Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

When the buffer is empty, reset b.off to the beginning of the buffer

Browse source 
to avoid growing unnecessarily.

R=rsc
CC=golang-dev
https://golang.org/cl/176071
This commit is contained in:
Rob Pike 2009-12-14 13:13:01 +11:00
parent 58578905ba
commit d14c813377
1 changed files with 20 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

22
src/pkg/bytes/buffer.go
View file

@ -84,6 +84,10 @@ func (b *Buffer) resize(n int) {
// value n is the length of p; err is always nil. // value n is the length of p; err is always nil.
func (b *Buffer) Write(p []byte) (n int, err os.Error) { func (b *Buffer) Write(p []byte) (n int, err os.Error) {
m := b.Len(); m := b.Len();
// If buffer is empty, reset to recover space.
if m == 0 && b.off != 0 {
b.Truncate(0)
}
n = len(p); n = len(p);
if len(b.buf)+n > cap(b.buf) { if len(b.buf)+n > cap(b.buf) {
b.resize(n) b.resize(n)
@ -97,6 +101,10 @@ func (b *Buffer) Write(p []byte) (n int, err os.Error) {
// value n is the length of s; err is always nil. // value n is the length of s; err is always nil.
func (b *Buffer) WriteString(s string) (n int, err os.Error) { func (b *Buffer) WriteString(s string) (n int, err os.Error) {
m := b.Len(); m := b.Len();
// If buffer is empty, reset to recover space.
if m == 0 && b.off != 0 {
b.Truncate(0)
}
n = len(s); n = len(s);
if len(b.buf)+n > cap(b.buf) { if len(b.buf)+n > cap(b.buf) {
b.resize(n) b.resize(n)
@ -117,6 +125,10 @@ const MinRead = 512
// Any error except os.EOF encountered during the read // Any error except os.EOF encountered during the read
// is also returned. // is also returned.
func (b *Buffer) ReadFrom(r io.Reader) (n int64, err os.Error) { func (b *Buffer) ReadFrom(r io.Reader) (n int64, err os.Error) {
// If buffer is empty, reset to recover space.
if b.off >= len(b.buf) {
b.Truncate(0)
}
for { for {
if cap(b.buf)-len(b.buf) < MinRead { if cap(b.buf)-len(b.buf) < MinRead {
var newBuf []byte; var newBuf []byte;
@ -157,6 +169,8 @@ func (b *Buffer) WriteTo(w io.Writer) (n int64, err os.Error) {
return n, e return n, e
} }
} }
// Buffer is now empty; reset.
b.Truncate(0);
return; return;
} }
@ -175,7 +189,9 @@ func (b *Buffer) WriteByte(c byte) os.Error {
// otherwise it is nil. // otherwise it is nil.
func (b *Buffer) Read(p []byte) (n int, err os.Error) { func (b *Buffer) Read(p []byte) (n int, err os.Error) {
if b.off >= len(b.buf) { if b.off >= len(b.buf) {
return 0, os.EOF // Buffer is empty, reset to recover space.
b.Truncate(0);
return 0, os.EOF;
} }
m := b.Len(); m := b.Len();
n = len(p); n = len(p);
@ -194,7 +210,9 @@ func (b *Buffer) Read(p []byte) (n int, err os.Error) {
// If no byte is available, it returns error os.EOF. // If no byte is available, it returns error os.EOF.
func (b *Buffer) ReadByte() (c byte, err os.Error) { func (b *Buffer) ReadByte() (c byte, err os.Error) {
if b.off >= len(b.buf) { if b.off >= len(b.buf) {
return 0, os.EOF // Buffer is empty, reset to recover space.
b.Truncate(0);
return 0, os.EOF;
} }
c = b.buf[b.off]; c = b.buf[b.off];
b.off++; b.off++;