From 16b68b6fbaadf1c714e1b4d6a0501c040666d0f6 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 22 Sep 2025 10:44:56 +0100
Subject: [PATCH] object: add a type for storing, parsing, and stringifying
 date/time values

---
 object/datetime.c                     | 489 ++++++++++++++++++++++++++
 object/datetime.h                     |  17 +
 object/include/blue/object/datetime.h |  49 +++
 object/include/blue/object/type.h     |   1 +
 4 files changed, 556 insertions(+)
 create mode 100644 object/datetime.c
 create mode 100644 object/datetime.h
 create mode 100644 object/include/blue/object/datetime.h

diff --git a/object/datetime.c b/object/datetime.c
new file mode 100644
index 0000000..4e6e6eb
--- /dev/null
+++ b/object/datetime.c
@@ -0,0 +1,489 @@
+#include "datetime.h"
+
+#include "blue/core/stream.h"
+#include "blue/object/string.h"
+
+#include <blue/object/datetime.h>
+
+static void datetime_to_string(const struct b_object *obj, struct b_stream *out);
+
+static struct b_object_type string_type = {
+	.t_name = "corelib::string",
+	.t_flags = B_OBJECT_FUNDAMENTAL,
+	.t_id = B_OBJECT_TYPE_DATETIME,
+	.t_instance_size = sizeof(struct b_datetime),
+	.t_to_string = datetime_to_string,
+};
+
+struct b_datetime *b_datetime_create(void)
+{
+	return (struct b_datetime *)b_object_type_instantiate(&string_type);
+}
+
+static bool is_leap_year(const struct b_datetime *dt)
+{
+	if ((dt->dt_year % 400) == 0) {
+		return true;
+	}
+
+	if ((dt->dt_year % 4) == 0 && (dt->dt_year % 100) != 0) {
+		return true;
+	}
+
+	return false;
+}
+
+static bool is_year_valid(const struct b_datetime *dt)
+{
+	return dt->dt_year >= 0;
+}
+
+static bool is_month_valid(const struct b_datetime *dt)
+{
+	return dt->dt_month >= 1 && dt->dt_month <= 12;
+}
+
+static bool is_day_valid(const struct b_datetime *dt)
+{
+	if (dt->dt_day < 1) {
+		return false;
+	}
+
+	switch (dt->dt_month) {
+	case 2:
+		return dt->dt_day <= (is_leap_year(dt) ? 29 : 28);
+	case 4:
+	case 6:
+	case 9:
+	case 11:
+		return dt->dt_day <= 30;
+	case 1:
+	case 3:
+	case 5:
+	case 7:
+	case 8:
+	case 10:
+	case 12:
+		return dt->dt_day <= 31;
+	default:
+		return false;
+	}
+}
+
+static bool is_time_valid(const struct b_datetime *dt)
+{
+	if (!(dt->dt_hour >= 0 && dt->dt_hour <= 23)) {
+		return false;
+	}
+
+	if (!(dt->dt_min >= 0 && dt->dt_min <= 59)) {
+		return false;
+	}
+
+	if (!(dt->dt_sec >= 0 && dt->dt_sec <= 60)) {
+		return false;
+	}
+
+	return true;
+}
+
+static bool is_zone_valid(const struct b_datetime *dt)
+{
+	if (!(dt->dt_zone_offset_hour >= 0 && dt->dt_zone_offset_hour <= 23)) {
+		return false;
+	}
+
+	if (!(dt->dt_zone_offset_minute >= 0 && dt->dt_zone_offset_minute <= 59)) {
+		return false;
+	}
+
+	return true;
+}
+
+static bool validate(const struct b_datetime *dt)
+{
+	if (dt->dt_has_date) {
+		if (!is_year_valid(dt)) {
+			return false;
+		}
+
+		if (!is_month_valid(dt)) {
+			return false;
+		}
+
+		if (!is_day_valid(dt)) {
+			return false;
+		}
+	}
+
+	if (dt->dt_has_time) {
+		if (!is_time_valid(dt)) {
+			return false;
+		}
+
+		if (!is_zone_valid(dt)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+struct b_datetime *parse_rfc3339(const char *s)
+{
+	struct b_datetime *dt = b_datetime_create();
+	if (!dt) {
+		return NULL;
+	}
+
+	size_t len = strlen(s);
+
+	size_t i = 0, c = 0;
+
+	bool has_date = false, has_time = false;
+	dt->dt_localtime = true;
+
+	if (len >= 10 && s[4] == '-' && s[7] == '-') {
+		has_date = true;
+	}
+
+	if (len >= 8 && s[2] == ':' && s[5] == ':') {
+		has_time = true;
+	}
+
+	if (len >= 19 && s[4] == '-' && s[7] == '-'
+	    && (s[10] == 'T' || s[10] == 't' || s[10] == ' ') && s[13] == ':'
+	    && s[16] == ':') {
+		has_date = true;
+		has_time = true;
+	}
+
+	if (!has_date && !has_time) {
+		goto fail;
+	}
+
+	if (has_date) {
+		for (c = 0; c < 4; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_year *= 10;
+			dt->dt_year += (s[i] - '0');
+		}
+
+		if (s[i++] != '-') {
+			goto fail;
+		}
+
+		for (c = 0; c < 2; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_month *= 10;
+			dt->dt_month += (s[i] - '0');
+		}
+
+		if (s[i++] != '-' || dt->dt_month > 12) {
+			goto fail;
+		}
+
+		for (c = 0; c < 2; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_day *= 10;
+			dt->dt_day += (s[i] - '0');
+		}
+
+		if (dt->dt_day > 31) {
+			goto fail;
+		}
+	}
+
+	if ((s[i] == 'T' || s[i] == 't' || s[i] == ' ') && !has_time) {
+		goto fail;
+	}
+
+	if (has_date && has_time) {
+		if (s[i] != 'T' && s[i] != 't' && s[i] != ' ') {
+			goto fail;
+		}
+
+		i++;
+	}
+
+	if (has_time) {
+		for (c = 0; c < 2; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_hour *= 10;
+			dt->dt_hour += (s[i] - '0');
+		}
+
+		if (s[i++] != ':') {
+			goto fail;
+		}
+
+		for (c = 0; c < 2; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_min *= 10;
+			dt->dt_min += (s[i] - '0');
+		}
+
+		if (s[i++] != ':') {
+			goto fail;
+		}
+
+		for (c = 0; c < 2; c++, i++) {
+			if (!isdigit(s[i])) {
+				goto fail;
+			}
+
+			dt->dt_sec *= 10;
+			dt->dt_sec += (s[i] - '0');
+		}
+
+		if (s[i] == '.') {
+			i++;
+			for (c = 0; s[i]; c++, i++) {
+				if (!isdigit(s[i])) {
+					break;
+				}
+
+				dt->dt_msec *= 10;
+				dt->dt_msec += (s[i] - '0');
+			}
+
+			if (c == 0) {
+				goto fail;
+			}
+		}
+
+		if (s[i] == '+' || s[i] == '-') {
+			dt->dt_localtime = false;
+			dt->dt_zone_offset_negative = s[i] == '-';
+			i++;
+
+			for (c = 0; c < 2; c++, i++) {
+				if (!isdigit(s[i])) {
+					goto fail;
+				}
+
+				dt->dt_zone_offset_hour *= 10;
+				dt->dt_zone_offset_hour += (s[i] - '0');
+			}
+
+			if (s[i++] != ':') {
+				goto fail;
+			}
+
+			for (c = 0; c < 2; c++, i++) {
+				if (!isdigit(s[i])) {
+					goto fail;
+				}
+
+				dt->dt_zone_offset_minute *= 10;
+				dt->dt_zone_offset_minute += (s[i] - '0');
+			}
+		} else if (s[i] == 'Z' || s[i] == 'z') {
+			dt->dt_localtime = false;
+			i++;
+		}
+	}
+
+	if (s[i] != 0) {
+		goto fail;
+	}
+
+	dt->dt_has_date = has_date;
+	dt->dt_has_time = has_time;
+	return dt;
+fail:
+	b_datetime_release(dt);
+	return NULL;
+}
+
+struct b_datetime *b_datetime_parse(enum b_datetime_format format, const char *s)
+{
+	struct b_datetime *dt = NULL;
+
+	switch (format) {
+	case B_DATETIME_FORMAT_RFC3339:
+		dt = parse_rfc3339(s);
+		break;
+	default:
+		return NULL;
+	}
+
+	if (!dt) {
+		return NULL;
+	}
+
+	if (!validate(dt)) {
+		b_datetime_release(dt);
+		return NULL;
+	}
+
+	return dt;
+}
+
+enum b_status encode_rfc3339(const struct b_datetime *dt, struct b_stream *out)
+{
+	if (dt->dt_has_date) {
+		b_stream_write_fmt(
+			out, NULL, "%04ld-%02ld-%02ld", dt->dt_year,
+			dt->dt_month, dt->dt_day);
+	}
+
+	if (dt->dt_has_date && dt->dt_has_time) {
+		b_stream_write_char(out, 'T');
+	}
+
+	if (dt->dt_has_time) {
+		b_stream_write_fmt(
+			out, NULL, "%02ld:%02ld:%02ld", dt->dt_hour, dt->dt_min,
+			dt->dt_sec);
+
+		if (dt->dt_msec > 0) {
+			b_stream_write_fmt(out, NULL, ".%04ld", dt->dt_msec);
+		}
+
+		if (!dt->dt_localtime) {
+			if (dt->dt_zone_offset_hour == 0
+			    && dt->dt_zone_offset_minute == 0) {
+				b_stream_write_char(out, 'Z');
+			} else {
+				b_stream_write_fmt(
+					out, NULL, "%c%02ld:%02ld",
+					dt->dt_zone_offset_negative ? '-' : '+',
+					dt->dt_zone_offset_hour,
+					dt->dt_zone_offset_minute);
+			}
+		}
+	}
+
+	return B_SUCCESS;
+}
+
+void b_datetime_to_string(
+	const b_datetime *dt, b_datetime_format format, struct b_string *dest)
+{
+	struct b_stream *out;
+	b_string_open_stream(dest, &out);
+
+	switch (format) {
+	case B_DATETIME_FORMAT_RFC3339:
+		encode_rfc3339(dt, out);
+		break;
+	default:
+		break;
+	}
+
+	b_stream_close(out);
+}
+
+bool b_datetime_is_localtime(const b_datetime *dt)
+{
+	return dt->dt_localtime;
+}
+
+bool b_datetime_has_date(const b_datetime *dt)
+{
+	return dt->dt_has_date;
+}
+
+bool b_datetime_has_time(const b_datetime *dt)
+{
+	return dt->dt_has_time;
+}
+
+long b_datetime_year(const b_datetime *dt)
+{
+	return dt->dt_year;
+}
+
+long b_datetime_month(const b_datetime *dt)
+{
+	return dt->dt_month;
+}
+
+long b_datetime_day(const b_datetime *dt)
+{
+	return dt->dt_day;
+}
+
+long b_datetime_hour(const b_datetime *dt)
+{
+	return dt->dt_hour;
+}
+
+long b_datetime_minute(const b_datetime *dt)
+{
+	return dt->dt_min;
+}
+
+long b_datetime_second(const b_datetime *dt)
+{
+	return dt->dt_sec;
+}
+
+long b_datetime_subsecond(const b_datetime *dt)
+{
+	return dt->dt_msec;
+}
+
+bool b_datetime_zone_offset_is_negative(const b_datetime *dt)
+{
+	return dt->dt_zone_offset_negative;
+}
+
+long b_datetime_zone_offset_hour(const b_datetime *dt)
+{
+	return dt->dt_zone_offset_hour;
+}
+
+long b_datetime_zone_offset_minute(const b_datetime *dt)
+{
+	return dt->dt_zone_offset_minute;
+}
+
+static void datetime_to_string(const struct b_object *obj, struct b_stream *out)
+{
+	struct b_datetime *dt = B_DATETIME(obj);
+
+	if (dt->dt_has_date) {
+		b_stream_write_fmt(
+			out, NULL, "%04ld-%02ld-%02ld", dt->dt_year,
+			dt->dt_month, dt->dt_day);
+	}
+
+	if (dt->dt_has_date && dt->dt_has_time) {
+		b_stream_write_char(out, ' ');
+	}
+
+	if (dt->dt_has_time) {
+		b_stream_write_fmt(
+			out, NULL, "%02ld:%02ld:%02ld", dt->dt_hour, dt->dt_min,
+			dt->dt_sec);
+
+		if (dt->dt_msec > 0) {
+			b_stream_write_fmt(out, NULL, ".%04ld", dt->dt_msec);
+		}
+
+		if (!dt->dt_localtime) {
+			b_stream_write_fmt(
+				out, NULL, " %c%02ld:%02ld",
+				dt->dt_zone_offset_negative ? '-' : '+',
+				dt->dt_zone_offset_hour,
+				dt->dt_zone_offset_minute);
+		}
+	}
+}
diff --git a/object/datetime.h b/object/datetime.h
new file mode 100644
index 0000000..ff391f8
--- /dev/null
+++ b/object/datetime.h
@@ -0,0 +1,17 @@
+#ifndef _BLUELIB_DATETIME_H_
+#define _BLUELIB_DATETIME_H_
+
+#include "object.h"
+
+struct b_datetime {
+	struct b_object dt_base;
+	unsigned int dt_year, dt_month, dt_day;
+	unsigned short dt_hour, dt_min, dt_sec;
+	unsigned int dt_msec;
+
+	bool dt_has_date, dt_has_time, dt_localtime;
+	unsigned short dt_zone_offset_hour, dt_zone_offset_minute;
+	bool dt_zone_offset_negative;
+};
+
+#endif
diff --git a/object/include/blue/object/datetime.h b/object/include/blue/object/datetime.h
new file mode 100644
index 0000000..0f07fbd
--- /dev/null
+++ b/object/include/blue/object/datetime.h
@@ -0,0 +1,49 @@
+#ifndef BLUELIB_DATETIME_H_
+#define BLUELIB_DATETIME_H_
+
+#include <blue/core/status.h>
+#include <blue/object/object.h>
+#include <blue/object/type.h>
+#include <ctype.h>
+
+struct b_string;
+
+#define B_DATETIME(p) ((b_datetime *)(p))
+
+typedef struct b_datetime b_datetime;
+
+typedef enum b_datetime_format {
+	B_DATETIME_FORMAT_RFC3339 = 1,
+} b_datetime_format;
+
+BLUE_API b_datetime *b_datetime_create(void);
+BLUE_API b_datetime *b_datetime_parse(b_datetime_format format, const char *s);
+BLUE_API void b_datetime_to_string(
+	const b_datetime *dt, b_datetime_format format, struct b_string *dest);
+
+static inline b_datetime *b_datetime_retain(b_datetime *dt)
+{
+	return B_DATETIME(b_retain(B_OBJECT(dt)));
+}
+static inline void b_datetime_release(b_datetime *dt)
+{
+	b_release(B_OBJECT(dt));
+}
+
+BLUE_API bool b_datetime_is_localtime(const b_datetime *dt);
+BLUE_API bool b_datetime_has_date(const b_datetime *dt);
+BLUE_API bool b_datetime_has_time(const b_datetime *dt);
+
+BLUE_API long b_datetime_year(const b_datetime *dt);
+BLUE_API long b_datetime_month(const b_datetime *dt);
+BLUE_API long b_datetime_day(const b_datetime *dt);
+BLUE_API long b_datetime_hour(const b_datetime *dt);
+BLUE_API long b_datetime_minute(const b_datetime *dt);
+BLUE_API long b_datetime_second(const b_datetime *dt);
+BLUE_API long b_datetime_subsecond(const b_datetime *dt);
+
+BLUE_API bool b_datetime_zone_offset_is_negative(const b_datetime *dt);
+BLUE_API long b_datetime_zone_offset_hour(const b_datetime *dt);
+BLUE_API long b_datetime_zone_offset_minute(const b_datetime *dt);
+
+#endif
diff --git a/object/include/blue/object/type.h b/object/include/blue/object/type.h
index b45c200..2888813 100644
--- a/object/include/blue/object/type.h
+++ b/object/include/blue/object/type.h
@@ -30,6 +30,7 @@ typedef enum b_fundamental_type_id {
 	B_OBJECT_TYPE_PATH,
 	B_OBJECT_TYPE_FILE,
 	B_OBJECT_TYPE_DIRECTORY,
+	B_OBJECT_TYPE_DATETIME,
 } b_fundamental_type_id;
 
 typedef enum b_object_type_flags {