Grow buffer instead of using a tmp slice
diff --git a/buffer.go b/buffer.go
index 12ca0cc..feeebe1 100644
--- a/buffer.go
+++ b/buffer.go
@@ -9,13 +9,9 @@
package mysql
-import (
- "io"
-)
+import "io"
-const (
- defaultBufSize = 4096
-)
+const defaultBufSize = 4096
type buffer struct {
buf []byte
@@ -38,6 +34,11 @@
copy(b.buf[0:b.length], b.buf[b.idx:])
}
+ // grow buffer if necessary
+ if need > len(b.buf) {
+ b.grow(need)
+ }
+
b.idx = 0
var n int
@@ -54,48 +55,32 @@
return
}
+// credit for this code snippet goes to Maxim Khitrov
+// https://groups.google.com/forum/#!topic/golang-nuts/ETbw1ECDgRs
+func (b *buffer) grow(size int) {
+ if size > 2*cap(b.buf) {
+ newBuf := make([]byte, size)
+ copy(newBuf, b.buf)
+ b.buf = newBuf
+ return
+ } else {
+ for cap(b.buf) < size {
+ b.buf = append(b.buf[:cap(b.buf)], 0)
+ }
+ b.buf = b.buf[:cap(b.buf)]
+ }
+}
+
// returns next N bytes from buffer.
// The returned slice is only guaranteed to be valid until the next read
func (b *buffer) readNext(need int) (p []byte, err error) {
- // return slice from buffer if possible
- if b.length >= need {
- p = b.buf[b.idx : b.idx+need]
- b.idx += need
- b.length -= need
- return
-
- } else {
-
- // does the data fit into the buffer?
- if need < len(b.buf) {
- // refill
- err = b.fill(need) // err deferred
- p = b.buf[:need]
- b.idx += need
- b.length -= need
- return
-
- } else {
- p = make([]byte, need)
- has := 0
-
- // copy data that is already in the buffer
- if b.length > 0 {
- copy(p[0:b.length], b.buf[b.idx:])
- has = b.length
- need -= has
- b.idx = 0
- b.length = 0
- }
-
- // read rest directly into the new slice
- var n int
- for err == nil && need > 0 {
- n, err = b.rd.Read(p[has:])
- has += n
- need -= n
- }
- }
+ if b.length < need {
+ // refill
+ err = b.fill(need) // err deferred
}
+
+ p = b.buf[b.idx : b.idx+need]
+ b.idx += need
+ b.length -= need
return
}
