added base62

langext/base62.go

@@ -0,0 +1,74 @@
+package langext
+
+import (
+	"crypto/rand"
+	"errors"
+	"math"
+	"math/big"
+	"strings"
+)
+
+var (
+	base62Base         = uint64(62)
+	base62CharacterSet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+)
+
+func RandBase62(rlen int) string {
+	bi52 := big.NewInt(int64(len(base62CharacterSet)))
+
+	randMax := big.NewInt(math.MaxInt64)
+
+	r := ""
+
+	for i := 0; i < rlen; i++ {
+		v, err := rand.Int(rand.Reader, randMax)
+		if err != nil {
+			panic(err)
+		}
+
+		r += string(base62CharacterSet[v.Mod(v, bi52).Int64()])
+	}
+
+	return r
+}
+
+func EncodeBase62(num uint64) string {
+	if num == 0 {
+		return "0"
+	}
+
+	b := make([]byte, 0)
+
+	// loop as long the num is bigger than zero
+	for num > 0 {
+		r := num % base62Base
+
+		num -= r
+		num /= base62Base
+
+		b = append([]byte{base62CharacterSet[int(r)]}, b...)
+	}
+
+	return string(b)
+}
+
+func DecodeBase62(str string) (uint64, error) {
+	if str == "" {
+		return 0, errors.New("empty string")
+	}
+
+	result := uint64(0)
+
+	for _, v := range str {
+		result *= base62Base
+
+		pos := strings.IndexRune(base62CharacterSet, v)
+		if pos == -1 {
+			return 0, errors.New("invalid character: " + string(v))
+		}
+
+		result += uint64(pos)
+	}
+
+	return result, nil
+}

langext/rand.go

@@ -3,8 +3,6 @@ package langext
 import (
 	"crypto/rand"
 	"io"
-	"math"
-	"math/big"
 )
 
 func RandBytes(size int) []byte {
@@ -15,24 +13,3 @@ func RandBytes(size int) []byte {
 	}
 	return b
 }
-
-func RandBase62(rlen int) string {
-	ecs := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
-
-	bi52 := big.NewInt(int64(len(ecs)))
-
-	randMax := big.NewInt(math.MaxInt64)
-
-	r := ""
-
-	for i := 0; i < rlen; i++ {
-		v, err := rand.Int(rand.Reader, randMax)
-		if err != nil {
-			panic(err)
-		}
-
-		r += string(ecs[v.Mod(v, bi52).Int64()])
-	}
-
-	return r
-}

timeext/time.go

@@ -17,14 +17,14 @@ func init() {
 }
 
 // TimeToDatePart returns a timestamp at the start of the day which contains t (= 00:00:00)
-func TimeToDatePart(t time.Time) time.Time {
-	t = t.In(TimezoneBerlin)
+func TimeToDatePart(t time.Time, tz *time.Location) time.Time {
+	t = t.In(tz)
 	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, t.Location())
 }
 
 // TimeToWeekStart returns a timestamp at the start of the week which contains t (= Monday 00:00:00)
-func TimeToWeekStart(t time.Time) time.Time {
-	t = TimeToDatePart(t)
+func TimeToWeekStart(t time.Time, tz *time.Location) time.Time {
+	t = TimeToDatePart(t, tz)
 
 	delta := time.Duration(((int64(t.Weekday()) + 6) % 7) * 24 * int64(time.Hour))
 	t = t.Add(-1 * delta)
@@ -33,32 +33,32 @@ func TimeToWeekStart(t time.Time) time.Time {
 }
 
 // TimeToMonthStart returns a timestamp at the start of the month which contains t (= yyyy-MM-00 00:00:00)
-func TimeToMonthStart(t time.Time) time.Time {
-	t = t.In(TimezoneBerlin)
+func TimeToMonthStart(t time.Time, tz *time.Location) time.Time {
+	t = t.In(tz)
 	return time.Date(t.Year(), t.Month(), 1, 0, 0, 0, 0, t.Location())
 }
 
 // TimeToMonthEnd returns a timestamp at the end of the month which contains t (= yyyy-MM-31 23:59:59.999999999)
-func TimeToMonthEnd(t time.Time) time.Time {
-	return TimeToMonthStart(t).AddDate(0, 1, 0).Add(-1)
+func TimeToMonthEnd(t time.Time, tz *time.Location) time.Time {
+	return TimeToMonthStart(t, tz).AddDate(0, 1, 0).Add(-1)
 }
 
 // TimeToYearStart returns a timestamp at the start of the year which contains t (= yyyy-01-01 00:00:00)
-func TimeToYearStart(t time.Time) time.Time {
-	t = t.In(TimezoneBerlin)
+func TimeToYearStart(t time.Time, tz *time.Location) time.Time {
+	t = t.In(tz)
 	return time.Date(t.Year(), 1, 1, 0, 0, 0, 0, t.Location())
 }
 
 // TimeToYearEnd returns a timestamp at the end of the month which contains t (= yyyy-12-31 23:59:59.999999999)
-func TimeToYearEnd(t time.Time) time.Time {
-	return TimeToYearStart(t).AddDate(1, 0, 0).Add(-1)
+func TimeToYearEnd(t time.Time, tz *time.Location) time.Time {
+	return TimeToYearStart(t, tz).AddDate(1, 0, 0).Add(-1)
 }
 
 // IsSameDayIncludingDateBoundaries returns true if t1 and t2 are part of the same day (TZ/Berlin), the boundaries of the day are
 // inclusive, this means 2021-09-15T00:00:00 is still part of the day 2021-09-14
-func IsSameDayIncludingDateBoundaries(t1 time.Time, t2 time.Time) bool {
-	dp1 := TimeToDatePart(t1)
-	dp2 := TimeToDatePart(t2)
+func IsSameDayIncludingDateBoundaries(t1 time.Time, t2 time.Time, tz *time.Location) bool {
+	dp1 := TimeToDatePart(t1, tz)
+	dp2 := TimeToDatePart(t2, tz)
 
 	if dp1.Equal(dp2) {
 		return true
@@ -72,9 +72,9 @@ func IsSameDayIncludingDateBoundaries(t1 time.Time, t2 time.Time) bool {
 }
 
 // IsDatePartEqual returns true if a and b have the same date part (`yyyy`, `MM` and `dd`)
-func IsDatePartEqual(a time.Time, b time.Time) bool {
-	yy1, mm1, dd1 := a.In(TimezoneBerlin).Date()
-	yy2, mm2, dd2 := b.In(TimezoneBerlin).Date()
+func IsDatePartEqual(a time.Time, b time.Time, tz *time.Location) bool {
+	yy1, mm1, dd1 := a.In(tz).Date()
+	yy2, mm2, dd2 := b.In(tz).Date()
 
 	return yy1 == yy2 && mm1 == mm2 && dd1 == dd2
 }
@@ -82,7 +82,7 @@ func IsDatePartEqual(a time.Time, b time.Time) bool {
 // WithTimePart returns a timestamp with the date-part (`yyyy`, `MM`, `dd`) from base
 // and the time (`HH`, `mm`, `ss`) from the parameter
 func WithTimePart(base time.Time, hour, minute, second int) time.Time {
-	datepart := TimeToDatePart(base)
+	datepart := TimeToDatePart(base, base.Location())
 
 	delta := time.Duration(hour*int(time.Hour) + minute*int(time.Minute) + second*int(time.Second))
 
@@ -92,7 +92,7 @@ func WithTimePart(base time.Time, hour, minute, second int) time.Time {
 // CombineDateAndTime returns a timestamp with the date-part (`yyyy`, `MM`, `dd`) from the d parameter
 // and the time (`HH`, `mm`, `ss`) from the t parameter
 func CombineDateAndTime(d time.Time, t time.Time) time.Time {
-	datepart := TimeToDatePart(d)
+	datepart := TimeToDatePart(d, d.Location())
 
 	delta := time.Duration(t.Hour()*int(time.Hour) + t.Minute()*int(time.Minute) + t.Second()*int(time.Second) + t.Nanosecond()*int(time.Nanosecond))
 
@@ -100,8 +100,8 @@ func CombineDateAndTime(d time.Time, t time.Time) time.Time {
 }
 
 // IsSunday returns true if t is a sunday (in TZ/Berlin)
-func IsSunday(t time.Time) bool {
-	if t.In(TimezoneBerlin).Weekday() == time.Sunday {
+func IsSunday(t time.Time, tz *time.Location) bool {
+	if t.In(tz).Weekday() == time.Sunday {
 		return true
 	}
 	return false
@@ -131,3 +131,7 @@ func UnixFloatSeconds(v float64) time.Time {
 	sec, dec := math.Modf(v)
 	return time.Unix(int64(sec), int64(dec*(1e9)))
 }
+
+func FloorTime(t time.Time) time.Time {
+	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, t.Location())
+}