Update vendor for next release (#1343)

1 files changed, 709 insertions, 0 deletions

diff --git a/vendor/golang.org/x/image/tiff/reader.go b/vendor/golang.org/x/image/tiff/reader.go
new file mode 100644
index 00000000..de73f4b9
--- /dev/null
+++ b/vendor/golang.org/x/image/tiff/reader.go
@@ -0,0 +1,709 @@
+// 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 tiff implements a TIFF image decoder and encoder.
+//
+// The TIFF specification is at http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf
+package tiff // import "golang.org/x/image/tiff"
+
+import (
+	"compress/zlib"
+	"encoding/binary"
+	"fmt"
+	"image"
+	"image/color"
+	"io"
+	"io/ioutil"
+	"math"
+
+	"golang.org/x/image/ccitt"
+	"golang.org/x/image/tiff/lzw"
+)
+
+// A FormatError reports that the input is not a valid TIFF image.
+type FormatError string
+
+func (e FormatError) Error() string {
+	return "tiff: invalid format: " + string(e)
+}
+
+// An UnsupportedError reports that the input uses a valid but
+// unimplemented feature.
+type UnsupportedError string
+
+func (e UnsupportedError) Error() string {
+	return "tiff: unsupported feature: " + string(e)
+}
+
+var errNoPixels = FormatError("not enough pixel data")
+
+type decoder struct {
+	r         io.ReaderAt
+	byteOrder binary.ByteOrder
+	config    image.Config
+	mode      imageMode
+	bpp       uint
+	features  map[int][]uint
+	palette   []color.Color
+
+	buf   []byte
+	off   int    // Current offset in buf.
+	v     uint32 // Buffer value for reading with arbitrary bit depths.
+	nbits uint   // Remaining number of bits in v.
+}
+
+// firstVal returns the first uint of the features entry with the given tag,
+// or 0 if the tag does not exist.
+func (d *decoder) firstVal(tag int) uint {
+	f := d.features[tag]
+	if len(f) == 0 {
+		return 0
+	}
+	return f[0]
+}
+
+// ifdUint decodes the IFD entry in p, which must be of the Byte, Short
+// or Long type, and returns the decoded uint values.
+func (d *decoder) ifdUint(p []byte) (u []uint, err error) {
+	var raw []byte
+	if len(p) < ifdLen {
+		return nil, FormatError("bad IFD entry")
+	}
+
+	datatype := d.byteOrder.Uint16(p[2:4])
+	if dt := int(datatype); dt <= 0 || dt >= len(lengths) {
+		return nil, UnsupportedError("IFD entry datatype")
+	}
+
+	count := d.byteOrder.Uint32(p[4:8])
+	if count > math.MaxInt32/lengths[datatype] {
+		return nil, FormatError("IFD data too large")
+	}
+	if datalen := lengths[datatype] * count; datalen > 4 {
+		// The IFD contains a pointer to the real value.
+		raw = make([]byte, datalen)
+		_, err = d.r.ReadAt(raw, int64(d.byteOrder.Uint32(p[8:12])))
+	} else {
+		raw = p[8 : 8+datalen]
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	u = make([]uint, count)
+	switch datatype {
+	case dtByte:
+		for i := uint32(0); i < count; i++ {
+			u[i] = uint(raw[i])
+		}
+	case dtShort:
+		for i := uint32(0); i < count; i++ {
+			u[i] = uint(d.byteOrder.Uint16(raw[2*i : 2*(i+1)]))
+		}
+	case dtLong:
+		for i := uint32(0); i < count; i++ {
+			u[i] = uint(d.byteOrder.Uint32(raw[4*i : 4*(i+1)]))
+		}
+	default:
+		return nil, UnsupportedError("data type")
+	}
+	return u, nil
+}
+
+// parseIFD decides whether the IFD entry in p is "interesting" and
+// stows away the data in the decoder. It returns the tag number of the
+// entry and an error, if any.
+func (d *decoder) parseIFD(p []byte) (int, error) {
+	tag := d.byteOrder.Uint16(p[0:2])
+	switch tag {
+	case tBitsPerSample,
+		tExtraSamples,
+		tPhotometricInterpretation,
+		tCompression,
+		tPredictor,
+		tStripOffsets,
+		tStripByteCounts,
+		tRowsPerStrip,
+		tTileWidth,
+		tTileLength,
+		tTileOffsets,
+		tTileByteCounts,
+		tImageLength,
+		tImageWidth,
+		tFillOrder,
+		tT4Options,
+		tT6Options:
+		val, err := d.ifdUint(p)
+		if err != nil {
+			return 0, err
+		}
+		d.features[int(tag)] = val
+	case tColorMap:
+		val, err := d.ifdUint(p)
+		if err != nil {
+			return 0, err
+		}
+		numcolors := len(val) / 3
+		if len(val)%3 != 0 || numcolors <= 0 || numcolors > 256 {
+			return 0, FormatError("bad ColorMap length")
+		}
+		d.palette = make([]color.Color, numcolors)
+		for i := 0; i < numcolors; i++ {
+			d.palette[i] = color.RGBA64{
+				uint16(val[i]),
+				uint16(val[i+numcolors]),
+				uint16(val[i+2*numcolors]),
+				0xffff,
+			}
+		}
+	case tSampleFormat:
+		// Page 27 of the spec: If the SampleFormat is present and
+		// the value is not 1 [= unsigned integer data], a Baseline
+		// TIFF reader that cannot handle the SampleFormat value
+		// must terminate the import process gracefully.
+		val, err := d.ifdUint(p)
+		if err != nil {
+			return 0, err
+		}
+		for _, v := range val {
+			if v != 1 {
+				return 0, UnsupportedError("sample format")
+			}
+		}
+	}
+	return int(tag), nil
+}
+
+// readBits reads n bits from the internal buffer starting at the current offset.
+func (d *decoder) readBits(n uint) (v uint32, ok bool) {
+	for d.nbits < n {
+		d.v <<= 8
+		if d.off >= len(d.buf) {
+			return 0, false
+		}
+		d.v |= uint32(d.buf[d.off])
+		d.off++
+		d.nbits += 8
+	}
+	d.nbits -= n
+	rv := d.v >> d.nbits
+	d.v &^= rv << d.nbits
+	return rv, true
+}
+
+// flushBits discards the unread bits in the buffer used by readBits.
+// It is used at the end of a line.
+func (d *decoder) flushBits() {
+	d.v = 0
+	d.nbits = 0
+}
+
+// minInt returns the smaller of x or y.
+func minInt(a, b int) int {
+	if a <= b {
+		return a
+	}
+	return b
+}
+
+// decode decodes the raw data of an image.
+// It reads from d.buf and writes the strip or tile into dst.
+func (d *decoder) decode(dst image.Image, xmin, ymin, xmax, ymax int) error {
+	d.off = 0
+
+	// Apply horizontal predictor if necessary.
+	// In this case, p contains the color difference to the preceding pixel.
+	// See page 64-65 of the spec.
+	if d.firstVal(tPredictor) == prHorizontal {
+		switch d.bpp {
+		case 16:
+			var off int
+			n := 2 * len(d.features[tBitsPerSample]) // bytes per sample times samples per pixel
+			for y := ymin; y < ymax; y++ {
+				off += n
+				for x := 0; x < (xmax-xmin-1)*n; x += 2 {
+					if off+2 > len(d.buf) {
+						return errNoPixels
+					}
+					v0 := d.byteOrder.Uint16(d.buf[off-n : off-n+2])
+					v1 := d.byteOrder.Uint16(d.buf[off : off+2])
+					d.byteOrder.PutUint16(d.buf[off:off+2], v1+v0)
+					off += 2
+				}
+			}
+		case 8:
+			var off int
+			n := 1 * len(d.features[tBitsPerSample]) // bytes per sample times samples per pixel
+			for y := ymin; y < ymax; y++ {
+				off += n
+				for x := 0; x < (xmax-xmin-1)*n; x++ {
+					if off >= len(d.buf) {
+						return errNoPixels
+					}
+					d.buf[off] += d.buf[off-n]
+					off++
+				}
+			}
+		case 1:
+			return UnsupportedError("horizontal predictor with 1 BitsPerSample")
+		}
+	}
+
+	rMaxX := minInt(xmax, dst.Bounds().Max.X)
+	rMaxY := minInt(ymax, dst.Bounds().Max.Y)
+	switch d.mode {
+	case mGray, mGrayInvert:
+		if d.bpp == 16 {
+			img := dst.(*image.Gray16)
+			for y := ymin; y < rMaxY; y++ {
+				for x := xmin; x < rMaxX; x++ {
+					if d.off+2 > len(d.buf) {
+						return errNoPixels
+					}
+					v := d.byteOrder.Uint16(d.buf[d.off : d.off+2])
+					d.off += 2
+					if d.mode == mGrayInvert {
+						v = 0xffff - v
+					}
+					img.SetGray16(x, y, color.Gray16{v})
+				}
+				if rMaxX == img.Bounds().Max.X {
+					d.off += 2 * (xmax - img.Bounds().Max.X)
+				}
+			}
+		} else {
+			img := dst.(*image.Gray)
+			max := uint32((1 << d.bpp) - 1)
+			for y := ymin; y < rMaxY; y++ {
+				for x := xmin; x < rMaxX; x++ {
+					v, ok := d.readBits(d.bpp)
+					if !ok {
+						return errNoPixels
+					}
+					v = v * 0xff / max
+					if d.mode == mGrayInvert {
+						v = 0xff - v
+					}
+					img.SetGray(x, y, color.Gray{uint8(v)})
+				}
+				d.flushBits()
+			}
+		}
+	case mPaletted:
+		img := dst.(*image.Paletted)
+		for y := ymin; y < rMaxY; y++ {
+			for x := xmin; x < rMaxX; x++ {
+				v, ok := d.readBits(d.bpp)
+				if !ok {
+					return errNoPixels
+				}
+				img.SetColorIndex(x, y, uint8(v))
+			}
+			d.flushBits()
+		}
+	case mRGB:
+		if d.bpp == 16 {
+			img := dst.(*image.RGBA64)
+			for y := ymin; y < rMaxY; y++ {
+				for x := xmin; x < rMaxX; x++ {
+					if d.off+6 > len(d.buf) {
+						return errNoPixels
+					}
+					r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
+					g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
+					b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
+					d.off += 6
+					img.SetRGBA64(x, y, color.RGBA64{r, g, b, 0xffff})
+				}
+			}
+		} else {
+			img := dst.(*image.RGBA)
+			for y := ymin; y < rMaxY; y++ {
+				min := img.PixOffset(xmin, y)
+				max := img.PixOffset(rMaxX, y)
+				off := (y - ymin) * (xmax - xmin) * 3
+				for i := min; i < max; i += 4 {
+					if off+3 > len(d.buf) {
+						return errNoPixels
+					}
+					img.Pix[i+0] = d.buf[off+0]
+					img.Pix[i+1] = d.buf[off+1]
+					img.Pix[i+2] = d.buf[off+2]
+					img.Pix[i+3] = 0xff
+					off += 3
+				}
+			}
+		}
+	case mNRGBA:
+		if d.bpp == 16 {
+			img := dst.(*image.NRGBA64)
+			for y := ymin; y < rMaxY; y++ {
+				for x := xmin; x < rMaxX; x++ {
+					if d.off+8 > len(d.buf) {
+						return errNoPixels
+					}
+					r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
+					g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
+					b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
+					a := d.byteOrder.Uint16(d.buf[d.off+6 : d.off+8])
+					d.off += 8
+					img.SetNRGBA64(x, y, color.NRGBA64{r, g, b, a})
+				}
+			}
+		} else {
+			img := dst.(*image.NRGBA)
+			for y := ymin; y < rMaxY; y++ {
+				min := img.PixOffset(xmin, y)
+				max := img.PixOffset(rMaxX, y)
+				i0, i1 := (y-ymin)*(xmax-xmin)*4, (y-ymin+1)*(xmax-xmin)*4
+				if i1 > len(d.buf) {
+					return errNoPixels
+				}
+				copy(img.Pix[min:max], d.buf[i0:i1])
+			}
+		}
+	case mRGBA:
+		if d.bpp == 16 {
+			img := dst.(*image.RGBA64)
+			for y := ymin; y < rMaxY; y++ {
+				for x := xmin; x < rMaxX; x++ {
+					if d.off+8 > len(d.buf) {
+						return errNoPixels
+					}
+					r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
+					g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
+					b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
+					a := d.byteOrder.Uint16(d.buf[d.off+6 : d.off+8])
+					d.off += 8
+					img.SetRGBA64(x, y, color.RGBA64{r, g, b, a})
+				}
+			}
+		} else {
+			img := dst.(*image.RGBA)
+			for y := ymin; y < rMaxY; y++ {
+				min := img.PixOffset(xmin, y)
+				max := img.PixOffset(rMaxX, y)
+				i0, i1 := (y-ymin)*(xmax-xmin)*4, (y-ymin+1)*(xmax-xmin)*4
+				if i1 > len(d.buf) {
+					return errNoPixels
+				}
+				copy(img.Pix[min:max], d.buf[i0:i1])
+			}
+		}
+	}
+
+	return nil
+}
+
+func newDecoder(r io.Reader) (*decoder, error) {
+	d := &decoder{
+		r:        newReaderAt(r),
+		features: make(map[int][]uint),
+	}
+
+	p := make([]byte, 8)
+	if _, err := d.r.ReadAt(p, 0); err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return nil, err
+	}
+	switch string(p[0:4]) {
+	case leHeader:
+		d.byteOrder = binary.LittleEndian
+	case beHeader:
+		d.byteOrder = binary.BigEndian
+	default:
+		return nil, FormatError("malformed header")
+	}
+
+	ifdOffset := int64(d.byteOrder.Uint32(p[4:8]))
+
+	// The first two bytes contain the number of entries (12 bytes each).
+	if _, err := d.r.ReadAt(p[0:2], ifdOffset); err != nil {
+		return nil, err
+	}
+	numItems := int(d.byteOrder.Uint16(p[0:2]))
+
+	// All IFD entries are read in one chunk.
+	p = make([]byte, ifdLen*numItems)
+	if _, err := d.r.ReadAt(p, ifdOffset+2); err != nil {
+		return nil, err
+	}
+
+	prevTag := -1
+	for i := 0; i < len(p); i += ifdLen {
+		tag, err := d.parseIFD(p[i : i+ifdLen])
+		if err != nil {
+			return nil, err
+		}
+		if tag <= prevTag {
+			return nil, FormatError("tags are not sorted in ascending order")
+		}
+		prevTag = tag
+	}
+
+	d.config.Width = int(d.firstVal(tImageWidth))
+	d.config.Height = int(d.firstVal(tImageLength))
+
+	if _, ok := d.features[tBitsPerSample]; !ok {
+		// Default is 1 per specification.
+		d.features[tBitsPerSample] = []uint{1}
+	}
+	d.bpp = d.firstVal(tBitsPerSample)
+	switch d.bpp {
+	case 0:
+		return nil, FormatError("BitsPerSample must not be 0")
+	case 1, 8, 16:
+		// Nothing to do, these are accepted by this implementation.
+	default:
+		return nil, UnsupportedError(fmt.Sprintf("BitsPerSample of %v", d.bpp))
+	}
+
+	// Determine the image mode.
+	switch d.firstVal(tPhotometricInterpretation) {
+	case pRGB:
+		if d.bpp == 16 {
+			for _, b := range d.features[tBitsPerSample] {
+				if b != 16 {
+					return nil, FormatError("wrong number of samples for 16bit RGB")
+				}
+			}
+		} else {
+			for _, b := range d.features[tBitsPerSample] {
+				if b != 8 {
+					return nil, FormatError("wrong number of samples for 8bit RGB")
+				}
+			}
+		}
+		// RGB images normally have 3 samples per pixel.
+		// If there are more, ExtraSamples (p. 31-32 of the spec)
+		// gives their meaning (usually an alpha channel).
+		//
+		// This implementation does not support extra samples
+		// of an unspecified type.
+		switch len(d.features[tBitsPerSample]) {
+		case 3:
+			d.mode = mRGB
+			if d.bpp == 16 {
+				d.config.ColorModel = color.RGBA64Model
+			} else {
+				d.config.ColorModel = color.RGBAModel
+			}
+		case 4:
+			switch d.firstVal(tExtraSamples) {
+			case 1:
+				d.mode = mRGBA
+				if d.bpp == 16 {
+					d.config.ColorModel = color.RGBA64Model
+				} else {
+					d.config.ColorModel = color.RGBAModel
+				}
+			case 2:
+				d.mode = mNRGBA
+				if d.bpp == 16 {
+					d.config.ColorModel = color.NRGBA64Model
+				} else {
+					d.config.ColorModel = color.NRGBAModel
+				}
+			default:
+				return nil, FormatError("wrong number of samples for RGB")
+			}
+		default:
+			return nil, FormatError("wrong number of samples for RGB")
+		}
+	case pPaletted:
+		d.mode = mPaletted
+		d.config.ColorModel = color.Palette(d.palette)
+	case pWhiteIsZero:
+		d.mode = mGrayInvert
+		if d.bpp == 16 {
+			d.config.ColorModel = color.Gray16Model
+		} else {
+			d.config.ColorModel = color.GrayModel
+		}
+	case pBlackIsZero:
+		d.mode = mGray
+		if d.bpp == 16 {
+			d.config.ColorModel = color.Gray16Model
+		} else {
+			d.config.ColorModel = color.GrayModel
+		}
+	default:
+		return nil, UnsupportedError("color model")
+	}
+
+	return d, nil
+}
+
+// DecodeConfig returns the color model and dimensions of a TIFF image without
+// decoding the entire image.
+func DecodeConfig(r io.Reader) (image.Config, error) {
+	d, err := newDecoder(r)
+	if err != nil {
+		return image.Config{}, err
+	}
+	return d.config, nil
+}
+
+func ccittFillOrder(tiffFillOrder uint) ccitt.Order {
+	if tiffFillOrder == 2 {
+		return ccitt.LSB
+	}
+	return ccitt.MSB
+}
+
+// Decode reads a TIFF image from r and returns it as an image.Image.
+// The type of Image returned depends on the contents of the TIFF.
+func Decode(r io.Reader) (img image.Image, err error) {
+	d, err := newDecoder(r)
+	if err != nil {
+		return
+	}
+
+	blockPadding := false
+	blockWidth := d.config.Width
+	blockHeight := d.config.Height
+	blocksAcross := 1
+	blocksDown := 1
+
+	if d.config.Width == 0 {
+		blocksAcross = 0
+	}
+	if d.config.Height == 0 {
+		blocksDown = 0
+	}
+
+	var blockOffsets, blockCounts []uint
+
+	if int(d.firstVal(tTileWidth)) != 0 {
+		blockPadding = true
+
+		blockWidth = int(d.firstVal(tTileWidth))
+		blockHeight = int(d.firstVal(tTileLength))
+
+		if blockWidth != 0 {
+			blocksAcross = (d.config.Width + blockWidth - 1) / blockWidth
+		}
+		if blockHeight != 0 {
+			blocksDown = (d.config.Height + blockHeight - 1) / blockHeight
+		}
+
+		blockCounts = d.features[tTileByteCounts]
+		blockOffsets = d.features[tTileOffsets]
+
+	} else {
+		if int(d.firstVal(tRowsPerStrip)) != 0 {
+			blockHeight = int(d.firstVal(tRowsPerStrip))
+		}
+
+		if blockHeight != 0 {
+			blocksDown = (d.config.Height + blockHeight - 1) / blockHeight
+		}
+
+		blockOffsets = d.features[tStripOffsets]
+		blockCounts = d.features[tStripByteCounts]
+	}
+
+	// Check if we have the right number of strips/tiles, offsets and counts.
+	if n := blocksAcross * blocksDown; len(blockOffsets) < n || len(blockCounts) < n {
+		return nil, FormatError("inconsistent header")
+	}
+
+	imgRect := image.Rect(0, 0, d.config.Width, d.config.Height)
+	switch d.mode {
+	case mGray, mGrayInvert:
+		if d.bpp == 16 {
+			img = image.NewGray16(imgRect)
+		} else {
+			img = image.NewGray(imgRect)
+		}
+	case mPaletted:
+		img = image.NewPaletted(imgRect, d.palette)
+	case mNRGBA:
+		if d.bpp == 16 {
+			img = image.NewNRGBA64(imgRect)
+		} else {
+			img = image.NewNRGBA(imgRect)
+		}
+	case mRGB, mRGBA:
+		if d.bpp == 16 {
+			img = image.NewRGBA64(imgRect)
+		} else {
+			img = image.NewRGBA(imgRect)
+		}
+	}
+
+	for i := 0; i < blocksAcross; i++ {
+		blkW := blockWidth
+		if !blockPadding && i == blocksAcross-1 && d.config.Width%blockWidth != 0 {
+			blkW = d.config.Width % blockWidth
+		}
+		for j := 0; j < blocksDown; j++ {
+			blkH := blockHeight
+			if !blockPadding && j == blocksDown-1 && d.config.Height%blockHeight != 0 {
+				blkH = d.config.Height % blockHeight
+			}
+			offset := int64(blockOffsets[j*blocksAcross+i])
+			n := int64(blockCounts[j*blocksAcross+i])
+			switch d.firstVal(tCompression) {
+
+			// According to the spec, Compression does not have a default value,
+			// but some tools interpret a missing Compression value as none so we do
+			// the same.
+			case cNone, 0:
+				if b, ok := d.r.(*buffer); ok {
+					d.buf, err = b.Slice(int(offset), int(n))
+				} else {
+					d.buf = make([]byte, n)
+					_, err = d.r.ReadAt(d.buf, offset)
+				}
+			case cG3:
+				inv := d.firstVal(tPhotometricInterpretation) == pWhiteIsZero
+				order := ccittFillOrder(d.firstVal(tFillOrder))
+				r := ccitt.NewReader(io.NewSectionReader(d.r, offset, n), order, ccitt.Group3, blkW, blkH, &ccitt.Options{Invert: inv, Align: false})
+				d.buf, err = ioutil.ReadAll(r)
+			case cG4:
+				inv := d.firstVal(tPhotometricInterpretation) == pWhiteIsZero
+				order := ccittFillOrder(d.firstVal(tFillOrder))
+				r := ccitt.NewReader(io.NewSectionReader(d.r, offset, n), order, ccitt.Group4, blkW, blkH, &ccitt.Options{Invert: inv, Align: false})
+				d.buf, err = ioutil.ReadAll(r)
+			case cLZW:
+				r := lzw.NewReader(io.NewSectionReader(d.r, offset, n), lzw.MSB, 8)
+				d.buf, err = ioutil.ReadAll(r)
+				r.Close()
+			case cDeflate, cDeflateOld:
+				var r io.ReadCloser
+				r, err = zlib.NewReader(io.NewSectionReader(d.r, offset, n))
+				if err != nil {
+					return nil, err
+				}
+				d.buf, err = ioutil.ReadAll(r)
+				r.Close()
+			case cPackBits:
+				d.buf, err = unpackBits(io.NewSectionReader(d.r, offset, n))
+			default:
+				err = UnsupportedError(fmt.Sprintf("compression value %d", d.firstVal(tCompression)))
+			}
+			if err != nil {
+				return nil, err
+			}
+
+			xmin := i * blockWidth
+			ymin := j * blockHeight
+			xmax := xmin + blkW
+			ymax := ymin + blkH
+			err = d.decode(img, xmin, ymin, xmax, ymax)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return
+}
+
+func init() {
+	image.RegisterFormat("tiff", leHeader, Decode, DecodeConfig)
+	image.RegisterFormat("tiff", beHeader, Decode, DecodeConfig)
+}