From 8617c6a4a345b047d7a48a34644ff157ef1ba1ec Mon Sep 17 00:00:00 2001 From: Jack Date: Wed, 23 Sep 2015 20:10:11 -0700 Subject: godep fix --- .../src/golang.org/x/image/tiff/reader.go | 681 +++++++++++++++++++++ 1 file changed, 681 insertions(+) create mode 100644 Godeps/_workspace/src/golang.org/x/image/tiff/reader.go (limited to 'Godeps/_workspace/src/golang.org/x/image/tiff/reader.go') diff --git a/Godeps/_workspace/src/golang.org/x/image/tiff/reader.go b/Godeps/_workspace/src/golang.org/x/image/tiff/reader.go new file mode 100644 index 000000000..714e3dda7 --- /dev/null +++ b/Godeps/_workspace/src/golang.org/x/image/tiff/reader.go @@ -0,0 +1,681 @@ +// 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 ( + "compress/zlib" + "encoding/binary" + "fmt" + "image" + "image/color" + "io" + "io/ioutil" + "math" + + "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) +} + +// An InternalError reports that an internal error was encountered. +type InternalError string + +func (e InternalError) Error() string { + return "tiff: internal error: " + 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 the IFD entry in p is "interesting" and +// stows away the data in the decoder. +func (d *decoder) parseIFD(p []byte) 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: + val, err := d.ifdUint(p) + if err != nil { + return err + } + d.features[int(tag)] = val + case tColorMap: + val, err := d.ifdUint(p) + if err != nil { + return err + } + numcolors := len(val) / 3 + if len(val)%3 != 0 || numcolors <= 0 || numcolors > 256 { + return 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 err + } + for _, v := range val { + if v != 1 { + return UnsupportedError("sample format") + } + } + } + return 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}) + } + } + } 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 { + 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 + } + + for i := 0; i < len(p); i += ifdLen { + if err := d.parseIFD(p[i : i+ifdLen]); err != nil { + return nil, err + } + } + + d.config.Width = int(d.firstVal(tImageWidth)) + d.config.Height = int(d.firstVal(tImageLength)) + + if _, ok := d.features[tBitsPerSample]; !ok { + return nil, FormatError("BitsPerSample tag missing") + } + 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 +} + +// 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 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) +} -- cgit v1.2.3-1-g7c22