packets: use AppendFormat to format time values (#615)

* use AppendFormat to format time values

* drop support for Go 1.4

Author: achille-roussel

.travis.yml

@@ -1,7 +1,6 @@
 sudo: false
 language: go
 go:
-  - 1.4
   - 1.5
   - 1.6
   - 1.7

AUTHORS

@@ -12,6 +12,7 @@
 # Individual Persons
 
 Aaron Hopkins <go-sql-driver at die.net>
+Achille Roussel <achille.roussel at gmail.com>
 Arne Hormann <arnehormann at gmail.com>
 Asta Xie <xiemengjun at gmail.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>

README.md

@@ -39,7 +39,7 @@ A MySQL-Driver for Go's [database/sql](https://golang.org/pkg/database/sql/) pac
   * Optional placeholder interpolation
 
 ## Requirements
-  * Go 1.4 or higher
+  * Go 1.5 or higher
   * MySQL (4.1+), MariaDB, Percona Server, Google CloudSQL or Sphinx (2.2.3+)
 
 ---------------------------------------

packets.go

@@ -1078,17 +1078,19 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 				paramTypes[i+i] = fieldTypeString
 				paramTypes[i+i+1] = 0x00
 
-				var val []byte
+				var a [64]byte
+				var b = a[:0]
+
 				if v.IsZero() {
-					val = []byte("0000-00-00")
+					b = append(b, "0000-00-00"...)
 				} else {
-					val = []byte(v.In(mc.cfg.Loc).Format(timeFormat))
+					b = v.In(mc.cfg.Loc).AppendFormat(b, timeFormat)
 				}
 
 				paramValues = appendLengthEncodedInteger(paramValues,
-					uint64(len(val)),
+					uint64(len(b)),
 				)
-				paramValues = append(paramValues, val...)
+				paramValues = append(paramValues, b...)
 
 			default:
 				return fmt.Errorf("can not convert type: %T", arg)