assure_size(out, out->opts->dump_opts.before_size + out->opts->dump_opts.after_size + 2);
	if (0 < out->opts->dump_opts.before_size) {
	    strcpy(out->cur, out->opts->dump_opts.before_sep);
	    out->cur += out->opts->dump_opts.before_size;
	}
	*out->cur++ = ':';
	if (0 < out->opts->dump_opts.after_size) {
	    strcpy(out->cur, out->opts->dump_opts.after_sep);
	    out->cur += out->opts->dump_opts.after_size;
	}
    }
    oj_dump_compat_val(value, depth, out, true);
    out->depth = depth;
    *out->cur++ = ',';

    return ST_CONTINUE;
}

static void
dump_hash(VALUE obj, int depth, Out out, bool as_ok) {
    int		cnt;
    long	id = oj_check_circular(obj, out);

    if (0 > id) {
	raise_json_err("Too deeply nested", "NestingError");
	return;
    }
    if (as_ok && !oj_use_hash_alt && rb_obj_class(obj) != rb_cHash && rb_respond_to(obj, oj_to_json_id)) {
	dump_to_json(obj, out);
	return;
    }	
    cnt = (int)RHASH_SIZE(obj);
    assure_size(out, 2);
    if (0 == cnt) {
	*out->cur++ = '{';
	*out->cur++ = '}';
    } else {
	*out->cur++ = '{';
	out->depth = depth + 1;
	rb_hash_foreach(obj, hash_cb, (VALUE)out);
	if (',' == *(out->cur - 1)) {
	    out->cur--; // backup to overwrite last comma
	}
	if (!out->opts->dump_opts.use) {
	    assure_size(out, depth * out->indent + 2);
	    fill_indent(out, depth);
	} else {
	    assure_size(out, depth * out->opts->dump_opts.indent_size + out->opts->dump_opts.hash_size + 1);
	    if (0 < out->opts->dump_opts.hash_size) {
		strcpy(out->cur, out->opts->dump_opts.hash_nl);
		out->cur += out->opts->dump_opts.hash_size;
	    }
	    if (0 < out->opts->dump_opts.indent_size) {
		int	i;

		for (i = depth; 0 < i; i--) {
		    strcpy(out->cur, out->opts->dump_opts.indent_str);
		    out->cur += out->opts->dump_opts.indent_size;
		}
	    }
	}
	*out->cur++ = '}';
    }
    *out->cur = '\0';
}

// In compat mode only the first call check for to_json. After that to_s is
// called.
static void
dump_obj(VALUE obj, int depth, Out out, bool as_ok) {
    if (oj_code_dump(oj_compat_codes, obj, depth, out)) {
	return;
    }
    if (use_exception_alt && rb_obj_is_kind_of(obj, rb_eException)) {
	exception_alt(obj, depth, out);
	return;
    }
    if (as_ok && rb_respond_to(obj, oj_to_json_id)) {
	dump_to_json(obj, out);

	return;
    }
    // Nothing else matched so encode as a JSON object with Ruby obj members
    // as JSON object members.
    oj_dump_obj_to_s(obj, out);
}

static void
dump_struct(VALUE obj, int depth, Out out, bool as_ok) {
    VALUE	clas = rb_obj_class(obj);

    if (oj_code_dump(oj_compat_codes, obj, depth, out)) {
	return;
    }
    if (rb_cRange == clas) {
	*out->cur++ = '"';
	oj_dump_compat_val(rb_funcall(obj, oj_begin_id, 0), 0, out, false);
	assure_size(out, 3);
	*out->cur++ = '.';
	*out->cur++ = '.';
	if (Qtrue == rb_funcall(obj, oj_exclude_end_id, 0)) {
	    *out->cur++ = '.';
	}
	oj_dump_compat_val(rb_funcall(obj, oj_end_id, 0), 0, out, false);
	*out->cur++ = '"';

	return;
    }
    if (as_ok && rb_respond_to(obj, oj_to_json_id)) {
	dump_to_json(obj, out);

	return;
    }
    if (use_struct_alt) {
	int		d3 = depth + 2;
	size_t		size = d3 * out->indent + 2;
	size_t		sep_len = out->opts->dump_opts.before_size + out->opts->dump_opts.after_size + 2;
	const char	*classname = rb_class2name(rb_obj_class(obj));
	VALUE		args[100];
	int		cnt;
	int		i;

	if (NULL == classname || '#' == *classname) {
	    raise_json_err("Only named structs are supported.", "JSONError");
	}
#ifdef RSTRUCT_LEN
#if RSTRUCT_LEN_RETURNS_INTEGER_OBJECT
	cnt = (int)NUM2LONG(RSTRUCT_LEN(obj));
#else // RSTRUCT_LEN_RETURNS_INTEGER_OBJECT
	cnt = (int)RSTRUCT_LEN(obj);
#endif // RSTRUCT_LEN_RETURNS_INTEGER_OBJECT
#else
	// This is a bit risky as a struct in C ruby is not the same as a Struct
	// class in interpreted Ruby so length() may not be defined.
	cnt = FIX2INT(rb_funcall2(obj, oj_length_id, 0, 0));
#endif
	if (sizeof(args) / sizeof(*args) <= (size_t)cnt) {
	    // TBD allocate and try again
	    cnt = 99;
	}
	dump_obj_classname(rb_class2name(rb_obj_class(obj)), depth, out);

	assure_size(out, size + sep_len + 6);
	*out->cur++ = ',';
	fill_indent(out, d3);
	*out->cur++ = '"';
	*out->cur++ = 'v';
	*out->cur++ = '"';
	if (0 < out->opts->dump_opts.before_size) {
	    strcpy(out->cur, out->opts->dump_opts.before_sep);
	    out->cur += out->opts->dump_opts.before_size;
	}
	*out->cur++ = ':';
	if (0 < out->opts->dump_opts.after_size) {
	    strcpy(out->cur, out->opts->dump_opts.after_sep);
	    out->cur += out->opts->dump_opts.after_size;
	}
	for (i = 0; i < cnt; i++) {
#ifdef RSTRUCT_LEN
	    args[i] = RSTRUCT_GET(obj, i);
#else
	    args[i] = rb_struct_aref(obj, INT2FIX(i));
#endif
	}
	args[cnt] = Qundef;
	dump_values_array(args, depth, out);
	fill_indent(out, depth);
	*out->cur++ = '}';
	*out->cur = '\0';
    } else {
	oj_dump_obj_to_s(obj, out);
    }
}

static void
dump_bignum(VALUE obj, int depth, Out out, bool as_ok) {
    // The json gem uses to_s explicitly. to_s can be overridden while
    // rb_big2str can not so unless overridden by using add_to_json(Integer)
    // this must use to_s to pass the json gem unit tests.
    volatile VALUE	rs;
    int			cnt;

    if (use_bignum_alt) {
	rs = rb_big2str(obj, 10);
    } else {
	rs = rb_funcall(obj, oj_to_s_id, 0);
    }
    rb_check_type(rs, T_STRING);
    cnt = (int)RSTRING_LEN(rs);
    assure_size(out, cnt);
    memcpy(out->cur, rb_string_value_ptr((VALUE*)&rs), cnt);
    out->cur += cnt;
    *out->cur = '\0';
}

static DumpFunc	compat_funcs[] = {
    NULL,	 	// RUBY_T_NONE   = 0x00,
    dump_obj,		// RUBY_T_OBJECT = 0x01,
    oj_dump_class, 	// RUBY_T_CLASS  = 0x02,
    oj_dump_class,	// RUBY_T_MODULE = 0x03,
    dump_float, 	// RUBY_T_FLOAT  = 0x04,
    oj_dump_str, 	// RUBY_T_STRING = 0x05,
    dump_obj,		// RUBY_T_REGEXP = 0x06,
    dump_array,		// RUBY_T_ARRAY  = 0x07,
    dump_hash,	 	// RUBY_T_HASH   = 0x08,
    dump_struct,	// RUBY_T_STRUCT = 0x09,
    dump_bignum,	// RUBY_T_BIGNUM = 0x0a,
    NULL, 		// RUBY_T_FILE   = 0x0b,
    dump_obj,		// RUBY_T_DATA   = 0x0c,
    NULL, 		// RUBY_T_MATCH  = 0x0d,
    dump_obj, 		// RUBY_T_COMPLEX  = 0x0e,
    dump_obj,	 	// RUBY_T_RATIONAL = 0x0f,
    NULL, 		// 0x10
    oj_dump_nil, 	// RUBY_T_NIL    = 0x11,
    oj_dump_true, 	// RUBY_T_TRUE   = 0x12,
    oj_dump_false,	// RUBY_T_FALSE  = 0x13,
    oj_dump_sym,	// RUBY_T_SYMBOL = 0x14,
    oj_dump_fixnum,	// RUBY_T_FIXNUM = 0x15,
};

static void
set_state_depth(VALUE state, int depth) {
    VALUE	json_module = rb_const_get_at(rb_cObject, rb_intern("JSON"));
    VALUE	ext = rb_const_get(json_module, rb_intern("Ext"));
    VALUE	generator = rb_const_get(ext, rb_intern("Generator"));
    VALUE	state_class = rb_const_get(generator, rb_intern("State"));

    if (state_class == rb_obj_class(state)) {
	rb_funcall(state, rb_intern("depth="), 1, INT2NUM(depth));
    }
}

void
oj_dump_compat_val(VALUE obj, int depth, Out out, bool as_ok) {
    int	type = rb_type(obj);
    
    if (out->opts->dump_opts.max_depth <= depth) {
	// When JSON.dump is called then an ArgumentError is expected and the
	// limit is the depth inclusive. If JSON.generate is called then a
	// NestingError is expected and the limit is inclusive. Worse than
	// that there are unit tests for both.
	if (CALLER_DUMP == out->caller) {
	    if (0 < out->argc) {
		set_state_depth(*out->argv, depth);
	    }
	    rb_raise(rb_eArgError, "Too deeply nested.");
	} else if (out->opts->dump_opts.max_depth < depth) {
	    if (0 < out->argc) {
		set_state_depth(*out->argv, depth - 1);
	    }
	    raise_json_err("Too deeply nested", "NestingError");
	}
    }
    if (0 < type && type <= RUBY_T_FIXNUM) {
	DumpFunc	f = compat_funcs[type];

	if (NULL != f) {
	    f(obj, depth, out, as_ok);
	    return;
	}
    }
    oj_dump_nil(Qnil, depth, out, false);
}
