commit 31993e51017b4c26d7149eb1be431beec50aab28
parent 9fc0ff6ffd1ea984549b4f2bce45e2db5052e629
Author: bsandro <brian.drosan@gmail.com>
Date: Tue, 17 Nov 2020 00:50:37 +0300
webp compression support
Diffstat:
24 files changed, 4211 insertions(+), 6 deletions(-)
diff --git a/Makefile b/Makefile
@@ -20,4 +20,4 @@ run: gen
.PHONY: clean
clean:
- rm -f ebitest ebitest.exe assets.go
+ @rm -f ebitest ebitest.exe assets.go
diff --git a/assets/BakaHa.webp b/assets/BakaHa.webp
Binary files differ.
diff --git a/assets/BakaHa1.webp b/assets/BakaHa1.webp
Binary files differ.
diff --git a/assets/BakaHa2.webp b/assets/BakaHa2.webp
Binary files differ.
diff --git a/assets/BakaHa3.webp b/assets/BakaHa3.webp
Binary files differ.
diff --git a/generate/embed.go b/generate/embed.go
@@ -12,7 +12,7 @@ func main() {
out.Write([]byte("package main\n\nvar Assets = map[string][]byte{\n"))
for _, asset := range assets {
assetFile, _ := ioutil.ReadFile("assets/" + asset.Name())
- fmt.Fprintf(out, "\t\"%s\": []byte(%q)", asset.Name(), string(assetFile))
+ fmt.Fprintf(out, "\t\"%s\": []byte(%q),", asset.Name(), string(assetFile))
}
out.Write([]byte("}\n"))
}
diff --git a/go.mod b/go.mod
@@ -2,4 +2,7 @@ module bsandro.org/git/ebitest
go 1.15
-require github.com/hajimehoshi/ebiten/v2 v2.0.0
+require (
+ github.com/hajimehoshi/ebiten/v2 v2.0.0
+ golang.org/x/image v0.0.0-20200927104501-e162460cd6b5
+)
diff --git a/init.go b/init.go
@@ -5,9 +5,8 @@ import (
"fmt"
"github.com/hajimehoshi/ebiten/v2"
"log"
- //"github.com/hajimehoshi/ebiten/v2/ebitenutil"
"image"
- _ "image/png"
+ _ "golang.org/x/image/webp"
)
//go:generate go run generate/embed.go
@@ -17,7 +16,7 @@ func init() {
for fname, raw := range Assets {
fmt.Printf("Loaded '%s' - %d bytes\n", fname, len(raw))
}
- rawImage, format, err := image.Decode(bytes.NewReader(Assets["BakaHa.png"]))
+ rawImage, format, err := image.Decode(bytes.NewReader(Assets["BakaHa3.webp"]))
log.Println("bakaHa detected format:", format)
if err != nil {
log.Fatal(err)
diff --git a/vendor/golang.org/x/image/riff/riff.go b/vendor/golang.org/x/image/riff/riff.go
@@ -0,0 +1,193 @@
+// 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 riff implements the Resource Interchange File Format, used by media
+// formats such as AVI, WAVE and WEBP.
+//
+// A RIFF stream contains a sequence of chunks. Each chunk consists of an 8-byte
+// header (containing a 4-byte chunk type and a 4-byte chunk length), the chunk
+// data (presented as an io.Reader), and some padding bytes.
+//
+// A detailed description of the format is at
+// http://www.tactilemedia.com/info/MCI_Control_Info.html
+package riff // import "golang.org/x/image/riff"
+
+import (
+ "errors"
+ "io"
+ "io/ioutil"
+ "math"
+)
+
+var (
+ errMissingPaddingByte = errors.New("riff: missing padding byte")
+ errMissingRIFFChunkHeader = errors.New("riff: missing RIFF chunk header")
+ errListSubchunkTooLong = errors.New("riff: list subchunk too long")
+ errShortChunkData = errors.New("riff: short chunk data")
+ errShortChunkHeader = errors.New("riff: short chunk header")
+ errStaleReader = errors.New("riff: stale reader")
+)
+
+// u32 decodes the first four bytes of b as a little-endian integer.
+func u32(b []byte) uint32 {
+ return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+}
+
+const chunkHeaderSize = 8
+
+// FourCC is a four character code.
+type FourCC [4]byte
+
+// LIST is the "LIST" FourCC.
+var LIST = FourCC{'L', 'I', 'S', 'T'}
+
+// NewReader returns the RIFF stream's form type, such as "AVI " or "WAVE", and
+// its chunks as a *Reader.
+func NewReader(r io.Reader) (formType FourCC, data *Reader, err error) {
+ var buf [chunkHeaderSize]byte
+ if _, err := io.ReadFull(r, buf[:]); err != nil {
+ if err == io.EOF || err == io.ErrUnexpectedEOF {
+ err = errMissingRIFFChunkHeader
+ }
+ return FourCC{}, nil, err
+ }
+ if buf[0] != 'R' || buf[1] != 'I' || buf[2] != 'F' || buf[3] != 'F' {
+ return FourCC{}, nil, errMissingRIFFChunkHeader
+ }
+ return NewListReader(u32(buf[4:]), r)
+}
+
+// NewListReader returns a LIST chunk's list type, such as "movi" or "wavl",
+// and its chunks as a *Reader.
+func NewListReader(chunkLen uint32, chunkData io.Reader) (listType FourCC, data *Reader, err error) {
+ if chunkLen < 4 {
+ return FourCC{}, nil, errShortChunkData
+ }
+ z := &Reader{r: chunkData}
+ if _, err := io.ReadFull(chunkData, z.buf[:4]); err != nil {
+ if err == io.EOF || err == io.ErrUnexpectedEOF {
+ err = errShortChunkData
+ }
+ return FourCC{}, nil, err
+ }
+ z.totalLen = chunkLen - 4
+ return FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}, z, nil
+}
+
+// Reader reads chunks from an underlying io.Reader.
+type Reader struct {
+ r io.Reader
+ err error
+
+ totalLen uint32
+ chunkLen uint32
+
+ chunkReader *chunkReader
+ buf [chunkHeaderSize]byte
+ padded bool
+}
+
+// Next returns the next chunk's ID, length and data. It returns io.EOF if there
+// are no more chunks. The io.Reader returned becomes stale after the next Next
+// call, and should no longer be used.
+//
+// It is valid to call Next even if all of the previous chunk's data has not
+// been read.
+func (z *Reader) Next() (chunkID FourCC, chunkLen uint32, chunkData io.Reader, err error) {
+ if z.err != nil {
+ return FourCC{}, 0, nil, z.err
+ }
+
+ // Drain the rest of the previous chunk.
+ if z.chunkLen != 0 {
+ want := z.chunkLen
+ var got int64
+ got, z.err = io.Copy(ioutil.Discard, z.chunkReader)
+ if z.err == nil && uint32(got) != want {
+ z.err = errShortChunkData
+ }
+ if z.err != nil {
+ return FourCC{}, 0, nil, z.err
+ }
+ }
+ z.chunkReader = nil
+ if z.padded {
+ if z.totalLen == 0 {
+ z.err = errListSubchunkTooLong
+ return FourCC{}, 0, nil, z.err
+ }
+ z.totalLen--
+ _, z.err = io.ReadFull(z.r, z.buf[:1])
+ if z.err != nil {
+ if z.err == io.EOF {
+ z.err = errMissingPaddingByte
+ }
+ return FourCC{}, 0, nil, z.err
+ }
+ }
+
+ // We are done if we have no more data.
+ if z.totalLen == 0 {
+ z.err = io.EOF
+ return FourCC{}, 0, nil, z.err
+ }
+
+ // Read the next chunk header.
+ if z.totalLen < chunkHeaderSize {
+ z.err = errShortChunkHeader
+ return FourCC{}, 0, nil, z.err
+ }
+ z.totalLen -= chunkHeaderSize
+ if _, z.err = io.ReadFull(z.r, z.buf[:chunkHeaderSize]); z.err != nil {
+ if z.err == io.EOF || z.err == io.ErrUnexpectedEOF {
+ z.err = errShortChunkHeader
+ }
+ return FourCC{}, 0, nil, z.err
+ }
+ chunkID = FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}
+ z.chunkLen = u32(z.buf[4:])
+ if z.chunkLen > z.totalLen {
+ z.err = errListSubchunkTooLong
+ return FourCC{}, 0, nil, z.err
+ }
+ z.padded = z.chunkLen&1 == 1
+ z.chunkReader = &chunkReader{z}
+ return chunkID, z.chunkLen, z.chunkReader, nil
+}
+
+type chunkReader struct {
+ z *Reader
+}
+
+func (c *chunkReader) Read(p []byte) (int, error) {
+ if c != c.z.chunkReader {
+ return 0, errStaleReader
+ }
+ z := c.z
+ if z.err != nil {
+ if z.err == io.EOF {
+ return 0, errStaleReader
+ }
+ return 0, z.err
+ }
+
+ n := int(z.chunkLen)
+ if n == 0 {
+ return 0, io.EOF
+ }
+ if n < 0 {
+ // Converting uint32 to int overflowed.
+ n = math.MaxInt32
+ }
+ if n > len(p) {
+ n = len(p)
+ }
+ n, err := z.r.Read(p[:n])
+ z.totalLen -= uint32(n)
+ z.chunkLen -= uint32(n)
+ if err != io.EOF {
+ z.err = err
+ }
+ return n, err
+}
diff --git a/vendor/golang.org/x/image/vp8/decode.go b/vendor/golang.org/x/image/vp8/decode.go
@@ -0,0 +1,403 @@
+// Copyright 2011 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 vp8 implements a decoder for the VP8 lossy image format.
+//
+// The VP8 specification is RFC 6386.
+package vp8 // import "golang.org/x/image/vp8"
+
+// This file implements the top-level decoding algorithm.
+
+import (
+ "errors"
+ "image"
+ "io"
+)
+
+// limitReader wraps an io.Reader to read at most n bytes from it.
+type limitReader struct {
+ r io.Reader
+ n int
+}
+
+// ReadFull reads exactly len(p) bytes into p.
+func (r *limitReader) ReadFull(p []byte) error {
+ if len(p) > r.n {
+ return io.ErrUnexpectedEOF
+ }
+ n, err := io.ReadFull(r.r, p)
+ r.n -= n
+ return err
+}
+
+// FrameHeader is a frame header, as specified in section 9.1.
+type FrameHeader struct {
+ KeyFrame bool
+ VersionNumber uint8
+ ShowFrame bool
+ FirstPartitionLen uint32
+ Width int
+ Height int
+ XScale uint8
+ YScale uint8
+}
+
+const (
+ nSegment = 4
+ nSegmentProb = 3
+)
+
+// segmentHeader holds segment-related header information.
+type segmentHeader struct {
+ useSegment bool
+ updateMap bool
+ relativeDelta bool
+ quantizer [nSegment]int8
+ filterStrength [nSegment]int8
+ prob [nSegmentProb]uint8
+}
+
+const (
+ nRefLFDelta = 4
+ nModeLFDelta = 4
+)
+
+// filterHeader holds filter-related header information.
+type filterHeader struct {
+ simple bool
+ level int8
+ sharpness uint8
+ useLFDelta bool
+ refLFDelta [nRefLFDelta]int8
+ modeLFDelta [nModeLFDelta]int8
+ perSegmentLevel [nSegment]int8
+}
+
+// mb is the per-macroblock decode state. A decoder maintains mbw+1 of these
+// as it is decoding macroblocks left-to-right and top-to-bottom: mbw for the
+// macroblocks in the row above, and one for the macroblock to the left.
+type mb struct {
+ // pred is the predictor mode for the 4 bottom or right 4x4 luma regions.
+ pred [4]uint8
+ // nzMask is a mask of 8 bits: 4 for the bottom or right 4x4 luma regions,
+ // and 2 + 2 for the bottom or right 4x4 chroma regions. A 1 bit indicates
+ // that region has non-zero coefficients.
+ nzMask uint8
+ // nzY16 is a 0/1 value that is 1 if the macroblock used Y16 prediction and
+ // had non-zero coefficients.
+ nzY16 uint8
+}
+
+// Decoder decodes VP8 bitstreams into frames. Decoding one frame consists of
+// calling Init, DecodeFrameHeader and then DecodeFrame in that order.
+// A Decoder can be re-used to decode multiple frames.
+type Decoder struct {
+ // r is the input bitsream.
+ r limitReader
+ // scratch is a scratch buffer.
+ scratch [8]byte
+ // img is the YCbCr image to decode into.
+ img *image.YCbCr
+ // mbw and mbh are the number of 16x16 macroblocks wide and high the image is.
+ mbw, mbh int
+ // frameHeader is the frame header. When decoding multiple frames,
+ // frames that aren't key frames will inherit the Width, Height,
+ // XScale and YScale of the most recent key frame.
+ frameHeader FrameHeader
+ // Other headers.
+ segmentHeader segmentHeader
+ filterHeader filterHeader
+ // The image data is divided into a number of independent partitions.
+ // There is 1 "first partition" and between 1 and 8 "other partitions"
+ // for coefficient data.
+ fp partition
+ op [8]partition
+ nOP int
+ // Quantization factors.
+ quant [nSegment]quant
+ // DCT/WHT coefficient decoding probabilities.
+ tokenProb [nPlane][nBand][nContext][nProb]uint8
+ useSkipProb bool
+ skipProb uint8
+ // Loop filter parameters.
+ filterParams [nSegment][2]filterParam
+ perMBFilterParams []filterParam
+
+ // The eight fields below relate to the current macroblock being decoded.
+ //
+ // Segment-based adjustments.
+ segment int
+ // Per-macroblock state for the macroblock immediately left of and those
+ // macroblocks immediately above the current macroblock.
+ leftMB mb
+ upMB []mb
+ // Bitmasks for which 4x4 regions of coeff contain non-zero coefficients.
+ nzDCMask, nzACMask uint32
+ // Predictor modes.
+ usePredY16 bool // The libwebp C code calls this !is_i4x4_.
+ predY16 uint8
+ predC8 uint8
+ predY4 [4][4]uint8
+
+ // The two fields below form a workspace for reconstructing a macroblock.
+ // Their specific sizes are documented in reconstruct.go.
+ coeff [1*16*16 + 2*8*8 + 1*4*4]int16
+ ybr [1 + 16 + 1 + 8][32]uint8
+}
+
+// NewDecoder returns a new Decoder.
+func NewDecoder() *Decoder {
+ return &Decoder{}
+}
+
+// Init initializes the decoder to read at most n bytes from r.
+func (d *Decoder) Init(r io.Reader, n int) {
+ d.r = limitReader{r, n}
+}
+
+// DecodeFrameHeader decodes the frame header.
+func (d *Decoder) DecodeFrameHeader() (fh FrameHeader, err error) {
+ // All frame headers are at least 3 bytes long.
+ b := d.scratch[:3]
+ if err = d.r.ReadFull(b); err != nil {
+ return
+ }
+ d.frameHeader.KeyFrame = (b[0] & 1) == 0
+ d.frameHeader.VersionNumber = (b[0] >> 1) & 7
+ d.frameHeader.ShowFrame = (b[0]>>4)&1 == 1
+ d.frameHeader.FirstPartitionLen = uint32(b[0])>>5 | uint32(b[1])<<3 | uint32(b[2])<<11
+ if !d.frameHeader.KeyFrame {
+ return d.frameHeader, nil
+ }
+ // Frame headers for key frames are an additional 7 bytes long.
+ b = d.scratch[:7]
+ if err = d.r.ReadFull(b); err != nil {
+ return
+ }
+ // Check the magic sync code.
+ if b[0] != 0x9d || b[1] != 0x01 || b[2] != 0x2a {
+ err = errors.New("vp8: invalid format")
+ return
+ }
+ d.frameHeader.Width = int(b[4]&0x3f)<<8 | int(b[3])
+ d.frameHeader.Height = int(b[6]&0x3f)<<8 | int(b[5])
+ d.frameHeader.XScale = b[4] >> 6
+ d.frameHeader.YScale = b[6] >> 6
+ d.mbw = (d.frameHeader.Width + 0x0f) >> 4
+ d.mbh = (d.frameHeader.Height + 0x0f) >> 4
+ d.segmentHeader = segmentHeader{
+ prob: [3]uint8{0xff, 0xff, 0xff},
+ }
+ d.tokenProb = defaultTokenProb
+ d.segment = 0
+ return d.frameHeader, nil
+}
+
+// ensureImg ensures that d.img is large enough to hold the decoded frame.
+func (d *Decoder) ensureImg() {
+ if d.img != nil {
+ p0, p1 := d.img.Rect.Min, d.img.Rect.Max
+ if p0.X == 0 && p0.Y == 0 && p1.X >= 16*d.mbw && p1.Y >= 16*d.mbh {
+ return
+ }
+ }
+ m := image.NewYCbCr(image.Rect(0, 0, 16*d.mbw, 16*d.mbh), image.YCbCrSubsampleRatio420)
+ d.img = m.SubImage(image.Rect(0, 0, d.frameHeader.Width, d.frameHeader.Height)).(*image.YCbCr)
+ d.perMBFilterParams = make([]filterParam, d.mbw*d.mbh)
+ d.upMB = make([]mb, d.mbw)
+}
+
+// parseSegmentHeader parses the segment header, as specified in section 9.3.
+func (d *Decoder) parseSegmentHeader() {
+ d.segmentHeader.useSegment = d.fp.readBit(uniformProb)
+ if !d.segmentHeader.useSegment {
+ d.segmentHeader.updateMap = false
+ return
+ }
+ d.segmentHeader.updateMap = d.fp.readBit(uniformProb)
+ if d.fp.readBit(uniformProb) {
+ d.segmentHeader.relativeDelta = !d.fp.readBit(uniformProb)
+ for i := range d.segmentHeader.quantizer {
+ d.segmentHeader.quantizer[i] = int8(d.fp.readOptionalInt(uniformProb, 7))
+ }
+ for i := range d.segmentHeader.filterStrength {
+ d.segmentHeader.filterStrength[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
+ }
+ }
+ if !d.segmentHeader.updateMap {
+ return
+ }
+ for i := range d.segmentHeader.prob {
+ if d.fp.readBit(uniformProb) {
+ d.segmentHeader.prob[i] = uint8(d.fp.readUint(uniformProb, 8))
+ } else {
+ d.segmentHeader.prob[i] = 0xff
+ }
+ }
+}
+
+// parseFilterHeader parses the filter header, as specified in section 9.4.
+func (d *Decoder) parseFilterHeader() {
+ d.filterHeader.simple = d.fp.readBit(uniformProb)
+ d.filterHeader.level = int8(d.fp.readUint(uniformProb, 6))
+ d.filterHeader.sharpness = uint8(d.fp.readUint(uniformProb, 3))
+ d.filterHeader.useLFDelta = d.fp.readBit(uniformProb)
+ if d.filterHeader.useLFDelta && d.fp.readBit(uniformProb) {
+ for i := range d.filterHeader.refLFDelta {
+ d.filterHeader.refLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
+ }
+ for i := range d.filterHeader.modeLFDelta {
+ d.filterHeader.modeLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
+ }
+ }
+ if d.filterHeader.level == 0 {
+ return
+ }
+ if d.segmentHeader.useSegment {
+ for i := range d.filterHeader.perSegmentLevel {
+ strength := d.segmentHeader.filterStrength[i]
+ if d.segmentHeader.relativeDelta {
+ strength += d.filterHeader.level
+ }
+ d.filterHeader.perSegmentLevel[i] = strength
+ }
+ } else {
+ d.filterHeader.perSegmentLevel[0] = d.filterHeader.level
+ }
+ d.computeFilterParams()
+}
+
+// parseOtherPartitions parses the other partitions, as specified in section 9.5.
+func (d *Decoder) parseOtherPartitions() error {
+ const maxNOP = 1 << 3
+ var partLens [maxNOP]int
+ d.nOP = 1 << d.fp.readUint(uniformProb, 2)
+
+ // The final partition length is implied by the remaining chunk data
+ // (d.r.n) and the other d.nOP-1 partition lengths. Those d.nOP-1 partition
+ // lengths are stored as 24-bit uints, i.e. up to 16 MiB per partition.
+ n := 3 * (d.nOP - 1)
+ partLens[d.nOP-1] = d.r.n - n
+ if partLens[d.nOP-1] < 0 {
+ return io.ErrUnexpectedEOF
+ }
+ if n > 0 {
+ buf := make([]byte, n)
+ if err := d.r.ReadFull(buf); err != nil {
+ return err
+ }
+ for i := 0; i < d.nOP-1; i++ {
+ pl := int(buf[3*i+0]) | int(buf[3*i+1])<<8 | int(buf[3*i+2])<<16
+ if pl > partLens[d.nOP-1] {
+ return io.ErrUnexpectedEOF
+ }
+ partLens[i] = pl
+ partLens[d.nOP-1] -= pl
+ }
+ }
+
+ // We check if the final partition length can also fit into a 24-bit uint.
+ // Strictly speaking, this isn't part of the spec, but it guards against a
+ // malicious WEBP image that is too large to ReadFull the encoded DCT
+ // coefficients into memory, whether that's because the actual WEBP file is
+ // too large, or whether its RIFF metadata lists too large a chunk.
+ if 1<<24 <= partLens[d.nOP-1] {
+ return errors.New("vp8: too much data to decode")
+ }
+
+ buf := make([]byte, d.r.n)
+ if err := d.r.ReadFull(buf); err != nil {
+ return err
+ }
+ for i, pl := range partLens {
+ if i == d.nOP {
+ break
+ }
+ d.op[i].init(buf[:pl])
+ buf = buf[pl:]
+ }
+ return nil
+}
+
+// parseOtherHeaders parses header information other than the frame header.
+func (d *Decoder) parseOtherHeaders() error {
+ // Initialize and parse the first partition.
+ firstPartition := make([]byte, d.frameHeader.FirstPartitionLen)
+ if err := d.r.ReadFull(firstPartition); err != nil {
+ return err
+ }
+ d.fp.init(firstPartition)
+ if d.frameHeader.KeyFrame {
+ // Read and ignore the color space and pixel clamp values. They are
+ // specified in section 9.2, but are unimplemented.
+ d.fp.readBit(uniformProb)
+ d.fp.readBit(uniformProb)
+ }
+ d.parseSegmentHeader()
+ d.parseFilterHeader()
+ if err := d.parseOtherPartitions(); err != nil {
+ return err
+ }
+ d.parseQuant()
+ if !d.frameHeader.KeyFrame {
+ // Golden and AltRef frames are specified in section 9.7.
+ // TODO(nigeltao): implement. Note that they are only used for video, not still images.
+ return errors.New("vp8: Golden / AltRef frames are not implemented")
+ }
+ // Read and ignore the refreshLastFrameBuffer bit, specified in section 9.8.
+ // It applies only to video, and not still images.
+ d.fp.readBit(uniformProb)
+ d.parseTokenProb()
+ d.useSkipProb = d.fp.readBit(uniformProb)
+ if d.useSkipProb {
+ d.skipProb = uint8(d.fp.readUint(uniformProb, 8))
+ }
+ if d.fp.unexpectedEOF {
+ return io.ErrUnexpectedEOF
+ }
+ return nil
+}
+
+// DecodeFrame decodes the frame and returns it as an YCbCr image.
+// The image's contents are valid up until the next call to Decoder.Init.
+func (d *Decoder) DecodeFrame() (*image.YCbCr, error) {
+ d.ensureImg()
+ if err := d.parseOtherHeaders(); err != nil {
+ return nil, err
+ }
+ // Reconstruct the rows.
+ for mbx := 0; mbx < d.mbw; mbx++ {
+ d.upMB[mbx] = mb{}
+ }
+ for mby := 0; mby < d.mbh; mby++ {
+ d.leftMB = mb{}
+ for mbx := 0; mbx < d.mbw; mbx++ {
+ skip := d.reconstruct(mbx, mby)
+ fs := d.filterParams[d.segment][btou(!d.usePredY16)]
+ fs.inner = fs.inner || !skip
+ d.perMBFilterParams[d.mbw*mby+mbx] = fs
+ }
+ }
+ if d.fp.unexpectedEOF {
+ return nil, io.ErrUnexpectedEOF
+ }
+ for i := 0; i < d.nOP; i++ {
+ if d.op[i].unexpectedEOF {
+ return nil, io.ErrUnexpectedEOF
+ }
+ }
+ // Apply the loop filter.
+ //
+ // Even if we are using per-segment levels, section 15 says that "loop
+ // filtering must be skipped entirely if loop_filter_level at either the
+ // frame header level or macroblock override level is 0".
+ if d.filterHeader.level != 0 {
+ if d.filterHeader.simple {
+ d.simpleFilter()
+ } else {
+ d.normalFilter()
+ }
+ }
+ return d.img, nil
+}
diff --git a/vendor/golang.org/x/image/vp8/filter.go b/vendor/golang.org/x/image/vp8/filter.go
@@ -0,0 +1,273 @@
+// 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 vp8
+
+// filter2 modifies a 2-pixel wide or 2-pixel high band along an edge.
+func filter2(pix []byte, level, index, iStep, jStep int) {
+ for n := 16; n > 0; n, index = n-1, index+iStep {
+ p1 := int(pix[index-2*jStep])
+ p0 := int(pix[index-1*jStep])
+ q0 := int(pix[index+0*jStep])
+ q1 := int(pix[index+1*jStep])
+ if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
+ continue
+ }
+ a := 3*(q0-p0) + clamp127(p1-q1)
+ a1 := clamp15((a + 4) >> 3)
+ a2 := clamp15((a + 3) >> 3)
+ pix[index-1*jStep] = clamp255(p0 + a2)
+ pix[index+0*jStep] = clamp255(q0 - a1)
+ }
+}
+
+// filter246 modifies a 2-, 4- or 6-pixel wide or high band along an edge.
+func filter246(pix []byte, n, level, ilevel, hlevel, index, iStep, jStep int, fourNotSix bool) {
+ for ; n > 0; n, index = n-1, index+iStep {
+ p3 := int(pix[index-4*jStep])
+ p2 := int(pix[index-3*jStep])
+ p1 := int(pix[index-2*jStep])
+ p0 := int(pix[index-1*jStep])
+ q0 := int(pix[index+0*jStep])
+ q1 := int(pix[index+1*jStep])
+ q2 := int(pix[index+2*jStep])
+ q3 := int(pix[index+3*jStep])
+ if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
+ continue
+ }
+ if abs(p3-p2) > ilevel ||
+ abs(p2-p1) > ilevel ||
+ abs(p1-p0) > ilevel ||
+ abs(q1-q0) > ilevel ||
+ abs(q2-q1) > ilevel ||
+ abs(q3-q2) > ilevel {
+ continue
+ }
+ if abs(p1-p0) > hlevel || abs(q1-q0) > hlevel {
+ // Filter 2 pixels.
+ a := 3*(q0-p0) + clamp127(p1-q1)
+ a1 := clamp15((a + 4) >> 3)
+ a2 := clamp15((a + 3) >> 3)
+ pix[index-1*jStep] = clamp255(p0 + a2)
+ pix[index+0*jStep] = clamp255(q0 - a1)
+ } else if fourNotSix {
+ // Filter 4 pixels.
+ a := 3 * (q0 - p0)
+ a1 := clamp15((a + 4) >> 3)
+ a2 := clamp15((a + 3) >> 3)
+ a3 := (a1 + 1) >> 1
+ pix[index-2*jStep] = clamp255(p1 + a3)
+ pix[index-1*jStep] = clamp255(p0 + a2)
+ pix[index+0*jStep] = clamp255(q0 - a1)
+ pix[index+1*jStep] = clamp255(q1 - a3)
+ } else {
+ // Filter 6 pixels.
+ a := clamp127(3*(q0-p0) + clamp127(p1-q1))
+ a1 := (27*a + 63) >> 7
+ a2 := (18*a + 63) >> 7
+ a3 := (9*a + 63) >> 7
+ pix[index-3*jStep] = clamp255(p2 + a3)
+ pix[index-2*jStep] = clamp255(p1 + a2)
+ pix[index-1*jStep] = clamp255(p0 + a1)
+ pix[index+0*jStep] = clamp255(q0 - a1)
+ pix[index+1*jStep] = clamp255(q1 - a2)
+ pix[index+2*jStep] = clamp255(q2 - a3)
+ }
+ }
+}
+
+// simpleFilter implements the simple filter, as specified in section 15.2.
+func (d *Decoder) simpleFilter() {
+ for mby := 0; mby < d.mbh; mby++ {
+ for mbx := 0; mbx < d.mbw; mbx++ {
+ f := d.perMBFilterParams[d.mbw*mby+mbx]
+ if f.level == 0 {
+ continue
+ }
+ l := int(f.level)
+ yIndex := (mby*d.img.YStride + mbx) * 16
+ if mbx > 0 {
+ filter2(d.img.Y, l+4, yIndex, d.img.YStride, 1)
+ }
+ if f.inner {
+ filter2(d.img.Y, l, yIndex+0x4, d.img.YStride, 1)
+ filter2(d.img.Y, l, yIndex+0x8, d.img.YStride, 1)
+ filter2(d.img.Y, l, yIndex+0xc, d.img.YStride, 1)
+ }
+ if mby > 0 {
+ filter2(d.img.Y, l+4, yIndex, 1, d.img.YStride)
+ }
+ if f.inner {
+ filter2(d.img.Y, l, yIndex+d.img.YStride*0x4, 1, d.img.YStride)
+ filter2(d.img.Y, l, yIndex+d.img.YStride*0x8, 1, d.img.YStride)
+ filter2(d.img.Y, l, yIndex+d.img.YStride*0xc, 1, d.img.YStride)
+ }
+ }
+ }
+}
+
+// normalFilter implements the normal filter, as specified in section 15.3.
+func (d *Decoder) normalFilter() {
+ for mby := 0; mby < d.mbh; mby++ {
+ for mbx := 0; mbx < d.mbw; mbx++ {
+ f := d.perMBFilterParams[d.mbw*mby+mbx]
+ if f.level == 0 {
+ continue
+ }
+ l, il, hl := int(f.level), int(f.ilevel), int(f.hlevel)
+ yIndex := (mby*d.img.YStride + mbx) * 16
+ cIndex := (mby*d.img.CStride + mbx) * 8
+ if mbx > 0 {
+ filter246(d.img.Y, 16, l+4, il, hl, yIndex, d.img.YStride, 1, false)
+ filter246(d.img.Cb, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
+ filter246(d.img.Cr, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
+ }
+ if f.inner {
+ filter246(d.img.Y, 16, l, il, hl, yIndex+0x4, d.img.YStride, 1, true)
+ filter246(d.img.Y, 16, l, il, hl, yIndex+0x8, d.img.YStride, 1, true)
+ filter246(d.img.Y, 16, l, il, hl, yIndex+0xc, d.img.YStride, 1, true)
+ filter246(d.img.Cb, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
+ filter246(d.img.Cr, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
+ }
+ if mby > 0 {
+ filter246(d.img.Y, 16, l+4, il, hl, yIndex, 1, d.img.YStride, false)
+ filter246(d.img.Cb, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
+ filter246(d.img.Cr, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
+ }
+ if f.inner {
+ filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x4, 1, d.img.YStride, true)
+ filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x8, 1, d.img.YStride, true)
+ filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0xc, 1, d.img.YStride, true)
+ filter246(d.img.Cb, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
+ filter246(d.img.Cr, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
+ }
+ }
+ }
+}
+
+// filterParam holds the loop filter parameters for a macroblock.
+type filterParam struct {
+ // The first three fields are thresholds used by the loop filter to smooth
+ // over the edges and interior of a macroblock. level is used by both the
+ // simple and normal filters. The inner level and high edge variance level
+ // are only used by the normal filter.
+ level, ilevel, hlevel uint8
+ // inner is whether the inner loop filter cannot be optimized out as a
+ // no-op for this particular macroblock.
+ inner bool
+}
+
+// computeFilterParams computes the loop filter parameters, as specified in
+// section 15.4.
+func (d *Decoder) computeFilterParams() {
+ for i := range d.filterParams {
+ baseLevel := d.filterHeader.level
+ if d.segmentHeader.useSegment {
+ baseLevel = d.segmentHeader.filterStrength[i]
+ if d.segmentHeader.relativeDelta {
+ baseLevel += d.filterHeader.level
+ }
+ }
+
+ for j := range d.filterParams[i] {
+ p := &d.filterParams[i][j]
+ p.inner = j != 0
+ level := baseLevel
+ if d.filterHeader.useLFDelta {
+ // The libwebp C code has a "TODO: only CURRENT is handled for now."
+ level += d.filterHeader.refLFDelta[0]
+ if j != 0 {
+ level += d.filterHeader.modeLFDelta[0]
+ }
+ }
+ if level <= 0 {
+ p.level = 0
+ continue
+ }
+ if level > 63 {
+ level = 63
+ }
+ ilevel := level
+ if d.filterHeader.sharpness > 0 {
+ if d.filterHeader.sharpness > 4 {
+ ilevel >>= 2
+ } else {
+ ilevel >>= 1
+ }
+ if x := int8(9 - d.filterHeader.sharpness); ilevel > x {
+ ilevel = x
+ }
+ }
+ if ilevel < 1 {
+ ilevel = 1
+ }
+ p.ilevel = uint8(ilevel)
+ p.level = uint8(2*level + ilevel)
+ if d.frameHeader.KeyFrame {
+ if level < 15 {
+ p.hlevel = 0
+ } else if level < 40 {
+ p.hlevel = 1
+ } else {
+ p.hlevel = 2
+ }
+ } else {
+ if level < 15 {
+ p.hlevel = 0
+ } else if level < 20 {
+ p.hlevel = 1
+ } else if level < 40 {
+ p.hlevel = 2
+ } else {
+ p.hlevel = 3
+ }
+ }
+ }
+ }
+}
+
+// intSize is either 32 or 64.
+const intSize = 32 << (^uint(0) >> 63)
+
+func abs(x int) int {
+ // m := -1 if x < 0. m := 0 otherwise.
+ m := x >> (intSize - 1)
+
+ // In two's complement representation, the negative number
+ // of any number (except the smallest one) can be computed
+ // by flipping all the bits and add 1. This is faster than
+ // code with a branch.
+ // See Hacker's Delight, section 2-4.
+ return (x ^ m) - m
+}
+
+func clamp15(x int) int {
+ if x < -16 {
+ return -16
+ }
+ if x > 15 {
+ return 15
+ }
+ return x
+}
+
+func clamp127(x int) int {
+ if x < -128 {
+ return -128
+ }
+ if x > 127 {
+ return 127
+ }
+ return x
+}
+
+func clamp255(x int) uint8 {
+ if x < 0 {
+ return 0
+ }
+ if x > 255 {
+ return 255
+ }
+ return uint8(x)
+}
diff --git a/vendor/golang.org/x/image/vp8/idct.go b/vendor/golang.org/x/image/vp8/idct.go
@@ -0,0 +1,98 @@
+// Copyright 2011 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 vp8
+
+// This file implements the inverse Discrete Cosine Transform and the inverse
+// Walsh Hadamard Transform (WHT), as specified in sections 14.3 and 14.4.
+
+func clip8(i int32) uint8 {
+ if i < 0 {
+ return 0
+ }
+ if i > 255 {
+ return 255
+ }
+ return uint8(i)
+}
+
+func (z *Decoder) inverseDCT4(y, x, coeffBase int) {
+ const (
+ c1 = 85627 // 65536 * cos(pi/8) * sqrt(2).
+ c2 = 35468 // 65536 * sin(pi/8) * sqrt(2).
+ )
+ var m [4][4]int32
+ for i := 0; i < 4; i++ {
+ a := int32(z.coeff[coeffBase+0]) + int32(z.coeff[coeffBase+8])
+ b := int32(z.coeff[coeffBase+0]) - int32(z.coeff[coeffBase+8])
+ c := (int32(z.coeff[coeffBase+4])*c2)>>16 - (int32(z.coeff[coeffBase+12])*c1)>>16
+ d := (int32(z.coeff[coeffBase+4])*c1)>>16 + (int32(z.coeff[coeffBase+12])*c2)>>16
+ m[i][0] = a + d
+ m[i][1] = b + c
+ m[i][2] = b - c
+ m[i][3] = a - d
+ coeffBase++
+ }
+ for j := 0; j < 4; j++ {
+ dc := m[0][j] + 4
+ a := dc + m[2][j]
+ b := dc - m[2][j]
+ c := (m[1][j]*c2)>>16 - (m[3][j]*c1)>>16
+ d := (m[1][j]*c1)>>16 + (m[3][j]*c2)>>16
+ z.ybr[y+j][x+0] = clip8(int32(z.ybr[y+j][x+0]) + (a+d)>>3)
+ z.ybr[y+j][x+1] = clip8(int32(z.ybr[y+j][x+1]) + (b+c)>>3)
+ z.ybr[y+j][x+2] = clip8(int32(z.ybr[y+j][x+2]) + (b-c)>>3)
+ z.ybr[y+j][x+3] = clip8(int32(z.ybr[y+j][x+3]) + (a-d)>>3)
+ }
+}
+
+func (z *Decoder) inverseDCT4DCOnly(y, x, coeffBase int) {
+ dc := (int32(z.coeff[coeffBase+0]) + 4) >> 3
+ for j := 0; j < 4; j++ {
+ for i := 0; i < 4; i++ {
+ z.ybr[y+j][x+i] = clip8(int32(z.ybr[y+j][x+i]) + dc)
+ }
+ }
+}
+
+func (z *Decoder) inverseDCT8(y, x, coeffBase int) {
+ z.inverseDCT4(y+0, x+0, coeffBase+0*16)
+ z.inverseDCT4(y+0, x+4, coeffBase+1*16)
+ z.inverseDCT4(y+4, x+0, coeffBase+2*16)
+ z.inverseDCT4(y+4, x+4, coeffBase+3*16)
+}
+
+func (z *Decoder) inverseDCT8DCOnly(y, x, coeffBase int) {
+ z.inverseDCT4DCOnly(y+0, x+0, coeffBase+0*16)
+ z.inverseDCT4DCOnly(y+0, x+4, coeffBase+1*16)
+ z.inverseDCT4DCOnly(y+4, x+0, coeffBase+2*16)
+ z.inverseDCT4DCOnly(y+4, x+4, coeffBase+3*16)
+}
+
+func (d *Decoder) inverseWHT16() {
+ var m [16]int32
+ for i := 0; i < 4; i++ {
+ a0 := int32(d.coeff[384+0+i]) + int32(d.coeff[384+12+i])
+ a1 := int32(d.coeff[384+4+i]) + int32(d.coeff[384+8+i])
+ a2 := int32(d.coeff[384+4+i]) - int32(d.coeff[384+8+i])
+ a3 := int32(d.coeff[384+0+i]) - int32(d.coeff[384+12+i])
+ m[0+i] = a0 + a1
+ m[8+i] = a0 - a1
+ m[4+i] = a3 + a2
+ m[12+i] = a3 - a2
+ }
+ out := 0
+ for i := 0; i < 4; i++ {
+ dc := m[0+i*4] + 3
+ a0 := dc + m[3+i*4]
+ a1 := m[1+i*4] + m[2+i*4]
+ a2 := m[1+i*4] - m[2+i*4]
+ a3 := dc - m[3+i*4]
+ d.coeff[out+0] = int16((a0 + a1) >> 3)
+ d.coeff[out+16] = int16((a3 + a2) >> 3)
+ d.coeff[out+32] = int16((a0 - a1) >> 3)
+ d.coeff[out+48] = int16((a3 - a2) >> 3)
+ out += 64
+ }
+}
diff --git a/vendor/golang.org/x/image/vp8/partition.go b/vendor/golang.org/x/image/vp8/partition.go
@@ -0,0 +1,129 @@
+// Copyright 2011 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 vp8
+
+// Each VP8 frame consists of between 2 and 9 bitstream partitions.
+// Each partition is byte-aligned and is independently arithmetic-encoded.
+//
+// This file implements decoding a partition's bitstream, as specified in
+// chapter 7. The implementation follows libwebp's approach instead of the
+// specification's reference C implementation. For example, we use a look-up
+// table instead of a for loop to recalibrate the encoded range.
+
+var (
+ lutShift = [127]uint8{
+ 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
+ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ }
+ lutRangeM1 = [127]uint8{
+ 127,
+ 127, 191,
+ 127, 159, 191, 223,
+ 127, 143, 159, 175, 191, 207, 223, 239,
+ 127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239, 247,
+ 127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179, 183, 187,
+ 191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251,
+ 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
+ 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
+ 191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221,
+ 223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253,
+ }
+)
+
+// uniformProb represents a 50% probability that the next bit is 0.
+const uniformProb = 128
+
+// partition holds arithmetic-coded bits.
+type partition struct {
+ // buf is the input bytes.
+ buf []byte
+ // r is how many of buf's bytes have been consumed.
+ r int
+ // rangeM1 is range minus 1, where range is in the arithmetic coding sense,
+ // not the Go language sense.
+ rangeM1 uint32
+ // bits and nBits hold those bits shifted out of buf but not yet consumed.
+ bits uint32
+ nBits uint8
+ // unexpectedEOF tells whether we tried to read past buf.
+ unexpectedEOF bool
+}
+
+// init initializes the partition.
+func (p *partition) init(buf []byte) {
+ p.buf = buf
+ p.r = 0
+ p.rangeM1 = 254
+ p.bits = 0
+ p.nBits = 0
+ p.unexpectedEOF = false
+}
+
+// readBit returns the next bit.
+func (p *partition) readBit(prob uint8) bool {
+ if p.nBits < 8 {
+ if p.r >= len(p.buf) {
+ p.unexpectedEOF = true
+ return false
+ }
+ // Expression split for 386 compiler.
+ x := uint32(p.buf[p.r])
+ p.bits |= x << (8 - p.nBits)
+ p.r++
+ p.nBits += 8
+ }
+ split := (p.rangeM1*uint32(prob))>>8 + 1
+ bit := p.bits >= split<<8
+ if bit {
+ p.rangeM1 -= split
+ p.bits -= split << 8
+ } else {
+ p.rangeM1 = split - 1
+ }
+ if p.rangeM1 < 127 {
+ shift := lutShift[p.rangeM1]
+ p.rangeM1 = uint32(lutRangeM1[p.rangeM1])
+ p.bits <<= shift
+ p.nBits -= shift
+ }
+ return bit
+}
+
+// readUint returns the next n-bit unsigned integer.
+func (p *partition) readUint(prob, n uint8) uint32 {
+ var u uint32
+ for n > 0 {
+ n--
+ if p.readBit(prob) {
+ u |= 1 << n
+ }
+ }
+ return u
+}
+
+// readInt returns the next n-bit signed integer.
+func (p *partition) readInt(prob, n uint8) int32 {
+ u := p.readUint(prob, n)
+ b := p.readBit(prob)
+ if b {
+ return -int32(u)
+ }
+ return int32(u)
+}
+
+// readOptionalInt returns the next n-bit signed integer in an encoding
+// where the likely result is zero.
+func (p *partition) readOptionalInt(prob, n uint8) int32 {
+ if !p.readBit(prob) {
+ return 0
+ }
+ return p.readInt(prob, n)
+}
diff --git a/vendor/golang.org/x/image/vp8/pred.go b/vendor/golang.org/x/image/vp8/pred.go
@@ -0,0 +1,201 @@
+// Copyright 2011 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 vp8
+
+// This file implements parsing the predictor modes, as specified in chapter
+// 11.
+
+func (d *Decoder) parsePredModeY16(mbx int) {
+ var p uint8
+ if !d.fp.readBit(156) {
+ if !d.fp.readBit(163) {
+ p = predDC
+ } else {
+ p = predVE
+ }
+ } else if !d.fp.readBit(128) {
+ p = predHE
+ } else {
+ p = predTM
+ }
+ for i := 0; i < 4; i++ {
+ d.upMB[mbx].pred[i] = p
+ d.leftMB.pred[i] = p
+ }
+ d.predY16 = p
+}
+
+func (d *Decoder) parsePredModeC8() {
+ if !d.fp.readBit(142) {
+ d.predC8 = predDC
+ } else if !d.fp.readBit(114) {
+ d.predC8 = predVE
+ } else if !d.fp.readBit(183) {
+ d.predC8 = predHE
+ } else {
+ d.predC8 = predTM
+ }
+}
+
+func (d *Decoder) parsePredModeY4(mbx int) {
+ for j := 0; j < 4; j++ {
+ p := d.leftMB.pred[j]
+ for i := 0; i < 4; i++ {
+ prob := &predProb[d.upMB[mbx].pred[i]][p]
+ if !d.fp.readBit(prob[0]) {
+ p = predDC
+ } else if !d.fp.readBit(prob[1]) {
+ p = predTM
+ } else if !d.fp.readBit(prob[2]) {
+ p = predVE
+ } else if !d.fp.readBit(prob[3]) {
+ if !d.fp.readBit(prob[4]) {
+ p = predHE
+ } else if !d.fp.readBit(prob[5]) {
+ p = predRD
+ } else {
+ p = predVR
+ }
+ } else if !d.fp.readBit(prob[6]) {
+ p = predLD
+ } else if !d.fp.readBit(prob[7]) {
+ p = predVL
+ } else if !d.fp.readBit(prob[8]) {
+ p = predHD
+ } else {
+ p = predHU
+ }
+ d.predY4[j][i] = p
+ d.upMB[mbx].pred[i] = p
+ }
+ d.leftMB.pred[j] = p
+ }
+}
+
+// predProb are the probabilities to decode a 4x4 region's predictor mode given
+// the predictor modes of the regions above and left of it.
+// These values are specified in section 11.5.
+var predProb = [nPred][nPred][9]uint8{
+ {
+ {231, 120, 48, 89, 115, 113, 120, 152, 112},
+ {152, 179, 64, 126, 170, 118, 46, 70, 95},
+ {175, 69, 143, 80, 85, 82, 72, 155, 103},
+ {56, 58, 10, 171, 218, 189, 17, 13, 152},
+ {114, 26, 17, 163, 44, 195, 21, 10, 173},
+ {121, 24, 80, 195, 26, 62, 44, 64, 85},
+ {144, 71, 10, 38, 171, 213, 144, 34, 26},
+ {170, 46, 55, 19, 136, 160, 33, 206, 71},
+ {63, 20, 8, 114, 114, 208, 12, 9, 226},
+ {81, 40, 11, 96, 182, 84, 29, 16, 36},
+ },
+ {
+ {134, 183, 89, 137, 98, 101, 106, 165, 148},
+ {72, 187, 100, 130, 157, 111, 32, 75, 80},
+ {66, 102, 167, 99, 74, 62, 40, 234, 128},
+ {41, 53, 9, 178, 241, 141, 26, 8, 107},
+ {74, 43, 26, 146, 73, 166, 49, 23, 157},
+ {65, 38, 105, 160, 51, 52, 31, 115, 128},
+ {104, 79, 12, 27, 217, 255, 87, 17, 7},
+ {87, 68, 71, 44, 114, 51, 15, 186, 23},
+ {47, 41, 14, 110, 182, 183, 21, 17, 194},
+ {66, 45, 25, 102, 197, 189, 23, 18, 22},
+ },
+ {
+ {88, 88, 147, 150, 42, 46, 45, 196, 205},
+ {43, 97, 183, 117, 85, 38, 35, 179, 61},
+ {39, 53, 200, 87, 26, 21, 43, 232, 171},
+ {56, 34, 51, 104, 114, 102, 29, 93, 77},
+ {39, 28, 85, 171, 58, 165, 90, 98, 64},
+ {34, 22, 116, 206, 23, 34, 43, 166, 73},
+ {107, 54, 32, 26, 51, 1, 81, 43, 31},
+ {68, 25, 106, 22, 64, 171, 36, 225, 114},
+ {34, 19, 21, 102, 132, 188, 16, 76, 124},
+ {62, 18, 78, 95, 85, 57, 50, 48, 51},
+ },
+ {
+ {193, 101, 35, 159, 215, 111, 89, 46, 111},
+ {60, 148, 31, 172, 219, 228, 21, 18, 111},
+ {112, 113, 77, 85, 179, 255, 38, 120, 114},
+ {40, 42, 1, 196, 245, 209, 10, 25, 109},
+ {88, 43, 29, 140, 166, 213, 37, 43, 154},
+ {61, 63, 30, 155, 67, 45, 68, 1, 209},
+ {100, 80, 8, 43, 154, 1, 51, 26, 71},
+ {142, 78, 78, 16, 255, 128, 34, 197, 171},
+ {41, 40, 5, 102, 211, 183, 4, 1, 221},
+ {51, 50, 17, 168, 209, 192, 23, 25, 82},
+ },
+ {
+ {138, 31, 36, 171, 27, 166, 38, 44, 229},
+ {67, 87, 58, 169, 82, 115, 26, 59, 179},
+ {63, 59, 90, 180, 59, 166, 93, 73, 154},
+ {40, 40, 21, 116, 143, 209, 34, 39, 175},
+ {47, 15, 16, 183, 34, 223, 49, 45, 183},
+ {46, 17, 33, 183, 6, 98, 15, 32, 183},
+ {57, 46, 22, 24, 128, 1, 54, 17, 37},
+ {65, 32, 73, 115, 28, 128, 23, 128, 205},
+ {40, 3, 9, 115, 51, 192, 18, 6, 223},
+ {87, 37, 9, 115, 59, 77, 64, 21, 47},
+ },
+ {
+ {104, 55, 44, 218, 9, 54, 53, 130, 226},
+ {64, 90, 70, 205, 40, 41, 23, 26, 57},
+ {54, 57, 112, 184, 5, 41, 38, 166, 213},
+ {30, 34, 26, 133, 152, 116, 10, 32, 134},
+ {39, 19, 53, 221, 26, 114, 32, 73, 255},
+ {31, 9, 65, 234, 2, 15, 1, 118, 73},
+ {75, 32, 12, 51, 192, 255, 160, 43, 51},
+ {88, 31, 35, 67, 102, 85, 55, 186, 85},
+ {56, 21, 23, 111, 59, 205, 45, 37, 192},
+ {55, 38, 70, 124, 73, 102, 1, 34, 98},
+ },
+ {
+ {125, 98, 42, 88, 104, 85, 117, 175, 82},
+ {95, 84, 53, 89, 128, 100, 113, 101, 45},
+ {75, 79, 123, 47, 51, 128, 81, 171, 1},
+ {57, 17, 5, 71, 102, 57, 53, 41, 49},
+ {38, 33, 13, 121, 57, 73, 26, 1, 85},
+ {41, 10, 67, 138, 77, 110, 90, 47, 114},
+ {115, 21, 2, 10, 102, 255, 166, 23, 6},
+ {101, 29, 16, 10, 85, 128, 101, 196, 26},
+ {57, 18, 10, 102, 102, 213, 34, 20, 43},
+ {117, 20, 15, 36, 163, 128, 68, 1, 26},
+ },
+ {
+ {102, 61, 71, 37, 34, 53, 31, 243, 192},
+ {69, 60, 71, 38, 73, 119, 28, 222, 37},
+ {68, 45, 128, 34, 1, 47, 11, 245, 171},
+ {62, 17, 19, 70, 146, 85, 55, 62, 70},
+ {37, 43, 37, 154, 100, 163, 85, 160, 1},
+ {63, 9, 92, 136, 28, 64, 32, 201, 85},
+ {75, 15, 9, 9, 64, 255, 184, 119, 16},
+ {86, 6, 28, 5, 64, 255, 25, 248, 1},
+ {56, 8, 17, 132, 137, 255, 55, 116, 128},
+ {58, 15, 20, 82, 135, 57, 26, 121, 40},
+ },
+ {
+ {164, 50, 31, 137, 154, 133, 25, 35, 218},
+ {51, 103, 44, 131, 131, 123, 31, 6, 158},
+ {86, 40, 64, 135, 148, 224, 45, 183, 128},
+ {22, 26, 17, 131, 240, 154, 14, 1, 209},
+ {45, 16, 21, 91, 64, 222, 7, 1, 197},
+ {56, 21, 39, 155, 60, 138, 23, 102, 213},
+ {83, 12, 13, 54, 192, 255, 68, 47, 28},
+ {85, 26, 85, 85, 128, 128, 32, 146, 171},
+ {18, 11, 7, 63, 144, 171, 4, 4, 246},
+ {35, 27, 10, 146, 174, 171, 12, 26, 128},
+ },
+ {
+ {190, 80, 35, 99, 180, 80, 126, 54, 45},
+ {85, 126, 47, 87, 176, 51, 41, 20, 32},
+ {101, 75, 128, 139, 118, 146, 116, 128, 85},
+ {56, 41, 15, 176, 236, 85, 37, 9, 62},
+ {71, 30, 17, 119, 118, 255, 17, 18, 138},
+ {101, 38, 60, 138, 55, 70, 43, 26, 142},
+ {146, 36, 19, 30, 171, 255, 97, 27, 20},
+ {138, 45, 61, 62, 219, 1, 81, 188, 64},
+ {32, 41, 20, 117, 151, 142, 20, 21, 163},
+ {112, 19, 12, 61, 195, 128, 48, 4, 24},
+ },
+}
diff --git a/vendor/golang.org/x/image/vp8/predfunc.go b/vendor/golang.org/x/image/vp8/predfunc.go
@@ -0,0 +1,553 @@
+// Copyright 2011 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 vp8
+
+// This file implements the predicition functions, as specified in chapter 12.
+//
+// For each macroblock (of 1x16x16 luma and 2x8x8 chroma coefficients), the
+// luma values are either predicted as one large 16x16 region or 16 separate
+// 4x4 regions. The chroma values are always predicted as one 8x8 region.
+//
+// For 4x4 regions, the target block's predicted values (Xs) are a function of
+// its previously-decoded top and left border values, as well as a number of
+// pixels from the top-right:
+//
+// a b c d e f g h
+// p X X X X
+// q X X X X
+// r X X X X
+// s X X X X
+//
+// The predictor modes are:
+// - DC: all Xs = (b + c + d + e + p + q + r + s + 4) / 8.
+// - TM: the first X = (b + p - a), the second X = (c + p - a), and so on.
+// - VE: each X = the weighted average of its column's top value and that
+// value's neighbors, i.e. averages of abc, bcd, cde or def.
+// - HE: similar to VE except rows instead of columns, and the final row is
+// an average of r, s and s.
+// - RD, VR, LD, VL, HD, HU: these diagonal modes ("Right Down", "Vertical
+// Right", etc) are more complicated and are described in section 12.3.
+// All Xs are clipped to the range [0, 255].
+//
+// For 8x8 and 16x16 regions, the target block's predicted values are a
+// function of the top and left border values without the top-right overhang,
+// i.e. without the 8x8 or 16x16 equivalent of f, g and h. Furthermore:
+// - There are no diagonal predictor modes, only DC, TM, VE and HE.
+// - The DC mode has variants for macroblocks in the top row and/or left
+// column, i.e. for macroblocks with mby == 0 || mbx == 0.
+// - The VE and HE modes take only the column top or row left values; they do
+// not smooth that top/left value with its neighbors.
+
+// nPred is the number of predictor modes, not including the Top/Left versions
+// of the DC predictor mode.
+const nPred = 10
+
+const (
+ predDC = iota
+ predTM
+ predVE
+ predHE
+ predRD
+ predVR
+ predLD
+ predVL
+ predHD
+ predHU
+ predDCTop
+ predDCLeft
+ predDCTopLeft
+)
+
+func checkTopLeftPred(mbx, mby int, p uint8) uint8 {
+ if p != predDC {
+ return p
+ }
+ if mbx == 0 {
+ if mby == 0 {
+ return predDCTopLeft
+ }
+ return predDCLeft
+ }
+ if mby == 0 {
+ return predDCTop
+ }
+ return predDC
+}
+
+var predFunc4 = [...]func(*Decoder, int, int){
+ predFunc4DC,
+ predFunc4TM,
+ predFunc4VE,
+ predFunc4HE,
+ predFunc4RD,
+ predFunc4VR,
+ predFunc4LD,
+ predFunc4VL,
+ predFunc4HD,
+ predFunc4HU,
+ nil,
+ nil,
+ nil,
+}
+
+var predFunc8 = [...]func(*Decoder, int, int){
+ predFunc8DC,
+ predFunc8TM,
+ predFunc8VE,
+ predFunc8HE,
+ nil,
+ nil,
+ nil,
+ nil,
+ nil,
+ nil,
+ predFunc8DCTop,
+ predFunc8DCLeft,
+ predFunc8DCTopLeft,
+}
+
+var predFunc16 = [...]func(*Decoder, int, int){
+ predFunc16DC,
+ predFunc16TM,
+ predFunc16VE,
+ predFunc16HE,
+ nil,
+ nil,
+ nil,
+ nil,
+ nil,
+ nil,
+ predFunc16DCTop,
+ predFunc16DCLeft,
+ predFunc16DCTopLeft,
+}
+
+func predFunc4DC(z *Decoder, y, x int) {
+ sum := uint32(4)
+ for i := 0; i < 4; i++ {
+ sum += uint32(z.ybr[y-1][x+i])
+ }
+ for j := 0; j < 4; j++ {
+ sum += uint32(z.ybr[y+j][x-1])
+ }
+ avg := uint8(sum / 8)
+ for j := 0; j < 4; j++ {
+ for i := 0; i < 4; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc4TM(z *Decoder, y, x int) {
+ delta0 := -int32(z.ybr[y-1][x-1])
+ for j := 0; j < 4; j++ {
+ delta1 := delta0 + int32(z.ybr[y+j][x-1])
+ for i := 0; i < 4; i++ {
+ delta2 := delta1 + int32(z.ybr[y-1][x+i])
+ z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
+ }
+ }
+}
+
+func predFunc4VE(z *Decoder, y, x int) {
+ a := int32(z.ybr[y-1][x-1])
+ b := int32(z.ybr[y-1][x+0])
+ c := int32(z.ybr[y-1][x+1])
+ d := int32(z.ybr[y-1][x+2])
+ e := int32(z.ybr[y-1][x+3])
+ f := int32(z.ybr[y-1][x+4])
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ cde := uint8((c + 2*d + e + 2) / 4)
+ def := uint8((d + 2*e + f + 2) / 4)
+ for j := 0; j < 4; j++ {
+ z.ybr[y+j][x+0] = abc
+ z.ybr[y+j][x+1] = bcd
+ z.ybr[y+j][x+2] = cde
+ z.ybr[y+j][x+3] = def
+ }
+}
+
+func predFunc4HE(z *Decoder, y, x int) {
+ s := int32(z.ybr[y+3][x-1])
+ r := int32(z.ybr[y+2][x-1])
+ q := int32(z.ybr[y+1][x-1])
+ p := int32(z.ybr[y+0][x-1])
+ a := int32(z.ybr[y-1][x-1])
+ ssr := uint8((s + 2*s + r + 2) / 4)
+ srq := uint8((s + 2*r + q + 2) / 4)
+ rqp := uint8((r + 2*q + p + 2) / 4)
+ apq := uint8((a + 2*p + q + 2) / 4)
+ for i := 0; i < 4; i++ {
+ z.ybr[y+0][x+i] = apq
+ z.ybr[y+1][x+i] = rqp
+ z.ybr[y+2][x+i] = srq
+ z.ybr[y+3][x+i] = ssr
+ }
+}
+
+func predFunc4RD(z *Decoder, y, x int) {
+ s := int32(z.ybr[y+3][x-1])
+ r := int32(z.ybr[y+2][x-1])
+ q := int32(z.ybr[y+1][x-1])
+ p := int32(z.ybr[y+0][x-1])
+ a := int32(z.ybr[y-1][x-1])
+ b := int32(z.ybr[y-1][x+0])
+ c := int32(z.ybr[y-1][x+1])
+ d := int32(z.ybr[y-1][x+2])
+ e := int32(z.ybr[y-1][x+3])
+ srq := uint8((s + 2*r + q + 2) / 4)
+ rqp := uint8((r + 2*q + p + 2) / 4)
+ qpa := uint8((q + 2*p + a + 2) / 4)
+ pab := uint8((p + 2*a + b + 2) / 4)
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ cde := uint8((c + 2*d + e + 2) / 4)
+ z.ybr[y+0][x+0] = pab
+ z.ybr[y+0][x+1] = abc
+ z.ybr[y+0][x+2] = bcd
+ z.ybr[y+0][x+3] = cde
+ z.ybr[y+1][x+0] = qpa
+ z.ybr[y+1][x+1] = pab
+ z.ybr[y+1][x+2] = abc
+ z.ybr[y+1][x+3] = bcd
+ z.ybr[y+2][x+0] = rqp
+ z.ybr[y+2][x+1] = qpa
+ z.ybr[y+2][x+2] = pab
+ z.ybr[y+2][x+3] = abc
+ z.ybr[y+3][x+0] = srq
+ z.ybr[y+3][x+1] = rqp
+ z.ybr[y+3][x+2] = qpa
+ z.ybr[y+3][x+3] = pab
+}
+
+func predFunc4VR(z *Decoder, y, x int) {
+ r := int32(z.ybr[y+2][x-1])
+ q := int32(z.ybr[y+1][x-1])
+ p := int32(z.ybr[y+0][x-1])
+ a := int32(z.ybr[y-1][x-1])
+ b := int32(z.ybr[y-1][x+0])
+ c := int32(z.ybr[y-1][x+1])
+ d := int32(z.ybr[y-1][x+2])
+ e := int32(z.ybr[y-1][x+3])
+ ab := uint8((a + b + 1) / 2)
+ bc := uint8((b + c + 1) / 2)
+ cd := uint8((c + d + 1) / 2)
+ de := uint8((d + e + 1) / 2)
+ rqp := uint8((r + 2*q + p + 2) / 4)
+ qpa := uint8((q + 2*p + a + 2) / 4)
+ pab := uint8((p + 2*a + b + 2) / 4)
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ cde := uint8((c + 2*d + e + 2) / 4)
+ z.ybr[y+0][x+0] = ab
+ z.ybr[y+0][x+1] = bc
+ z.ybr[y+0][x+2] = cd
+ z.ybr[y+0][x+3] = de
+ z.ybr[y+1][x+0] = pab
+ z.ybr[y+1][x+1] = abc
+ z.ybr[y+1][x+2] = bcd
+ z.ybr[y+1][x+3] = cde
+ z.ybr[y+2][x+0] = qpa
+ z.ybr[y+2][x+1] = ab
+ z.ybr[y+2][x+2] = bc
+ z.ybr[y+2][x+3] = cd
+ z.ybr[y+3][x+0] = rqp
+ z.ybr[y+3][x+1] = pab
+ z.ybr[y+3][x+2] = abc
+ z.ybr[y+3][x+3] = bcd
+}
+
+func predFunc4LD(z *Decoder, y, x int) {
+ a := int32(z.ybr[y-1][x+0])
+ b := int32(z.ybr[y-1][x+1])
+ c := int32(z.ybr[y-1][x+2])
+ d := int32(z.ybr[y-1][x+3])
+ e := int32(z.ybr[y-1][x+4])
+ f := int32(z.ybr[y-1][x+5])
+ g := int32(z.ybr[y-1][x+6])
+ h := int32(z.ybr[y-1][x+7])
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ cde := uint8((c + 2*d + e + 2) / 4)
+ def := uint8((d + 2*e + f + 2) / 4)
+ efg := uint8((e + 2*f + g + 2) / 4)
+ fgh := uint8((f + 2*g + h + 2) / 4)
+ ghh := uint8((g + 2*h + h + 2) / 4)
+ z.ybr[y+0][x+0] = abc
+ z.ybr[y+0][x+1] = bcd
+ z.ybr[y+0][x+2] = cde
+ z.ybr[y+0][x+3] = def
+ z.ybr[y+1][x+0] = bcd
+ z.ybr[y+1][x+1] = cde
+ z.ybr[y+1][x+2] = def
+ z.ybr[y+1][x+3] = efg
+ z.ybr[y+2][x+0] = cde
+ z.ybr[y+2][x+1] = def
+ z.ybr[y+2][x+2] = efg
+ z.ybr[y+2][x+3] = fgh
+ z.ybr[y+3][x+0] = def
+ z.ybr[y+3][x+1] = efg
+ z.ybr[y+3][x+2] = fgh
+ z.ybr[y+3][x+3] = ghh
+}
+
+func predFunc4VL(z *Decoder, y, x int) {
+ a := int32(z.ybr[y-1][x+0])
+ b := int32(z.ybr[y-1][x+1])
+ c := int32(z.ybr[y-1][x+2])
+ d := int32(z.ybr[y-1][x+3])
+ e := int32(z.ybr[y-1][x+4])
+ f := int32(z.ybr[y-1][x+5])
+ g := int32(z.ybr[y-1][x+6])
+ h := int32(z.ybr[y-1][x+7])
+ ab := uint8((a + b + 1) / 2)
+ bc := uint8((b + c + 1) / 2)
+ cd := uint8((c + d + 1) / 2)
+ de := uint8((d + e + 1) / 2)
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ cde := uint8((c + 2*d + e + 2) / 4)
+ def := uint8((d + 2*e + f + 2) / 4)
+ efg := uint8((e + 2*f + g + 2) / 4)
+ fgh := uint8((f + 2*g + h + 2) / 4)
+ z.ybr[y+0][x+0] = ab
+ z.ybr[y+0][x+1] = bc
+ z.ybr[y+0][x+2] = cd
+ z.ybr[y+0][x+3] = de
+ z.ybr[y+1][x+0] = abc
+ z.ybr[y+1][x+1] = bcd
+ z.ybr[y+1][x+2] = cde
+ z.ybr[y+1][x+3] = def
+ z.ybr[y+2][x+0] = bc
+ z.ybr[y+2][x+1] = cd
+ z.ybr[y+2][x+2] = de
+ z.ybr[y+2][x+3] = efg
+ z.ybr[y+3][x+0] = bcd
+ z.ybr[y+3][x+1] = cde
+ z.ybr[y+3][x+2] = def
+ z.ybr[y+3][x+3] = fgh
+}
+
+func predFunc4HD(z *Decoder, y, x int) {
+ s := int32(z.ybr[y+3][x-1])
+ r := int32(z.ybr[y+2][x-1])
+ q := int32(z.ybr[y+1][x-1])
+ p := int32(z.ybr[y+0][x-1])
+ a := int32(z.ybr[y-1][x-1])
+ b := int32(z.ybr[y-1][x+0])
+ c := int32(z.ybr[y-1][x+1])
+ d := int32(z.ybr[y-1][x+2])
+ sr := uint8((s + r + 1) / 2)
+ rq := uint8((r + q + 1) / 2)
+ qp := uint8((q + p + 1) / 2)
+ pa := uint8((p + a + 1) / 2)
+ srq := uint8((s + 2*r + q + 2) / 4)
+ rqp := uint8((r + 2*q + p + 2) / 4)
+ qpa := uint8((q + 2*p + a + 2) / 4)
+ pab := uint8((p + 2*a + b + 2) / 4)
+ abc := uint8((a + 2*b + c + 2) / 4)
+ bcd := uint8((b + 2*c + d + 2) / 4)
+ z.ybr[y+0][x+0] = pa
+ z.ybr[y+0][x+1] = pab
+ z.ybr[y+0][x+2] = abc
+ z.ybr[y+0][x+3] = bcd
+ z.ybr[y+1][x+0] = qp
+ z.ybr[y+1][x+1] = qpa
+ z.ybr[y+1][x+2] = pa
+ z.ybr[y+1][x+3] = pab
+ z.ybr[y+2][x+0] = rq
+ z.ybr[y+2][x+1] = rqp
+ z.ybr[y+2][x+2] = qp
+ z.ybr[y+2][x+3] = qpa
+ z.ybr[y+3][x+0] = sr
+ z.ybr[y+3][x+1] = srq
+ z.ybr[y+3][x+2] = rq
+ z.ybr[y+3][x+3] = rqp
+}
+
+func predFunc4HU(z *Decoder, y, x int) {
+ s := int32(z.ybr[y+3][x-1])
+ r := int32(z.ybr[y+2][x-1])
+ q := int32(z.ybr[y+1][x-1])
+ p := int32(z.ybr[y+0][x-1])
+ pq := uint8((p + q + 1) / 2)
+ qr := uint8((q + r + 1) / 2)
+ rs := uint8((r + s + 1) / 2)
+ pqr := uint8((p + 2*q + r + 2) / 4)
+ qrs := uint8((q + 2*r + s + 2) / 4)
+ rss := uint8((r + 2*s + s + 2) / 4)
+ sss := uint8(s)
+ z.ybr[y+0][x+0] = pq
+ z.ybr[y+0][x+1] = pqr
+ z.ybr[y+0][x+2] = qr
+ z.ybr[y+0][x+3] = qrs
+ z.ybr[y+1][x+0] = qr
+ z.ybr[y+1][x+1] = qrs
+ z.ybr[y+1][x+2] = rs
+ z.ybr[y+1][x+3] = rss
+ z.ybr[y+2][x+0] = rs
+ z.ybr[y+2][x+1] = rss
+ z.ybr[y+2][x+2] = sss
+ z.ybr[y+2][x+3] = sss
+ z.ybr[y+3][x+0] = sss
+ z.ybr[y+3][x+1] = sss
+ z.ybr[y+3][x+2] = sss
+ z.ybr[y+3][x+3] = sss
+}
+
+func predFunc8DC(z *Decoder, y, x int) {
+ sum := uint32(8)
+ for i := 0; i < 8; i++ {
+ sum += uint32(z.ybr[y-1][x+i])
+ }
+ for j := 0; j < 8; j++ {
+ sum += uint32(z.ybr[y+j][x-1])
+ }
+ avg := uint8(sum / 16)
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc8TM(z *Decoder, y, x int) {
+ delta0 := -int32(z.ybr[y-1][x-1])
+ for j := 0; j < 8; j++ {
+ delta1 := delta0 + int32(z.ybr[y+j][x-1])
+ for i := 0; i < 8; i++ {
+ delta2 := delta1 + int32(z.ybr[y-1][x+i])
+ z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
+ }
+ }
+}
+
+func predFunc8VE(z *Decoder, y, x int) {
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
+ }
+ }
+}
+
+func predFunc8HE(z *Decoder, y, x int) {
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
+ }
+ }
+}
+
+func predFunc8DCTop(z *Decoder, y, x int) {
+ sum := uint32(4)
+ for j := 0; j < 8; j++ {
+ sum += uint32(z.ybr[y+j][x-1])
+ }
+ avg := uint8(sum / 8)
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc8DCLeft(z *Decoder, y, x int) {
+ sum := uint32(4)
+ for i := 0; i < 8; i++ {
+ sum += uint32(z.ybr[y-1][x+i])
+ }
+ avg := uint8(sum / 8)
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc8DCTopLeft(z *Decoder, y, x int) {
+ for j := 0; j < 8; j++ {
+ for i := 0; i < 8; i++ {
+ z.ybr[y+j][x+i] = 0x80
+ }
+ }
+}
+
+func predFunc16DC(z *Decoder, y, x int) {
+ sum := uint32(16)
+ for i := 0; i < 16; i++ {
+ sum += uint32(z.ybr[y-1][x+i])
+ }
+ for j := 0; j < 16; j++ {
+ sum += uint32(z.ybr[y+j][x-1])
+ }
+ avg := uint8(sum / 32)
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc16TM(z *Decoder, y, x int) {
+ delta0 := -int32(z.ybr[y-1][x-1])
+ for j := 0; j < 16; j++ {
+ delta1 := delta0 + int32(z.ybr[y+j][x-1])
+ for i := 0; i < 16; i++ {
+ delta2 := delta1 + int32(z.ybr[y-1][x+i])
+ z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
+ }
+ }
+}
+
+func predFunc16VE(z *Decoder, y, x int) {
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
+ }
+ }
+}
+
+func predFunc16HE(z *Decoder, y, x int) {
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
+ }
+ }
+}
+
+func predFunc16DCTop(z *Decoder, y, x int) {
+ sum := uint32(8)
+ for j := 0; j < 16; j++ {
+ sum += uint32(z.ybr[y+j][x-1])
+ }
+ avg := uint8(sum / 16)
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc16DCLeft(z *Decoder, y, x int) {
+ sum := uint32(8)
+ for i := 0; i < 16; i++ {
+ sum += uint32(z.ybr[y-1][x+i])
+ }
+ avg := uint8(sum / 16)
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = avg
+ }
+ }
+}
+
+func predFunc16DCTopLeft(z *Decoder, y, x int) {
+ for j := 0; j < 16; j++ {
+ for i := 0; i < 16; i++ {
+ z.ybr[y+j][x+i] = 0x80
+ }
+ }
+}
diff --git a/vendor/golang.org/x/image/vp8/quant.go b/vendor/golang.org/x/image/vp8/quant.go
@@ -0,0 +1,98 @@
+// Copyright 2011 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 vp8
+
+// This file implements parsing the quantization factors.
+
+// quant are DC/AC quantization factors.
+type quant struct {
+ y1 [2]uint16
+ y2 [2]uint16
+ uv [2]uint16
+}
+
+// clip clips x to the range [min, max] inclusive.
+func clip(x, min, max int32) int32 {
+ if x < min {
+ return min
+ }
+ if x > max {
+ return max
+ }
+ return x
+}
+
+// parseQuant parses the quantization factors, as specified in section 9.6.
+func (d *Decoder) parseQuant() {
+ baseQ0 := d.fp.readUint(uniformProb, 7)
+ dqy1DC := d.fp.readOptionalInt(uniformProb, 4)
+ const dqy1AC = 0
+ dqy2DC := d.fp.readOptionalInt(uniformProb, 4)
+ dqy2AC := d.fp.readOptionalInt(uniformProb, 4)
+ dquvDC := d.fp.readOptionalInt(uniformProb, 4)
+ dquvAC := d.fp.readOptionalInt(uniformProb, 4)
+ for i := 0; i < nSegment; i++ {
+ q := int32(baseQ0)
+ if d.segmentHeader.useSegment {
+ if d.segmentHeader.relativeDelta {
+ q += int32(d.segmentHeader.quantizer[i])
+ } else {
+ q = int32(d.segmentHeader.quantizer[i])
+ }
+ }
+ d.quant[i].y1[0] = dequantTableDC[clip(q+dqy1DC, 0, 127)]
+ d.quant[i].y1[1] = dequantTableAC[clip(q+dqy1AC, 0, 127)]
+ d.quant[i].y2[0] = dequantTableDC[clip(q+dqy2DC, 0, 127)] * 2
+ d.quant[i].y2[1] = dequantTableAC[clip(q+dqy2AC, 0, 127)] * 155 / 100
+ if d.quant[i].y2[1] < 8 {
+ d.quant[i].y2[1] = 8
+ }
+ // The 117 is not a typo. The dequant_init function in the spec's Reference
+ // Decoder Source Code (http://tools.ietf.org/html/rfc6386#section-9.6 Page 145)
+ // says to clamp the LHS value at 132, which is equal to dequantTableDC[117].
+ d.quant[i].uv[0] = dequantTableDC[clip(q+dquvDC, 0, 117)]
+ d.quant[i].uv[1] = dequantTableAC[clip(q+dquvAC, 0, 127)]
+ }
+}
+
+// The dequantization tables are specified in section 14.1.
+var (
+ dequantTableDC = [128]uint16{
+ 4, 5, 6, 7, 8, 9, 10, 10,
+ 11, 12, 13, 14, 15, 16, 17, 17,
+ 18, 19, 20, 20, 21, 21, 22, 22,
+ 23, 23, 24, 25, 25, 26, 27, 28,
+ 29, 30, 31, 32, 33, 34, 35, 36,
+ 37, 37, 38, 39, 40, 41, 42, 43,
+ 44, 45, 46, 46, 47, 48, 49, 50,
+ 51, 52, 53, 54, 55, 56, 57, 58,
+ 59, 60, 61, 62, 63, 64, 65, 66,
+ 67, 68, 69, 70, 71, 72, 73, 74,
+ 75, 76, 76, 77, 78, 79, 80, 81,
+ 82, 83, 84, 85, 86, 87, 88, 89,
+ 91, 93, 95, 96, 98, 100, 101, 102,
+ 104, 106, 108, 110, 112, 114, 116, 118,
+ 122, 124, 126, 128, 130, 132, 134, 136,
+ 138, 140, 143, 145, 148, 151, 154, 157,
+ }
+ dequantTableAC = [128]uint16{
+ 4, 5, 6, 7, 8, 9, 10, 11,
+ 12, 13, 14, 15, 16, 17, 18, 19,
+ 20, 21, 22, 23, 24, 25, 26, 27,
+ 28, 29, 30, 31, 32, 33, 34, 35,
+ 36, 37, 38, 39, 40, 41, 42, 43,
+ 44, 45, 46, 47, 48, 49, 50, 51,
+ 52, 53, 54, 55, 56, 57, 58, 60,
+ 62, 64, 66, 68, 70, 72, 74, 76,
+ 78, 80, 82, 84, 86, 88, 90, 92,
+ 94, 96, 98, 100, 102, 104, 106, 108,
+ 110, 112, 114, 116, 119, 122, 125, 128,
+ 131, 134, 137, 140, 143, 146, 149, 152,
+ 155, 158, 161, 164, 167, 170, 173, 177,
+ 181, 185, 189, 193, 197, 201, 205, 209,
+ 213, 217, 221, 225, 229, 234, 239, 245,
+ 249, 254, 259, 264, 269, 274, 279, 284,
+ }
+)
diff --git a/vendor/golang.org/x/image/vp8/reconstruct.go b/vendor/golang.org/x/image/vp8/reconstruct.go
@@ -0,0 +1,442 @@
+// Copyright 2011 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 vp8
+
+// This file implements decoding DCT/WHT residual coefficients and
+// reconstructing YCbCr data equal to predicted values plus residuals.
+//
+// There are 1*16*16 + 2*8*8 + 1*4*4 coefficients per macroblock:
+// - 1*16*16 luma DCT coefficients,
+// - 2*8*8 chroma DCT coefficients, and
+// - 1*4*4 luma WHT coefficients.
+// Coefficients are read in lots of 16, and the later coefficients in each lot
+// are often zero.
+//
+// The YCbCr data consists of 1*16*16 luma values and 2*8*8 chroma values,
+// plus previously decoded values along the top and left borders. The combined
+// values are laid out as a [1+16+1+8][32]uint8 so that vertically adjacent
+// samples are 32 bytes apart. In detail, the layout is:
+//
+// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+// . . . . . . . a b b b b b b b b b b b b b b b b c c c c . . . . 0
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 1
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 2
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 3
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 4
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 5
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 6
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 7
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 8
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 9
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 10
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 11
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 12
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 13
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 14
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 15
+// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 16
+// . . . . . . . e f f f f f f f f . . . . . . . g h h h h h h h h 17
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 18
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 19
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 20
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 21
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 22
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 23
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 24
+// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 25
+//
+// Y, B and R are the reconstructed luma (Y) and chroma (B, R) values.
+// The Y values are predicted (either as one 16x16 region or 16 4x4 regions)
+// based on the row above's Y values (some combination of {abc} or {dYC}) and
+// the column left's Y values (either {ad} or {bY}). Similarly, B and R values
+// are predicted on the row above and column left of their respective 8x8
+// region: {efi} for B, {ghj} for R.
+//
+// For uppermost macroblocks (i.e. those with mby == 0), the {abcefgh} values
+// are initialized to 0x81. Otherwise, they are copied from the bottom row of
+// the macroblock above. The {c} values are then duplicated from row 0 to rows
+// 4, 8 and 12 of the ybr workspace.
+// Similarly, for leftmost macroblocks (i.e. those with mbx == 0), the {adeigj}
+// values are initialized to 0x7f. Otherwise, they are copied from the right
+// column of the macroblock to the left.
+// For the top-left macroblock (with mby == 0 && mbx == 0), {aeg} is 0x81.
+//
+// When moving from one macroblock to the next horizontally, the {adeigj}
+// values can simply be copied from the workspace to itself, shifted by 8 or
+// 16 columns. When moving from one macroblock to the next vertically,
+// filtering can occur and hence the row values have to be copied from the
+// post-filtered image instead of the pre-filtered workspace.
+
+const (
+ bCoeffBase = 1*16*16 + 0*8*8
+ rCoeffBase = 1*16*16 + 1*8*8
+ whtCoeffBase = 1*16*16 + 2*8*8
+)
+
+const (
+ ybrYX = 8
+ ybrYY = 1
+ ybrBX = 8
+ ybrBY = 18
+ ybrRX = 24
+ ybrRY = 18
+)
+
+// prepareYBR prepares the {abcdefghij} elements of ybr.
+func (d *Decoder) prepareYBR(mbx, mby int) {
+ if mbx == 0 {
+ for y := 0; y < 17; y++ {
+ d.ybr[y][7] = 0x81
+ }
+ for y := 17; y < 26; y++ {
+ d.ybr[y][7] = 0x81
+ d.ybr[y][23] = 0x81
+ }
+ } else {
+ for y := 0; y < 17; y++ {
+ d.ybr[y][7] = d.ybr[y][7+16]
+ }
+ for y := 17; y < 26; y++ {
+ d.ybr[y][7] = d.ybr[y][15]
+ d.ybr[y][23] = d.ybr[y][31]
+ }
+ }
+ if mby == 0 {
+ for x := 7; x < 28; x++ {
+ d.ybr[0][x] = 0x7f
+ }
+ for x := 7; x < 16; x++ {
+ d.ybr[17][x] = 0x7f
+ }
+ for x := 23; x < 32; x++ {
+ d.ybr[17][x] = 0x7f
+ }
+ } else {
+ for i := 0; i < 16; i++ {
+ d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
+ }
+ for i := 0; i < 8; i++ {
+ d.ybr[17][8+i] = d.img.Cb[(8*mby-1)*d.img.CStride+8*mbx+i]
+ }
+ for i := 0; i < 8; i++ {
+ d.ybr[17][24+i] = d.img.Cr[(8*mby-1)*d.img.CStride+8*mbx+i]
+ }
+ if mbx == d.mbw-1 {
+ for i := 16; i < 20; i++ {
+ d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+15]
+ }
+ } else {
+ for i := 16; i < 20; i++ {
+ d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
+ }
+ }
+ }
+ for y := 4; y < 16; y += 4 {
+ d.ybr[y][24] = d.ybr[0][24]
+ d.ybr[y][25] = d.ybr[0][25]
+ d.ybr[y][26] = d.ybr[0][26]
+ d.ybr[y][27] = d.ybr[0][27]
+ }
+}
+
+// btou converts a bool to a 0/1 value.
+func btou(b bool) uint8 {
+ if b {
+ return 1
+ }
+ return 0
+}
+
+// pack packs four 0/1 values into four bits of a uint32.
+func pack(x [4]uint8, shift int) uint32 {
+ u := uint32(x[0])<<0 | uint32(x[1])<<1 | uint32(x[2])<<2 | uint32(x[3])<<3
+ return u << uint(shift)
+}
+
+// unpack unpacks four 0/1 values from a four-bit value.
+var unpack = [16][4]uint8{
+ {0, 0, 0, 0},
+ {1, 0, 0, 0},
+ {0, 1, 0, 0},
+ {1, 1, 0, 0},
+ {0, 0, 1, 0},
+ {1, 0, 1, 0},
+ {0, 1, 1, 0},
+ {1, 1, 1, 0},
+ {0, 0, 0, 1},
+ {1, 0, 0, 1},
+ {0, 1, 0, 1},
+ {1, 1, 0, 1},
+ {0, 0, 1, 1},
+ {1, 0, 1, 1},
+ {0, 1, 1, 1},
+ {1, 1, 1, 1},
+}
+
+var (
+ // The mapping from 4x4 region position to band is specified in section 13.3.
+ bands = [17]uint8{0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0}
+ // Category probabilties are specified in section 13.2.
+ // Decoding categories 1 and 2 are done inline.
+ cat3456 = [4][12]uint8{
+ {173, 148, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {176, 155, 140, 135, 0, 0, 0, 0, 0, 0, 0, 0},
+ {180, 157, 141, 134, 130, 0, 0, 0, 0, 0, 0, 0},
+ {254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0},
+ }
+ // The zigzag order is:
+ // 0 1 5 6
+ // 2 4 7 12
+ // 3 8 11 13
+ // 9 10 14 15
+ zigzag = [16]uint8{0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15}
+)
+
+// parseResiduals4 parses a 4x4 region of residual coefficients, as specified
+// in section 13.3, and returns a 0/1 value indicating whether there was at
+// least one non-zero coefficient.
+// r is the partition to read bits from.
+// plane and context describe which token probability table to use. context is
+// either 0, 1 or 2, and equals how many of the macroblock left and macroblock
+// above have non-zero coefficients.
+// quant are the DC/AC quantization factors.
+// skipFirstCoeff is whether the DC coefficient has already been parsed.
+// coeffBase is the base index of d.coeff to write to.
+func (d *Decoder) parseResiduals4(r *partition, plane int, context uint8, quant [2]uint16, skipFirstCoeff bool, coeffBase int) uint8 {
+ prob, n := &d.tokenProb[plane], 0
+ if skipFirstCoeff {
+ n = 1
+ }
+ p := prob[bands[n]][context]
+ if !r.readBit(p[0]) {
+ return 0
+ }
+ for n != 16 {
+ n++
+ if !r.readBit(p[1]) {
+ p = prob[bands[n]][0]
+ continue
+ }
+ var v uint32
+ if !r.readBit(p[2]) {
+ v = 1
+ p = prob[bands[n]][1]
+ } else {
+ if !r.readBit(p[3]) {
+ if !r.readBit(p[4]) {
+ v = 2
+ } else {
+ v = 3 + r.readUint(p[5], 1)
+ }
+ } else if !r.readBit(p[6]) {
+ if !r.readBit(p[7]) {
+ // Category 1.
+ v = 5 + r.readUint(159, 1)
+ } else {
+ // Category 2.
+ v = 7 + 2*r.readUint(165, 1) + r.readUint(145, 1)
+ }
+ } else {
+ // Categories 3, 4, 5 or 6.
+ b1 := r.readUint(p[8], 1)
+ b0 := r.readUint(p[9+b1], 1)
+ cat := 2*b1 + b0
+ tab := &cat3456[cat]
+ v = 0
+ for i := 0; tab[i] != 0; i++ {
+ v *= 2
+ v += r.readUint(tab[i], 1)
+ }
+ v += 3 + (8 << cat)
+ }
+ p = prob[bands[n]][2]
+ }
+ z := zigzag[n-1]
+ c := int32(v) * int32(quant[btou(z > 0)])
+ if r.readBit(uniformProb) {
+ c = -c
+ }
+ d.coeff[coeffBase+int(z)] = int16(c)
+ if n == 16 || !r.readBit(p[0]) {
+ return 1
+ }
+ }
+ return 1
+}
+
+// parseResiduals parses the residuals and returns whether inner loop filtering
+// should be skipped for this macroblock.
+func (d *Decoder) parseResiduals(mbx, mby int) (skip bool) {
+ partition := &d.op[mby&(d.nOP-1)]
+ plane := planeY1SansY2
+ quant := &d.quant[d.segment]
+
+ // Parse the DC coefficient of each 4x4 luma region.
+ if d.usePredY16 {
+ nz := d.parseResiduals4(partition, planeY2, d.leftMB.nzY16+d.upMB[mbx].nzY16, quant.y2, false, whtCoeffBase)
+ d.leftMB.nzY16 = nz
+ d.upMB[mbx].nzY16 = nz
+ d.inverseWHT16()
+ plane = planeY1WithY2
+ }
+
+ var (
+ nzDC, nzAC [4]uint8
+ nzDCMask, nzACMask uint32
+ coeffBase int
+ )
+
+ // Parse the luma coefficients.
+ lnz := unpack[d.leftMB.nzMask&0x0f]
+ unz := unpack[d.upMB[mbx].nzMask&0x0f]
+ for y := 0; y < 4; y++ {
+ nz := lnz[y]
+ for x := 0; x < 4; x++ {
+ nz = d.parseResiduals4(partition, plane, nz+unz[x], quant.y1, d.usePredY16, coeffBase)
+ unz[x] = nz
+ nzAC[x] = nz
+ nzDC[x] = btou(d.coeff[coeffBase] != 0)
+ coeffBase += 16
+ }
+ lnz[y] = nz
+ nzDCMask |= pack(nzDC, y*4)
+ nzACMask |= pack(nzAC, y*4)
+ }
+ lnzMask := pack(lnz, 0)
+ unzMask := pack(unz, 0)
+
+ // Parse the chroma coefficients.
+ lnz = unpack[d.leftMB.nzMask>>4]
+ unz = unpack[d.upMB[mbx].nzMask>>4]
+ for c := 0; c < 4; c += 2 {
+ for y := 0; y < 2; y++ {
+ nz := lnz[y+c]
+ for x := 0; x < 2; x++ {
+ nz = d.parseResiduals4(partition, planeUV, nz+unz[x+c], quant.uv, false, coeffBase)
+ unz[x+c] = nz
+ nzAC[y*2+x] = nz
+ nzDC[y*2+x] = btou(d.coeff[coeffBase] != 0)
+ coeffBase += 16
+ }
+ lnz[y+c] = nz
+ }
+ nzDCMask |= pack(nzDC, 16+c*2)
+ nzACMask |= pack(nzAC, 16+c*2)
+ }
+ lnzMask |= pack(lnz, 4)
+ unzMask |= pack(unz, 4)
+
+ // Save decoder state.
+ d.leftMB.nzMask = uint8(lnzMask)
+ d.upMB[mbx].nzMask = uint8(unzMask)
+ d.nzDCMask = nzDCMask
+ d.nzACMask = nzACMask
+
+ // Section 15.1 of the spec says that "Steps 2 and 4 [of the loop filter]
+ // are skipped... [if] there is no DCT coefficient coded for the whole
+ // macroblock."
+ return nzDCMask == 0 && nzACMask == 0
+}
+
+// reconstructMacroblock applies the predictor functions and adds the inverse-
+// DCT transformed residuals to recover the YCbCr data.
+func (d *Decoder) reconstructMacroblock(mbx, mby int) {
+ if d.usePredY16 {
+ p := checkTopLeftPred(mbx, mby, d.predY16)
+ predFunc16[p](d, 1, 8)
+ for j := 0; j < 4; j++ {
+ for i := 0; i < 4; i++ {
+ n := 4*j + i
+ y := 4*j + 1
+ x := 4*i + 8
+ mask := uint32(1) << uint(n)
+ if d.nzACMask&mask != 0 {
+ d.inverseDCT4(y, x, 16*n)
+ } else if d.nzDCMask&mask != 0 {
+ d.inverseDCT4DCOnly(y, x, 16*n)
+ }
+ }
+ }
+ } else {
+ for j := 0; j < 4; j++ {
+ for i := 0; i < 4; i++ {
+ n := 4*j + i
+ y := 4*j + 1
+ x := 4*i + 8
+ predFunc4[d.predY4[j][i]](d, y, x)
+ mask := uint32(1) << uint(n)
+ if d.nzACMask&mask != 0 {
+ d.inverseDCT4(y, x, 16*n)
+ } else if d.nzDCMask&mask != 0 {
+ d.inverseDCT4DCOnly(y, x, 16*n)
+ }
+ }
+ }
+ }
+ p := checkTopLeftPred(mbx, mby, d.predC8)
+ predFunc8[p](d, ybrBY, ybrBX)
+ if d.nzACMask&0x0f0000 != 0 {
+ d.inverseDCT8(ybrBY, ybrBX, bCoeffBase)
+ } else if d.nzDCMask&0x0f0000 != 0 {
+ d.inverseDCT8DCOnly(ybrBY, ybrBX, bCoeffBase)
+ }
+ predFunc8[p](d, ybrRY, ybrRX)
+ if d.nzACMask&0xf00000 != 0 {
+ d.inverseDCT8(ybrRY, ybrRX, rCoeffBase)
+ } else if d.nzDCMask&0xf00000 != 0 {
+ d.inverseDCT8DCOnly(ybrRY, ybrRX, rCoeffBase)
+ }
+}
+
+// reconstruct reconstructs one macroblock and returns whether inner loop
+// filtering should be skipped for it.
+func (d *Decoder) reconstruct(mbx, mby int) (skip bool) {
+ if d.segmentHeader.updateMap {
+ if !d.fp.readBit(d.segmentHeader.prob[0]) {
+ d.segment = int(d.fp.readUint(d.segmentHeader.prob[1], 1))
+ } else {
+ d.segment = int(d.fp.readUint(d.segmentHeader.prob[2], 1)) + 2
+ }
+ }
+ if d.useSkipProb {
+ skip = d.fp.readBit(d.skipProb)
+ }
+ // Prepare the workspace.
+ for i := range d.coeff {
+ d.coeff[i] = 0
+ }
+ d.prepareYBR(mbx, mby)
+ // Parse the predictor modes.
+ d.usePredY16 = d.fp.readBit(145)
+ if d.usePredY16 {
+ d.parsePredModeY16(mbx)
+ } else {
+ d.parsePredModeY4(mbx)
+ }
+ d.parsePredModeC8()
+ // Parse the residuals.
+ if !skip {
+ skip = d.parseResiduals(mbx, mby)
+ } else {
+ if d.usePredY16 {
+ d.leftMB.nzY16 = 0
+ d.upMB[mbx].nzY16 = 0
+ }
+ d.leftMB.nzMask = 0
+ d.upMB[mbx].nzMask = 0
+ d.nzDCMask = 0
+ d.nzACMask = 0
+ }
+ // Reconstruct the YCbCr data and copy it to the image.
+ d.reconstructMacroblock(mbx, mby)
+ for i, y := (mby*d.img.YStride+mbx)*16, 0; y < 16; i, y = i+d.img.YStride, y+1 {
+ copy(d.img.Y[i:i+16], d.ybr[ybrYY+y][ybrYX:ybrYX+16])
+ }
+ for i, y := (mby*d.img.CStride+mbx)*8, 0; y < 8; i, y = i+d.img.CStride, y+1 {
+ copy(d.img.Cb[i:i+8], d.ybr[ybrBY+y][ybrBX:ybrBX+8])
+ copy(d.img.Cr[i:i+8], d.ybr[ybrRY+y][ybrRX:ybrRX+8])
+ }
+ return skip
+}
diff --git a/vendor/golang.org/x/image/vp8/token.go b/vendor/golang.org/x/image/vp8/token.go
@@ -0,0 +1,381 @@
+// Copyright 2011 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 vp8
+
+// This file contains token probabilities for decoding DCT/WHT coefficients, as
+// specified in chapter 13.
+
+func (d *Decoder) parseTokenProb() {
+ for i := range d.tokenProb {
+ for j := range d.tokenProb[i] {
+ for k := range d.tokenProb[i][j] {
+ for l := range d.tokenProb[i][j][k] {
+ if d.fp.readBit(tokenProbUpdateProb[i][j][k][l]) {
+ d.tokenProb[i][j][k][l] = uint8(d.fp.readUint(uniformProb, 8))
+ }
+ }
+ }
+ }
+ }
+}
+
+// The plane enumeration is specified in section 13.3.
+const (
+ planeY1WithY2 = iota
+ planeY2
+ planeUV
+ planeY1SansY2
+ nPlane
+)
+
+const (
+ nBand = 8
+ nContext = 3
+ nProb = 11
+)
+
+// Token probability update probabilities are specified in section 13.4.
+var tokenProbUpdateProb = [nPlane][nBand][nContext][nProb]uint8{
+ {
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255},
+ {249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255},
+ {234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255},
+ {250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255},
+ {254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ },
+ {
+ {
+ {217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255},
+ {234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255},
+ },
+ {
+ {255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ },
+ {
+ {
+ {186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255},
+ {234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255},
+ {251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255},
+ },
+ {
+ {255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ },
+ {
+ {
+ {248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255},
+ {248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255},
+ {248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255},
+ {250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ {
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
+ },
+ },
+}
+
+// Default token probabilities are specified in section 13.5.
+var defaultTokenProb = [nPlane][nBand][nContext][nProb]uint8{
+ {
+ {
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ {
+ {253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128},
+ {189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128},
+ {106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128},
+ },
+ {
+ {1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128},
+ {181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128},
+ {78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128},
+ },
+ {
+ {1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128},
+ {184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128},
+ {77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128},
+ {170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128},
+ {37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128},
+ },
+ {
+ {1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128},
+ {207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128},
+ {102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128},
+ {177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128},
+ {80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ },
+ {
+ {
+ {198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62},
+ {131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1},
+ {68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128},
+ },
+ {
+ {1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128},
+ {184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128},
+ {81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128},
+ },
+ {
+ {1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128},
+ {99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128},
+ {23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128},
+ },
+ {
+ {1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128},
+ {109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128},
+ {44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128},
+ },
+ {
+ {1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128},
+ {94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128},
+ {22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128},
+ },
+ {
+ {1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128},
+ {124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128},
+ {35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128},
+ },
+ {
+ {1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128},
+ {121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128},
+ {45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128},
+ },
+ {
+ {1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128},
+ {203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128},
+ {137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128},
+ },
+ },
+ {
+ {
+ {253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128},
+ {175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128},
+ {73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128},
+ },
+ {
+ {1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128},
+ {239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128},
+ {155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128},
+ },
+ {
+ {1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128},
+ {201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128},
+ {69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128},
+ },
+ {
+ {1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128},
+ {223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128},
+ {141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128},
+ {190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128},
+ {149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ {
+ {1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128},
+ {213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128},
+ {55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ {
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ {128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ },
+ {
+ {
+ {202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255},
+ {126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128},
+ {61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128},
+ },
+ {
+ {1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128},
+ {166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128},
+ {39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128},
+ },
+ {
+ {1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128},
+ {124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128},
+ {24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128},
+ },
+ {
+ {1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128},
+ {149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128},
+ {28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128},
+ },
+ {
+ {1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128},
+ {123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128},
+ {20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128},
+ },
+ {
+ {1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128},
+ {168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128},
+ {47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128},
+ },
+ {
+ {1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128},
+ {141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128},
+ {42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128},
+ },
+ {
+ {1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ {238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
+ },
+ },
+}
diff --git a/vendor/golang.org/x/image/vp8l/decode.go b/vendor/golang.org/x/image/vp8l/decode.go
@@ -0,0 +1,603 @@
+// 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 vp8l implements a decoder for the VP8L lossless image format.
+//
+// The VP8L specification is at:
+// https://developers.google.com/speed/webp/docs/riff_container
+package vp8l // import "golang.org/x/image/vp8l"
+
+import (
+ "bufio"
+ "errors"
+ "image"
+ "image/color"
+ "io"
+)
+
+var (
+ errInvalidCodeLengths = errors.New("vp8l: invalid code lengths")
+ errInvalidHuffmanTree = errors.New("vp8l: invalid Huffman tree")
+)
+
+// colorCacheMultiplier is the multiplier used for the color cache hash
+// function, specified in section 4.2.3.
+const colorCacheMultiplier = 0x1e35a7bd
+
+// distanceMapTable is the look-up table for distanceMap.
+var distanceMapTable = [120]uint8{
+ 0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
+ 0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
+ 0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
+ 0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
+ 0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
+ 0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
+ 0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
+ 0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
+ 0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
+ 0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
+ 0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
+ 0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70,
+}
+
+// distanceMap maps a LZ77 backwards reference distance to a two-dimensional
+// pixel offset, specified in section 4.2.2.
+func distanceMap(w int32, code uint32) int32 {
+ if int32(code) > int32(len(distanceMapTable)) {
+ return int32(code) - int32(len(distanceMapTable))
+ }
+ distCode := int32(distanceMapTable[code-1])
+ yOffset := distCode >> 4
+ xOffset := 8 - distCode&0xf
+ if d := yOffset*w + xOffset; d >= 1 {
+ return d
+ }
+ return 1
+}
+
+// decoder holds the bit-stream for a VP8L image.
+type decoder struct {
+ r io.ByteReader
+ bits uint32
+ nBits uint32
+}
+
+// read reads the next n bits from the decoder's bit-stream.
+func (d *decoder) read(n uint32) (uint32, error) {
+ for d.nBits < n {
+ c, err := d.r.ReadByte()
+ if err != nil {
+ if err == io.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return 0, err
+ }
+ d.bits |= uint32(c) << d.nBits
+ d.nBits += 8
+ }
+ u := d.bits & (1<<n - 1)
+ d.bits >>= n
+ d.nBits -= n
+ return u, nil
+}
+
+// decodeTransform decodes the next transform and the width of the image after
+// transformation (or equivalently, before inverse transformation), specified
+// in section 3.
+func (d *decoder) decodeTransform(w int32, h int32) (t transform, newWidth int32, err error) {
+ t.oldWidth = w
+ t.transformType, err = d.read(2)
+ if err != nil {
+ return transform{}, 0, err
+ }
+ switch t.transformType {
+ case transformTypePredictor, transformTypeCrossColor:
+ t.bits, err = d.read(3)
+ if err != nil {
+ return transform{}, 0, err
+ }
+ t.bits += 2
+ t.pix, err = d.decodePix(nTiles(w, t.bits), nTiles(h, t.bits), 0, false)
+ if err != nil {
+ return transform{}, 0, err
+ }
+ case transformTypeSubtractGreen:
+ // No-op.
+ case transformTypeColorIndexing:
+ nColors, err := d.read(8)
+ if err != nil {
+ return transform{}, 0, err
+ }
+ nColors++
+ t.bits = 0
+ switch {
+ case nColors <= 2:
+ t.bits = 3
+ case nColors <= 4:
+ t.bits = 2
+ case nColors <= 16:
+ t.bits = 1
+ }
+ w = nTiles(w, t.bits)
+ pix, err := d.decodePix(int32(nColors), 1, 4*256, false)
+ if err != nil {
+ return transform{}, 0, err
+ }
+ for p := 4; p < len(pix); p += 4 {
+ pix[p+0] += pix[p-4]
+ pix[p+1] += pix[p-3]
+ pix[p+2] += pix[p-2]
+ pix[p+3] += pix[p-1]
+ }
+ // The spec says that "if the index is equal or larger than color_table_size,
+ // the argb color value should be set to 0x00000000 (transparent black)."
+ // We re-slice up to 256 4-byte pixels.
+ t.pix = pix[:4*256]
+ }
+ return t, w, nil
+}
+
+// repeatsCodeLength is the minimum code length for repeated codes.
+const repeatsCodeLength = 16
+
+// These magic numbers are specified at the end of section 5.2.2.
+// The 3-length arrays apply to code lengths >= repeatsCodeLength.
+var (
+ codeLengthCodeOrder = [19]uint8{
+ 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+ }
+ repeatBits = [3]uint8{2, 3, 7}
+ repeatOffsets = [3]uint8{3, 3, 11}
+)
+
+// decodeCodeLengths decodes a Huffman tree's code lengths which are themselves
+// encoded via a Huffman tree, specified in section 5.2.2.
+func (d *decoder) decodeCodeLengths(dst []uint32, codeLengthCodeLengths []uint32) error {
+ h := hTree{}
+ if err := h.build(codeLengthCodeLengths); err != nil {
+ return err
+ }
+
+ maxSymbol := len(dst)
+ useLength, err := d.read(1)
+ if err != nil {
+ return err
+ }
+ if useLength != 0 {
+ n, err := d.read(3)
+ if err != nil {
+ return err
+ }
+ n = 2 + 2*n
+ ms, err := d.read(n)
+ if err != nil {
+ return err
+ }
+ maxSymbol = int(ms) + 2
+ if maxSymbol > len(dst) {
+ return errInvalidCodeLengths
+ }
+ }
+
+ // The spec says that "if code 16 [meaning repeat] is used before
+ // a non-zero value has been emitted, a value of 8 is repeated."
+ prevCodeLength := uint32(8)
+
+ for symbol := 0; symbol < len(dst); {
+ if maxSymbol == 0 {
+ break
+ }
+ maxSymbol--
+ codeLength, err := h.next(d)
+ if err != nil {
+ return err
+ }
+ if codeLength < repeatsCodeLength {
+ dst[symbol] = codeLength
+ symbol++
+ if codeLength != 0 {
+ prevCodeLength = codeLength
+ }
+ continue
+ }
+
+ repeat, err := d.read(uint32(repeatBits[codeLength-repeatsCodeLength]))
+ if err != nil {
+ return err
+ }
+ repeat += uint32(repeatOffsets[codeLength-repeatsCodeLength])
+ if symbol+int(repeat) > len(dst) {
+ return errInvalidCodeLengths
+ }
+ // A code length of 16 repeats the previous non-zero code.
+ // A code length of 17 or 18 repeats zeroes.
+ cl := uint32(0)
+ if codeLength == 16 {
+ cl = prevCodeLength
+ }
+ for ; repeat > 0; repeat-- {
+ dst[symbol] = cl
+ symbol++
+ }
+ }
+ return nil
+}
+
+// decodeHuffmanTree decodes a Huffman tree into h.
+func (d *decoder) decodeHuffmanTree(h *hTree, alphabetSize uint32) error {
+ useSimple, err := d.read(1)
+ if err != nil {
+ return err
+ }
+ if useSimple != 0 {
+ nSymbols, err := d.read(1)
+ if err != nil {
+ return err
+ }
+ nSymbols++
+ firstSymbolLengthCode, err := d.read(1)
+ if err != nil {
+ return err
+ }
+ firstSymbolLengthCode = 7*firstSymbolLengthCode + 1
+ var symbols [2]uint32
+ symbols[0], err = d.read(firstSymbolLengthCode)
+ if err != nil {
+ return err
+ }
+ if nSymbols == 2 {
+ symbols[1], err = d.read(8)
+ if err != nil {
+ return err
+ }
+ }
+ return h.buildSimple(nSymbols, symbols, alphabetSize)
+ }
+
+ nCodes, err := d.read(4)
+ if err != nil {
+ return err
+ }
+ nCodes += 4
+ if int(nCodes) > len(codeLengthCodeOrder) {
+ return errInvalidHuffmanTree
+ }
+ codeLengthCodeLengths := [len(codeLengthCodeOrder)]uint32{}
+ for i := uint32(0); i < nCodes; i++ {
+ codeLengthCodeLengths[codeLengthCodeOrder[i]], err = d.read(3)
+ if err != nil {
+ return err
+ }
+ }
+ codeLengths := make([]uint32, alphabetSize)
+ if err = d.decodeCodeLengths(codeLengths, codeLengthCodeLengths[:]); err != nil {
+ return err
+ }
+ return h.build(codeLengths)
+}
+
+const (
+ huffGreen = 0
+ huffRed = 1
+ huffBlue = 2
+ huffAlpha = 3
+ huffDistance = 4
+ nHuff = 5
+)
+
+// hGroup is an array of 5 Huffman trees.
+type hGroup [nHuff]hTree
+
+// decodeHuffmanGroups decodes the one or more hGroups used to decode the pixel
+// data. If one hGroup is used for the entire image, then hPix and hBits will
+// be zero. If more than one hGroup is used, then hPix contains the meta-image
+// that maps tiles to hGroup index, and hBits contains the log-2 tile size.
+func (d *decoder) decodeHuffmanGroups(w int32, h int32, topLevel bool, ccBits uint32) (
+ hGroups []hGroup, hPix []byte, hBits uint32, err error) {
+
+ maxHGroupIndex := 0
+ if topLevel {
+ useMeta, err := d.read(1)
+ if err != nil {
+ return nil, nil, 0, err
+ }
+ if useMeta != 0 {
+ hBits, err = d.read(3)
+ if err != nil {
+ return nil, nil, 0, err
+ }
+ hBits += 2
+ hPix, err = d.decodePix(nTiles(w, hBits), nTiles(h, hBits), 0, false)
+ if err != nil {
+ return nil, nil, 0, err
+ }
+ for p := 0; p < len(hPix); p += 4 {
+ i := int(hPix[p])<<8 | int(hPix[p+1])
+ if maxHGroupIndex < i {
+ maxHGroupIndex = i
+ }
+ }
+ }
+ }
+ hGroups = make([]hGroup, maxHGroupIndex+1)
+ for i := range hGroups {
+ for j, alphabetSize := range alphabetSizes {
+ if j == 0 && ccBits > 0 {
+ alphabetSize += 1 << ccBits
+ }
+ if err := d.decodeHuffmanTree(&hGroups[i][j], alphabetSize); err != nil {
+ return nil, nil, 0, err
+ }
+ }
+ }
+ return hGroups, hPix, hBits, nil
+}
+
+const (
+ nLiteralCodes = 256
+ nLengthCodes = 24
+ nDistanceCodes = 40
+)
+
+var alphabetSizes = [nHuff]uint32{
+ nLiteralCodes + nLengthCodes,
+ nLiteralCodes,
+ nLiteralCodes,
+ nLiteralCodes,
+ nDistanceCodes,
+}
+
+// decodePix decodes pixel data, specified in section 5.2.2.
+func (d *decoder) decodePix(w int32, h int32, minCap int32, topLevel bool) ([]byte, error) {
+ // Decode the color cache parameters.
+ ccBits, ccShift, ccEntries := uint32(0), uint32(0), ([]uint32)(nil)
+ useColorCache, err := d.read(1)
+ if err != nil {
+ return nil, err
+ }
+ if useColorCache != 0 {
+ ccBits, err = d.read(4)
+ if err != nil {
+ return nil, err
+ }
+ if ccBits < 1 || 11 < ccBits {
+ return nil, errors.New("vp8l: invalid color cache parameters")
+ }
+ ccShift = 32 - ccBits
+ ccEntries = make([]uint32, 1<<ccBits)
+ }
+
+ // Decode the Huffman groups.
+ hGroups, hPix, hBits, err := d.decodeHuffmanGroups(w, h, topLevel, ccBits)
+ if err != nil {
+ return nil, err
+ }
+ hMask, tilesPerRow := int32(0), int32(0)
+ if hBits != 0 {
+ hMask, tilesPerRow = 1<<hBits-1, nTiles(w, hBits)
+ }
+
+ // Decode the pixels.
+ if minCap < 4*w*h {
+ minCap = 4 * w * h
+ }
+ pix := make([]byte, 4*w*h, minCap)
+ p, cachedP := 0, 0
+ x, y := int32(0), int32(0)
+ hg, lookupHG := &hGroups[0], hMask != 0
+ for p < len(pix) {
+ if lookupHG {
+ i := 4 * (tilesPerRow*(y>>hBits) + (x >> hBits))
+ hg = &hGroups[uint32(hPix[i])<<8|uint32(hPix[i+1])]
+ }
+
+ green, err := hg[huffGreen].next(d)
+ if err != nil {
+ return nil, err
+ }
+ switch {
+ case green < nLiteralCodes:
+ // We have a literal pixel.
+ red, err := hg[huffRed].next(d)
+ if err != nil {
+ return nil, err
+ }
+ blue, err := hg[huffBlue].next(d)
+ if err != nil {
+ return nil, err
+ }
+ alpha, err := hg[huffAlpha].next(d)
+ if err != nil {
+ return nil, err
+ }
+ pix[p+0] = uint8(red)
+ pix[p+1] = uint8(green)
+ pix[p+2] = uint8(blue)
+ pix[p+3] = uint8(alpha)
+ p += 4
+
+ x++
+ if x == w {
+ x, y = 0, y+1
+ }
+ lookupHG = hMask != 0 && x&hMask == 0
+
+ case green < nLiteralCodes+nLengthCodes:
+ // We have a LZ77 backwards reference.
+ length, err := d.lz77Param(green - nLiteralCodes)
+ if err != nil {
+ return nil, err
+ }
+ distSym, err := hg[huffDistance].next(d)
+ if err != nil {
+ return nil, err
+ }
+ distCode, err := d.lz77Param(distSym)
+ if err != nil {
+ return nil, err
+ }
+ dist := distanceMap(w, distCode)
+ pEnd := p + 4*int(length)
+ q := p - 4*int(dist)
+ qEnd := pEnd - 4*int(dist)
+ if p < 0 || len(pix) < pEnd || q < 0 || len(pix) < qEnd {
+ return nil, errors.New("vp8l: invalid LZ77 parameters")
+ }
+ for ; p < pEnd; p, q = p+1, q+1 {
+ pix[p] = pix[q]
+ }
+
+ x += int32(length)
+ for x >= w {
+ x, y = x-w, y+1
+ }
+ lookupHG = hMask != 0
+
+ default:
+ // We have a color cache lookup. First, insert previous pixels
+ // into the cache. Note that VP8L assumes ARGB order, but the
+ // Go image.RGBA type is in RGBA order.
+ for ; cachedP < p; cachedP += 4 {
+ argb := uint32(pix[cachedP+0])<<16 |
+ uint32(pix[cachedP+1])<<8 |
+ uint32(pix[cachedP+2])<<0 |
+ uint32(pix[cachedP+3])<<24
+ ccEntries[(argb*colorCacheMultiplier)>>ccShift] = argb
+ }
+ green -= nLiteralCodes + nLengthCodes
+ if int(green) >= len(ccEntries) {
+ return nil, errors.New("vp8l: invalid color cache index")
+ }
+ argb := ccEntries[green]
+ pix[p+0] = uint8(argb >> 16)
+ pix[p+1] = uint8(argb >> 8)
+ pix[p+2] = uint8(argb >> 0)
+ pix[p+3] = uint8(argb >> 24)
+ p += 4
+
+ x++
+ if x == w {
+ x, y = 0, y+1
+ }
+ lookupHG = hMask != 0 && x&hMask == 0
+ }
+ }
+ return pix, nil
+}
+
+// lz77Param returns the next LZ77 parameter: a length or a distance, specified
+// in section 4.2.2.
+func (d *decoder) lz77Param(symbol uint32) (uint32, error) {
+ if symbol < 4 {
+ return symbol + 1, nil
+ }
+ extraBits := (symbol - 2) >> 1
+ offset := (2 + symbol&1) << extraBits
+ n, err := d.read(extraBits)
+ if err != nil {
+ return 0, err
+ }
+ return offset + n + 1, nil
+}
+
+// decodeHeader decodes the VP8L header from r.
+func decodeHeader(r io.Reader) (d *decoder, w int32, h int32, err error) {
+ rr, ok := r.(io.ByteReader)
+ if !ok {
+ rr = bufio.NewReader(r)
+ }
+ d = &decoder{r: rr}
+ magic, err := d.read(8)
+ if err != nil {
+ return nil, 0, 0, err
+ }
+ if magic != 0x2f {
+ return nil, 0, 0, errors.New("vp8l: invalid header")
+ }
+ width, err := d.read(14)
+ if err != nil {
+ return nil, 0, 0, err
+ }
+ width++
+ height, err := d.read(14)
+ if err != nil {
+ return nil, 0, 0, err
+ }
+ height++
+ _, err = d.read(1) // Read and ignore the hasAlpha hint.
+ if err != nil {
+ return nil, 0, 0, err
+ }
+ version, err := d.read(3)
+ if err != nil {
+ return nil, 0, 0, err
+ }
+ if version != 0 {
+ return nil, 0, 0, errors.New("vp8l: invalid version")
+ }
+ return d, int32(width), int32(height), nil
+}
+
+// DecodeConfig decodes the color model and dimensions of a VP8L image from r.
+func DecodeConfig(r io.Reader) (image.Config, error) {
+ _, w, h, err := decodeHeader(r)
+ if err != nil {
+ return image.Config{}, err
+ }
+ return image.Config{
+ ColorModel: color.NRGBAModel,
+ Width: int(w),
+ Height: int(h),
+ }, nil
+}
+
+// Decode decodes a VP8L image from r.
+func Decode(r io.Reader) (image.Image, error) {
+ d, w, h, err := decodeHeader(r)
+ if err != nil {
+ return nil, err
+ }
+ // Decode the transforms.
+ var (
+ nTransforms int
+ transforms [nTransformTypes]transform
+ transformsSeen [nTransformTypes]bool
+ originalW = w
+ )
+ for {
+ more, err := d.read(1)
+ if err != nil {
+ return nil, err
+ }
+ if more == 0 {
+ break
+ }
+ var t transform
+ t, w, err = d.decodeTransform(w, h)
+ if err != nil {
+ return nil, err
+ }
+ if transformsSeen[t.transformType] {
+ return nil, errors.New("vp8l: repeated transform")
+ }
+ transformsSeen[t.transformType] = true
+ transforms[nTransforms] = t
+ nTransforms++
+ }
+ // Decode the transformed pixels.
+ pix, err := d.decodePix(w, h, 0, true)
+ if err != nil {
+ return nil, err
+ }
+ // Apply the inverse transformations.
+ for i := nTransforms - 1; i >= 0; i-- {
+ t := &transforms[i]
+ pix = inverseTransforms[t.transformType](t, pix, h)
+ }
+ return &image.NRGBA{
+ Pix: pix,
+ Stride: 4 * int(originalW),
+ Rect: image.Rect(0, 0, int(originalW), int(h)),
+ }, nil
+}
diff --git a/vendor/golang.org/x/image/vp8l/huffman.go b/vendor/golang.org/x/image/vp8l/huffman.go
@@ -0,0 +1,245 @@
+// 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 vp8l
+
+import (
+ "io"
+)
+
+// reverseBits reverses the bits in a byte.
+var reverseBits = [256]uint8{
+ 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+ 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+ 0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+ 0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+ 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+ 0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+ 0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+ 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+ 0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+ 0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+ 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+ 0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+ 0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+ 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+ 0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+ 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
+}
+
+// hNode is a node in a Huffman tree.
+type hNode struct {
+ // symbol is the symbol held by this node.
+ symbol uint32
+ // children, if positive, is the hTree.nodes index of the first of
+ // this node's two children. Zero means an uninitialized node,
+ // and -1 means a leaf node.
+ children int32
+}
+
+const leafNode = -1
+
+// lutSize is the log-2 size of an hTree's look-up table.
+const lutSize, lutMask = 7, 1<<7 - 1
+
+// hTree is a Huffman tree.
+type hTree struct {
+ // nodes are the nodes of the Huffman tree. During construction,
+ // len(nodes) grows from 1 up to cap(nodes) by steps of two.
+ // After construction, len(nodes) == cap(nodes), and both equal
+ // 2*theNumberOfSymbols - 1.
+ nodes []hNode
+ // lut is a look-up table for walking the nodes. The x in lut[x] is
+ // the next lutSize bits in the bit-stream. The low 8 bits of lut[x]
+ // equals 1 plus the number of bits in the next code, or 0 if the
+ // next code requires more than lutSize bits. The high 24 bits are:
+ // - the symbol, if the code requires lutSize or fewer bits, or
+ // - the hTree.nodes index to start the tree traversal from, if
+ // the next code requires more than lutSize bits.
+ lut [1 << lutSize]uint32
+}
+
+// insert inserts into the hTree a symbol whose encoding is the least
+// significant codeLength bits of code.
+func (h *hTree) insert(symbol uint32, code uint32, codeLength uint32) error {
+ if symbol > 0xffff || codeLength > 0xfe {
+ return errInvalidHuffmanTree
+ }
+ baseCode := uint32(0)
+ if codeLength > lutSize {
+ baseCode = uint32(reverseBits[(code>>(codeLength-lutSize))&0xff]) >> (8 - lutSize)
+ } else {
+ baseCode = uint32(reverseBits[code&0xff]) >> (8 - codeLength)
+ for i := 0; i < 1<<(lutSize-codeLength); i++ {
+ h.lut[baseCode|uint32(i)<<codeLength] = symbol<<8 | (codeLength + 1)
+ }
+ }
+
+ n := uint32(0)
+ for jump := lutSize; codeLength > 0; {
+ codeLength--
+ if int(n) > len(h.nodes) {
+ return errInvalidHuffmanTree
+ }
+ switch h.nodes[n].children {
+ case leafNode:
+ return errInvalidHuffmanTree
+ case 0:
+ if len(h.nodes) == cap(h.nodes) {
+ return errInvalidHuffmanTree
+ }
+ // Create two empty child nodes.
+ h.nodes[n].children = int32(len(h.nodes))
+ h.nodes = h.nodes[:len(h.nodes)+2]
+ }
+ n = uint32(h.nodes[n].children) + 1&(code>>codeLength)
+ jump--
+ if jump == 0 && h.lut[baseCode] == 0 {
+ h.lut[baseCode] = n << 8
+ }
+ }
+
+ switch h.nodes[n].children {
+ case leafNode:
+ // No-op.
+ case 0:
+ // Turn the uninitialized node into a leaf.
+ h.nodes[n].children = leafNode
+ default:
+ return errInvalidHuffmanTree
+ }
+ h.nodes[n].symbol = symbol
+ return nil
+}
+
+// codeLengthsToCodes returns the canonical Huffman codes implied by the
+// sequence of code lengths.
+func codeLengthsToCodes(codeLengths []uint32) ([]uint32, error) {
+ maxCodeLength := uint32(0)
+ for _, cl := range codeLengths {
+ if maxCodeLength < cl {
+ maxCodeLength = cl
+ }
+ }
+ const maxAllowedCodeLength = 15
+ if len(codeLengths) == 0 || maxCodeLength > maxAllowedCodeLength {
+ return nil, errInvalidHuffmanTree
+ }
+ histogram := [maxAllowedCodeLength + 1]uint32{}
+ for _, cl := range codeLengths {
+ histogram[cl]++
+ }
+ currCode, nextCodes := uint32(0), [maxAllowedCodeLength + 1]uint32{}
+ for cl := 1; cl < len(nextCodes); cl++ {
+ currCode = (currCode + histogram[cl-1]) << 1
+ nextCodes[cl] = currCode
+ }
+ codes := make([]uint32, len(codeLengths))
+ for symbol, cl := range codeLengths {
+ if cl > 0 {
+ codes[symbol] = nextCodes[cl]
+ nextCodes[cl]++
+ }
+ }
+ return codes, nil
+}
+
+// build builds a canonical Huffman tree from the given code lengths.
+func (h *hTree) build(codeLengths []uint32) error {
+ // Calculate the number of symbols.
+ var nSymbols, lastSymbol uint32
+ for symbol, cl := range codeLengths {
+ if cl != 0 {
+ nSymbols++
+ lastSymbol = uint32(symbol)
+ }
+ }
+ if nSymbols == 0 {
+ return errInvalidHuffmanTree
+ }
+ h.nodes = make([]hNode, 1, 2*nSymbols-1)
+ // Handle the trivial case.
+ if nSymbols == 1 {
+ if len(codeLengths) <= int(lastSymbol) {
+ return errInvalidHuffmanTree
+ }
+ return h.insert(lastSymbol, 0, 0)
+ }
+ // Handle the non-trivial case.
+ codes, err := codeLengthsToCodes(codeLengths)
+ if err != nil {
+ return err
+ }
+ for symbol, cl := range codeLengths {
+ if cl > 0 {
+ if err := h.insert(uint32(symbol), codes[symbol], cl); err != nil {
+ return err
+ }
+ }
+ }
+ return nil
+}
+
+// buildSimple builds a Huffman tree with 1 or 2 symbols.
+func (h *hTree) buildSimple(nSymbols uint32, symbols [2]uint32, alphabetSize uint32) error {
+ h.nodes = make([]hNode, 1, 2*nSymbols-1)
+ for i := uint32(0); i < nSymbols; i++ {
+ if symbols[i] >= alphabetSize {
+ return errInvalidHuffmanTree
+ }
+ if err := h.insert(symbols[i], i, nSymbols-1); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+// next returns the next Huffman-encoded symbol from the bit-stream d.
+func (h *hTree) next(d *decoder) (uint32, error) {
+ var n uint32
+ // Read enough bits so that we can use the look-up table.
+ if d.nBits < lutSize {
+ c, err := d.r.ReadByte()
+ if err != nil {
+ if err == io.EOF {
+ // There are no more bytes of data, but we may still be able
+ // to read the next symbol out of the previously read bits.
+ goto slowPath
+ }
+ return 0, err
+ }
+ d.bits |= uint32(c) << d.nBits
+ d.nBits += 8
+ }
+ // Use the look-up table.
+ n = h.lut[d.bits&lutMask]
+ if b := n & 0xff; b != 0 {
+ b--
+ d.bits >>= b
+ d.nBits -= b
+ return n >> 8, nil
+ }
+ n >>= 8
+ d.bits >>= lutSize
+ d.nBits -= lutSize
+
+slowPath:
+ for h.nodes[n].children != leafNode {
+ if d.nBits == 0 {
+ c, err := d.r.ReadByte()
+ if err != nil {
+ if err == io.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return 0, err
+ }
+ d.bits = uint32(c)
+ d.nBits = 8
+ }
+ n = uint32(h.nodes[n].children) + 1&d.bits
+ d.bits >>= 1
+ d.nBits--
+ }
+ return h.nodes[n].symbol, nil
+}
diff --git a/vendor/golang.org/x/image/vp8l/transform.go b/vendor/golang.org/x/image/vp8l/transform.go
@@ -0,0 +1,299 @@
+// 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 vp8l
+
+// This file deals with image transforms, specified in section 3.
+
+// nTiles returns the number of tiles needed to cover size pixels, where each
+// tile's side is 1<<bits pixels long.
+func nTiles(size int32, bits uint32) int32 {
+ return (size + 1<<bits - 1) >> bits
+}
+
+const (
+ transformTypePredictor = 0
+ transformTypeCrossColor = 1
+ transformTypeSubtractGreen = 2
+ transformTypeColorIndexing = 3
+ nTransformTypes = 4
+)
+
+// transform holds the parameters for an invertible transform.
+type transform struct {
+ // transformType is the type of the transform.
+ transformType uint32
+ // oldWidth is the width of the image before transformation (or
+ // equivalently, after inverse transformation). The color-indexing
+ // transform can reduce the width. For example, a 50-pixel-wide
+ // image that only needs 4 bits (half a byte) per color index can
+ // be transformed into a 25-pixel-wide image.
+ oldWidth int32
+ // bits is the log-2 size of the transform's tiles, for the predictor
+ // and cross-color transforms. 8>>bits is the number of bits per
+ // color index, for the color-index transform.
+ bits uint32
+ // pix is the tile values, for the predictor and cross-color
+ // transforms, and the color palette, for the color-index transform.
+ pix []byte
+}
+
+var inverseTransforms = [nTransformTypes]func(*transform, []byte, int32) []byte{
+ transformTypePredictor: inversePredictor,
+ transformTypeCrossColor: inverseCrossColor,
+ transformTypeSubtractGreen: inverseSubtractGreen,
+ transformTypeColorIndexing: inverseColorIndexing,
+}
+
+func inversePredictor(t *transform, pix []byte, h int32) []byte {
+ if t.oldWidth == 0 || h == 0 {
+ return pix
+ }
+ // The first pixel's predictor is mode 0 (opaque black).
+ pix[3] += 0xff
+ p, mask := int32(4), int32(1)<<t.bits-1
+ for x := int32(1); x < t.oldWidth; x++ {
+ // The rest of the first row's predictor is mode 1 (L).
+ pix[p+0] += pix[p-4]
+ pix[p+1] += pix[p-3]
+ pix[p+2] += pix[p-2]
+ pix[p+3] += pix[p-1]
+ p += 4
+ }
+ top, tilesPerRow := 0, nTiles(t.oldWidth, t.bits)
+ for y := int32(1); y < h; y++ {
+ // The first column's predictor is mode 2 (T).
+ pix[p+0] += pix[top+0]
+ pix[p+1] += pix[top+1]
+ pix[p+2] += pix[top+2]
+ pix[p+3] += pix[top+3]
+ p, top = p+4, top+4
+
+ q := 4 * (y >> t.bits) * tilesPerRow
+ predictorMode := t.pix[q+1] & 0x0f
+ q += 4
+ for x := int32(1); x < t.oldWidth; x++ {
+ if x&mask == 0 {
+ predictorMode = t.pix[q+1] & 0x0f
+ q += 4
+ }
+ switch predictorMode {
+ case 0: // Opaque black.
+ pix[p+3] += 0xff
+
+ case 1: // L.
+ pix[p+0] += pix[p-4]
+ pix[p+1] += pix[p-3]
+ pix[p+2] += pix[p-2]
+ pix[p+3] += pix[p-1]
+
+ case 2: // T.
+ pix[p+0] += pix[top+0]
+ pix[p+1] += pix[top+1]
+ pix[p+2] += pix[top+2]
+ pix[p+3] += pix[top+3]
+
+ case 3: // TR.
+ pix[p+0] += pix[top+4]
+ pix[p+1] += pix[top+5]
+ pix[p+2] += pix[top+6]
+ pix[p+3] += pix[top+7]
+
+ case 4: // TL.
+ pix[p+0] += pix[top-4]
+ pix[p+1] += pix[top-3]
+ pix[p+2] += pix[top-2]
+ pix[p+3] += pix[top-1]
+
+ case 5: // Average2(Average2(L, TR), T).
+ pix[p+0] += avg2(avg2(pix[p-4], pix[top+4]), pix[top+0])
+ pix[p+1] += avg2(avg2(pix[p-3], pix[top+5]), pix[top+1])
+ pix[p+2] += avg2(avg2(pix[p-2], pix[top+6]), pix[top+2])
+ pix[p+3] += avg2(avg2(pix[p-1], pix[top+7]), pix[top+3])
+
+ case 6: // Average2(L, TL).
+ pix[p+0] += avg2(pix[p-4], pix[top-4])
+ pix[p+1] += avg2(pix[p-3], pix[top-3])
+ pix[p+2] += avg2(pix[p-2], pix[top-2])
+ pix[p+3] += avg2(pix[p-1], pix[top-1])
+
+ case 7: // Average2(L, T).
+ pix[p+0] += avg2(pix[p-4], pix[top+0])
+ pix[p+1] += avg2(pix[p-3], pix[top+1])
+ pix[p+2] += avg2(pix[p-2], pix[top+2])
+ pix[p+3] += avg2(pix[p-1], pix[top+3])
+
+ case 8: // Average2(TL, T).
+ pix[p+0] += avg2(pix[top-4], pix[top+0])
+ pix[p+1] += avg2(pix[top-3], pix[top+1])
+ pix[p+2] += avg2(pix[top-2], pix[top+2])
+ pix[p+3] += avg2(pix[top-1], pix[top+3])
+
+ case 9: // Average2(T, TR).
+ pix[p+0] += avg2(pix[top+0], pix[top+4])
+ pix[p+1] += avg2(pix[top+1], pix[top+5])
+ pix[p+2] += avg2(pix[top+2], pix[top+6])
+ pix[p+3] += avg2(pix[top+3], pix[top+7])
+
+ case 10: // Average2(Average2(L, TL), Average2(T, TR)).
+ pix[p+0] += avg2(avg2(pix[p-4], pix[top-4]), avg2(pix[top+0], pix[top+4]))
+ pix[p+1] += avg2(avg2(pix[p-3], pix[top-3]), avg2(pix[top+1], pix[top+5]))
+ pix[p+2] += avg2(avg2(pix[p-2], pix[top-2]), avg2(pix[top+2], pix[top+6]))
+ pix[p+3] += avg2(avg2(pix[p-1], pix[top-1]), avg2(pix[top+3], pix[top+7]))
+
+ case 11: // Select(L, T, TL).
+ l0 := int32(pix[p-4])
+ l1 := int32(pix[p-3])
+ l2 := int32(pix[p-2])
+ l3 := int32(pix[p-1])
+ c0 := int32(pix[top-4])
+ c1 := int32(pix[top-3])
+ c2 := int32(pix[top-2])
+ c3 := int32(pix[top-1])
+ t0 := int32(pix[top+0])
+ t1 := int32(pix[top+1])
+ t2 := int32(pix[top+2])
+ t3 := int32(pix[top+3])
+ l := abs(c0-t0) + abs(c1-t1) + abs(c2-t2) + abs(c3-t3)
+ t := abs(c0-l0) + abs(c1-l1) + abs(c2-l2) + abs(c3-l3)
+ if l < t {
+ pix[p+0] += uint8(l0)
+ pix[p+1] += uint8(l1)
+ pix[p+2] += uint8(l2)
+ pix[p+3] += uint8(l3)
+ } else {
+ pix[p+0] += uint8(t0)
+ pix[p+1] += uint8(t1)
+ pix[p+2] += uint8(t2)
+ pix[p+3] += uint8(t3)
+ }
+
+ case 12: // ClampAddSubtractFull(L, T, TL).
+ pix[p+0] += clampAddSubtractFull(pix[p-4], pix[top+0], pix[top-4])
+ pix[p+1] += clampAddSubtractFull(pix[p-3], pix[top+1], pix[top-3])
+ pix[p+2] += clampAddSubtractFull(pix[p-2], pix[top+2], pix[top-2])
+ pix[p+3] += clampAddSubtractFull(pix[p-1], pix[top+3], pix[top-1])
+
+ case 13: // ClampAddSubtractHalf(Average2(L, T), TL).
+ pix[p+0] += clampAddSubtractHalf(avg2(pix[p-4], pix[top+0]), pix[top-4])
+ pix[p+1] += clampAddSubtractHalf(avg2(pix[p-3], pix[top+1]), pix[top-3])
+ pix[p+2] += clampAddSubtractHalf(avg2(pix[p-2], pix[top+2]), pix[top-2])
+ pix[p+3] += clampAddSubtractHalf(avg2(pix[p-1], pix[top+3]), pix[top-1])
+ }
+ p, top = p+4, top+4
+ }
+ }
+ return pix
+}
+
+func inverseCrossColor(t *transform, pix []byte, h int32) []byte {
+ var greenToRed, greenToBlue, redToBlue int32
+ p, mask, tilesPerRow := int32(0), int32(1)<<t.bits-1, nTiles(t.oldWidth, t.bits)
+ for y := int32(0); y < h; y++ {
+ q := 4 * (y >> t.bits) * tilesPerRow
+ for x := int32(0); x < t.oldWidth; x++ {
+ if x&mask == 0 {
+ redToBlue = int32(int8(t.pix[q+0]))
+ greenToBlue = int32(int8(t.pix[q+1]))
+ greenToRed = int32(int8(t.pix[q+2]))
+ q += 4
+ }
+ red := pix[p+0]
+ green := pix[p+1]
+ blue := pix[p+2]
+ red += uint8(uint32(greenToRed*int32(int8(green))) >> 5)
+ blue += uint8(uint32(greenToBlue*int32(int8(green))) >> 5)
+ blue += uint8(uint32(redToBlue*int32(int8(red))) >> 5)
+ pix[p+0] = red
+ pix[p+2] = blue
+ p += 4
+ }
+ }
+ return pix
+}
+
+func inverseSubtractGreen(t *transform, pix []byte, h int32) []byte {
+ for p := 0; p < len(pix); p += 4 {
+ green := pix[p+1]
+ pix[p+0] += green
+ pix[p+2] += green
+ }
+ return pix
+}
+
+func inverseColorIndexing(t *transform, pix []byte, h int32) []byte {
+ if t.bits == 0 {
+ for p := 0; p < len(pix); p += 4 {
+ i := 4 * uint32(pix[p+1])
+ pix[p+0] = t.pix[i+0]
+ pix[p+1] = t.pix[i+1]
+ pix[p+2] = t.pix[i+2]
+ pix[p+3] = t.pix[i+3]
+ }
+ return pix
+ }
+
+ vMask, xMask, bitsPerPixel := uint32(0), int32(0), uint32(8>>t.bits)
+ switch t.bits {
+ case 1:
+ vMask, xMask = 0x0f, 0x01
+ case 2:
+ vMask, xMask = 0x03, 0x03
+ case 3:
+ vMask, xMask = 0x01, 0x07
+ }
+
+ d, p, v, dst := 0, 0, uint32(0), make([]byte, 4*t.oldWidth*h)
+ for y := int32(0); y < h; y++ {
+ for x := int32(0); x < t.oldWidth; x++ {
+ if x&xMask == 0 {
+ v = uint32(pix[p+1])
+ p += 4
+ }
+
+ i := 4 * (v & vMask)
+ dst[d+0] = t.pix[i+0]
+ dst[d+1] = t.pix[i+1]
+ dst[d+2] = t.pix[i+2]
+ dst[d+3] = t.pix[i+3]
+ d += 4
+
+ v >>= bitsPerPixel
+ }
+ }
+ return dst
+}
+
+func abs(x int32) int32 {
+ if x < 0 {
+ return -x
+ }
+ return x
+}
+
+func avg2(a, b uint8) uint8 {
+ return uint8((int32(a) + int32(b)) / 2)
+}
+
+func clampAddSubtractFull(a, b, c uint8) uint8 {
+ x := int32(a) + int32(b) - int32(c)
+ if x < 0 {
+ return 0
+ }
+ if x > 255 {
+ return 255
+ }
+ return uint8(x)
+}
+
+func clampAddSubtractHalf(a, b uint8) uint8 {
+ x := int32(a) + (int32(a)-int32(b))/2
+ if x < 0 {
+ return 0
+ }
+ if x > 255 {
+ return 255
+ }
+ return uint8(x)
+}
diff --git a/vendor/golang.org/x/image/webp/decode.go b/vendor/golang.org/x/image/webp/decode.go
@@ -0,0 +1,271 @@
+// Copyright 2011 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 webp
+
+import (
+ "bytes"
+ "errors"
+ "image"
+ "image/color"
+ "io"
+
+ "golang.org/x/image/riff"
+ "golang.org/x/image/vp8"
+ "golang.org/x/image/vp8l"
+)
+
+var errInvalidFormat = errors.New("webp: invalid format")
+
+var (
+ fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
+ fccVP8 = riff.FourCC{'V', 'P', '8', ' '}
+ fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
+ fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
+ fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
+)
+
+func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
+ formType, riffReader, err := riff.NewReader(r)
+ if err != nil {
+ return nil, image.Config{}, err
+ }
+ if formType != fccWEBP {
+ return nil, image.Config{}, errInvalidFormat
+ }
+
+ var (
+ alpha []byte
+ alphaStride int
+ wantAlpha bool
+ widthMinusOne uint32
+ heightMinusOne uint32
+ buf [10]byte
+ )
+ for {
+ chunkID, chunkLen, chunkData, err := riffReader.Next()
+ if err == io.EOF {
+ err = errInvalidFormat
+ }
+ if err != nil {
+ return nil, image.Config{}, err
+ }
+
+ switch chunkID {
+ case fccALPH:
+ if !wantAlpha {
+ return nil, image.Config{}, errInvalidFormat
+ }
+ wantAlpha = false
+ // Read the Pre-processing | Filter | Compression byte.
+ if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
+ if err == io.EOF {
+ err = errInvalidFormat
+ }
+ return nil, image.Config{}, err
+ }
+ alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
+ if err != nil {
+ return nil, image.Config{}, err
+ }
+ unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
+
+ case fccVP8:
+ if wantAlpha || int32(chunkLen) < 0 {
+ return nil, image.Config{}, errInvalidFormat
+ }
+ d := vp8.NewDecoder()
+ d.Init(chunkData, int(chunkLen))
+ fh, err := d.DecodeFrameHeader()
+ if err != nil {
+ return nil, image.Config{}, err
+ }
+ if configOnly {
+ return nil, image.Config{
+ ColorModel: color.YCbCrModel,
+ Width: fh.Width,
+ Height: fh.Height,
+ }, nil
+ }
+ m, err := d.DecodeFrame()
+ if err != nil {
+ return nil, image.Config{}, err
+ }
+ if alpha != nil {
+ return &image.NYCbCrA{
+ YCbCr: *m,
+ A: alpha,
+ AStride: alphaStride,
+ }, image.Config{}, nil
+ }
+ return m, image.Config{}, nil
+
+ case fccVP8L:
+ if wantAlpha || alpha != nil {
+ return nil, image.Config{}, errInvalidFormat
+ }
+ if configOnly {
+ c, err := vp8l.DecodeConfig(chunkData)
+ return nil, c, err
+ }
+ m, err := vp8l.Decode(chunkData)
+ return m, image.Config{}, err
+
+ case fccVP8X:
+ if chunkLen != 10 {
+ return nil, image.Config{}, errInvalidFormat
+ }
+ if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
+ return nil, image.Config{}, err
+ }
+ const (
+ animationBit = 1 << 1
+ xmpMetadataBit = 1 << 2
+ exifMetadataBit = 1 << 3
+ alphaBit = 1 << 4
+ iccProfileBit = 1 << 5
+ )
+ wantAlpha = (buf[0] & alphaBit) != 0
+ widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
+ heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
+ if configOnly {
+ if wantAlpha {
+ return nil, image.Config{
+ ColorModel: color.NYCbCrAModel,
+ Width: int(widthMinusOne) + 1,
+ Height: int(heightMinusOne) + 1,
+ }, nil
+ }
+ return nil, image.Config{
+ ColorModel: color.YCbCrModel,
+ Width: int(widthMinusOne) + 1,
+ Height: int(heightMinusOne) + 1,
+ }, nil
+ }
+ }
+ }
+}
+
+func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
+ alpha []byte, alphaStride int, err error) {
+
+ switch compression {
+ case 0:
+ w := int(widthMinusOne) + 1
+ h := int(heightMinusOne) + 1
+ alpha = make([]byte, w*h)
+ if _, err := io.ReadFull(chunkData, alpha); err != nil {
+ return nil, 0, err
+ }
+ return alpha, w, nil
+
+ case 1:
+ // Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
+ // a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
+ // a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
+ // TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
+ // extract the green values to a separately allocated []byte. Fixing this
+ // will require changes to the vp8l package's API.
+ if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
+ return nil, 0, errors.New("webp: invalid format")
+ }
+ alphaImage, err := vp8l.Decode(io.MultiReader(
+ bytes.NewReader([]byte{
+ 0x2f, // VP8L magic number.
+ uint8(widthMinusOne),
+ uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
+ uint8(heightMinusOne >> 2),
+ uint8(heightMinusOne >> 10),
+ }),
+ chunkData,
+ ))
+ if err != nil {
+ return nil, 0, err
+ }
+ // The green values of the inner NRGBA image are the alpha values of the
+ // outer NYCbCrA image.
+ pix := alphaImage.(*image.NRGBA).Pix
+ alpha = make([]byte, len(pix)/4)
+ for i := range alpha {
+ alpha[i] = pix[4*i+1]
+ }
+ return alpha, int(widthMinusOne) + 1, nil
+ }
+ return nil, 0, errInvalidFormat
+}
+
+func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
+ if len(alpha) == 0 || alphaStride == 0 {
+ return
+ }
+ switch filter {
+ case 1: // Horizontal filter.
+ for i := 1; i < alphaStride; i++ {
+ alpha[i] += alpha[i-1]
+ }
+ for i := alphaStride; i < len(alpha); i += alphaStride {
+ // The first column is equivalent to the vertical filter.
+ alpha[i] += alpha[i-alphaStride]
+
+ for j := 1; j < alphaStride; j++ {
+ alpha[i+j] += alpha[i+j-1]
+ }
+ }
+
+ case 2: // Vertical filter.
+ // The first row is equivalent to the horizontal filter.
+ for i := 1; i < alphaStride; i++ {
+ alpha[i] += alpha[i-1]
+ }
+
+ for i := alphaStride; i < len(alpha); i++ {
+ alpha[i] += alpha[i-alphaStride]
+ }
+
+ case 3: // Gradient filter.
+ // The first row is equivalent to the horizontal filter.
+ for i := 1; i < alphaStride; i++ {
+ alpha[i] += alpha[i-1]
+ }
+
+ for i := alphaStride; i < len(alpha); i += alphaStride {
+ // The first column is equivalent to the vertical filter.
+ alpha[i] += alpha[i-alphaStride]
+
+ // The interior is predicted on the three top/left pixels.
+ for j := 1; j < alphaStride; j++ {
+ c := int(alpha[i+j-alphaStride-1])
+ b := int(alpha[i+j-alphaStride])
+ a := int(alpha[i+j-1])
+ x := a + b - c
+ if x < 0 {
+ x = 0
+ } else if x > 255 {
+ x = 255
+ }
+ alpha[i+j] += uint8(x)
+ }
+ }
+ }
+}
+
+// Decode reads a WEBP image from r and returns it as an image.Image.
+func Decode(r io.Reader) (image.Image, error) {
+ m, _, err := decode(r, false)
+ if err != nil {
+ return nil, err
+ }
+ return m, err
+}
+
+// DecodeConfig returns the color model and dimensions of a WEBP image without
+// decoding the entire image.
+func DecodeConfig(r io.Reader) (image.Config, error) {
+ _, c, err := decode(r, true)
+ return c, err
+}
+
+func init() {
+ image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
+}
diff --git a/vendor/golang.org/x/image/webp/doc.go b/vendor/golang.org/x/image/webp/doc.go
@@ -0,0 +1,9 @@
+// Copyright 2016 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 webp implements a decoder for WEBP images.
+//
+// WEBP is defined at:
+// https://developers.google.com/speed/webp/docs/riff_container
+package webp // import "golang.org/x/image/webp"
diff --git a/vendor/modules.txt b/vendor/modules.txt
@@ -52,7 +52,12 @@ golang.org/x/exp/shiny/driver/internal/win32
golang.org/x/exp/shiny/driver/internal/x11key
golang.org/x/exp/shiny/screen
# golang.org/x/image v0.0.0-20200927104501-e162460cd6b5
+## explicit
golang.org/x/image/math/f64
+golang.org/x/image/riff
+golang.org/x/image/vp8
+golang.org/x/image/vp8l
+golang.org/x/image/webp
# golang.org/x/mobile v0.0.0-20200801112145-973feb4309de
golang.org/x/mobile/app
golang.org/x/mobile/app/internal/callfn
