flag: use strconv instead of fmt in values' String funcs

The existing implementation of flag values with fmt package uses
more memory and works slower than the implementation with strconv
package.

Change-Id: I9e749179f66d5c50cafe98186641bcdbc546d2db
Reviewed-on: https://go-review.googlesource.com/28914
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/flag/flag.go b/src/flag/flag.go
index e4705f23925dd154f066b8ff1cb5c9990cab6972..cb9f2837bf15018d6543a28c09fca3875c124821 100644 (file)
--- a/src/flag/flag.go
+++ b/src/flag/flag.go
@@ -94,7 +94,7 @@ func (b *boolValue) Set(s string) error {
 
 func (b *boolValue) Get() interface{} { return bool(*b) }
 
-func (b *boolValue) String() string { return fmt.Sprintf("%v", *b) }
+func (b *boolValue) String() string { return strconv.FormatBool(bool(*b)) }
 
 func (b *boolValue) IsBoolFlag() bool { return true }
 
@@ -121,7 +121,7 @@ func (i *intValue) Set(s string) error {
 
 func (i *intValue) Get() interface{} { return int(*i) }
 
-func (i *intValue) String() string { return fmt.Sprintf("%v", *i) }
+func (i *intValue) String() string { return strconv.Itoa(int(*i)) }
 
 // -- int64 Value
 type int64Value int64
@@ -139,7 +139,7 @@ func (i *int64Value) Set(s string) error {
 
 func (i *int64Value) Get() interface{} { return int64(*i) }
 
-func (i *int64Value) String() string { return fmt.Sprintf("%v", *i) }
+func (i *int64Value) String() string { return strconv.FormatInt(int64(*i), 10) }
 
 // -- uint Value
 type uintValue uint
@@ -157,7 +157,7 @@ func (i *uintValue) Set(s string) error {
 
 func (i *uintValue) Get() interface{} { return uint(*i) }
 
-func (i *uintValue) String() string { return fmt.Sprintf("%v", *i) }
+func (i *uintValue) String() string { return strconv.FormatUint(uint64(*i), 10) }
 
 // -- uint64 Value
 type uint64Value uint64
@@ -175,7 +175,7 @@ func (i *uint64Value) Set(s string) error {
 
 func (i *uint64Value) Get() interface{} { return uint64(*i) }
 
-func (i *uint64Value) String() string { return fmt.Sprintf("%v", *i) }
+func (i *uint64Value) String() string { return strconv.FormatUint(uint64(*i), 10) }
 
 // -- string Value
 type stringValue string
@@ -192,7 +192,7 @@ func (s *stringValue) Set(val string) error {
 
 func (s *stringValue) Get() interface{} { return string(*s) }
 
-func (s *stringValue) String() string { return fmt.Sprintf("%s", *s) }
+func (s *stringValue) String() string { return string(*s) }
 
 // -- float64 Value
 type float64Value float64
@@ -210,7 +210,7 @@ func (f *float64Value) Set(s string) error {
 
 func (f *float64Value) Get() interface{} { return float64(*f) }
 
-func (f *float64Value) String() string { return fmt.Sprintf("%v", *f) }
+func (f *float64Value) String() string { return strconv.FormatFloat(float64(*f), 'g', -1, 64) }
 
 // -- time.Duration Value
 type durationValue time.Duration