添加依赖库

vendor/github.com/cznic/internal/buffer/Makefile

@@ -0,0 +1,60 @@
+# Copyright 2016 The Internal Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+.PHONY:	all clean cover cpu editor internalError later mem nuke todo edit
+
+grep=--include=*.go --include=*.l --include=*.y --include=*.yy
+ngrep='TODOOK\|parser\.go\|scanner\.go\|.*_string\.go'
+
+all: editor
+	go vet 2>&1 | grep -v $(ngrep) || true
+	go vet 2>&1 | grep -v $(ngrep) || true
+	golint 2>&1 | grep -v $(ngrep) || true
+	make todo
+	unused . || true
+	misspell *.go
+	gosimple || true
+	codesweep || true
+	maligned || true
+	unconvert -apply
+
+clean:
+	go clean
+	rm -f *~ *.test *.out
+
+cover:
+	t=$(shell tempfile) ; go test -coverprofile $$t && go tool cover -html $$t && unlink $$t
+
+cpu: clean
+	go test -run @ -bench . -cpuprofile cpu.out
+	go tool pprof -lines *.test cpu.out
+
+edit:
+	@ 1>/dev/null 2>/dev/null gvim -p Makefile log *.go
+
+editor:
+	gofmt -l -s -w *.go
+	go test -i
+	go test 2>&1 | tee log
+	go install
+
+internalError:
+	egrep -ho '"internal error.*"' *.go | sort | cat -n
+
+later:
+	@grep -n $(grep) LATER * || true
+	@grep -n $(grep) MAYBE * || true
+
+mem: clean
+	go test -run @ -bench . -memprofile mem.out -memprofilerate 1 -timeout 24h
+	go tool pprof -lines -web -alloc_space *.test mem.out
+
+nuke: clean
+	go clean -i
+
+todo:
+	@grep -nr $(grep) ^[[:space:]]*_[[:space:]]*=[[:space:]][[:alpha:]][[:alnum:]]* * | grep -v $(ngrep) || true
+	@grep -nr $(grep) TODO * | grep -v $(ngrep) || true
+	@grep -nr $(grep) BUG * | grep -v $(ngrep) || true
+	@grep -nr $(grep) [^[:alpha:]]println * | grep -v $(ngrep) || true

vendor/github.com/cznic/internal/buffer/buffer.go

@@ -0,0 +1,146 @@
+// Copyright 2016 The Internal Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package buffer implements a pool of pointers to byte slices.
+//
+// Example usage pattern
+//
+//	p := buffer.Get(size)
+//	b := *p	// Now you can use b in any way you need.
+//	...
+//	// When b will not be used anymore
+//	buffer.Put(p)
+//	...
+//	// If b or p are not going out of scope soon, optionally
+//	b = nil
+//	p = nil
+//
+// Otherwise the pool cannot release the buffer on garbage collection.
+//
+// Do not do
+//
+//	p := buffer.Get(size)
+//	b := *p
+//	...
+//	buffer.Put(&b)
+//
+// or
+//
+//	b := *buffer.Get(size)
+//	...
+//	buffer.Put(&b)
+package buffer
+
+import (
+	"github.com/cznic/internal/slice"
+	"io"
+)
+
+// CGet returns a pointer to a byte slice of len size. The pointed to byte
+// slice is zeroed up to its cap. CGet panics for size < 0.
+//
+// CGet is safe for concurrent use by multiple goroutines.
+func CGet(size int) *[]byte { return slice.Bytes.CGet(size).(*[]byte) }
+
+// Get returns a pointer to a byte slice of len size. The pointed to byte slice
+// is not zeroed. Get panics for size < 0.
+//
+// Get is safe for concurrent use by multiple goroutines.
+func Get(size int) *[]byte { return slice.Bytes.Get(size).(*[]byte) }
+
+// Put puts a pointer to a byte slice into a pool for possible later reuse by
+// CGet or Get.
+//
+// Put is safe for concurrent use by multiple goroutines.
+func Put(p *[]byte) { slice.Bytes.Put(p) }
+
+// Bytes is similar to bytes.Buffer but may generate less garbage when properly
+// Closed. Zero value is ready to use.
+type Bytes struct {
+	p *[]byte
+}
+
+// Bytes return the content of b. The result is R/O.
+func (b *Bytes) Bytes() []byte {
+	if b.p != nil {
+		return *b.p
+	}
+
+	return nil
+}
+
+// Close will recycle the underlying storage, if any. After Close, b is again
+// the zero value.
+func (b *Bytes) Close() error {
+	if b.p != nil {
+		Put(b.p)
+		b.p = nil
+	}
+	return nil
+}
+
+// Len returns the size of content in b.
+func (b *Bytes) Len() int {
+	if b.p != nil {
+		return len(*b.p)
+	}
+
+	return 0
+}
+
+// Reset discard the content of Bytes while keeping the internal storage, if any.
+func (b *Bytes) Reset() {
+	if b.p != nil {
+		*b.p = (*b.p)[:0]
+	}
+}
+
+// Write writes p into b and returns (len(p), nil).
+func (b *Bytes) Write(p []byte) (int, error) {
+	n := b.Len()
+	b.grow(n + len(p))
+	copy((*b.p)[n:], p)
+	return len(p), nil
+}
+
+// WriteByte writes p into b and returns nil.
+func (b *Bytes) WriteByte(p byte) error {
+	n := b.Len()
+	b.grow(n + 1)
+	(*b.p)[n] = p
+	return nil
+}
+
+// WriteTo writes b's content to w and returns the number of bytes written to w
+// and an error, if any.
+func (b *Bytes) WriteTo(w io.Writer) (int64, error) {
+	n, err := w.Write(b.Bytes())
+	return int64(n), err
+}
+
+// WriteString writes s to b and returns (len(s), nil).
+func (b *Bytes) WriteString(s string) (int, error) {
+	n := b.Len()
+	b.grow(n + len(s))
+	copy((*b.p)[n:], s)
+	return len(s), nil
+}
+
+func (b *Bytes) grow(n int) {
+	if b.p != nil {
+		if n <= cap(*b.p) {
+			*b.p = (*b.p)[:n]
+			return
+		}
+
+		np := Get(2 * n)
+		*np = (*np)[:n]
+		copy(*np, *b.p)
+		Put(b.p)
+		b.p = np
+		return
+	}
+
+	b.p = Get(n)
+}

vendor/github.com/cznic/internal/file/Makefile

@@ -0,0 +1,55 @@
+# Copyright 2016 The Internal Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+.PHONY:	all clean cover cpu editor internalError later mem nuke todo edit
+
+grep=--include=*.go --include=*.l --include=*.y --include=*.yy
+ngrep='TODOOK\|parser\.go\|scanner\.go\|.*_string\.go'
+
+all: editor
+	go vet 2>&1 | grep -v $(ngrep) || true
+	golint 2>&1 | grep -v $(ngrep) || true
+	make todo
+	unused . || true
+	misspell *.go
+	gosimple || true
+
+clean:
+	go clean
+	rm -f *~ *.test *.out
+
+cover:
+	t=$(shell tempfile) ; go test -coverprofile $$t && go tool cover -html $$t && unlink $$t
+
+cpu: clean
+	go test -run @ -bench . -cpuprofile cpu.out
+	go tool pprof -lines *.test cpu.out
+
+edit:
+	@ 1>/dev/null 2>/dev/null gvim -p Makefile log *.go
+
+editor:
+	gofmt -l -s -w *.go
+	go test 2>&1 | tee log
+	go build
+
+internalError:
+	egrep -ho '"internal error.*"' *.go | sort | cat -n
+
+later:
+	@grep -n $(grep) LATER * || true
+	@grep -n $(grep) MAYBE * || true
+
+mem: clean
+	go test -run @ -bench BenchmarkReadWrite -benchmem -memprofile mem.out -memprofilerate 1 -timeout 24h
+	go tool pprof -lines -web -alloc_space *.test mem.out
+
+nuke: clean
+	go clean -i
+
+todo:
+	@grep -nr $(grep) ^[[:space:]]*_[[:space:]]*=[[:space:]][[:alpha:]][[:alnum:]]* * | grep -v $(ngrep) || true
+	@grep -nr $(grep) TODO * | grep -v $(ngrep) || true
+	@grep -nr $(grep) BUG * | grep -v $(ngrep) || true
+	@grep -nr $(grep) [^[:alpha:]]println * | grep -v $(ngrep) || true

vendor/github.com/cznic/internal/file/file.go

@@ -0,0 +1,434 @@
+// Copyright 2016 The Internal Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package file provides an os.File-like interface of a memory mapped file.
+package file
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/cznic/fileutil"
+	"github.com/cznic/internal/buffer"
+	"github.com/cznic/mathutil"
+	"github.com/edsrzf/mmap-go"
+)
+
+const copyBufSize = 1 << 20 // 1 MB.
+
+var (
+	_ Interface = (*mem)(nil)
+	_ Interface = (*file)(nil)
+
+	_ os.FileInfo = stat{}
+
+	sysPage = os.Getpagesize()
+)
+
+// Interface is a os.File-like entity.
+type Interface interface {
+	io.ReaderAt
+	io.ReaderFrom
+	io.WriterAt
+	io.WriterTo
+
+	Close() error
+	Stat() (os.FileInfo, error)
+	Sync() error
+	Truncate(int64) error
+}
+
+// Open returns a new Interface backed by f, or an error, if any.
+func Open(f *os.File) (Interface, error) { return newFile(f, 1<<30, 20) }
+
+// OpenMem returns a new Interface, or an error, if any. The Interface content
+// is volatile, it's backed only by process' memory.
+func OpenMem(name string) (Interface, error) { return newMem(name, 18), nil }
+
+type memMap map[int64]*[]byte
+
+type mem struct {
+	m       memMap
+	modTime time.Time
+	name    string
+	pgBits  uint
+	pgMask  int
+	pgSize  int
+	size    int64
+}
+
+func newMem(name string, pgBits uint) *mem {
+	pgSize := 1 << pgBits
+	return &mem{
+		m:       memMap{},
+		modTime: time.Now(),
+		name:    name,
+		pgBits:  pgBits,
+		pgMask:  pgSize - 1,
+		pgSize:  pgSize,
+	}
+}
+
+func (f *mem) IsDir() bool                               { return false }
+func (f *mem) Mode() os.FileMode                         { return os.ModeTemporary + 0600 }
+func (f *mem) ModTime() time.Time                        { return f.modTime }
+func (f *mem) Name() string                              { return f.name }
+func (f *mem) ReadFrom(r io.Reader) (n int64, err error) { return readFrom(f, r) }
+func (f *mem) Size() (n int64)                           { return f.size }
+func (f *mem) Stat() (os.FileInfo, error)                { return f, nil }
+func (f *mem) Sync() error                               { return nil }
+func (f *mem) Sys() interface{}                          { return nil }
+func (f *mem) WriteTo(w io.Writer) (n int64, err error)  { return writeTo(f, w) }
+
+func (f *mem) Close() error {
+	f.Truncate(0)
+	f.m = nil
+	return nil
+}
+
+func (f *mem) ReadAt(b []byte, off int64) (n int, err error) {
+	avail := f.size - off
+	pi := off >> f.pgBits
+	po := int(off) & f.pgMask
+	rem := len(b)
+	if int64(rem) >= avail {
+		rem = int(avail)
+		err = io.EOF
+	}
+	var zeroPage *[]byte
+	for rem != 0 && avail > 0 {
+		pg := f.m[pi]
+		if pg == nil {
+			if zeroPage == nil {
+				zeroPage = buffer.CGet(f.pgSize)
+				defer buffer.Put(zeroPage)
+			}
+			pg = zeroPage
+		}
+		nc := copy(b[:mathutil.Min(rem, f.pgSize)], (*pg)[po:])
+		pi++
+		po = 0
+		rem -= nc
+		n += nc
+		b = b[nc:]
+	}
+	return n, err
+}
+
+func (f *mem) Truncate(size int64) (err error) {
+	if size < 0 {
+		return fmt.Errorf("invalid truncate size: %d", size)
+	}
+
+	first := size >> f.pgBits
+	if size&int64(f.pgMask) != 0 {
+		first++
+	}
+	last := f.size >> f.pgBits
+	if f.size&int64(f.pgMask) != 0 {
+		last++
+	}
+	for ; first <= last; first++ {
+		if p := f.m[first]; p != nil {
+			buffer.Put(p)
+		}
+		delete(f.m, first)
+	}
+
+	f.size = size
+	return nil
+}
+
+func (f *mem) WriteAt(b []byte, off int64) (n int, err error) {
+	pi := off >> f.pgBits
+	po := int(off) & f.pgMask
+	n = len(b)
+	rem := n
+	var nc int
+	for rem != 0 {
+		pg := f.m[pi]
+		if pg == nil {
+			pg = buffer.CGet(f.pgSize)
+			f.m[pi] = pg
+		}
+		nc = copy((*pg)[po:], b)
+		pi++
+		po = 0
+		rem -= nc
+		b = b[nc:]
+	}
+	f.size = mathutil.MaxInt64(f.size, off+int64(n))
+	return n, nil
+}
+
+type stat struct {
+	os.FileInfo
+	size int64
+}
+
+func (s stat) Size() int64 { return s.size }
+
+type fileMap map[int64]mmap.MMap
+
+type file struct {
+	f        *os.File
+	m        fileMap
+	maxPages int
+	pgBits   uint
+	pgMask   int
+	pgSize   int
+	size     int64
+	fsize    int64
+}
+
+func newFile(f *os.File, maxSize int64, pgBits uint) (*file, error) {
+	if maxSize < 0 {
+		panic("internal error")
+	}
+
+	pgSize := 1 << pgBits
+	switch {
+	case sysPage > pgSize:
+		pgBits = uint(mathutil.Log2Uint64(uint64(sysPage)))
+	default:
+		pgBits = uint(mathutil.Log2Uint64(uint64(pgSize / sysPage * sysPage)))
+	}
+	pgSize = 1 << pgBits
+	fi := &file{
+		f: f,
+		m: fileMap{},
+		maxPages: int(mathutil.MinInt64(
+			1024,
+			mathutil.MaxInt64(maxSize/int64(pgSize), 1)),
+		),
+		pgBits: pgBits,
+		pgMask: pgSize - 1,
+		pgSize: pgSize,
+	}
+	info, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	if err = fi.Truncate(info.Size()); err != nil {
+		return nil, err
+	}
+
+	return fi, nil
+}
+
+func (f *file) ReadFrom(r io.Reader) (n int64, err error) { return readFrom(f, r) }
+func (f *file) Sync() (err error)                         { return f.f.Sync() }
+func (f *file) WriteTo(w io.Writer) (n int64, err error)  { return writeTo(f, w) }
+
+func (f *file) Close() (err error) {
+	for _, p := range f.m {
+		if err = p.Unmap(); err != nil {
+			return err
+		}
+	}
+
+	if err = f.f.Truncate(f.size); err != nil {
+		return err
+	}
+
+	if err = f.f.Sync(); err != nil {
+		return err
+	}
+
+	if err = f.f.Close(); err != nil {
+		return err
+	}
+
+	f.m = nil
+	f.f = nil
+	return nil
+}
+
+func (f *file) page(index int64) (mmap.MMap, error) {
+	if len(f.m) == f.maxPages {
+		for i, p := range f.m {
+			if err := p.Unmap(); err != nil {
+				return nil, err
+			}
+
+			delete(f.m, i)
+			break
+		}
+	}
+
+	off := index << f.pgBits
+	fsize := off + int64(f.pgSize)
+	if fsize > f.fsize {
+		if err := f.f.Truncate(fsize); err != nil {
+			return nil, err
+		}
+
+		f.fsize = fsize
+	}
+	p, err := mmap.MapRegion(f.f, f.pgSize, mmap.RDWR, 0, off)
+	if err != nil {
+		return nil, err
+	}
+
+	f.m[index] = p
+	return p, nil
+}
+
+func (f *file) ReadAt(b []byte, off int64) (n int, err error) {
+	avail := f.size - off
+	pi := off >> f.pgBits
+	po := int(off) & f.pgMask
+	rem := len(b)
+	if int64(rem) >= avail {
+		rem = int(avail)
+		err = io.EOF
+	}
+	for rem != 0 && avail > 0 {
+		pg := f.m[pi]
+		if pg == nil {
+			if pg, err = f.page(pi); err != nil {
+				return n, err
+			}
+		}
+		nc := copy(b[:mathutil.Min(rem, f.pgSize)], pg[po:])
+		pi++
+		po = 0
+		rem -= nc
+		n += nc
+		b = b[nc:]
+	}
+	return n, err
+}
+
+func (f *file) Stat() (os.FileInfo, error) {
+	fi, err := f.f.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	return stat{fi, f.size}, nil
+}
+
+func (f *file) Truncate(size int64) (err error) {
+	if size < 0 {
+		return fmt.Errorf("invalid truncate size: %d", size)
+	}
+
+	first := size >> f.pgBits
+	if size&int64(f.pgMask) != 0 {
+		first++
+	}
+	last := f.size >> f.pgBits
+	if f.size&int64(f.pgMask) != 0 {
+		last++
+	}
+	for ; first <= last; first++ {
+		if p := f.m[first]; p != nil {
+			if err := p.Unmap(); err != nil {
+				return err
+			}
+		}
+
+		delete(f.m, first)
+	}
+
+	f.size = size
+	fsize := (size + int64(f.pgSize) - 1) &^ int64(f.pgMask)
+	if fsize != f.fsize {
+		if err := f.f.Truncate(fsize); err != nil {
+			return err
+		}
+
+	}
+	f.fsize = fsize
+	return nil
+}
+
+func (f *file) WriteAt(b []byte, off int64) (n int, err error) {
+	pi := off >> f.pgBits
+	po := int(off) & f.pgMask
+	n = len(b)
+	rem := n
+	var nc int
+	for rem != 0 {
+		pg := f.m[pi]
+		if pg == nil {
+			pg, err = f.page(pi)
+			if err != nil {
+				return n, err
+			}
+		}
+		nc = copy(pg[po:], b)
+		pi++
+		po = 0
+		rem -= nc
+		b = b[nc:]
+	}
+	f.size = mathutil.MaxInt64(f.size, off+int64(n))
+	return n, nil
+}
+
+// ----------------------------------------------------------------------------
+
+func readFrom(f Interface, r io.Reader) (n int64, err error) {
+	f.Truncate(0)
+	p := buffer.Get(copyBufSize)
+	b := *p
+	defer buffer.Put(p)
+
+	var off int64
+	var werr error
+	for {
+		rn, rerr := r.Read(b)
+		if rn != 0 {
+			_, werr = f.WriteAt(b[:rn], off)
+			n += int64(rn)
+			off += int64(rn)
+		}
+		if rerr != nil {
+			if !fileutil.IsEOF(rerr) {
+				err = rerr
+			}
+			break
+		}
+
+		if werr != nil {
+			err = werr
+			break
+		}
+	}
+	return n, err
+}
+
+func writeTo(f Interface, w io.Writer) (n int64, err error) {
+	p := buffer.Get(copyBufSize)
+	b := *p
+	defer buffer.Put(p)
+
+	var off int64
+	var werr error
+	for {
+		rn, rerr := f.ReadAt(b, off)
+		if rn != 0 {
+			_, werr = w.Write(b[:rn])
+			n += int64(rn)
+			off += int64(rn)
+		}
+		if rerr != nil {
+			if !fileutil.IsEOF(rerr) {
+				err = rerr
+			}
+			break
+		}
+
+		if werr != nil {
+			err = werr
+			break
+		}
+	}
+	return n, err
+}

vendor/github.com/cznic/internal/slice/Makefile

@@ -0,0 +1,55 @@
+# Copyright 2016 The Internal Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+.PHONY:	all clean cover cpu editor internalError later mem nuke todo edit
+
+grep=--include=*.go --include=*.l --include=*.y --include=*.yy
+ngrep='TODOOK\|parser\.go\|scanner\.go\|.*_string\.go'
+
+all: editor
+	go vet 2>&1 | grep -v $(ngrep) || true
+	golint 2>&1 | grep -v $(ngrep) || true
+	make todo
+	unused . || true
+	misspell *.go
+	gosimple || true
+
+clean:
+	go clean
+	rm -f *~ *.test *.out
+
+cover:
+	t=$(shell tempfile) ; go test -coverprofile $$t && go tool cover -html $$t && unlink $$t
+
+cpu: clean
+	go test -run @ -bench . -cpuprofile cpu.out
+	go tool pprof -lines *.test cpu.out
+
+edit:
+	@ 1>/dev/null 2>/dev/null gvim -p Makefile log *.go
+
+editor:
+	gofmt -l -s -w *.go
+	go test 2>&1 | tee log
+	go build
+
+internalError:
+	egrep -ho '"internal error.*"' *.go | sort | cat -n
+
+later:
+	@grep -n $(grep) LATER * || true
+	@grep -n $(grep) MAYBE * || true
+
+mem: clean
+	go test -run @ -bench . -memprofile mem.out -memprofilerate 1 -timeout 24h
+	go tool pprof -lines -web -alloc_space *.test mem.out
+
+nuke: clean
+	go clean -i
+
+todo:
+	@grep -nr $(grep) ^[[:space:]]*_[[:space:]]*=[[:space:]][[:alpha:]][[:alnum:]]* * | grep -v $(ngrep) || true
+	@grep -nr $(grep) TODO * | grep -v $(ngrep) || true
+	@grep -nr $(grep) BUG * | grep -v $(ngrep) || true
+	@grep -nr $(grep) [^[:alpha:]]println * | grep -v $(ngrep) || true

vendor/github.com/cznic/internal/slice/pool.go

@@ -0,0 +1,173 @@
+// Copyright 2016 The Internal Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package slice implements pools of pointers to slices.
+package slice
+
+import (
+	"sync"
+
+	"github.com/cznic/mathutil"
+)
+
+var (
+	// Bytes is a ready to use *[]byte Pool.
+	Bytes *Pool
+	// Ints is a ready to use *[]int Pool.
+	Ints *Pool
+)
+
+func init() {
+	Bytes = newBytes()
+	Ints = NewPool(
+		func(size int) interface{} { // create
+			b := make([]int, size)
+			return &b
+		},
+		func(s interface{}) { // clear
+			b := *s.(*[]int)
+			b = b[:cap(b)]
+			for i := range b {
+				b[i] = 0
+			}
+		},
+		func(s interface{}, size int) { // setSize
+			p := s.(*[]int)
+			*p = (*p)[:size]
+		},
+		func(s interface{}) int { return cap(*s.(*[]int)) }, // cap
+	)
+}
+
+func newBytes() *Pool {
+	return NewPool(
+		func(size int) interface{} { // create
+			b := make([]byte, size)
+			return &b
+		},
+		func(s interface{}) { // clear
+			b := *s.(*[]byte)
+			b = b[:cap(b)]
+			for i := range b {
+				b[i] = 0
+			}
+		},
+		func(s interface{}, size int) { // setSize
+			p := s.(*[]byte)
+			*p = (*p)[:size]
+		},
+		func(s interface{}) int { return cap(*s.(*[]byte)) }, // cap
+	)
+}
+
+// Pool implements a pool of pointers to slices.
+//
+// Example usage pattern (assuming pool is, for example, a *[]byte Pool)
+//
+//	p := pool.Get(size).(*[]byte)
+//	b := *p	// Now you can use b in any way you need.
+//	...
+//	// When b will not be used anymore
+//	pool.Put(p)
+//	...
+//	// If b or p are not going out of scope soon, optionally
+//	b = nil
+//	p = nil
+//
+// Otherwise the pool cannot release the slice on garbage collection.
+//
+// Do not do
+//
+//	p := pool.Get(size).(*[]byte)
+//	b := *p
+//	...
+//	pool.Put(&b)
+//
+// or
+//
+//	b := *pool.Get(size).(*[]byte)
+//	...
+//	pool.Put(&b)
+type Pool struct {
+	cap     func(interface{}) int
+	clear   func(interface{})
+	m       [63]sync.Pool
+	null    interface{}
+	setSize func(interface{}, int)
+}
+
+// NewPool returns a newly created Pool. Assuming the desired slice type is
+// []T:
+//
+// The create function returns a *[]T of len == cap == size.
+//
+// The argument of clear is *[]T and the function sets all the slice elements
+// to the respective zero value.
+//
+// The setSize function gets a *[]T and sets its len to size.
+//
+// The cap function gets a *[]T and returns its capacity.
+func NewPool(
+	create func(size int) interface{},
+	clear func(interface{}),
+	setSize func(p interface{}, size int),
+	cap func(p interface{}) int,
+) *Pool {
+	p := &Pool{clear: clear, setSize: setSize, cap: cap, null: create(0)}
+	for i := range p.m {
+		size := 1 << uint(i)
+		p.m[i] = sync.Pool{New: func() interface{} {
+			// 0:     1 -      1
+			// 1:    10 -     10
+			// 2:    11 -    100
+			// 3:   101 -   1000
+			// 4:  1001 -  10000
+			// 5: 10001 - 100000
+			return create(size)
+		}}
+	}
+	return p
+}
+
+// CGet returns a *[]T of len size. The pointed to slice is zeroed up to its
+// cap. CGet panics for size < 0.
+//
+// CGet is safe for concurrent use by multiple goroutines.
+func (p *Pool) CGet(size int) interface{} {
+	s := p.Get(size)
+	p.clear(s)
+	return s
+}
+
+// Get returns a *[]T of len size. The pointed to slice is not zeroed. Get
+// panics for size < 0.
+//
+// Get is safe for concurrent use by multiple goroutines.
+func (p *Pool) Get(size int) interface{} {
+	var index int
+	switch {
+	case size < 0:
+		panic("Pool.Get: negative size")
+	case size == 0:
+		return p.null
+	case size > 1:
+		index = mathutil.Log2Uint64(uint64(size-1)) + 1
+	}
+	s := p.m[index].Get()
+	p.setSize(s, size)
+	return s
+}
+
+// Put puts a *[]T into a pool for possible later reuse by CGet or Get. Put
+// panics is its argument is not of type *[]T.
+//
+// Put is safe for concurrent use by multiple goroutines.
+func (p *Pool) Put(b interface{}) {
+	size := p.cap(b)
+	if size == 0 {
+		return
+	}
+
+	p.m[mathutil.Log2Uint64(uint64(size))].Put(b)
+}