John Howard <******@****.***> 1718030154 -0700

	ROUND1(Rd, Ra, Rb, Rc,  1, 12, Rc1)
	ROUND1(Rc, Rd, Ra, Rb,  2, 17, Rc2)
	ROUND1(Rb, Rc, Rd, Ra,  3, 22, Rc3)

	MOVM.IA.W (Rtable), [Rc0,Rc1,Rc2,Rc3]
	ROUND1(Ra, Rb, Rc, Rd,  4,	7, Rc0)
	ROUND1(Rd, Ra, Rb, Rc,  5, 12, Rc1)
	ROUND1(Rc, Rd, Ra, Rb,  6, 17, Rc2)
	ROUND1(Rb, Rc, Rd, Ra,  7, 22, Rc3)

	MOVM.IA.W (Rtable), [Rc0,Rc1,Rc2,Rc3]
	ROUND1(Ra, Rb, Rc, Rd,  8,	7, Rc0)
	ROUND1(Rd, Ra, Rb, Rc,  9, 12, Rc1)

	rb.AppendRuleV6(command, chain, table, params...)
	return rb
}

func (rb *IptablesRuleBuilder) AppendRuleV6(command log.Command, chain string, table string, params ...string) *IptablesRuleBuilder {
	if !rb.cfg.EnableIPv6 {
		return rb
	}
	return rb.appendInternal(&rb.rules.rulesv6, command, chain, table, params...)
}

func (rb *IptablesRuleBuilder) buildRules(rules []*Rule) [][]string {
	output := make([][]string, 0)

	ROUND1x(Re, Ra, Rb, Rc, Rd)
	ROUND1x(Rd, Re, Ra, Rb, Rc)
	ROUND1x(Rc, Rd, Re, Ra, Rb)
	ROUND1x(Rb, Rc, Rd, Re, Ra)

	MOVW	$0x6ED9EBA1, Rconst
	MOVW	$4, Rctr
loop2:	ROUND2(Ra, Rb, Rc, Rd, Re)
	ROUND2(Re, Ra, Rb, Rc, Rd)
	ROUND2(Rd, Re, Ra, Rb, Rc)
	ROUND2(Rc, Rd, Re, Ra, Rb)
	ROUND2(Rb, Rc, Rd, Re, Ra)
	SUB.S	$1, Rctr
	BNE	loop2

	MOVW	$0x8F1BBCDC, Rconst
	MOVW	$4, Rctr
loop3:	ROUND3(Ra, Rb, Rc, Rd, Re)

	Flags      uint32
	PathBuffer [1]uint16
}

// Path returns path stored in rb.
func (rb *SymbolicLinkReparseBuffer) Path() string {
	n1 := rb.SubstituteNameOffset / 2
	n2 := (rb.SubstituteNameOffset + rb.SubstituteNameLength) / 2
	return syscall.UTF16ToString((*[0xffff]uint16)(unsafe.Pointer(&rb.PathBuffer[0]))[n1:n2:n2])
}

type MountPointReparseBuffer struct {

	}
	if rb.Length() != 8 {
		t.Fatalf("expect len 16 bytes but got %d. r.w=%d, r.r=%d", rb.Length(), rb.w, rb.r)
	}
	if rb.Free() != 56 {
		t.Fatalf("expect free 48 bytes but got %d. r.w=%d, r.r=%d", rb.Free(), rb.w, rb.r)
	}
	buf := make([]byte, 5)
	rb.Read(buf)
	if rb.Length() != 3 {
		t.Fatalf("expect len 3 bytes but got %d. r.w=%d, r.r=%d", rb.Length(), rb.w, rb.r)
	}

# Usage

```go
package main

import (
	"fmt"

	"github.com/smallnest/ringbuffer"
)

func main() {
	rb := ringbuffer.New(1024)

	// write
	rb.Write([]byte("abcd"))
	fmt.Println(rb.Length())
	fmt.Println(rb.Free())

	// read
	buf := make([]byte, 4)
	rb.Read(buf)
	fmt.Println(string(buf))
}
```

It is possible to use an existing buffer with by replacing `New` with `NewBuffer`.

	go func() {
		for {
			rb.Read(buf)
		}
	}()

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		rb.Write(data)
	}
}

func BenchmarkRingBuffer_AsyncReadBlocking(b *testing.B) {
	const sz = 512
	const buffers = 10
	rb := New(sz * buffers)
	rb.SetBlocking(true)
	data := []byte(strings.Repeat("a", sz))
	buf := make([]byte, sz)

	go func() {
		for {
			rb.Read(buf)
		}
	}()

    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")
    path2 = tmp_path / "test2.txt"
    path2.write_bytes(b"<file content2>")

    client = TestClient(app)
    with path.open("rb") as file, path2.open("rb") as file2:
        response = client.post(
            "/files/",
            files=(
                ("files", ("test.txt", file)),
                ("files", ("test2.txt", file2)),
            ),

    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")
    path2 = tmp_path / "test2.txt"
    path2.write_bytes(b"<file content2>")

    client = TestClient(app)
    with path.open("rb") as file, path2.open("rb") as file2:
        response = client.post(
            "/files/",
            files=(
                ("files", ("test.txt", file)),
                ("files", ("test2.txt", file2)),
            ),