new /x/jsonx and /x/mathx util sub-packages

x/jsonx/time_notation.go

@@ -0,0 +1,88 @@
+package jsonx
+
+import (
+	"bytes"
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// TimeNotationDuration is a JSON representation of the standard Duration type in 00:00:00 (hour, minute seconds).
+type TimeNotationDuration time.Duration
+
+func fmtDuration(d time.Duration) string {
+	d = d.Round(time.Minute)
+	h := d / time.Hour
+	d -= h * time.Hour
+	m := d / time.Minute
+	return fmt.Sprintf("%02d:%02d", h, m)
+}
+
+func (d TimeNotationDuration) MarshalJSON() ([]byte, error) {
+	v := d.ToDuration()
+
+	format := fmtDuration(v)
+	return []byte(strconv.Quote(format)), nil
+}
+
+func (d *TimeNotationDuration) UnmarshalJSON(b []byte) error {
+	if len(b) == 0 || bytes.Equal(b, nullLiteral) || bytes.Equal(b, emptyQuoteBytes) { // if null or empty don't throw an error.
+		return nil
+	}
+
+	var v interface{}
+	if err := json.Unmarshal(b, &v); err != nil {
+		return err
+	}
+	switch value := v.(type) {
+	case float64:
+		*d = TimeNotationDuration(value)
+		return nil
+	case string:
+		entries := strings.SplitN(value, ":", 2)
+		if len(entries) < 2 {
+			return fmt.Errorf("invalid duration format: expected hours:minutes:seconds (e.g. 01:05) but got: %s", value)
+		}
+
+		hours, err := strconv.Atoi(entries[0])
+		if err != nil {
+			return err
+		}
+		minutes, err := strconv.Atoi(entries[1])
+		if err != nil {
+			return err
+		}
+
+		format := fmt.Sprintf("%02dh%02dm", hours, minutes)
+		v, err := time.ParseDuration(format)
+		if err != nil {
+			return err
+		}
+		*d = TimeNotationDuration(v)
+		return nil
+	default:
+		return errors.New("invalid duration")
+	}
+}
+
+func (d TimeNotationDuration) ToDuration() time.Duration {
+	return time.Duration(d)
+}
+
+func (d TimeNotationDuration) Value() (driver.Value, error) {
+	return int64(d), nil
+}
+
+// Set sets the value of duration in nanoseconds.
+func (d *TimeNotationDuration) Set(v float64) {
+	if math.IsNaN(v) {
+		return
+	}
+
+	*d = TimeNotationDuration(v)
+}