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ring_buffer_unix.go
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ring_buffer_unix.go
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// Copyright (c) 2021 Andy Pan
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build linux || freebsd || dragonfly || darwin
// +build linux freebsd dragonfly darwin
package ring
import (
"golang.org/x/sys/unix"
"github.com/panjf2000/gnet/v2/internal/io"
)
// ========================= gnet specific APIs =========================
// CopyFromSocket copies data from a socket fd into ring-buffer.
func (rb *Buffer) CopyFromSocket(fd int) (n int, err error) {
if rb.r == rb.w {
if !rb.isEmpty {
rb.grow(rb.size + rb.size/2)
n, err = unix.Read(fd, rb.buf[rb.w:])
if n > 0 {
rb.w = (rb.w + n) % rb.size
}
return
}
rb.r, rb.w = 0, 0
n, err = unix.Read(fd, rb.buf)
if n > 0 {
rb.w = (rb.w + n) % rb.size
rb.isEmpty = false
}
return
}
if rb.w < rb.r {
n, err = unix.Read(fd, rb.buf[rb.w:rb.r])
if n > 0 {
rb.w = (rb.w + n) % rb.size
}
return
}
rb.bs[0] = rb.buf[rb.w:]
rb.bs[1] = rb.buf[:rb.r]
n, err = io.Readv(fd, rb.bs)
if n > 0 {
rb.w = (rb.w + n) % rb.size
}
return
}
// Rewind moves the data from its tail to head and rewind its pointers of read and write.
func (rb *Buffer) Rewind() (n int) {
if rb.IsEmpty() {
rb.Reset()
return
}
if rb.w == 0 {
if rb.r < rb.size-rb.r {
rb.grow(rb.size + rb.size - rb.r)
return rb.size - rb.r
}
n = copy(rb.buf, rb.buf[rb.r:])
rb.r = 0
rb.w = n
} else if rb.size-rb.w < DefaultBufferSize {
if rb.r < rb.w-rb.r {
rb.grow(rb.size + rb.w - rb.r)
return rb.w - rb.r
}
n = copy(rb.buf, rb.buf[rb.r:rb.w])
rb.r = 0
rb.w = n
}
return
}