/
ring_buffer.go
215 lines (198 loc) · 4.3 KB
/
ring_buffer.go
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package DxCommonLib
import (
"errors"
)
type DxRingBuffer struct {
rawData []byte
rpos, wpos int
markrpos int
markwpos int
isEmpty bool
hasMark bool
}
func (buffer *DxRingBuffer) Capacity() int {
return len(buffer.rawData)
}
//DataSize 数据长度
func (buffer *DxRingBuffer) DataSize() int {
if buffer.isEmpty {
return 0
}
if buffer.wpos > buffer.rpos {
return buffer.wpos - buffer.rpos
}
if buffer.wpos == buffer.rpos {
return len(buffer.rawData)
}
return len(buffer.rawData) - buffer.rpos + buffer.wpos
}
//FreeSize 剩下的空余大小
func (buffer *DxRingBuffer) FreeSize() int {
if buffer.isEmpty {
return len(buffer.rawData)
}
if buffer.rpos == buffer.wpos {
return 0
}
if buffer.wpos < buffer.rpos {
return buffer.rpos - buffer.wpos
}
return len(buffer.rawData) - buffer.wpos + buffer.rpos
}
func (buffer *DxRingBuffer) MarkReadWrite() {
buffer.markrpos = buffer.rpos
buffer.markwpos = buffer.wpos
buffer.hasMark = true
}
func (buffer *DxRingBuffer) RestoreMark() {
if !buffer.hasMark {
return
}
buffer.rpos = buffer.markrpos
buffer.wpos = buffer.markwpos
buffer.hasMark = false
}
func (buffer *DxRingBuffer) Skip(n int) {
if buffer.isEmpty || n <= 0 {
return
}
if buffer.wpos > buffer.rpos {
vlen := buffer.wpos - buffer.rpos
if vlen > n {
buffer.rpos = buffer.rpos + n
} else {
buffer.isEmpty = true
buffer.rpos = buffer.wpos
}
return
}
size := len(buffer.rawData)
vlen := size - buffer.rpos + buffer.wpos
if vlen > n {
vlen = n
}
buffer.rpos = (buffer.rpos + vlen) % size
buffer.isEmpty = buffer.rpos == buffer.wpos
}
func (buffer *DxRingBuffer) Read(p []byte) (n int, err error) {
btlen := len(p)
if buffer.isEmpty || btlen == 0 {
return 0, nil
}
size := len(buffer.rawData)
if buffer.wpos > buffer.rpos {
n = buffer.wpos - buffer.rpos
if n > btlen {
n = btlen
}
copy(p, buffer.rawData[buffer.rpos:buffer.rpos+n])
buffer.rpos = (buffer.rpos + n) % size
buffer.isEmpty = buffer.rpos == buffer.wpos
return
}
n = size - buffer.rpos + buffer.wpos
if n > btlen {
n = btlen
}
if buffer.rpos+n <= size {
copy(p, buffer.rawData[buffer.rpos:buffer.rpos+n])
} else {
len1 := size - buffer.rpos
copy(p, buffer.rawData[buffer.rpos:size])
len2 := n - len1
copy(p[len1:], buffer.rawData[:len2])
}
buffer.rpos = (buffer.rpos + n) % size
buffer.isEmpty = buffer.rpos == buffer.wpos
return n, nil
}
func (buffer *DxRingBuffer) ReadByte() (b byte, err error) {
if buffer.isEmpty {
return 0, errors.New("IsEmpty")
}
b = buffer.rawData[buffer.rpos]
buffer.rpos++
if buffer.rpos == buffer.Capacity() {
buffer.rpos = 0
}
buffer.isEmpty = buffer.rpos == buffer.wpos
return b, nil
}
func (buffer *DxRingBuffer) Write(p []byte) (n int, err error) {
n = len(p)
if n == 0 {
return
}
free := buffer.FreeSize()
if n > free {
buffer.malloc(n - free)
}
size := len(buffer.rawData)
if buffer.wpos >= buffer.rpos {
c1 := size - buffer.wpos
if c1 >= n {
copy(buffer.rawData[buffer.wpos:], p)
buffer.wpos += n
} else {
copy(buffer.rawData[buffer.wpos:], p[:c1])
c2 := n - c1
copy(buffer.rawData[:c2], p[c1:])
buffer.wpos = c2
}
} else {
copy(buffer.rawData[buffer.wpos:], p)
buffer.wpos += n
}
if buffer.wpos == buffer.rpos {
buffer.wpos = 0
}
buffer.isEmpty = false
return
}
func (buffer *DxRingBuffer) WriteByte(b byte) {
if buffer.FreeSize() < 1 {
buffer.malloc(1)
}
buffer.rawData[buffer.wpos] = b
buffer.wpos++
if buffer.wpos == buffer.Capacity() {
buffer.wpos = 0
}
buffer.isEmpty = false
}
func (buffer *DxRingBuffer) IsFull() bool {
return buffer.rpos == buffer.wpos && !buffer.isEmpty
}
func (buffer *DxRingBuffer) IsEmpty() bool {
return buffer.isEmpty
}
func (buffer *DxRingBuffer) Reset() {
buffer.hasMark = false
buffer.rpos = 0
buffer.wpos = 0
buffer.isEmpty = true
}
func (buffer *DxRingBuffer) malloc(cap int) {
newcap := len(buffer.rawData) + cap
if newcap < 256 {
newcap = newcap * 2
} else if newcap < 512 {
newcap = newcap + 256
} else {
newcap = newcap + 512
}
newbuf := make([]byte, newcap)
oldlen := buffer.DataSize()
buffer.Read(newbuf)
buffer.rpos = 0
buffer.wpos = oldlen
buffer.rawData = newbuf
}
func NewRingBuffer(size int) *DxRingBuffer {
return &DxRingBuffer{
rawData: make([]byte, size),
rpos: 0,
wpos: 0,
isEmpty: true,
}
}