From be37d25444388ac0db3762331202519ba3ffac1f Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Sun, 18 Nov 2018 20:22:22 +0100
Subject: [PATCH] Simplify time format setup

---
 mysql/time.go      | 41 ++++++++++++++++++++---------------------
 tests/time_test.go |  9 +++++++++
 2 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/mysql/time.go b/mysql/time.go
index 35ece61..ca103a9 100644
--- a/mysql/time.go
+++ b/mysql/time.go
@@ -3,7 +3,6 @@ package mysql
 import (
 	"encoding/binary"
 	"fmt"
-	"strings"
 	"time"
 )
 
@@ -189,14 +188,29 @@ func DecodeTime2(data []byte, dec uint16) (string, int) {
 }
 
 var (
-	fracTimeFormat []string
+	fracTimeFormat = [...]string{
+		"2006-01-02T15:04:05Z",
+		"2006-01-02T15:04:05.0Z",
+		"2006-01-02T15:04:05.00Z",
+		"2006-01-02T15:04:05.000Z",
+		"2006-01-02T15:04:05.0000Z",
+		"2006-01-02T15:04:05.00000Z",
+		"2006-01-02T15:04:05.000000Z",
+	}
+	zeroTimes = [...]string{
+		"0000-00-00T00:00:00Z",
+		"0000-00-00T00:00:00.0Z",
+		"0000-00-00T00:00:00.00Z",
+		"0000-00-00T00:00:00.000Z",
+		"0000-00-00T00:00:00.0000Z",
+		"0000-00-00T00:00:00.00000Z",
+		"0000-00-00T00:00:00.000000Z",
+	}
 )
 
 // FracTime is a help structure wrapping Golang Time.
 type FracTime struct {
 	time.Time
-
-	// Dec must in [0, 6]
 	Dec int
 }
 
@@ -205,21 +219,6 @@ func (t FracTime) String() string {
 }
 
 func formatZeroTime(frac int, dec int) string {
-	if dec == 0 {
-		return "0000-00-00T00:00:00Z"
-	}
-
-	s := fmt.Sprintf("0000-00-00T00:00:00.%06dZ", frac)
-
-	// dec must < 6, if frac is 924000, but dec is 3, we must output 924 here.
-	return s[0 : len(s)-(6-dec)]
-}
-
-func init() {
-	fracTimeFormat = make([]string, 7)
-	fracTimeFormat[0] = "2006-01-02T15:04:05Z"
-
-	for i := 1; i <= 6; i++ {
-		fracTimeFormat[i] = fmt.Sprintf("2006-01-02T15:04:05.%sZ", strings.Repeat("0", i))
-	}
+	// We are going to ignore frac/dec distinction here
+	return zeroTimes[dec]
 }
diff --git a/tests/time_test.go b/tests/time_test.go
index f8f19b8..563ba98 100644
--- a/tests/time_test.go
+++ b/tests/time_test.go
@@ -23,6 +23,7 @@ func TestDate(t *testing.T) {
 	defer tbl.drop(t)
 
 	vals := []string{
+		"0000-00-00",
 		"1000-01-01",
 		"1234-05-06",
 		"1500-01-01",
@@ -61,6 +62,7 @@ func TestTimestamp(t *testing.T) {
 	defer tbl.drop(t)
 
 	vals := []string{
+		"0000-00-00T00:00:00Z",
 		// This is the lowest I could get
 		// Spec says 1970-01-01 00:00:01 should be supported
 		"1970-01-01T01:00:01Z",
@@ -81,6 +83,7 @@ func TestTimestamp(t *testing.T) {
 func TestDatetime(t *testing.T) {
 	inputs := map[string][]string{
 		"0": {
+			"0000-00-00T00:00:00Z",
 			"1000-01-01T00:00:00Z",
 			"1975-01-01T00:00:01Z",
 			"1985-01-01T00:00:01Z",
@@ -90,6 +93,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59Z",
 		},
 		"1": {
+			"0000-00-00T00:00:00.0Z",
 			"1000-01-01T00:00:00.1Z",
 			"1975-01-01T00:00:01.1Z",
 			"1985-01-01T00:00:01.1Z",
@@ -99,6 +103,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59.1Z",
 		},
 		"2": {
+			"0000-00-00T00:00:00.00Z",
 			"1000-01-01T00:00:00.22Z",
 			"1975-01-01T00:00:01.22Z",
 			"1985-01-01T00:00:01.22Z",
@@ -108,6 +113,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59.22Z",
 		},
 		"3": {
+			"0000-00-00T00:00:00.000Z",
 			"1000-01-01T00:00:00.333Z",
 			"1975-01-01T00:00:01.333Z",
 			"1985-01-01T00:00:01.333Z",
@@ -117,6 +123,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59.333Z",
 		},
 		"4": {
+			"0000-00-00T00:00:00.0000Z",
 			"1000-01-01T00:00:00.4444Z",
 			"1975-01-01T00:00:01.4444Z",
 			"1985-01-01T00:00:01.4444Z",
@@ -126,6 +133,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59.4444Z",
 		},
 		"5": {
+			"0000-00-00T00:00:00.00000Z",
 			"1000-01-01T00:00:00.55555Z",
 			"1975-01-01T00:00:01.55555Z",
 			"1985-01-01T00:00:01.55555Z",
@@ -135,6 +143,7 @@ func TestDatetime(t *testing.T) {
 			"9999-12-31T23:59:59.55555Z",
 		},
 		"6": {
+			"0000-00-00T00:00:00.000000Z",
 			"1000-01-01T00:00:00.666666Z",
 			"1975-01-01T00:00:01.666666Z",
 			"1985-01-01T00:00:01.666666Z",