vendor: import golang.org/x/net/http2

golang.org/x/net/http2 becomes net/http/h2_bundle.go (using adonovan's
x/tools/cmd/bundle tool), becoming a hidden part of the net/http package.

golang.org/x/net/http2/hpack becomes vendor/golang.org/x/net/http2/hpack.

At git rev 7331ef52 (https://go-review.googlesource.com/15821)

Change-Id: Ia6683e6f91a481b11a778638bf65b6a338744eea
Reviewed-on: https://go-review.googlesource.com/15822Reviewed-by: Andrew Gerrand <adg@golang.org>

src/vendor/golang.org/x/net/http2/hpack/encode.go

+// Copyright 2014 The Go 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 hpack
+
+import (
+	"io"
+)
+
+const (
+	uint32Max              = ^uint32(0)
+	initialHeaderTableSize = 4096
+)
+
+type Encoder struct {
+	dynTab dynamicTable
+	// minSize is the minimum table size set by
+	// SetMaxDynamicTableSize after the previous Header Table Size
+	// Update.
+	minSize uint32
+	// maxSizeLimit is the maximum table size this encoder
+	// supports. This will protect the encoder from too large
+	// size.
+	maxSizeLimit uint32
+	// tableSizeUpdate indicates whether "Header Table Size
+	// Update" is required.
+	tableSizeUpdate bool
+	w               io.Writer
+	buf             []byte
+}
+
+// NewEncoder returns a new Encoder which performs HPACK encoding. An
+// encoded data is written to w.
+func NewEncoder(w io.Writer) *Encoder {
+	e := &Encoder{
+		minSize:         uint32Max,
+		maxSizeLimit:    initialHeaderTableSize,
+		tableSizeUpdate: false,
+		w:               w,
+	}
+	e.dynTab.setMaxSize(initialHeaderTableSize)
+	return e
+}
+
+// WriteField encodes f into a single Write to e's underlying Writer.
+// This function may also produce bytes for "Header Table Size Update"
+// if necessary.  If produced, it is done before encoding f.
+func (e *Encoder) WriteField(f HeaderField) error {
+	e.buf = e.buf[:0]
+
+	if e.tableSizeUpdate {
+		e.tableSizeUpdate = false
+		if e.minSize < e.dynTab.maxSize {
+			e.buf = appendTableSize(e.buf, e.minSize)
+		}
+		e.minSize = uint32Max
+		e.buf = appendTableSize(e.buf, e.dynTab.maxSize)
+	}
+
+	idx, nameValueMatch := e.searchTable(f)
+	if nameValueMatch {
+		e.buf = appendIndexed(e.buf, idx)
+	} else {
+		indexing := e.shouldIndex(f)
+		if indexing {
+			e.dynTab.add(f)
+		}
+
+		if idx == 0 {
+			e.buf = appendNewName(e.buf, f, indexing)
+		} else {
+			e.buf = appendIndexedName(e.buf, f, idx, indexing)
+		}
+	}
+	n, err := e.w.Write(e.buf)
+	if err == nil && n != len(e.buf) {
+		err = io.ErrShortWrite
+	}
+	return err
+}
+
+// searchTable searches f in both stable and dynamic header tables.
+// The static header table is searched first. Only when there is no
+// exact match for both name and value, the dynamic header table is
+// then searched. If there is no match, i is 0. If both name and value
+// match, i is the matched index and nameValueMatch becomes true. If
+// only name matches, i points to that index and nameValueMatch
+// becomes false.
+func (e *Encoder) searchTable(f HeaderField) (i uint64, nameValueMatch bool) {
+	for idx, hf := range staticTable {
+		if !constantTimeStringCompare(hf.Name, f.Name) {
+			continue
+		}
+		if i == 0 {
+			i = uint64(idx + 1)
+		}
+		if f.Sensitive {
+			continue
+		}
+		if !constantTimeStringCompare(hf.Value, f.Value) {
+			continue
+		}
+		i = uint64(idx + 1)
+		nameValueMatch = true
+		return
+	}
+
+	j, nameValueMatch := e.dynTab.search(f)
+	if nameValueMatch || (i == 0 && j != 0) {
+		i = j + uint64(len(staticTable))
+	}
+	return
+}
+
+// SetMaxDynamicTableSize changes the dynamic header table size to v.
+// The actual size is bounded by the value passed to
+// SetMaxDynamicTableSizeLimit.
+func (e *Encoder) SetMaxDynamicTableSize(v uint32) {
+	if v > e.maxSizeLimit {
+		v = e.maxSizeLimit
+	}
+	if v < e.minSize {
+		e.minSize = v
+	}
+	e.tableSizeUpdate = true
+	e.dynTab.setMaxSize(v)
+}
+
+// SetMaxDynamicTableSizeLimit changes the maximum value that can be
+// specified in SetMaxDynamicTableSize to v. By default, it is set to
+// 4096, which is the same size of the default dynamic header table
+// size described in HPACK specification. If the current maximum
+// dynamic header table size is strictly greater than v, "Header Table
+// Size Update" will be done in the next WriteField call and the
+// maximum dynamic header table size is truncated to v.
+func (e *Encoder) SetMaxDynamicTableSizeLimit(v uint32) {
+	e.maxSizeLimit = v
+	if e.dynTab.maxSize > v {
+		e.tableSizeUpdate = true
+		e.dynTab.setMaxSize(v)
+	}
+}
+
+// shouldIndex reports whether f should be indexed.
+func (e *Encoder) shouldIndex(f HeaderField) bool {
+	return !f.Sensitive && f.size() <= e.dynTab.maxSize
+}
+
+// appendIndexed appends index i, as encoded in "Indexed Header Field"
+// representation, to dst and returns the extended buffer.
+func appendIndexed(dst []byte, i uint64) []byte {
+	first := len(dst)
+	dst = appendVarInt(dst, 7, i)
+	dst[first] |= 0x80
+	return dst
+}
+
+// appendNewName appends f, as encoded in one of "Literal Header field
+// - New Name" representation variants, to dst and returns the
+// extended buffer.
+//
+// If f.Sensitive is true, "Never Indexed" representation is used. If
+// f.Sensitive is false and indexing is true, "Inremental Indexing"
+// representation is used.
+func appendNewName(dst []byte, f HeaderField, indexing bool) []byte {
+	dst = append(dst, encodeTypeByte(indexing, f.Sensitive))
+	dst = appendHpackString(dst, f.Name)
+	return appendHpackString(dst, f.Value)
+}
+
+// appendIndexedName appends f and index i referring indexed name
+// entry, as encoded in one of "Literal Header field - Indexed Name"
+// representation variants, to dst and returns the extended buffer.
+//
+// If f.Sensitive is true, "Never Indexed" representation is used. If
+// f.Sensitive is false and indexing is true, "Incremental Indexing"
+// representation is used.
+func appendIndexedName(dst []byte, f HeaderField, i uint64, indexing bool) []byte {
+	first := len(dst)
+	var n byte
+	if indexing {
+		n = 6
+	} else {
+		n = 4
+	}
+	dst = appendVarInt(dst, n, i)
+	dst[first] |= encodeTypeByte(indexing, f.Sensitive)
+	return appendHpackString(dst, f.Value)
+}
+
+// appendTableSize appends v, as encoded in "Header Table Size Update"
+// representation, to dst and returns the extended buffer.
+func appendTableSize(dst []byte, v uint32) []byte {
+	first := len(dst)
+	dst = appendVarInt(dst, 5, uint64(v))
+	dst[first] |= 0x20
+	return dst
+}
+
+// appendVarInt appends i, as encoded in variable integer form using n
+// bit prefix, to dst and returns the extended buffer.
+//
+// See
+// http://http2.github.io/http2-spec/compression.html#integer.representation
+func appendVarInt(dst []byte, n byte, i uint64) []byte {
+	k := uint64((1 << n) - 1)
+	if i < k {
+		return append(dst, byte(i))
+	}
+	dst = append(dst, byte(k))
+	i -= k
+	for ; i >= 128; i >>= 7 {
+		dst = append(dst, byte(0x80|(i&0x7f)))
+	}
+	return append(dst, byte(i))
+}
+
+// appendHpackString appends s, as encoded in "String Literal"
+// representation, to dst and returns the the extended buffer.
+//
+// s will be encoded in Huffman codes only when it produces strictly
+// shorter byte string.
+func appendHpackString(dst []byte, s string) []byte {
+	huffmanLength := HuffmanEncodeLength(s)
+	if huffmanLength < uint64(len(s)) {
+		first := len(dst)
+		dst = appendVarInt(dst, 7, huffmanLength)
+		dst = AppendHuffmanString(dst, s)
+		dst[first] |= 0x80
+	} else {
+		dst = appendVarInt(dst, 7, uint64(len(s)))
+		dst = append(dst, s...)
+	}
+	return dst
+}
+
+// encodeTypeByte returns type byte. If sensitive is true, type byte
+// for "Never Indexed" representation is returned. If sensitive is
+// false and indexing is true, type byte for "Incremental Indexing"
+// representation is returned. Otherwise, type byte for "Without
+// Indexing" is returned.
+func encodeTypeByte(indexing, sensitive bool) byte {
+	if sensitive {
+		return 0x10
+	}
+	if indexing {
+		return 0x40
+	}
+	return 0
+}

src/vendor/golang.org/x/net/http2/hpack/encode_test.go

+// Copyright 2014 The Go 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 hpack
+
+import (
+	"bytes"
+	"encoding/hex"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestEncoderTableSizeUpdate(t *testing.T) {
+	tests := []struct {
+		size1, size2 uint32
+		wantHex      string
+	}{
+		// Should emit 2 table size updates (2048 and 4096)
+		{2048, 4096, "3fe10f 3fe11f 82"},
+
+		// Should emit 1 table size update (2048)
+		{16384, 2048, "3fe10f 82"},
+	}
+	for _, tt := range tests {
+		var buf bytes.Buffer
+		e := NewEncoder(&buf)
+		e.SetMaxDynamicTableSize(tt.size1)
+		e.SetMaxDynamicTableSize(tt.size2)
+		if err := e.WriteField(pair(":method", "GET")); err != nil {
+			t.Fatal(err)
+		}
+		want := removeSpace(tt.wantHex)
+		if got := hex.EncodeToString(buf.Bytes()); got != want {
+			t.Errorf("e.SetDynamicTableSize %v, %v = %q; want %q", tt.size1, tt.size2, got, want)
+		}
+	}
+}
+
+func TestEncoderWriteField(t *testing.T) {
+	var buf bytes.Buffer
+	e := NewEncoder(&buf)
+	var got []HeaderField
+	d := NewDecoder(4<<10, func(f HeaderField) {
+		got = append(got, f)
+	})
+
+	tests := []struct {
+		hdrs []HeaderField
+	}{
+		{[]HeaderField{
+			pair(":method", "GET"),
+			pair(":scheme", "http"),
+			pair(":path", "/"),
+			pair(":authority", "www.example.com"),
+		}},
+		{[]HeaderField{
+			pair(":method", "GET"),
+			pair(":scheme", "http"),
+			pair(":path", "/"),
+			pair(":authority", "www.example.com"),
+			pair("cache-control", "no-cache"),
+		}},
+		{[]HeaderField{
+			pair(":method", "GET"),
+			pair(":scheme", "https"),
+			pair(":path", "/index.html"),
+			pair(":authority", "www.example.com"),
+			pair("custom-key", "custom-value"),
+		}},
+	}
+	for i, tt := range tests {
+		buf.Reset()
+		got = got[:0]
+		for _, hf := range tt.hdrs {
+			if err := e.WriteField(hf); err != nil {
+				t.Fatal(err)
+			}
+		}
+		_, err := d.Write(buf.Bytes())
+		if err != nil {
+			t.Errorf("%d. Decoder Write = %v", i, err)
+		}
+		if !reflect.DeepEqual(got, tt.hdrs) {
+			t.Errorf("%d. Decoded %+v; want %+v", i, got, tt.hdrs)
+		}
+	}
+}
+
+func TestEncoderSearchTable(t *testing.T) {
+	e := NewEncoder(nil)
+
+	e.dynTab.add(pair("foo", "bar"))
+	e.dynTab.add(pair("blake", "miz"))
+	e.dynTab.add(pair(":method", "GET"))
+
+	tests := []struct {
+		hf        HeaderField
+		wantI     uint64
+		wantMatch bool
+	}{
+		// Name and Value match
+		{pair("foo", "bar"), uint64(len(staticTable) + 3), true},
+		{pair("blake", "miz"), uint64(len(staticTable) + 2), true},
+		{pair(":method", "GET"), 2, true},
+
+		// Only name match because Sensitive == true
+		{HeaderField{":method", "GET", true}, 2, false},
+
+		// Only Name matches
+		{pair("foo", "..."), uint64(len(staticTable) + 3), false},
+		{pair("blake", "..."), uint64(len(staticTable) + 2), false},
+		{pair(":method", "..."), 2, false},
+
+		// None match
+		{pair("foo-", "bar"), 0, false},
+	}
+	for _, tt := range tests {
+		if gotI, gotMatch := e.searchTable(tt.hf); gotI != tt.wantI || gotMatch != tt.wantMatch {
+			t.Errorf("d.search(%+v) = %v, %v; want %v, %v", tt.hf, gotI, gotMatch, tt.wantI, tt.wantMatch)
+		}
+	}
+}
+
+func TestAppendVarInt(t *testing.T) {
+	tests := []struct {
+		n    byte
+		i    uint64
+		want []byte
+	}{
+		// Fits in a byte:
+		{1, 0, []byte{0}},
+		{2, 2, []byte{2}},
+		{3, 6, []byte{6}},
+		{4, 14, []byte{14}},
+		{5, 30, []byte{30}},
+		{6, 62, []byte{62}},
+		{7, 126, []byte{126}},
+		{8, 254, []byte{254}},
+
+		// Multiple bytes:
+		{5, 1337, []byte{31, 154, 10}},
+	}
+	for _, tt := range tests {
+		got := appendVarInt(nil, tt.n, tt.i)
+		if !bytes.Equal(got, tt.want) {
+			t.Errorf("appendVarInt(nil, %v, %v) = %v; want %v", tt.n, tt.i, got, tt.want)
+		}
+	}
+}
+
+func TestAppendHpackString(t *testing.T) {
+	tests := []struct {
+		s, wantHex string
+	}{
+		// Huffman encoded
+		{"www.example.com", "8c f1e3 c2e5 f23a 6ba0 ab90 f4ff"},
+
+		// Not Huffman encoded
+		{"a", "01 61"},
+
+		// zero length
+		{"", "00"},
+	}
+	for _, tt := range tests {
+		want := removeSpace(tt.wantHex)
+		buf := appendHpackString(nil, tt.s)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("appendHpackString(nil, %q) = %q; want %q", tt.s, got, want)
+		}
+	}
+}
+
+func TestAppendIndexed(t *testing.T) {
+	tests := []struct {
+		i       uint64
+		wantHex string
+	}{
+		// 1 byte
+		{1, "81"},
+		{126, "fe"},
+
+		// 2 bytes
+		{127, "ff00"},
+		{128, "ff01"},
+	}
+	for _, tt := range tests {
+		want := removeSpace(tt.wantHex)
+		buf := appendIndexed(nil, tt.i)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("appendIndex(nil, %v) = %q; want %q", tt.i, got, want)
+		}
+	}
+}
+
+func TestAppendNewName(t *testing.T) {
+	tests := []struct {
+		f        HeaderField
+		indexing bool
+		wantHex  string
+	}{
+		// Incremental indexing
+		{HeaderField{"custom-key", "custom-value", false}, true, "40 88 25a8 49e9 5ba9 7d7f 89 25a8 49e9 5bb8 e8b4 bf"},
+
+		// Without indexing
+		{HeaderField{"custom-key", "custom-value", false}, false, "00 88 25a8 49e9 5ba9 7d7f 89 25a8 49e9 5bb8 e8b4 bf"},
+
+		// Never indexed
+		{HeaderField{"custom-key", "custom-value", true}, true, "10 88 25a8 49e9 5ba9 7d7f 89 25a8 49e9 5bb8 e8b4 bf"},
+		{HeaderField{"custom-key", "custom-value", true}, false, "10 88 25a8 49e9 5ba9 7d7f 89 25a8 49e9 5bb8 e8b4 bf"},
+	}
+	for _, tt := range tests {
+		want := removeSpace(tt.wantHex)
+		buf := appendNewName(nil, tt.f, tt.indexing)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("appendNewName(nil, %+v, %v) = %q; want %q", tt.f, tt.indexing, got, want)
+		}
+	}
+}
+
+func TestAppendIndexedName(t *testing.T) {
+	tests := []struct {
+		f        HeaderField
+		i        uint64
+		indexing bool
+		wantHex  string
+	}{
+		// Incremental indexing
+		{HeaderField{":status", "302", false}, 8, true, "48 82 6402"},
+
+		// Without indexing
+		{HeaderField{":status", "302", false}, 8, false, "08 82 6402"},
+
+		// Never indexed
+		{HeaderField{":status", "302", true}, 8, true, "18 82 6402"},
+		{HeaderField{":status", "302", true}, 8, false, "18 82 6402"},
+	}
+	for _, tt := range tests {
+		want := removeSpace(tt.wantHex)
+		buf := appendIndexedName(nil, tt.f, tt.i, tt.indexing)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("appendIndexedName(nil, %+v, %v) = %q; want %q", tt.f, tt.indexing, got, want)
+		}
+	}
+}
+
+func TestAppendTableSize(t *testing.T) {
+	tests := []struct {
+		i       uint32
+		wantHex string
+	}{
+		// Fits into 1 byte
+		{30, "3e"},
+
+		// Extra byte
+		{31, "3f00"},
+		{32, "3f01"},
+	}
+	for _, tt := range tests {
+		want := removeSpace(tt.wantHex)
+		buf := appendTableSize(nil, tt.i)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("appendTableSize(nil, %v) = %q; want %q", tt.i, got, want)
+		}
+	}
+}
+
+func TestEncoderSetMaxDynamicTableSize(t *testing.T) {
+	var buf bytes.Buffer
+	e := NewEncoder(&buf)
+	tests := []struct {
+		v           uint32
+		wantUpdate  bool
+		wantMinSize uint32
+		wantMaxSize uint32
+	}{
+		// Set new table size to 2048
+		{2048, true, 2048, 2048},
+
+		// Set new table size to 16384, but still limited to
+		// 4096
+		{16384, true, 2048, 4096},
+	}
+	for _, tt := range tests {
+		e.SetMaxDynamicTableSize(tt.v)
+		if got := e.tableSizeUpdate; tt.wantUpdate != got {
+			t.Errorf("e.tableSizeUpdate = %v; want %v", got, tt.wantUpdate)
+		}
+		if got := e.minSize; tt.wantMinSize != got {
+			t.Errorf("e.minSize = %v; want %v", got, tt.wantMinSize)
+		}
+		if got := e.dynTab.maxSize; tt.wantMaxSize != got {
+			t.Errorf("e.maxSize = %v; want %v", got, tt.wantMaxSize)
+		}
+	}
+}
+
+func TestEncoderSetMaxDynamicTableSizeLimit(t *testing.T) {
+	e := NewEncoder(nil)
+	// 4095 < initialHeaderTableSize means maxSize is truncated to
+	// 4095.
+	e.SetMaxDynamicTableSizeLimit(4095)
+	if got, want := e.dynTab.maxSize, uint32(4095); got != want {
+		t.Errorf("e.dynTab.maxSize = %v; want %v", got, want)
+	}
+	if got, want := e.maxSizeLimit, uint32(4095); got != want {
+		t.Errorf("e.maxSizeLimit = %v; want %v", got, want)
+	}
+	if got, want := e.tableSizeUpdate, true; got != want {
+		t.Errorf("e.tableSizeUpdate = %v; want %v", got, want)
+	}
+	// maxSize will be truncated to maxSizeLimit
+	e.SetMaxDynamicTableSize(16384)
+	if got, want := e.dynTab.maxSize, uint32(4095); got != want {
+		t.Errorf("e.dynTab.maxSize = %v; want %v", got, want)
+	}
+	// 8192 > current maxSizeLimit, so maxSize does not change.
+	e.SetMaxDynamicTableSizeLimit(8192)
+	if got, want := e.dynTab.maxSize, uint32(4095); got != want {
+		t.Errorf("e.dynTab.maxSize = %v; want %v", got, want)
+	}
+	if got, want := e.maxSizeLimit, uint32(8192); got != want {
+		t.Errorf("e.maxSizeLimit = %v; want %v", got, want)
+	}
+}
+
+func removeSpace(s string) string {
+	return strings.Replace(s, " ", "", -1)
+}

src/vendor/golang.org/x/net/http2/hpack/hpack.go

+// Copyright 2014 The Go 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 hpack implements HPACK, a compression format for
+// efficiently representing HTTP header fields in the context of HTTP/2.
+//
+// See http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09
+package hpack
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+// A DecodingError is something the spec defines as a decoding error.
+type DecodingError struct {
+	Err error
+}
+
+func (de DecodingError) Error() string {
+	return fmt.Sprintf("decoding error: %v", de.Err)
+}
+
+// An InvalidIndexError is returned when an encoder references a table
+// entry before the static table or after the end of the dynamic table.
+type InvalidIndexError int
+
+func (e InvalidIndexError) Error() string {
+	return fmt.Sprintf("invalid indexed representation index %d", int(e))
+}
+
+// A HeaderField is a name-value pair. Both the name and value are
+// treated as opaque sequences of octets.
+type HeaderField struct {
+	Name, Value string
+
+	// Sensitive means that this header field should never be
+	// indexed.
+	Sensitive bool
+}
+
+func (hf *HeaderField) size() uint32 {
+	// http://http2.github.io/http2-spec/compression.html#rfc.section.4.1
+	// "The size of the dynamic table is the sum of the size of
+	// its entries.  The size of an entry is the sum of its name's
+	// length in octets (as defined in Section 5.2), its value's
+	// length in octets (see Section 5.2), plus 32.  The size of
+	// an entry is calculated using the length of the name and
+	// value without any Huffman encoding applied."
+
+	// This can overflow if somebody makes a large HeaderField
+	// Name and/or Value by hand, but we don't care, because that
+	// won't happen on the wire because the encoding doesn't allow
+	// it.
+	return uint32(len(hf.Name) + len(hf.Value) + 32)
+}
+
+// A Decoder is the decoding context for incremental processing of
+// header blocks.
+type Decoder struct {
+	dynTab dynamicTable
+	emit   func(f HeaderField)
+
+	emitEnabled bool // whether calls to emit are enabled
+	maxStrLen   int  // 0 means unlimited
+
+	// buf is the unparsed buffer. It's only written to
+	// saveBuf if it was truncated in the middle of a header
+	// block. Because it's usually not owned, we can only
+	// process it under Write.
+	buf []byte // not owned; only valid during Write
+
+	// saveBuf is previous data passed to Write which we weren't able
+	// to fully parse before. Unlike buf, we own this data.
+	saveBuf bytes.Buffer
+}
+
+// NewDecoder returns a new decoder with the provided maximum dynamic
+// table size. The emitFunc will be called for each valid field
+// parsed, in the same goroutine as calls to Write, before Write returns.
+func NewDecoder(maxDynamicTableSize uint32, emitFunc func(f HeaderField)) *Decoder {
+	d := &Decoder{
+		emit:        emitFunc,
+		emitEnabled: true,
+	}
+	d.dynTab.allowedMaxSize = maxDynamicTableSize
+	d.dynTab.setMaxSize(maxDynamicTableSize)
+	return d
+}
+
+// ErrStringLength is returned by Decoder.Write when the max string length
+// (as configured by Decoder.SetMaxStringLength) would be violated.
+var ErrStringLength = errors.New("hpack: string too long")
+
+// SetMaxStringLength sets the maximum size of a HeaderField name or
+// value string. If a string exceeds this length (even after any
+// decompression), Write will return ErrStringLength.
+// A value of 0 means unlimited and is the default from NewDecoder.
+func (d *Decoder) SetMaxStringLength(n int) {
+	d.maxStrLen = n
+}
+
+// SetEmitEnabled controls whether the emitFunc provided to NewDecoder
+// should be called. The default is true.
+//
+// This facility exists to let servers enforce MAX_HEADER_LIST_SIZE
+// while still decoding and keeping in-sync with decoder state, but
+// without doing unnecessary decompression or generating unnecessary
+// garbage for header fields past the limit.
+func (d *Decoder) SetEmitEnabled(v bool) { d.emitEnabled = v }
+
+// EmitEnabled reports whether calls to the emitFunc provided to NewDecoder
+// are currently enabled. The default is true.
+func (d *Decoder) EmitEnabled() bool { return d.emitEnabled }
+
+// TODO: add method *Decoder.Reset(maxSize, emitFunc) to let callers re-use Decoders and their
+// underlying buffers for garbage reasons.
+
+func (d *Decoder) SetMaxDynamicTableSize(v uint32) {
+	d.dynTab.setMaxSize(v)
+}
+
+// SetAllowedMaxDynamicTableSize sets the upper bound that the encoded
+// stream (via dynamic table size updates) may set the maximum size
+// to.
+func (d *Decoder) SetAllowedMaxDynamicTableSize(v uint32) {
+	d.dynTab.allowedMaxSize = v
+}
+
+type dynamicTable struct {
+	// ents is the FIFO described at
+	// http://http2.github.io/http2-spec/compression.html#rfc.section.2.3.2
+	// The newest (low index) is append at the end, and items are
+	// evicted from the front.
+	ents           []HeaderField
+	size           uint32
+	maxSize        uint32 // current maxSize
+	allowedMaxSize uint32 // maxSize may go up to this, inclusive
+}
+
+func (dt *dynamicTable) setMaxSize(v uint32) {
+	dt.maxSize = v
+	dt.evict()
+}
+
+// TODO: change dynamicTable to be a struct with a slice and a size int field,
+// per http://http2.github.io/http2-spec/compression.html#rfc.section.4.1:
+//
+//
+// Then make add increment the size. maybe the max size should move from Decoder to
+// dynamicTable and add should return an ok bool if there was enough space.
+//
+// Later we'll need a remove operation on dynamicTable.
+
+func (dt *dynamicTable) add(f HeaderField) {
+	dt.ents = append(dt.ents, f)
+	dt.size += f.size()
+	dt.evict()
+}
+
+// If we're too big, evict old stuff (front of the slice)
+func (dt *dynamicTable) evict() {
+	base := dt.ents // keep base pointer of slice
+	for dt.size > dt.maxSize {
+		dt.size -= dt.ents[0].size()
+		dt.ents = dt.ents[1:]
+	}
+
+	// Shift slice contents down if we evicted things.
+	if len(dt.ents) != len(base) {
+		copy(base, dt.ents)
+		dt.ents = base[:len(dt.ents)]
+	}
+}
+
+// constantTimeStringCompare compares string a and b in a constant
+// time manner.
+func constantTimeStringCompare(a, b string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	c := byte(0)
+
+	for i := 0; i < len(a); i++ {
+		c |= a[i] ^ b[i]
+	}
+
+	return c == 0
+}
+
+// Search searches f in the table. The return value i is 0 if there is
+// no name match. If there is name match or name/value match, i is the
+// index of that entry (1-based). If both name and value match,
+// nameValueMatch becomes true.
+func (dt *dynamicTable) search(f HeaderField) (i uint64, nameValueMatch bool) {
+	l := len(dt.ents)
+	for j := l - 1; j >= 0; j-- {
+		ent := dt.ents[j]
+		if !constantTimeStringCompare(ent.Name, f.Name) {
+			continue
+		}
+		if i == 0 {
+			i = uint64(l - j)
+		}
+		if f.Sensitive {
+			continue
+		}
+		if !constantTimeStringCompare(ent.Value, f.Value) {
+			continue
+		}
+		i = uint64(l - j)
+		nameValueMatch = true
+		return
+	}
+	return
+}
+
+func (d *Decoder) maxTableIndex() int {
+	return len(d.dynTab.ents) + len(staticTable)
+}
+
+func (d *Decoder) at(i uint64) (hf HeaderField, ok bool) {
+	if i < 1 {
+		return
+	}
+	if i > uint64(d.maxTableIndex()) {
+		return
+	}
+	if i <= uint64(len(staticTable)) {
+		return staticTable[i-1], true
+	}
+	dents := d.dynTab.ents
+	return dents[len(dents)-(int(i)-len(staticTable))], true
+}
+
+// Decode decodes an entire block.
+//
+// TODO: remove this method and make it incremental later? This is
+// easier for debugging now.
+func (d *Decoder) DecodeFull(p []byte) ([]HeaderField, error) {
+	var hf []HeaderField
+	saveFunc := d.emit
+	defer func() { d.emit = saveFunc }()
+	d.emit = func(f HeaderField) { hf = append(hf, f) }
+	if _, err := d.Write(p); err != nil {
+		return nil, err
+	}
+	if err := d.Close(); err != nil {
+		return nil, err
+	}
+	return hf, nil
+}
+
+func (d *Decoder) Close() error {
+	if d.saveBuf.Len() > 0 {
+		d.saveBuf.Reset()
+		return DecodingError{errors.New("truncated headers")}
+	}
+	return nil
+}
+
+func (d *Decoder) Write(p []byte) (n int, err error) {
+	if len(p) == 0 {
+		// Prevent state machine CPU attacks (making us redo
+		// work up to the point of finding out we don't have
+		// enough data)
+		return
+	}
+	// Only copy the data if we have to. Optimistically assume
+	// that p will contain a complete header block.
+	if d.saveBuf.Len() == 0 {
+		d.buf = p
+	} else {
+		d.saveBuf.Write(p)
+		d.buf = d.saveBuf.Bytes()
+		d.saveBuf.Reset()
+	}
+
+	for len(d.buf) > 0 {
+		err = d.parseHeaderFieldRepr()
+		if err == errNeedMore {
+			const varIntOverhead = 8 // conservative
+			if d.maxStrLen != 0 && int64(len(d.buf)) > 2*(int64(d.maxStrLen)+varIntOverhead) {
+				return 0, ErrStringLength
+			}
+			d.saveBuf.Write(d.buf)
+			return len(p), nil
+		}
+		if err != nil {
+			break
+		}
+	}
+	return len(p), err
+}
+
+// errNeedMore is an internal sentinel error value that means the
+// buffer is truncated and we need to read more data before we can
+// continue parsing.
+var errNeedMore = errors.New("need more data")
+
+type indexType int
+
+const (
+	indexedTrue indexType = iota
+	indexedFalse
+	indexedNever
+)
+
+func (v indexType) indexed() bool   { return v == indexedTrue }
+func (v indexType) sensitive() bool { return v == indexedNever }
+
+// returns errNeedMore if there isn't enough data available.
+// any other error is fatal.
+// consumes d.buf iff it returns nil.
+// precondition: must be called with len(d.buf) > 0
+func (d *Decoder) parseHeaderFieldRepr() error {
+	b := d.buf[0]
+	switch {
+	case b&128 != 0:
+		// Indexed representation.
+		// High bit set?
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.1
+		return d.parseFieldIndexed()
+	case b&192 == 64:
+		// 6.2.1 Literal Header Field with Incremental Indexing
+		// 0b10xxxxxx: top two bits are 10
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.1
+		return d.parseFieldLiteral(6, indexedTrue)
+	case b&240 == 0:
+		// 6.2.2 Literal Header Field without Indexing
+		// 0b0000xxxx: top four bits are 0000
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.2
+		return d.parseFieldLiteral(4, indexedFalse)
+	case b&240 == 16:
+		// 6.2.3 Literal Header Field never Indexed
+		// 0b0001xxxx: top four bits are 0001
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.3
+		return d.parseFieldLiteral(4, indexedNever)
+	case b&224 == 32:
+		// 6.3 Dynamic Table Size Update
+		// Top three bits are '001'.
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.3
+		return d.parseDynamicTableSizeUpdate()
+	}
+
+	return DecodingError{errors.New("invalid encoding")}
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseFieldIndexed() error {
+	buf := d.buf
+	idx, buf, err := readVarInt(7, buf)
+	if err != nil {
+		return err
+	}
+	hf, ok := d.at(idx)
+	if !ok {
+		return DecodingError{InvalidIndexError(idx)}
+	}
+	d.buf = buf
+	return d.callEmit(HeaderField{Name: hf.Name, Value: hf.Value})
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseFieldLiteral(n uint8, it indexType) error {
+	buf := d.buf
+	nameIdx, buf, err := readVarInt(n, buf)
+	if err != nil {
+		return err
+	}
+
+	var hf HeaderField
+	wantStr := d.emitEnabled || it.indexed()
+	if nameIdx > 0 {
+		ihf, ok := d.at(nameIdx)
+		if !ok {
+			return DecodingError{InvalidIndexError(nameIdx)}
+		}
+		hf.Name = ihf.Name
+	} else {
+		hf.Name, buf, err = d.readString(buf, wantStr)
+		if err != nil {
+			return err
+		}
+	}
+	hf.Value, buf, err = d.readString(buf, wantStr)
+	if err != nil {
+		return err
+	}
+	d.buf = buf
+	if it.indexed() {
+		d.dynTab.add(hf)
+	}
+	hf.Sensitive = it.sensitive()
+	return d.callEmit(hf)
+}
+
+func (d *Decoder) callEmit(hf HeaderField) error {
+	if d.maxStrLen != 0 {
+		if len(hf.Name) > d.maxStrLen || len(hf.Value) > d.maxStrLen {
+			return ErrStringLength
+		}
+	}
+	if d.emitEnabled {
+		d.emit(hf)
+	}
+	return nil
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseDynamicTableSizeUpdate() error {
+	buf := d.buf
+	size, buf, err := readVarInt(5, buf)
+	if err != nil {
+		return err
+	}
+	if size > uint64(d.dynTab.allowedMaxSize) {
+		return DecodingError{errors.New("dynamic table size update too large")}
+	}
+	d.dynTab.setMaxSize(uint32(size))
+	d.buf = buf
+	return nil
+}
+
+var errVarintOverflow = DecodingError{errors.New("varint integer overflow")}
+
+// readVarInt reads an unsigned variable length integer off the
+// beginning of p. n is the parameter as described in
+// http://http2.github.io/http2-spec/compression.html#rfc.section.5.1.
+//
+// n must always be between 1 and 8.
+//
+// The returned remain buffer is either a smaller suffix of p, or err != nil.
+// The error is errNeedMore if p doesn't contain a complete integer.
+func readVarInt(n byte, p []byte) (i uint64, remain []byte, err error) {
+	if n < 1 || n > 8 {
+		panic("bad n")
+	}
+	if len(p) == 0 {
+		return 0, p, errNeedMore
+	}
+	i = uint64(p[0])
+	if n < 8 {
+		i &= (1 << uint64(n)) - 1
+	}
+	if i < (1<<uint64(n))-1 {
+		return i, p[1:], nil
+	}
+
+	origP := p
+	p = p[1:]
+	var m uint64
+	for len(p) > 0 {
+		b := p[0]
+		p = p[1:]
+		i += uint64(b&127) << m
+		if b&128 == 0 {
+			return i, p, nil
+		}
+		m += 7
+		if m >= 63 { // TODO: proper overflow check. making this up.
+			return 0, origP, errVarintOverflow
+		}
+	}
+	return 0, origP, errNeedMore
+}
+
+// readString decodes an hpack string from p.
+//
+// wantStr is whether s will be used. If false, decompression and
+// []byte->string garbage are skipped if s will be ignored
+// anyway. This does mean that huffman decoding errors for non-indexed
+// strings past the MAX_HEADER_LIST_SIZE are ignored, but the server
+// is returning an error anyway, and because they're not indexed, the error
+// won't affect the decoding state.
+func (d *Decoder) readString(p []byte, wantStr bool) (s string, remain []byte, err error) {
+	if len(p) == 0 {
+		return "", p, errNeedMore
+	}
+	isHuff := p[0]&128 != 0
+	strLen, p, err := readVarInt(7, p)
+	if err != nil {
+		return "", p, err
+	}
+	if d.maxStrLen != 0 && strLen > uint64(d.maxStrLen) {
+		return "", nil, ErrStringLength
+	}
+	if uint64(len(p)) < strLen {
+		return "", p, errNeedMore
+	}
+	if !isHuff {
+		if wantStr {
+			s = string(p[:strLen])
+		}
+		return s, p[strLen:], nil
+	}
+
+	if wantStr {
+		buf := bufPool.Get().(*bytes.Buffer)
+		buf.Reset() // don't trust others
+		defer bufPool.Put(buf)
+		if err := huffmanDecode(buf, d.maxStrLen, p[:strLen]); err != nil {
+			return "", nil, err
+		}
+		s = buf.String()
+		buf.Reset() // be nice to GC
+	}
+	return s, p[strLen:], nil
+}

src/vendor/golang.org/x/net/http2/hpack/hpack_test.go

+// Copyright 2014 The Go 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 hpack
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"math/rand"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestStaticTable(t *testing.T) {
+	fromSpec := `
+          +-------+-----------------------------+---------------+
+          | 1     | :authority                  |               |
+          | 2     | :method                     | GET           |
+          | 3     | :method                     | POST          |
+          | 4     | :path                       | /             |
+          | 5     | :path                       | /index.html   |
+          | 6     | :scheme                     | http          |
+          | 7     | :scheme                     | https         |
+          | 8     | :status                     | 200           |
+          | 9     | :status                     | 204           |
+          | 10    | :status                     | 206           |
+          | 11    | :status                     | 304           |
+          | 12    | :status                     | 400           |
+          | 13    | :status                     | 404           |
+          | 14    | :status                     | 500           |
+          | 15    | accept-charset              |               |
+          | 16    | accept-encoding             | gzip, deflate |
+          | 17    | accept-language             |               |
+          | 18    | accept-ranges               |               |
+          | 19    | accept                      |               |
+          | 20    | access-control-allow-origin |               |
+          | 21    | age                         |               |
+          | 22    | allow                       |               |
+          | 23    | authorization               |               |
+          | 24    | cache-control               |               |
+          | 25    | content-disposition         |               |
+          | 26    | content-encoding            |               |
+          | 27    | content-language            |               |
+          | 28    | content-length              |               |
+          | 29    | content-location            |               |
+          | 30    | content-range               |               |
+          | 31    | content-type                |               |
+          | 32    | cookie                      |               |
+          | 33    | date                        |               |
+          | 34    | etag                        |               |
+          | 35    | expect                      |               |
+          | 36    | expires                     |               |
+          | 37    | from                        |               |
+          | 38    | host                        |               |
+          | 39    | if-match                    |               |
+          | 40    | if-modified-since           |               |
+          | 41    | if-none-match               |               |
+          | 42    | if-range                    |               |
+          | 43    | if-unmodified-since         |               |
+          | 44    | last-modified               |               |
+          | 45    | link                        |               |
+          | 46    | location                    |               |
+          | 47    | max-forwards                |               |
+          | 48    | proxy-authenticate          |               |
+          | 49    | proxy-authorization         |               |
+          | 50    | range                       |               |
+          | 51    | referer                     |               |
+          | 52    | refresh                     |               |
+          | 53    | retry-after                 |               |
+          | 54    | server                      |               |
+          | 55    | set-cookie                  |               |
+          | 56    | strict-transport-security   |               |
+          | 57    | transfer-encoding           |               |
+          | 58    | user-agent                  |               |
+          | 59    | vary                        |               |
+          | 60    | via                         |               |
+          | 61    | www-authenticate            |               |
+          +-------+-----------------------------+---------------+
+`
+	bs := bufio.NewScanner(strings.NewReader(fromSpec))
+	re := regexp.MustCompile(`\| (\d+)\s+\| (\S+)\s*\| (\S(.*\S)?)?\s+\|`)
+	for bs.Scan() {
+		l := bs.Text()
+		if !strings.Contains(l, "|") {
+			continue
+		}
+		m := re.FindStringSubmatch(l)
+		if m == nil {
+			continue
+		}
+		i, err := strconv.Atoi(m[1])
+		if err != nil {
+			t.Errorf("Bogus integer on line %q", l)
+			continue
+		}
+		if i < 1 || i > len(staticTable) {
+			t.Errorf("Bogus index %d on line %q", i, l)
+			continue
+		}
+		if got, want := staticTable[i-1].Name, m[2]; got != want {
+			t.Errorf("header index %d name = %q; want %q", i, got, want)
+		}
+		if got, want := staticTable[i-1].Value, m[3]; got != want {
+			t.Errorf("header index %d value = %q; want %q", i, got, want)
+		}
+	}
+	if err := bs.Err(); err != nil {
+		t.Error(err)
+	}
+}
+
+func (d *Decoder) mustAt(idx int) HeaderField {
+	if hf, ok := d.at(uint64(idx)); !ok {
+		panic(fmt.Sprintf("bogus index %d", idx))
+	} else {
+		return hf
+	}
+}
+
+func TestDynamicTableAt(t *testing.T) {
+	d := NewDecoder(4096, nil)
+	at := d.mustAt
+	if got, want := at(2), (pair(":method", "GET")); got != want {
+		t.Errorf("at(2) = %v; want %v", got, want)
+	}
+	d.dynTab.add(pair("foo", "bar"))
+	d.dynTab.add(pair("blake", "miz"))
+	if got, want := at(len(staticTable)+1), (pair("blake", "miz")); got != want {
+		t.Errorf("at(dyn 1) = %v; want %v", got, want)
+	}
+	if got, want := at(len(staticTable)+2), (pair("foo", "bar")); got != want {
+		t.Errorf("at(dyn 2) = %v; want %v", got, want)
+	}
+	if got, want := at(3), (pair(":method", "POST")); got != want {
+		t.Errorf("at(3) = %v; want %v", got, want)
+	}
+}
+
+func TestDynamicTableSearch(t *testing.T) {
+	dt := dynamicTable{}
+	dt.setMaxSize(4096)
+
+	dt.add(pair("foo", "bar"))
+	dt.add(pair("blake", "miz"))
+	dt.add(pair(":method", "GET"))
+
+	tests := []struct {
+		hf        HeaderField
+		wantI     uint64
+		wantMatch bool
+	}{
+		// Name and Value match
+		{pair("foo", "bar"), 3, true},
+		{pair(":method", "GET"), 1, true},
+
+		// Only name match because of Sensitive == true
+		{HeaderField{"blake", "miz", true}, 2, false},
+
+		// Only Name matches
+		{pair("foo", "..."), 3, false},
+		{pair("blake", "..."), 2, false},
+		{pair(":method", "..."), 1, false},
+
+		// None match
+		{pair("foo-", "bar"), 0, false},
+	}
+	for _, tt := range tests {
+		if gotI, gotMatch := dt.search(tt.hf); gotI != tt.wantI || gotMatch != tt.wantMatch {
+			t.Errorf("d.search(%+v) = %v, %v; want %v, %v", tt.hf, gotI, gotMatch, tt.wantI, tt.wantMatch)
+		}
+	}
+}
+
+func TestDynamicTableSizeEvict(t *testing.T) {
+	d := NewDecoder(4096, nil)
+	if want := uint32(0); d.dynTab.size != want {
+		t.Fatalf("size = %d; want %d", d.dynTab.size, want)
+	}
+	add := d.dynTab.add
+	add(pair("blake", "eats pizza"))
+	if want := uint32(15 + 32); d.dynTab.size != want {
+		t.Fatalf("after pizza, size = %d; want %d", d.dynTab.size, want)
+	}
+	add(pair("foo", "bar"))
+	if want := uint32(15 + 32 + 6 + 32); d.dynTab.size != want {
+		t.Fatalf("after foo bar, size = %d; want %d", d.dynTab.size, want)
+	}
+	d.dynTab.setMaxSize(15 + 32 + 1 /* slop */)
+	if want := uint32(6 + 32); d.dynTab.size != want {
+		t.Fatalf("after setMaxSize, size = %d; want %d", d.dynTab.size, want)
+	}
+	if got, want := d.mustAt(len(staticTable)+1), (pair("foo", "bar")); got != want {
+		t.Errorf("at(dyn 1) = %v; want %v", got, want)
+	}
+	add(pair("long", strings.Repeat("x", 500)))
+	if want := uint32(0); d.dynTab.size != want {
+		t.Fatalf("after big one, size = %d; want %d", d.dynTab.size, want)
+	}
+}
+
+func TestDecoderDecode(t *testing.T) {
+	tests := []struct {
+		name       string
+		in         []byte
+		want       []HeaderField
+		wantDynTab []HeaderField // newest entry first
+	}{
+		// C.2.1 Literal Header Field with Indexing
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.C.2.1
+		{"C.2.1", dehex("400a 6375 7374 6f6d 2d6b 6579 0d63 7573 746f 6d2d 6865 6164 6572"),
+			[]HeaderField{pair("custom-key", "custom-header")},
+			[]HeaderField{pair("custom-key", "custom-header")},
+		},
+
+		// C.2.2 Literal Header Field without Indexing
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.C.2.2
+		{"C.2.2", dehex("040c 2f73 616d 706c 652f 7061 7468"),
+			[]HeaderField{pair(":path", "/sample/path")},
+			[]HeaderField{}},
+
+		// C.2.3 Literal Header Field never Indexed
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.C.2.3
+		{"C.2.3", dehex("1008 7061 7373 776f 7264 0673 6563 7265 74"),
+			[]HeaderField{{"password", "secret", true}},
+			[]HeaderField{}},
+
+		// C.2.4 Indexed Header Field
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.C.2.4
+		{"C.2.4", []byte("\x82"),
+			[]HeaderField{pair(":method", "GET")},
+			[]HeaderField{}},
+	}
+	for _, tt := range tests {
+		d := NewDecoder(4096, nil)
+		hf, err := d.DecodeFull(tt.in)
+		if err != nil {
+			t.Errorf("%s: %v", tt.name, err)
+			continue
+		}
+		if !reflect.DeepEqual(hf, tt.want) {
+			t.Errorf("%s: Got %v; want %v", tt.name, hf, tt.want)
+		}
+		gotDynTab := d.dynTab.reverseCopy()
+		if !reflect.DeepEqual(gotDynTab, tt.wantDynTab) {
+			t.Errorf("%s: dynamic table after = %v; want %v", tt.name, gotDynTab, tt.wantDynTab)
+		}
+	}
+}
+
+func (dt *dynamicTable) reverseCopy() (hf []HeaderField) {
+	hf = make([]HeaderField, len(dt.ents))
+	for i := range hf {
+		hf[i] = dt.ents[len(dt.ents)-1-i]
+	}
+	return
+}
+
+type encAndWant struct {
+	enc         []byte
+	want        []HeaderField
+	wantDynTab  []HeaderField
+	wantDynSize uint32
+}
+
+// C.3 Request Examples without Huffman Coding
+// http://http2.github.io/http2-spec/compression.html#rfc.section.C.3
+func TestDecodeC3_NoHuffman(t *testing.T) {
+	testDecodeSeries(t, 4096, []encAndWant{
+		{dehex("8286 8441 0f77 7777 2e65 7861 6d70 6c65 2e63 6f6d"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "http"),
+				pair(":path", "/"),
+				pair(":authority", "www.example.com"),
+			},
+			[]HeaderField{
+				pair(":authority", "www.example.com"),
+			},
+			57,
+		},
+		{dehex("8286 84be 5808 6e6f 2d63 6163 6865"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "http"),
+				pair(":path", "/"),
+				pair(":authority", "www.example.com"),
+				pair("cache-control", "no-cache"),
+			},
+			[]HeaderField{
+				pair("cache-control", "no-cache"),
+				pair(":authority", "www.example.com"),
+			},
+			110,
+		},
+		{dehex("8287 85bf 400a 6375 7374 6f6d 2d6b 6579 0c63 7573 746f 6d2d 7661 6c75 65"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "https"),
+				pair(":path", "/index.html"),
+				pair(":authority", "www.example.com"),
+				pair("custom-key", "custom-value"),
+			},
+			[]HeaderField{
+				pair("custom-key", "custom-value"),
+				pair("cache-control", "no-cache"),
+				pair(":authority", "www.example.com"),
+			},
+			164,
+		},
+	})
+}
+
+// C.4 Request Examples with Huffman Coding
+// http://http2.github.io/http2-spec/compression.html#rfc.section.C.4
+func TestDecodeC4_Huffman(t *testing.T) {
+	testDecodeSeries(t, 4096, []encAndWant{
+		{dehex("8286 8441 8cf1 e3c2 e5f2 3a6b a0ab 90f4 ff"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "http"),
+				pair(":path", "/"),
+				pair(":authority", "www.example.com"),
+			},
+			[]HeaderField{
+				pair(":authority", "www.example.com"),
+			},
+			57,
+		},
+		{dehex("8286 84be 5886 a8eb 1064 9cbf"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "http"),
+				pair(":path", "/"),
+				pair(":authority", "www.example.com"),
+				pair("cache-control", "no-cache"),
+			},
+			[]HeaderField{
+				pair("cache-control", "no-cache"),
+				pair(":authority", "www.example.com"),
+			},
+			110,
+		},
+		{dehex("8287 85bf 4088 25a8 49e9 5ba9 7d7f 8925 a849 e95b b8e8 b4bf"),
+			[]HeaderField{
+				pair(":method", "GET"),
+				pair(":scheme", "https"),
+				pair(":path", "/index.html"),
+				pair(":authority", "www.example.com"),
+				pair("custom-key", "custom-value"),
+			},
+			[]HeaderField{
+				pair("custom-key", "custom-value"),
+				pair("cache-control", "no-cache"),
+				pair(":authority", "www.example.com"),
+			},
+			164,
+		},
+	})
+}
+
+// http://http2.github.io/http2-spec/compression.html#rfc.section.C.5
+// "This section shows several consecutive header lists, corresponding
+// to HTTP responses, on the same connection. The HTTP/2 setting
+// parameter SETTINGS_HEADER_TABLE_SIZE is set to the value of 256
+// octets, causing some evictions to occur."
+func TestDecodeC5_ResponsesNoHuff(t *testing.T) {
+	testDecodeSeries(t, 256, []encAndWant{
+		{dehex(`
+4803 3330 3258 0770 7269 7661 7465 611d
+4d6f 6e2c 2032 3120 4f63 7420 3230 3133
+2032 303a 3133 3a32 3120 474d 546e 1768
+7474 7073 3a2f 2f77 7777 2e65 7861 6d70
+6c65 2e63 6f6d
+`),
+			[]HeaderField{
+				pair(":status", "302"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("location", "https://www.example.com"),
+			},
+			[]HeaderField{
+				pair("location", "https://www.example.com"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("cache-control", "private"),
+				pair(":status", "302"),
+			},
+			222,
+		},
+		{dehex("4803 3330 37c1 c0bf"),
+			[]HeaderField{
+				pair(":status", "307"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("location", "https://www.example.com"),
+			},
+			[]HeaderField{
+				pair(":status", "307"),
+				pair("location", "https://www.example.com"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("cache-control", "private"),
+			},
+			222,
+		},
+		{dehex(`
+88c1 611d 4d6f 6e2c 2032 3120 4f63 7420
+3230 3133 2032 303a 3133 3a32 3220 474d
+54c0 5a04 677a 6970 7738 666f 6f3d 4153
+444a 4b48 514b 425a 584f 5157 454f 5049
+5541 5851 5745 4f49 553b 206d 6178 2d61
+6765 3d33 3630 303b 2076 6572 7369 6f6e
+3d31
+`),
+			[]HeaderField{
+				pair(":status", "200"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:22 GMT"),
+				pair("location", "https://www.example.com"),
+				pair("content-encoding", "gzip"),
+				pair("set-cookie", "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1"),
+			},
+			[]HeaderField{
+				pair("set-cookie", "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1"),
+				pair("content-encoding", "gzip"),
+				pair("date", "Mon, 21 Oct 2013 20:13:22 GMT"),
+			},
+			215,
+		},
+	})
+}
+
+// http://http2.github.io/http2-spec/compression.html#rfc.section.C.6
+// "This section shows the same examples as the previous section, but
+// using Huffman encoding for the literal values. The HTTP/2 setting
+// parameter SETTINGS_HEADER_TABLE_SIZE is set to the value of 256
+// octets, causing some evictions to occur. The eviction mechanism
+// uses the length of the decoded literal values, so the same
+// evictions occurs as in the previous section."
+func TestDecodeC6_ResponsesHuffman(t *testing.T) {
+	testDecodeSeries(t, 256, []encAndWant{
+		{dehex(`
+4882 6402 5885 aec3 771a 4b61 96d0 7abe
+9410 54d4 44a8 2005 9504 0b81 66e0 82a6
+2d1b ff6e 919d 29ad 1718 63c7 8f0b 97c8
+e9ae 82ae 43d3
+`),
+			[]HeaderField{
+				pair(":status", "302"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("location", "https://www.example.com"),
+			},
+			[]HeaderField{
+				pair("location", "https://www.example.com"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("cache-control", "private"),
+				pair(":status", "302"),
+			},
+			222,
+		},
+		{dehex("4883 640e ffc1 c0bf"),
+			[]HeaderField{
+				pair(":status", "307"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("location", "https://www.example.com"),
+			},
+			[]HeaderField{
+				pair(":status", "307"),
+				pair("location", "https://www.example.com"),
+				pair("date", "Mon, 21 Oct 2013 20:13:21 GMT"),
+				pair("cache-control", "private"),
+			},
+			222,
+		},
+		{dehex(`
+88c1 6196 d07a be94 1054 d444 a820 0595
+040b 8166 e084 a62d 1bff c05a 839b d9ab
+77ad 94e7 821d d7f2 e6c7 b335 dfdf cd5b
+3960 d5af 2708 7f36 72c1 ab27 0fb5 291f
+9587 3160 65c0 03ed 4ee5 b106 3d50 07
+`),
+			[]HeaderField{
+				pair(":status", "200"),
+				pair("cache-control", "private"),
+				pair("date", "Mon, 21 Oct 2013 20:13:22 GMT"),
+				pair("location", "https://www.example.com"),
+				pair("content-encoding", "gzip"),
+				pair("set-cookie", "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1"),
+			},
+			[]HeaderField{
+				pair("set-cookie", "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1"),
+				pair("content-encoding", "gzip"),
+				pair("date", "Mon, 21 Oct 2013 20:13:22 GMT"),
+			},
+			215,
+		},
+	})
+}
+
+func testDecodeSeries(t *testing.T, size uint32, steps []encAndWant) {
+	d := NewDecoder(size, nil)
+	for i, step := range steps {
+		hf, err := d.DecodeFull(step.enc)
+		if err != nil {
+			t.Fatalf("Error at step index %d: %v", i, err)
+		}
+		if !reflect.DeepEqual(hf, step.want) {
+			t.Fatalf("At step index %d: Got headers %v; want %v", i, hf, step.want)
+		}
+		gotDynTab := d.dynTab.reverseCopy()
+		if !reflect.DeepEqual(gotDynTab, step.wantDynTab) {
+			t.Errorf("After step index %d, dynamic table = %v; want %v", i, gotDynTab, step.wantDynTab)
+		}
+		if d.dynTab.size != step.wantDynSize {
+			t.Errorf("After step index %d, dynamic table size = %v; want %v", i, d.dynTab.size, step.wantDynSize)
+		}
+	}
+}
+
+func TestHuffmanDecode(t *testing.T) {
+	tests := []struct {
+		inHex, want string
+	}{
+		{"f1e3 c2e5 f23a 6ba0 ab90 f4ff", "www.example.com"},
+		{"a8eb 1064 9cbf", "no-cache"},
+		{"25a8 49e9 5ba9 7d7f", "custom-key"},
+		{"25a8 49e9 5bb8 e8b4 bf", "custom-value"},
+		{"6402", "302"},
+		{"aec3 771a 4b", "private"},
+		{"d07a be94 1054 d444 a820 0595 040b 8166 e082 a62d 1bff", "Mon, 21 Oct 2013 20:13:21 GMT"},
+		{"9d29 ad17 1863 c78f 0b97 c8e9 ae82 ae43 d3", "https://www.example.com"},
+		{"9bd9 ab", "gzip"},
+		{"94e7 821d d7f2 e6c7 b335 dfdf cd5b 3960 d5af 2708 7f36 72c1 ab27 0fb5 291f 9587 3160 65c0 03ed 4ee5 b106 3d50 07",
+			"foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1"},
+	}
+	for i, tt := range tests {
+		var buf bytes.Buffer
+		in, err := hex.DecodeString(strings.Replace(tt.inHex, " ", "", -1))
+		if err != nil {
+			t.Errorf("%d. hex input error: %v", i, err)
+			continue
+		}
+		if _, err := HuffmanDecode(&buf, in); err != nil {
+			t.Errorf("%d. decode error: %v", i, err)
+			continue
+		}
+		if got := buf.String(); tt.want != got {
+			t.Errorf("%d. decode = %q; want %q", i, got, tt.want)
+		}
+	}
+}
+
+func TestAppendHuffmanString(t *testing.T) {
+	tests := []struct {
+		in, want string
+	}{
+		{"www.example.com", "f1e3 c2e5 f23a 6ba0 ab90 f4ff"},
+		{"no-cache", "a8eb 1064 9cbf"},
+		{"custom-key", "25a8 49e9 5ba9 7d7f"},
+		{"custom-value", "25a8 49e9 5bb8 e8b4 bf"},
+		{"302", "6402"},
+		{"private", "aec3 771a 4b"},
+		{"Mon, 21 Oct 2013 20:13:21 GMT", "d07a be94 1054 d444 a820 0595 040b 8166 e082 a62d 1bff"},
+		{"https://www.example.com", "9d29 ad17 1863 c78f 0b97 c8e9 ae82 ae43 d3"},
+		{"gzip", "9bd9 ab"},
+		{"foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1",
+			"94e7 821d d7f2 e6c7 b335 dfdf cd5b 3960 d5af 2708 7f36 72c1 ab27 0fb5 291f 9587 3160 65c0 03ed 4ee5 b106 3d50 07"},
+	}
+	for i, tt := range tests {
+		buf := []byte{}
+		want := strings.Replace(tt.want, " ", "", -1)
+		buf = AppendHuffmanString(buf, tt.in)
+		if got := hex.EncodeToString(buf); want != got {
+			t.Errorf("%d. encode = %q; want %q", i, got, want)
+		}
+	}
+}
+
+func TestHuffmanMaxStrLen(t *testing.T) {
+	const msg = "Some string"
+	huff := AppendHuffmanString(nil, msg)
+
+	testGood := func(max int) {
+		var out bytes.Buffer
+		if err := huffmanDecode(&out, max, huff); err != nil {
+			t.Errorf("For maxLen=%d, unexpected error: %v", max, err)
+		}
+		if out.String() != msg {
+			t.Errorf("For maxLen=%d, out = %q; want %q", max, out.String(), msg)
+		}
+	}
+	testGood(0)
+	testGood(len(msg))
+	testGood(len(msg) + 1)
+
+	var out bytes.Buffer
+	if err := huffmanDecode(&out, len(msg)-1, huff); err != ErrStringLength {
+		t.Errorf("err = %v; want ErrStringLength", err)
+	}
+}
+
+func TestHuffmanRoundtripStress(t *testing.T) {
+	const Len = 50 // of uncompressed string
+	input := make([]byte, Len)
+	var output bytes.Buffer
+	var huff []byte
+
+	n := 5000
+	if testing.Short() {
+		n = 100
+	}
+	seed := time.Now().UnixNano()
+	t.Logf("Seed = %v", seed)
+	src := rand.New(rand.NewSource(seed))
+	var encSize int64
+	for i := 0; i < n; i++ {
+		for l := range input {
+			input[l] = byte(src.Intn(256))
+		}
+		huff = AppendHuffmanString(huff[:0], string(input))
+		encSize += int64(len(huff))
+		output.Reset()
+		if err := huffmanDecode(&output, 0, huff); err != nil {
+			t.Errorf("Failed to decode %q -> %q -> error %v", input, huff, err)
+			continue
+		}
+		if !bytes.Equal(output.Bytes(), input) {
+			t.Errorf("Roundtrip failure on %q -> %q -> %q", input, huff, output.Bytes())
+		}
+	}
+	t.Logf("Compressed size of original: %0.02f%% (%v -> %v)", 100*(float64(encSize)/(Len*float64(n))), Len*n, encSize)
+}
+
+func TestHuffmanDecodeFuzz(t *testing.T) {
+	const Len = 50 // of compressed
+	var buf, zbuf bytes.Buffer
+
+	n := 5000
+	if testing.Short() {
+		n = 100
+	}
+	seed := time.Now().UnixNano()
+	t.Logf("Seed = %v", seed)
+	src := rand.New(rand.NewSource(seed))
+	numFail := 0
+	for i := 0; i < n; i++ {
+		zbuf.Reset()
+		if i == 0 {
+			// Start with at least one invalid one.
+			zbuf.WriteString("00\x91\xff\xff\xff\xff\xc8")
+		} else {
+			for l := 0; l < Len; l++ {
+				zbuf.WriteByte(byte(src.Intn(256)))
+			}
+		}
+
+		buf.Reset()
+		if err := huffmanDecode(&buf, 0, zbuf.Bytes()); err != nil {
+			if err == ErrInvalidHuffman {
+				numFail++
+				continue
+			}
+			t.Errorf("Failed to decode %q: %v", zbuf.Bytes(), err)
+			continue
+		}
+	}
+	t.Logf("%0.02f%% are invalid (%d / %d)", 100*float64(numFail)/float64(n), numFail, n)
+	if numFail < 1 {
+		t.Error("expected at least one invalid huffman encoding (test starts with one)")
+	}
+}
+
+func TestReadVarInt(t *testing.T) {
+	type res struct {
+		i        uint64
+		consumed int
+		err      error
+	}
+	tests := []struct {
+		n    byte
+		p    []byte
+		want res
+	}{
+		// Fits in a byte:
+		{1, []byte{0}, res{0, 1, nil}},
+		{2, []byte{2}, res{2, 1, nil}},
+		{3, []byte{6}, res{6, 1, nil}},
+		{4, []byte{14}, res{14, 1, nil}},
+		{5, []byte{30}, res{30, 1, nil}},
+		{6, []byte{62}, res{62, 1, nil}},
+		{7, []byte{126}, res{126, 1, nil}},
+		{8, []byte{254}, res{254, 1, nil}},
+
+		// Doesn't fit in a byte:
+		{1, []byte{1}, res{0, 0, errNeedMore}},
+		{2, []byte{3}, res{0, 0, errNeedMore}},
+		{3, []byte{7}, res{0, 0, errNeedMore}},
+		{4, []byte{15}, res{0, 0, errNeedMore}},
+		{5, []byte{31}, res{0, 0, errNeedMore}},
+		{6, []byte{63}, res{0, 0, errNeedMore}},
+		{7, []byte{127}, res{0, 0, errNeedMore}},
+		{8, []byte{255}, res{0, 0, errNeedMore}},
+
+		// Ignoring top bits:
+		{5, []byte{255, 154, 10}, res{1337, 3, nil}}, // high dummy three bits: 111
+		{5, []byte{159, 154, 10}, res{1337, 3, nil}}, // high dummy three bits: 100
+		{5, []byte{191, 154, 10}, res{1337, 3, nil}}, // high dummy three bits: 101
+
+		// Extra byte:
+		{5, []byte{191, 154, 10, 2}, res{1337, 3, nil}}, // extra byte
+
+		// Short a byte:
+		{5, []byte{191, 154}, res{0, 0, errNeedMore}},
+
+		// integer overflow:
+		{1, []byte{255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128}, res{0, 0, errVarintOverflow}},
+	}
+	for _, tt := range tests {
+		i, remain, err := readVarInt(tt.n, tt.p)
+		consumed := len(tt.p) - len(remain)
+		got := res{i, consumed, err}
+		if got != tt.want {
+			t.Errorf("readVarInt(%d, %v ~ %x) = %+v; want %+v", tt.n, tt.p, tt.p, got, tt.want)
+		}
+	}
+}
+
+// Fuzz crash, originally reported at https://github.com/bradfitz/http2/issues/56
+func TestHuffmanFuzzCrash(t *testing.T) {
+	got, err := HuffmanDecodeToString([]byte("00\x91\xff\xff\xff\xff\xc8"))
+	if got != "" {
+		t.Errorf("Got %q; want empty string", got)
+	}
+	if err != ErrInvalidHuffman {
+		t.Errorf("Err = %v; want ErrInvalidHuffman", err)
+	}
+}
+
+func dehex(s string) []byte {
+	s = strings.Replace(s, " ", "", -1)
+	s = strings.Replace(s, "\n", "", -1)
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+func TestEmitEnabled(t *testing.T) {
+	var buf bytes.Buffer
+	enc := NewEncoder(&buf)
+	enc.WriteField(HeaderField{Name: "foo", Value: "bar"})
+	enc.WriteField(HeaderField{Name: "foo", Value: "bar"})
+
+	numCallback := 0
+	var dec *Decoder
+	dec = NewDecoder(8<<20, func(HeaderField) {
+		numCallback++
+		dec.SetEmitEnabled(false)
+	})
+	if !dec.EmitEnabled() {
+		t.Errorf("initial emit enabled = false; want true")
+	}
+	if _, err := dec.Write(buf.Bytes()); err != nil {
+		t.Error(err)
+	}
+	if numCallback != 1 {
+		t.Errorf("num callbacks = %d; want 1", numCallback)
+	}
+	if dec.EmitEnabled() {
+		t.Errorf("emit enabled = true; want false")
+	}
+}
+
+func TestSaveBufLimit(t *testing.T) {
+	const maxStr = 1 << 10
+	var got []HeaderField
+	dec := NewDecoder(initialHeaderTableSize, func(hf HeaderField) {
+		got = append(got, hf)
+	})
+	dec.SetMaxStringLength(maxStr)
+	var frag []byte
+	frag = append(frag[:0], encodeTypeByte(false, false))
+	frag = appendVarInt(frag, 7, 3)
+	frag = append(frag, "foo"...)
+	frag = appendVarInt(frag, 7, 3)
+	frag = append(frag, "bar"...)
+
+	if _, err := dec.Write(frag); err != nil {
+		t.Fatal(err)
+	}
+
+	want := []HeaderField{{Name: "foo", Value: "bar"}}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("After small writes, got %v; want %v", got, want)
+	}
+
+	frag = append(frag[:0], encodeTypeByte(false, false))
+	frag = appendVarInt(frag, 7, maxStr*3)
+	frag = append(frag, make([]byte, maxStr*3)...)
+
+	_, err := dec.Write(frag)
+	if err != ErrStringLength {
+		t.Fatalf("Write error = %v; want ErrStringLength", err)
+	}
+}

src/vendor/golang.org/x/net/http2/hpack/huffman.go

+// Copyright 2014 The Go 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 hpack
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"sync"
+)
+
+var bufPool = sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
+// HuffmanDecode decodes the string in v and writes the expanded
+// result to w, returning the number of bytes written to w and the
+// Write call's return value. At most one Write call is made.
+func HuffmanDecode(w io.Writer, v []byte) (int, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufPool.Put(buf)
+	if err := huffmanDecode(buf, 0, v); err != nil {
+		return 0, err
+	}
+	return w.Write(buf.Bytes())
+}
+
+// HuffmanDecodeToString decodes the string in v.
+func HuffmanDecodeToString(v []byte) (string, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufPool.Put(buf)
+	if err := huffmanDecode(buf, 0, v); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+// ErrInvalidHuffman is returned for errors found decoding
+// Huffman-encoded strings.
+var ErrInvalidHuffman = errors.New("hpack: invalid Huffman-encoded data")
+
+// huffmanDecode decodes v to buf.
+// If maxLen is greater than 0, attempts to write more to buf than
+// maxLen bytes will return ErrStringLength.
+func huffmanDecode(buf *bytes.Buffer, maxLen int, v []byte) error {
+	n := rootHuffmanNode
+	cur, nbits := uint(0), uint8(0)
+	for _, b := range v {
+		cur = cur<<8 | uint(b)
+		nbits += 8
+		for nbits >= 8 {
+			idx := byte(cur >> (nbits - 8))
+			n = n.children[idx]
+			if n == nil {
+				return ErrInvalidHuffman
+			}
+			if n.children == nil {
+				if maxLen != 0 && buf.Len() == maxLen {
+					return ErrStringLength
+				}
+				buf.WriteByte(n.sym)
+				nbits -= n.codeLen
+				n = rootHuffmanNode
+			} else {
+				nbits -= 8
+			}
+		}
+	}
+	for nbits > 0 {
+		n = n.children[byte(cur<<(8-nbits))]
+		if n.children != nil || n.codeLen > nbits {
+			break
+		}
+		buf.WriteByte(n.sym)
+		nbits -= n.codeLen
+		n = rootHuffmanNode
+	}
+	return nil
+}
+
+type node struct {
+	// children is non-nil for internal nodes
+	children []*node
+
+	// The following are only valid if children is nil:
+	codeLen uint8 // number of bits that led to the output of sym
+	sym     byte  // output symbol
+}
+
+func newInternalNode() *node {
+	return &node{children: make([]*node, 256)}
+}
+
+var rootHuffmanNode = newInternalNode()
+
+func init() {
+	if len(huffmanCodes) != 256 {
+		panic("unexpected size")
+	}
+	for i, code := range huffmanCodes {
+		addDecoderNode(byte(i), code, huffmanCodeLen[i])
+	}
+}
+
+func addDecoderNode(sym byte, code uint32, codeLen uint8) {
+	cur := rootHuffmanNode
+	for codeLen > 8 {
+		codeLen -= 8
+		i := uint8(code >> codeLen)
+		if cur.children[i] == nil {
+			cur.children[i] = newInternalNode()
+		}
+		cur = cur.children[i]
+	}
+	shift := 8 - codeLen
+	start, end := int(uint8(code<<shift)), int(1<<shift)
+	for i := start; i < start+end; i++ {
+		cur.children[i] = &node{sym: sym, codeLen: codeLen}
+	}
+}
+
+// AppendHuffmanString appends s, as encoded in Huffman codes, to dst
+// and returns the extended buffer.
+func AppendHuffmanString(dst []byte, s string) []byte {
+	rembits := uint8(8)
+
+	for i := 0; i < len(s); i++ {
+		if rembits == 8 {
+			dst = append(dst, 0)
+		}
+		dst, rembits = appendByteToHuffmanCode(dst, rembits, s[i])
+	}
+
+	if rembits < 8 {
+		// special EOS symbol
+		code := uint32(0x3fffffff)
+		nbits := uint8(30)
+
+		t := uint8(code >> (nbits - rembits))
+		dst[len(dst)-1] |= t
+	}
+
+	return dst
+}
+
+// HuffmanEncodeLength returns the number of bytes required to encode
+// s in Huffman codes. The result is round up to byte boundary.
+func HuffmanEncodeLength(s string) uint64 {
+	n := uint64(0)
+	for i := 0; i < len(s); i++ {
+		n += uint64(huffmanCodeLen[s[i]])
+	}
+	return (n + 7) / 8
+}
+
+// appendByteToHuffmanCode appends Huffman code for c to dst and
+// returns the extended buffer and the remaining bits in the last
+// element. The appending is not byte aligned and the remaining bits
+// in the last element of dst is given in rembits.
+func appendByteToHuffmanCode(dst []byte, rembits uint8, c byte) ([]byte, uint8) {
+	code := huffmanCodes[c]
+	nbits := huffmanCodeLen[c]
+
+	for {
+		if rembits > nbits {
+			t := uint8(code << (rembits - nbits))
+			dst[len(dst)-1] |= t
+			rembits -= nbits
+			break
+		}
+
+		t := uint8(code >> (nbits - rembits))
+		dst[len(dst)-1] |= t
+
+		nbits -= rembits
+		rembits = 8
+
+		if nbits == 0 {
+			break
+		}
+
+		dst = append(dst, 0)
+	}
+
+	return dst, rembits
+}

src/vendor/golang.org/x/net/http2/hpack/tables.go

+// Copyright 2014 The Go 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 hpack
+
+func pair(name, value string) HeaderField {
+	return HeaderField{Name: name, Value: value}
+}
+
+// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07#appendix-B
+var staticTable = [...]HeaderField{
+	pair(":authority", ""), // index 1 (1-based)
+	pair(":method", "GET"),
+	pair(":method", "POST"),
+	pair(":path", "/"),
+	pair(":path", "/index.html"),
+	pair(":scheme", "http"),
+	pair(":scheme", "https"),
+	pair(":status", "200"),
+	pair(":status", "204"),
+	pair(":status", "206"),
+	pair(":status", "304"),
+	pair(":status", "400"),
+	pair(":status", "404"),
+	pair(":status", "500"),
+	pair("accept-charset", ""),
+	pair("accept-encoding", "gzip, deflate"),
+	pair("accept-language", ""),
+	pair("accept-ranges", ""),
+	pair("accept", ""),
+	pair("access-control-allow-origin", ""),
+	pair("age", ""),
+	pair("allow", ""),
+	pair("authorization", ""),
+	pair("cache-control", ""),
+	pair("content-disposition", ""),
+	pair("content-encoding", ""),
+	pair("content-language", ""),
+	pair("content-length", ""),
+	pair("content-location", ""),
+	pair("content-range", ""),
+	pair("content-type", ""),
+	pair("cookie", ""),
+	pair("date", ""),
+	pair("etag", ""),
+	pair("expect", ""),
+	pair("expires", ""),
+	pair("from", ""),
+	pair("host", ""),
+	pair("if-match", ""),
+	pair("if-modified-since", ""),
+	pair("if-none-match", ""),
+	pair("if-range", ""),
+	pair("if-unmodified-since", ""),
+	pair("last-modified", ""),
+	pair("link", ""),
+	pair("location", ""),
+	pair("max-forwards", ""),
+	pair("proxy-authenticate", ""),
+	pair("proxy-authorization", ""),
+	pair("range", ""),
+	pair("referer", ""),
+	pair("refresh", ""),
+	pair("retry-after", ""),
+	pair("server", ""),
+	pair("set-cookie", ""),
+	pair("strict-transport-security", ""),
+	pair("transfer-encoding", ""),
+	pair("user-agent", ""),
+	pair("vary", ""),
+	pair("via", ""),
+	pair("www-authenticate", ""),
+}
+
+var huffmanCodes = [256]uint32{
+	0x1ff8,
+	0x7fffd8,
+	0xfffffe2,
+	0xfffffe3,
+	0xfffffe4,
+	0xfffffe5,
+	0xfffffe6,
+	0xfffffe7,
+	0xfffffe8,
+	0xffffea,
+	0x3ffffffc,
+	0xfffffe9,
+	0xfffffea,
+	0x3ffffffd,
+	0xfffffeb,
+	0xfffffec,
+	0xfffffed,
+	0xfffffee,
+	0xfffffef,
+	0xffffff0,
+	0xffffff1,
+	0xffffff2,
+	0x3ffffffe,
+	0xffffff3,
+	0xffffff4,
+	0xffffff5,
+	0xffffff6,
+	0xffffff7,
+	0xffffff8,
+	0xffffff9,
+	0xffffffa,
+	0xffffffb,
+	0x14,
+	0x3f8,
+	0x3f9,
+	0xffa,
+	0x1ff9,
+	0x15,
+	0xf8,
+	0x7fa,
+	0x3fa,
+	0x3fb,
+	0xf9,
+	0x7fb,
+	0xfa,
+	0x16,
+	0x17,
+	0x18,
+	0x0,
+	0x1,
+	0x2,
+	0x19,
+	0x1a,
+	0x1b,
+	0x1c,
+	0x1d,
+	0x1e,
+	0x1f,
+	0x5c,
+	0xfb,
+	0x7ffc,
+	0x20,
+	0xffb,
+	0x3fc,
+	0x1ffa,
+	0x21,
+	0x5d,
+	0x5e,
+	0x5f,
+	0x60,
+	0x61,
+	0x62,
+	0x63,
+	0x64,
+	0x65,
+	0x66,
+	0x67,
+	0x68,
+	0x69,
+	0x6a,
+	0x6b,
+	0x6c,
+	0x6d,
+	0x6e,
+	0x6f,
+	0x70,
+	0x71,
+	0x72,
+	0xfc,
+	0x73,
+	0xfd,
+	0x1ffb,
+	0x7fff0,
+	0x1ffc,
+	0x3ffc,
+	0x22,
+	0x7ffd,
+	0x3,
+	0x23,
+	0x4,
+	0x24,
+	0x5,
+	0x25,
+	0x26,
+	0x27,
+	0x6,
+	0x74,
+	0x75,
+	0x28,
+	0x29,
+	0x2a,
+	0x7,
+	0x2b,
+	0x76,
+	0x2c,
+	0x8,
+	0x9,
+	0x2d,
+	0x77,
+	0x78,
+	0x79,
+	0x7a,
+	0x7b,
+	0x7ffe,
+	0x7fc,
+	0x3ffd,
+	0x1ffd,
+	0xffffffc,
+	0xfffe6,
+	0x3fffd2,
+	0xfffe7,
+	0xfffe8,
+	0x3fffd3,
+	0x3fffd4,
+	0x3fffd5,
+	0x7fffd9,
+	0x3fffd6,
+	0x7fffda,
+	0x7fffdb,
+	0x7fffdc,
+	0x7fffdd,
+	0x7fffde,
+	0xffffeb,
+	0x7fffdf,
+	0xffffec,
+	0xffffed,
+	0x3fffd7,
+	0x7fffe0,
+	0xffffee,
+	0x7fffe1,
+	0x7fffe2,
+	0x7fffe3,
+	0x7fffe4,
+	0x1fffdc,
+	0x3fffd8,
+	0x7fffe5,
+	0x3fffd9,
+	0x7fffe6,
+	0x7fffe7,
+	0xffffef,
+	0x3fffda,
+	0x1fffdd,
+	0xfffe9,
+	0x3fffdb,
+	0x3fffdc,
+	0x7fffe8,
+	0x7fffe9,
+	0x1fffde,
+	0x7fffea,
+	0x3fffdd,
+	0x3fffde,
+	0xfffff0,
+	0x1fffdf,
+	0x3fffdf,
+	0x7fffeb,
+	0x7fffec,
+	0x1fffe0,
+	0x1fffe1,
+	0x3fffe0,
+	0x1fffe2,
+	0x7fffed,
+	0x3fffe1,
+	0x7fffee,
+	0x7fffef,
+	0xfffea,
+	0x3fffe2,
+	0x3fffe3,
+	0x3fffe4,
+	0x7ffff0,
+	0x3fffe5,
+	0x3fffe6,
+	0x7ffff1,
+	0x3ffffe0,
+	0x3ffffe1,
+	0xfffeb,
+	0x7fff1,
+	0x3fffe7,
+	0x7ffff2,
+	0x3fffe8,
+	0x1ffffec,
+	0x3ffffe2,
+	0x3ffffe3,
+	0x3ffffe4,
+	0x7ffffde,
+	0x7ffffdf,
+	0x3ffffe5,
+	0xfffff1,
+	0x1ffffed,
+	0x7fff2,
+	0x1fffe3,
+	0x3ffffe6,
+	0x7ffffe0,
+	0x7ffffe1,
+	0x3ffffe7,
+	0x7ffffe2,
+	0xfffff2,
+	0x1fffe4,
+	0x1fffe5,
+	0x3ffffe8,
+	0x3ffffe9,
+	0xffffffd,
+	0x7ffffe3,
+	0x7ffffe4,
+	0x7ffffe5,
+	0xfffec,
+	0xfffff3,
+	0xfffed,
+	0x1fffe6,
+	0x3fffe9,
+	0x1fffe7,
+	0x1fffe8,
+	0x7ffff3,
+	0x3fffea,
+	0x3fffeb,
+	0x1ffffee,
+	0x1ffffef,
+	0xfffff4,
+	0xfffff5,
+	0x3ffffea,
+	0x7ffff4,
+	0x3ffffeb,
+	0x7ffffe6,
+	0x3ffffec,
+	0x3ffffed,
+	0x7ffffe7,
+	0x7ffffe8,
+	0x7ffffe9,
+	0x7ffffea,
+	0x7ffffeb,
+	0xffffffe,
+	0x7ffffec,
+	0x7ffffed,
+	0x7ffffee,
+	0x7ffffef,
+	0x7fffff0,
+	0x3ffffee,
+}
+
+var huffmanCodeLen = [256]uint8{
+	13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28,
+	28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+	6, 10, 10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6,
+	5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10,
+	13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6,
+	15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5,
+	6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28,
+	20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23,
+	24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24,
+	22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23,
+	21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23,
+	26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25,
+	19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27,
+	20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23,
+	26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26,
+}