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-rw-r--r--vendor/golang.org/x/image/ccitt/reader.go795
-rw-r--r--vendor/golang.org/x/image/ccitt/table.go972
-rw-r--r--vendor/golang.org/x/image/ccitt/writer.go102
3 files changed, 1869 insertions, 0 deletions
diff --git a/vendor/golang.org/x/image/ccitt/reader.go b/vendor/golang.org/x/image/ccitt/reader.go
new file mode 100644
index 00000000..340de053
--- /dev/null
+++ b/vendor/golang.org/x/image/ccitt/reader.go
@@ -0,0 +1,795 @@
+// Copyright 2019 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.
+
+//go:generate go run gen.go
+
+// Package ccitt implements a CCITT (fax) image decoder.
+package ccitt
+
+import (
+ "encoding/binary"
+ "errors"
+ "image"
+ "io"
+ "math/bits"
+)
+
+var (
+ errIncompleteCode = errors.New("ccitt: incomplete code")
+ errInvalidBounds = errors.New("ccitt: invalid bounds")
+ errInvalidCode = errors.New("ccitt: invalid code")
+ errInvalidMode = errors.New("ccitt: invalid mode")
+ errInvalidOffset = errors.New("ccitt: invalid offset")
+ errMissingEOL = errors.New("ccitt: missing End-of-Line")
+ errRunLengthOverflowsWidth = errors.New("ccitt: run length overflows width")
+ errRunLengthTooLong = errors.New("ccitt: run length too long")
+ errUnsupportedMode = errors.New("ccitt: unsupported mode")
+ errUnsupportedSubFormat = errors.New("ccitt: unsupported sub-format")
+ errUnsupportedWidth = errors.New("ccitt: unsupported width")
+)
+
+// Order specifies the bit ordering in a CCITT data stream.
+type Order uint32
+
+const (
+ // LSB means Least Significant Bits first.
+ LSB Order = iota
+ // MSB means Most Significant Bits first.
+ MSB
+)
+
+// SubFormat represents that the CCITT format consists of a number of
+// sub-formats. Decoding or encoding a CCITT data stream requires knowing the
+// sub-format context. It is not represented in the data stream per se.
+type SubFormat uint32
+
+const (
+ Group3 SubFormat = iota
+ Group4
+)
+
+// AutoDetectHeight is passed as the height argument to NewReader to indicate
+// that the image height (the number of rows) is not known in advance.
+const AutoDetectHeight = -1
+
+// Options are optional parameters.
+type Options struct {
+ // Align means that some variable-bit-width codes are byte-aligned.
+ Align bool
+ // Invert means that black is the 1 bit or 0xFF byte, and white is 0.
+ Invert bool
+}
+
+// maxWidth is the maximum (inclusive) supported width. This is a limitation of
+// this implementation, to guard against integer overflow, and not anything
+// inherent to the CCITT format.
+const maxWidth = 1 << 20
+
+func invertBytes(b []byte) {
+ for i, c := range b {
+ b[i] = ^c
+ }
+}
+
+func reverseBitsWithinBytes(b []byte) {
+ for i, c := range b {
+ b[i] = bits.Reverse8(c)
+ }
+}
+
+// highBits writes to dst (1 bit per pixel, most significant bit first) the
+// high (0x80) bits from src (1 byte per pixel). It returns the number of bytes
+// written and read such that dst[:d] is the packed form of src[:s].
+//
+// For example, if src starts with the 8 bytes [0x7D, 0x7E, 0x7F, 0x80, 0x81,
+// 0x82, 0x00, 0xFF] then 0x1D will be written to dst[0].
+//
+// If src has (8 * len(dst)) or more bytes then only len(dst) bytes are
+// written, (8 * len(dst)) bytes are read, and invert is ignored.
+//
+// Otherwise, if len(src) is not a multiple of 8 then the final byte written to
+// dst is padded with 1 bits (if invert is true) or 0 bits. If inverted, the 1s
+// are typically temporary, e.g. they will be flipped back to 0s by an
+// invertBytes call in the highBits caller, reader.Read.
+func highBits(dst []byte, src []byte, invert bool) (d int, s int) {
+ // Pack as many complete groups of 8 src bytes as we can.
+ n := len(src) / 8
+ if n > len(dst) {
+ n = len(dst)
+ }
+ dstN := dst[:n]
+ for i := range dstN {
+ src8 := src[i*8 : i*8+8]
+ dstN[i] = ((src8[0] & 0x80) >> 0) |
+ ((src8[1] & 0x80) >> 1) |
+ ((src8[2] & 0x80) >> 2) |
+ ((src8[3] & 0x80) >> 3) |
+ ((src8[4] & 0x80) >> 4) |
+ ((src8[5] & 0x80) >> 5) |
+ ((src8[6] & 0x80) >> 6) |
+ ((src8[7] & 0x80) >> 7)
+ }
+ d, s = n, 8*n
+ dst, src = dst[d:], src[s:]
+
+ // Pack up to 7 remaining src bytes, if there's room in dst.
+ if (len(dst) > 0) && (len(src) > 0) {
+ dstByte := byte(0)
+ if invert {
+ dstByte = 0xFF >> uint(len(src))
+ }
+ for n, srcByte := range src {
+ dstByte |= (srcByte & 0x80) >> uint(n)
+ }
+ dst[0] = dstByte
+ d, s = d+1, s+len(src)
+ }
+ return d, s
+}
+
+type bitReader struct {
+ r io.Reader
+
+ // readErr is the error returned from the most recent r.Read call. As the
+ // io.Reader documentation says, when r.Read returns (n, err), "always
+ // process the n > 0 bytes returned before considering the error err".
+ readErr error
+
+ // order is whether to process r's bytes LSB first or MSB first.
+ order Order
+
+ // The high nBits bits of the bits field hold upcoming bits in MSB order.
+ bits uint64
+ nBits uint32
+
+ // bytes[br:bw] holds bytes read from r but not yet loaded into bits.
+ br uint32
+ bw uint32
+ bytes [1024]uint8
+}
+
+func (b *bitReader) alignToByteBoundary() {
+ n := b.nBits & 7
+ b.bits <<= n
+ b.nBits -= n
+}
+
+// nextBitMaxNBits is the maximum possible value of bitReader.nBits after a
+// bitReader.nextBit call, provided that bitReader.nBits was not more than this
+// value before that call.
+//
+// Note that the decode function can unread bits, which can temporarily set the
+// bitReader.nBits value above nextBitMaxNBits.
+const nextBitMaxNBits = 31
+
+func (b *bitReader) nextBit() (uint64, error) {
+ for {
+ if b.nBits > 0 {
+ bit := b.bits >> 63
+ b.bits <<= 1
+ b.nBits--
+ return bit, nil
+ }
+
+ if available := b.bw - b.br; available >= 4 {
+ // Read 32 bits, even though b.bits is a uint64, since the decode
+ // function may need to unread up to maxCodeLength bits, putting
+ // them back in the remaining (64 - 32) bits. TestMaxCodeLength
+ // checks that the generated maxCodeLength constant fits.
+ //
+ // If changing the Uint32 call, also change nextBitMaxNBits.
+ b.bits = uint64(binary.BigEndian.Uint32(b.bytes[b.br:])) << 32
+ b.br += 4
+ b.nBits = 32
+ continue
+ } else if available > 0 {
+ b.bits = uint64(b.bytes[b.br]) << (7 * 8)
+ b.br++
+ b.nBits = 8
+ continue
+ }
+
+ if b.readErr != nil {
+ return 0, b.readErr
+ }
+
+ n, err := b.r.Read(b.bytes[:])
+ b.br = 0
+ b.bw = uint32(n)
+ b.readErr = err
+
+ if b.order != MSB {
+ reverseBitsWithinBytes(b.bytes[:b.bw])
+ }
+ }
+}
+
+func decode(b *bitReader, decodeTable [][2]int16) (uint32, error) {
+ nBitsRead, bitsRead, state := uint32(0), uint64(0), int32(1)
+ for {
+ bit, err := b.nextBit()
+ if err != nil {
+ if err == io.EOF {
+ err = errIncompleteCode
+ }
+ return 0, err
+ }
+ bitsRead |= bit << (63 - nBitsRead)
+ nBitsRead++
+
+ // The "&1" is redundant, but can eliminate a bounds check.
+ state = int32(decodeTable[state][bit&1])
+ if state < 0 {
+ return uint32(^state), nil
+ } else if state == 0 {
+ // Unread the bits we've read, then return errInvalidCode.
+ b.bits = (b.bits >> nBitsRead) | bitsRead
+ b.nBits += nBitsRead
+ return 0, errInvalidCode
+ }
+ }
+}
+
+// decodeEOL decodes the 12-bit EOL code 0000_0000_0001.
+func decodeEOL(b *bitReader) error {
+ nBitsRead, bitsRead := uint32(0), uint64(0)
+ for {
+ bit, err := b.nextBit()
+ if err != nil {
+ if err == io.EOF {
+ err = errMissingEOL
+ }
+ return err
+ }
+ bitsRead |= bit << (63 - nBitsRead)
+ nBitsRead++
+
+ if nBitsRead < 12 {
+ if bit&1 == 0 {
+ continue
+ }
+ } else if bit&1 != 0 {
+ return nil
+ }
+
+ // Unread the bits we've read, then return errMissingEOL.
+ b.bits = (b.bits >> nBitsRead) | bitsRead
+ b.nBits += nBitsRead
+ return errMissingEOL
+ }
+}
+
+type reader struct {
+ br bitReader
+ subFormat SubFormat
+
+ // width is the image width in pixels.
+ width int
+
+ // rowsRemaining starts at the image height in pixels, when the reader is
+ // driven through the io.Reader interface, and decrements to zero as rows
+ // are decoded. Alternatively, it may be negative if the image height is
+ // not known in advance at the time of the NewReader call.
+ //
+ // When driven through DecodeIntoGray, this field is unused.
+ rowsRemaining int
+
+ // curr and prev hold the current and previous rows. Each element is either
+ // 0x00 (black) or 0xFF (white).
+ //
+ // prev may be nil, when processing the first row.
+ curr []byte
+ prev []byte
+
+ // ri is the read index. curr[:ri] are those bytes of curr that have been
+ // passed along via the Read method.
+ //
+ // When the reader is driven through DecodeIntoGray, instead of through the
+ // io.Reader interface, this field is unused.
+ ri int
+
+ // wi is the write index. curr[:wi] are those bytes of curr that have
+ // already been decoded via the decodeRow method.
+ //
+ // What this implementation calls wi is roughly equivalent to what the spec
+ // calls the a0 index.
+ wi int
+
+ // These fields are copied from the *Options (which may be nil).
+ align bool
+ invert bool
+
+ // atStartOfRow is whether we have just started the row. Some parts of the
+ // spec say to treat this situation as if "wi = -1".
+ atStartOfRow bool
+
+ // penColorIsWhite is whether the next run is black or white.
+ penColorIsWhite bool
+
+ // seenStartOfImage is whether we've called the startDecode method.
+ seenStartOfImage bool
+
+ // truncated is whether the input is missing the final 6 consecutive EOL's
+ // (for Group3) or 2 consecutive EOL's (for Group4). Omitting that trailer
+ // (but otherwise padding to a byte boundary, with either all 0 bits or all
+ // 1 bits) is invalid according to the spec, but happens in practice when
+ // exporting from Adobe Acrobat to TIFF + CCITT. This package silently
+ // ignores the format error for CCITT input that has been truncated in that
+ // fashion, returning the full decoded image.
+ //
+ // Detecting trailer truncation (just after the final row of pixels)
+ // requires knowing which row is the final row, and therefore does not
+ // trigger if the image height is not known in advance.
+ truncated bool
+
+ // readErr is a sticky error for the Read method.
+ readErr error
+}
+
+func (z *reader) Read(p []byte) (int, error) {
+ if z.readErr != nil {
+ return 0, z.readErr
+ }
+ originalP := p
+
+ for len(p) > 0 {
+ // Allocate buffers (and decode any start-of-image codes), if
+ // processing the first or second row.
+ if z.curr == nil {
+ if !z.seenStartOfImage {
+ if z.readErr = z.startDecode(); z.readErr != nil {
+ break
+ }
+ z.atStartOfRow = true
+ }
+ z.curr = make([]byte, z.width)
+ }
+
+ // Decode the next row, if necessary.
+ if z.atStartOfRow {
+ if z.rowsRemaining < 0 {
+ // We do not know the image height in advance. See if the next
+ // code is an EOL. If it is, it is consumed. If it isn't, the
+ // bitReader shouldn't advance along the bit stream, and we
+ // simply decode another row of pixel data.
+ //
+ // For the Group4 subFormat, we may need to align to a byte
+ // boundary. For the Group3 subFormat, the previous z.decodeRow
+ // call (or z.startDecode call) has already consumed one of the
+ // 6 consecutive EOL's. The next EOL is actually the second of
+ // 6, in the middle, and we shouldn't align at that point.
+ if z.align && (z.subFormat == Group4) {
+ z.br.alignToByteBoundary()
+ }
+
+ if err := z.decodeEOL(); err == errMissingEOL {
+ // No-op. It's another row of pixel data.
+ } else if err != nil {
+ z.readErr = err
+ break
+ } else {
+ if z.readErr = z.finishDecode(true); z.readErr != nil {
+ break
+ }
+ z.readErr = io.EOF
+ break
+ }
+
+ } else if z.rowsRemaining == 0 {
+ // We do know the image height in advance, and we have already
+ // decoded exactly that many rows.
+ if z.readErr = z.finishDecode(false); z.readErr != nil {
+ break
+ }
+ z.readErr = io.EOF
+ break
+
+ } else {
+ z.rowsRemaining--
+ }
+
+ if z.readErr = z.decodeRow(z.rowsRemaining == 0); z.readErr != nil {
+ break
+ }
+ }
+
+ // Pack from z.curr (1 byte per pixel) to p (1 bit per pixel).
+ packD, packS := highBits(p, z.curr[z.ri:], z.invert)
+ p = p[packD:]
+ z.ri += packS
+
+ // Prepare to decode the next row, if necessary.
+ if z.ri == len(z.curr) {
+ z.ri, z.curr, z.prev = 0, z.prev, z.curr
+ z.atStartOfRow = true
+ }
+ }
+
+ n := len(originalP) - len(p)
+ if z.invert {
+ invertBytes(originalP[:n])
+ }
+ return n, z.readErr
+}
+
+func (z *reader) penColor() byte {
+ if z.penColorIsWhite {
+ return 0xFF
+ }
+ return 0x00
+}
+
+func (z *reader) startDecode() error {
+ switch z.subFormat {
+ case Group3:
+ if err := z.decodeEOL(); err != nil {
+ return err
+ }
+
+ case Group4:
+ // No-op.
+
+ default:
+ return errUnsupportedSubFormat
+ }
+
+ z.seenStartOfImage = true
+ return nil
+}
+
+func (z *reader) finishDecode(alreadySeenEOL bool) error {
+ numberOfEOLs := 0
+ switch z.subFormat {
+ case Group3:
+ if z.truncated {
+ return nil
+ }
+ // The stream ends with a RTC (Return To Control) of 6 consecutive
+ // EOL's, but we should have already just seen an EOL, either in
+ // z.startDecode (for a zero-height image) or in z.decodeRow.
+ numberOfEOLs = 5
+
+ case Group4:
+ autoDetectHeight := z.rowsRemaining < 0
+ if autoDetectHeight {
+ // Aligning to a byte boundary was already handled by reader.Read.
+ } else if z.align {
+ z.br.alignToByteBoundary()
+ }
+ // The stream ends with two EOL's. If the first one is missing, and we
+ // had an explicit image height, we just assume that the trailing two
+ // EOL's were truncated and return a nil error.
+ if err := z.decodeEOL(); err != nil {
+ if (err == errMissingEOL) && !autoDetectHeight {
+ z.truncated = true
+ return nil
+ }
+ return err
+ }
+ numberOfEOLs = 1
+
+ default:
+ return errUnsupportedSubFormat
+ }
+
+ if alreadySeenEOL {
+ numberOfEOLs--
+ }
+ for ; numberOfEOLs > 0; numberOfEOLs-- {
+ if err := z.decodeEOL(); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+func (z *reader) decodeEOL() error {
+ return decodeEOL(&z.br)
+}
+
+func (z *reader) decodeRow(finalRow bool) error {
+ z.wi = 0
+ z.atStartOfRow = true
+ z.penColorIsWhite = true
+
+ if z.align {
+ z.br.alignToByteBoundary()
+ }
+
+ switch z.subFormat {
+ case Group3:
+ for ; z.wi < len(z.curr); z.atStartOfRow = false {
+ if err := z.decodeRun(); err != nil {
+ return err
+ }
+ }
+ err := z.decodeEOL()
+ if finalRow && (err == errMissingEOL) {
+ z.truncated = true
+ return nil
+ }
+ return err
+
+ case Group4:
+ for ; z.wi < len(z.curr); z.atStartOfRow = false {
+ mode, err := decode(&z.br, modeDecodeTable[:])
+ if err != nil {
+ return err
+ }
+ rm := readerMode{}
+ if mode < uint32(len(readerModes)) {
+ rm = readerModes[mode]
+ }
+ if rm.function == nil {
+ return errInvalidMode
+ }
+ if err := rm.function(z, rm.arg); err != nil {
+ return err
+ }
+ }
+ return nil
+ }
+
+ return errUnsupportedSubFormat
+}
+
+func (z *reader) decodeRun() error {
+ table := blackDecodeTable[:]
+ if z.penColorIsWhite {
+ table = whiteDecodeTable[:]
+ }
+
+ total := 0
+ for {
+ n, err := decode(&z.br, table)
+ if err != nil {
+ return err
+ }
+ if n > maxWidth {
+ panic("unreachable")
+ }
+ total += int(n)
+ if total > maxWidth {
+ return errRunLengthTooLong
+ }
+ // Anything 0x3F or below is a terminal code.
+ if n <= 0x3F {
+ break
+ }
+ }
+
+ if total > (len(z.curr) - z.wi) {
+ return errRunLengthOverflowsWidth
+ }
+ dst := z.curr[z.wi : z.wi+total]
+ penColor := z.penColor()
+ for i := range dst {
+ dst[i] = penColor
+ }
+ z.wi += total
+ z.penColorIsWhite = !z.penColorIsWhite
+
+ return nil
+}
+
+// The various modes' semantics are based on determining a row of pixels'
+// "changing elements": those pixels whose color differs from the one on its
+// immediate left.
+//
+// The row above the first row is implicitly all white. Similarly, the column
+// to the left of the first column is implicitly all white.
+//
+// For example, here's Figure 1 in "ITU-T Recommendation T.6", where the
+// current and previous rows contain black (B) and white (w) pixels. The a?
+// indexes point into curr, the b? indexes point into prev.
+//
+// b1 b2
+// v v
+// prev: BBBBBwwwwwBBBwwwww
+// curr: BBBwwwwwBBBBBBwwww
+// ^ ^ ^
+// a0 a1 a2
+//
+// a0 is the "reference element" or current decoder position, roughly
+// equivalent to what this implementation calls reader.wi.
+//
+// a1 is the next changing element to the right of a0, on the "coding line"
+// (the current row).
+//
+// a2 is the next changing element to the right of a1, again on curr.
+//
+// b1 is the first changing element on the "reference line" (the previous row)
+// to the right of a0 and of opposite color to a0.
+//
+// b2 is the next changing element to the right of b1, again on prev.
+//
+// The various modes calculate a1 (and a2, for modeH):
+// - modePass calculates that a1 is at or to the right of b2.
+// - modeH calculates a1 and a2 without considering b1 or b2.
+// - modeV* calculates a1 to be b1 plus an adjustment (between -3 and +3).
+
+const (
+ findB1 = false
+ findB2 = true
+)
+
+// findB finds either the b1 or b2 value.
+func (z *reader) findB(whichB bool) int {
+ // The initial row is a special case. The previous row is implicitly all
+ // white, so that there are no changing pixel elements. We return b1 or b2
+ // to be at the end of the row.
+ if len(z.prev) != len(z.curr) {
+ return len(z.curr)
+ }
+
+ i := z.wi
+
+ if z.atStartOfRow {
+ // a0 is implicitly at -1, on a white pixel. b1 is the first black
+ // pixel in the previous row. b2 is the first white pixel after that.
+ for ; (i < len(z.prev)) && (z.prev[i] == 0xFF); i++ {
+ }
+ if whichB == findB2 {
+ for ; (i < len(z.prev)) && (z.prev[i] == 0x00); i++ {
+ }
+ }
+ return i
+ }
+
+ // As per figure 1 above, assume that the current pen color is white.
+ // First, walk past every contiguous black pixel in prev, starting at a0.
+ oppositeColor := ^z.penColor()
+ for ; (i < len(z.prev)) && (z.prev[i] == oppositeColor); i++ {
+ }
+
+ // Then walk past every contiguous white pixel.
+ penColor := ^oppositeColor
+ for ; (i < len(z.prev)) && (z.prev[i] == penColor); i++ {
+ }
+
+ // We're now at a black pixel (or at the end of the row). That's b1.
+ if whichB == findB2 {
+ // If we're looking for b2, walk past every contiguous black pixel
+ // again.
+ oppositeColor := ^penColor
+ for ; (i < len(z.prev)) && (z.prev[i] == oppositeColor); i++ {
+ }
+ }
+
+ return i
+}
+
+type readerMode struct {
+ function func(z *reader, arg int) error
+ arg int
+}
+
+var readerModes = [...]readerMode{
+ modePass: {function: readerModePass},
+ modeH: {function: readerModeH},
+ modeV0: {function: readerModeV, arg: +0},
+ modeVR1: {function: readerModeV, arg: +1},
+ modeVR2: {function: readerModeV, arg: +2},
+ modeVR3: {function: readerModeV, arg: +3},
+ modeVL1: {function: readerModeV, arg: -1},
+ modeVL2: {function: readerModeV, arg: -2},
+ modeVL3: {function: readerModeV, arg: -3},
+ modeExt: {function: readerModeExt},
+}
+
+func readerModePass(z *reader, arg int) error {
+ b2 := z.findB(findB2)
+ if (b2 < z.wi) || (len(z.curr) < b2) {
+ return errInvalidOffset
+ }
+ dst := z.curr[z.wi:b2]
+ penColor := z.penColor()
+ for i := range dst {
+ dst[i] = penColor
+ }
+ z.wi = b2
+ return nil
+}
+
+func readerModeH(z *reader, arg int) error {
+ // The first iteration finds a1. The second finds a2.
+ for i := 0; i < 2; i++ {
+ if err := z.decodeRun(); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+func readerModeV(z *reader, arg int) error {
+ a1 := z.findB(findB1) + arg
+ if (a1 < z.wi) || (len(z.curr) < a1) {
+ return errInvalidOffset
+ }
+ dst := z.curr[z.wi:a1]
+ penColor := z.penColor()
+ for i := range dst {
+ dst[i] = penColor
+ }
+ z.wi = a1
+ z.penColorIsWhite = !z.penColorIsWhite
+ return nil
+}
+
+func readerModeExt(z *reader, arg int) error {
+ return errUnsupportedMode
+}
+
+// DecodeIntoGray decodes the CCITT-formatted data in r into dst.
+//
+// It returns an error if dst's width and height don't match the implied width
+// and height of CCITT-formatted data.
+func DecodeIntoGray(dst *image.Gray, r io.Reader, order Order, sf SubFormat, opts *Options) error {
+ bounds := dst.Bounds()
+ if (bounds.Dx() < 0) || (bounds.Dy() < 0) {
+ return errInvalidBounds
+ }
+ if bounds.Dx() > maxWidth {
+ return errUnsupportedWidth
+ }
+
+ z := reader{
+ br: bitReader{r: r, order: order},
+ subFormat: sf,
+ align: (opts != nil) && opts.Align,
+ invert: (opts != nil) && opts.Invert,
+ width: bounds.Dx(),
+ }
+ if err := z.startDecode(); err != nil {
+ return err
+ }
+
+ width := bounds.Dx()
+ for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+ p := (y - bounds.Min.Y) * dst.Stride
+ z.curr = dst.Pix[p : p+width]
+ if err := z.decodeRow(y+1 == bounds.Max.Y); err != nil {
+ return err
+ }
+ z.curr, z.prev = nil, z.curr
+ }
+
+ if err := z.finishDecode(false); err != nil {
+ return err
+ }
+
+ if z.invert {
+ for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+ p := (y - bounds.Min.Y) * dst.Stride
+ invertBytes(dst.Pix[p : p+width])
+ }
+ }
+
+ return nil
+}
+
+// NewReader returns an io.Reader that decodes the CCITT-formatted data in r.
+// The resultant byte stream is one bit per pixel (MSB first), with 1 meaning
+// white and 0 meaning black. Each row in the result is byte-aligned.
+//
+// A negative height, such as passing AutoDetectHeight, means that the image
+// height is not known in advance. A negative width is invalid.
+func NewReader(r io.Reader, order Order, sf SubFormat, width int, height int, opts *Options) io.Reader {
+ readErr := error(nil)
+ if width < 0 {
+ readErr = errInvalidBounds
+ } else if width > maxWidth {
+ readErr = errUnsupportedWidth
+ }
+
+ return &reader{
+ br: bitReader{r: r, order: order},
+ subFormat: sf,
+ align: (opts != nil) && opts.Align,
+ invert: (opts != nil) && opts.Invert,
+ width: width,
+ rowsRemaining: height,
+ readErr: readErr,
+ }
+}
diff --git a/vendor/golang.org/x/image/ccitt/table.go b/vendor/golang.org/x/image/ccitt/table.go
new file mode 100644
index 00000000..ef7ea9d4
--- /dev/null
+++ b/vendor/golang.org/x/image/ccitt/table.go
@@ -0,0 +1,972 @@
+// generated by "go run gen.go". DO NOT EDIT.
+
+package ccitt
+
+// Each decodeTable is represented by an array of [2]int16's: a binary tree.
+// Each array element (other than element 0, which means invalid) is a branch
+// node in that tree. The root node is always element 1 (the second element).
+//
+// To walk the tree, look at the next bit in the bit stream, using it to select
+// the first or second element of the [2]int16. If that int16 is 0, we have an
+// invalid code. If it is positive, go to that branch node. If it is negative,
+// then we have a leaf node, whose value is the bitwise complement (the ^
+// operator) of that int16.
+//
+// Comments above each decodeTable also show the same structure visually. The
+// "b123" lines show the 123'rd branch node. The "=XXXXX" lines show an invalid
+// code. The "=v1234" lines show a leaf node with value 1234. When reading the
+// bit stream, a 0 or 1 bit means to go up or down, as you move left to right.
+//
+// For example, in modeDecodeTable, branch node b005 is three steps up from the
+// root node, meaning that we have already seen "000". If the next bit is "0"
+// then we move to branch node b006. Otherwise, the next bit is "1", and we
+// move to the leaf node v0000 (also known as the modePass constant). Indeed,
+// the bits that encode modePass are "0001".
+//
+// Tables 1, 2 and 3 come from the "ITU-T Recommendation T.6: FACSIMILE CODING
+// SCHEMES AND CODING CONTROL FUNCTIONS FOR GROUP 4 FACSIMILE APPARATUS"
+// specification:
+//
+// https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.6-198811-I!!PDF-E&type=items
+
+// modeDecodeTable represents Table 1 and the End-of-Line code.
+//
+// +=XXXXX
+// b009 +-+
+// | +=v0009
+// b007 +-+
+// | | +=v0008
+// b010 | +-+
+// | +=v0005
+// b006 +-+
+// | | +=v0007
+// b008 | +-+
+// | +=v0004
+// b005 +-+
+// | +=v0000
+// b003 +-+
+// | +=v0001
+// b002 +-+
+// | | +=v0006
+// b004 | +-+
+// | +=v0003
+// b001 +-+
+// +=v0002
+var modeDecodeTable = [...][2]int16{
+ 0: {0, 0},
+ 1: {2, ^2},
+ 2: {3, 4},
+ 3: {5, ^1},
+ 4: {^6, ^3},
+ 5: {6, ^0},
+ 6: {7, 8},
+ 7: {9, 10},
+ 8: {^7, ^4},
+ 9: {0, ^9},
+ 10: {^8, ^5},
+}
+
+// whiteDecodeTable represents Tables 2 and 3 for a white run.
+//
+// +=XXXXX
+// b059 +-+
+// | | +=v1792
+// b096 | | +-+
+// | | | | +=v1984
+// b100 | | | +-+
+// | | | +=v2048
+// b094 | | +-+
+// | | | | +=v2112
+// b101 | | | | +-+
+// | | | | | +=v2176
+// b097 | | | +-+
+// | | | | +=v2240
+// b102 | | | +-+
+// | | | +=v2304
+// b085 | +-+
+// | | +=v1856
+// b098 | | +-+
+// | | | +=v1920
+// b095 | +-+
+// | | +=v2368
+// b103 | | +-+
+// | | | +=v2432
+// b099 | +-+
+// | | +=v2496
+// b104 | +-+
+// | +=v2560
+// b040 +-+
+// | | +=v0029
+// b060 | +-+
+// | +=v0030
+// b026 +-+
+// | | +=v0045
+// b061 | | +-+
+// | | | +=v0046
+// b041 | +-+
+// | +=v0022
+// b016 +-+
+// | | +=v0023
+// b042 | | +-+
+// | | | | +=v0047
+// b062 | | | +-+
+// | | | +=v0048
+// b027 | +-+
+// | +=v0013
+// b008 +-+
+// | | +=v0020
+// b043 | | +-+
+// | | | | +=v0033
+// b063 | | | +-+
+// | | | +=v0034
+// b028 | | +-+
+// | | | | +=v0035
+// b064 | | | | +-+
+// | | | | | +=v0036
+// b044 | | | +-+
+// | | | | +=v0037
+// b065 | | | +-+
+// | | | +=v0038
+// b017 | +-+
+// | | +=v0019
+// b045 | | +-+
+// | | | | +=v0031
+// b066 | | | +-+
+// | | | +=v0032
+// b029 | +-+
+// | +=v0001
+// b004 +-+
+// | | +=v0012
+// b030 | | +-+
+// | | | | +=v0053
+// b067 | | | | +-+
+// | | | | | +=v0054
+// b046 | | | +-+
+// | | | +=v0026
+// b018 | | +-+
+// | | | | +=v0039
+// b068 | | | | +-+
+// | | | | | +=v0040
+// b047 | | | | +-+
+// | | | | | | +=v0041
+// b069 | | | | | +-+
+// | | | | | +=v0042
+// b031 | | | +-+
+// | | | | +=v0043
+// b070 | | | | +-+
+// | | | | | +=v0044
+// b048 | | | +-+
+// | | | +=v0021
+// b009 | +-+
+// | | +=v0028
+// b049 | | +-+
+// | | | | +=v0061
+// b071 | | | +-+
+// | | | +=v0062
+// b032 | | +-+
+// | | | | +=v0063
+// b072 | | | | +-+
+// | | | | | +=v0000
+// b050 | | | +-+
+// | | | | +=v0320
+// b073 | | | +-+
+// | | | +=v0384
+// b019 | +-+
+// | +=v0010
+// b002 +-+
+// | | +=v0011
+// b020 | | +-+
+// | | | | +=v0027
+// b051 | | | | +-+
+// | | | | | | +=v0059
+// b074 | | | | | +-+
+// | | | | | +=v0060
+// b033 | | | +-+
+// | | | | +=v1472
+// b086 | | | | +-+
+// | | | | | +=v1536
+// b075 | | | | +-+
+// | | | | | | +=v1600
+// b087 | | | | | +-+
+// | | | | | +=v1728
+// b052 | | | +-+
+// | | | +=v0018
+// b010 | | +-+
+// | | | | +=v0024
+// b053 | | | | +-+
+// | | | | | | +=v0049
+// b076 | | | | | +-+
+// | | | | | +=v0050
+// b034 | | | | +-+
+// | | | | | | +=v0051
+// b077 | | | | | | +-+
+// | | | | | | | +=v0052
+// b054 | | | | | +-+
+// | | | | | +=v0025
+// b021 | | | +-+
+// | | | | +=v0055
+// b078 | | | | +-+
+// | | | | | +=v0056
+// b055 | | | | +-+
+// | | | | | | +=v0057
+// b079 | | | | | +-+
+// | | | | | +=v0058
+// b035 | | | +-+
+// | | | +=v0192
+// b005 | +-+
+// | | +=v1664
+// b036 | | +-+
+// | | | | +=v0448
+// b080 | | | | +-+
+// | | | | | +=v0512
+// b056 | | | +-+
+// | | | | +=v0704
+// b088 | | | | +-+
+// | | | | | +=v0768
+// b081 | | | +-+
+// | | | +=v0640
+// b022 | | +-+
+// | | | | +=v0576
+// b082 | | | | +-+
+// | | | | | | +=v0832
+// b089 | | | | | +-+
+// | | | | | +=v0896
+// b057 | | | | +-+
+// | | | | | | +=v0960
+// b090 | | | | | | +-+
+// | | | | | | | +=v1024
+// b083 | | | | | +-+
+// | | | | | | +=v1088
+// b091 | | | | | +-+
+// | | | | | +=v1152
+// b037 | | | +-+
+// | | | | +=v1216
+// b092 | | | | +-+
+// | | | | | +=v1280
+// b084 | | | | +-+
+// | | | | | | +=v1344
+// b093 | | | | | +-+
+// | | | | | +=v1408
+// b058 | | | +-+
+// | | | +=v0256
+// b011 | +-+
+// | +=v0002
+// b001 +-+
+// | +=v0003
+// b012 | +-+
+// | | | +=v0128
+// b023 | | +-+
+// | | +=v0008
+// b006 | +-+
+// | | | +=v0009
+// b024 | | | +-+
+// | | | | | +=v0016
+// b038 | | | | +-+
+// | | | | +=v0017
+// b013 | | +-+
+// | | +=v0004
+// b003 +-+
+// | +=v0005
+// b014 | +-+
+// | | | +=v0014
+// b039 | | | +-+
+// | | | | +=v0015
+// b025 | | +-+
+// | | +=v0064
+// b007 +-+
+// | +=v0006
+// b015 +-+
+// +=v0007
+var whiteDecodeTable = [...][2]int16{
+ 0: {0, 0},
+ 1: {2, 3},
+ 2: {4, 5},
+ 3: {6, 7},
+ 4: {8, 9},
+ 5: {10, 11},
+ 6: {12, 13},
+ 7: {14, 15},
+ 8: {16, 17},
+ 9: {18, 19},
+ 10: {20, 21},
+ 11: {22, ^2},
+ 12: {^3, 23},
+ 13: {24, ^4},
+ 14: {^5, 25},
+ 15: {^6, ^7},
+ 16: {26, 27},
+ 17: {28, 29},
+ 18: {30, 31},
+ 19: {32, ^10},
+ 20: {^11, 33},
+ 21: {34, 35},
+ 22: {36, 37},
+ 23: {^128, ^8},
+ 24: {^9, 38},
+ 25: {39, ^64},
+ 26: {40, 41},
+ 27: {42, ^13},
+ 28: {43, 44},
+ 29: {45, ^1},
+ 30: {^12, 46},
+ 31: {47, 48},
+ 32: {49, 50},
+ 33: {51, 52},
+ 34: {53, 54},
+ 35: {55, ^192},
+ 36: {^1664, 56},
+ 37: {57, 58},
+ 38: {^16, ^17},
+ 39: {^14, ^15},
+ 40: {59, 60},
+ 41: {61, ^22},
+ 42: {^23, 62},
+ 43: {^20, 63},
+ 44: {64, 65},
+ 45: {^19, 66},
+ 46: {67, ^26},
+ 47: {68, 69},
+ 48: {70, ^21},
+ 49: {^28, 71},
+ 50: {72, 73},
+ 51: {^27, 74},
+ 52: {75, ^18},
+ 53: {^24, 76},
+ 54: {77, ^25},
+ 55: {78, 79},
+ 56: {80, 81},
+ 57: {82, 83},
+ 58: {84, ^256},
+ 59: {0, 85},
+ 60: {^29, ^30},
+ 61: {^45, ^46},
+ 62: {^47, ^48},
+ 63: {^33, ^34},
+ 64: {^35, ^36},
+ 65: {^37, ^38},
+ 66: {^31, ^32},
+ 67: {^53, ^54},
+ 68: {^39, ^40},
+ 69: {^41, ^42},
+ 70: {^43, ^44},
+ 71: {^61, ^62},
+ 72: {^63, ^0},
+ 73: {^320, ^384},
+ 74: {^59, ^60},
+ 75: {86, 87},
+ 76: {^49, ^50},
+ 77: {^51, ^52},
+ 78: {^55, ^56},
+ 79: {^57, ^58},
+ 80: {^448, ^512},
+ 81: {88, ^640},
+ 82: {^576, 89},
+ 83: {90, 91},
+ 84: {92, 93},
+ 85: {94, 95},
+ 86: {^1472, ^1536},
+ 87: {^1600, ^1728},
+ 88: {^704, ^768},
+ 89: {^832, ^896},
+ 90: {^960, ^1024},
+ 91: {^1088, ^1152},
+ 92: {^1216, ^1280},
+ 93: {^1344, ^1408},
+ 94: {96, 97},
+ 95: {98, 99},
+ 96: {^1792, 100},
+ 97: {101, 102},
+ 98: {^1856, ^1920},
+ 99: {103, 104},
+ 100: {^1984, ^2048},
+ 101: {^2112, ^2176},
+ 102: {^2240, ^2304},
+ 103: {^2368, ^2432},
+ 104: {^2496, ^2560},
+}
+
+// blackDecodeTable represents Tables 2 and 3 for a black run.
+//
+// +=XXXXX
+// b017 +-+
+// | | +=v1792
+// b042 | | +-+
+// | | | | +=v1984
+// b063 | | | +-+
+// | | | +=v2048
+// b029 | | +-+
+// | | | | +=v2112
+// b064 | | | | +-+
+// | | | | | +=v2176
+// b043 | | | +-+
+// | | | | +=v2240
+// b065 | | | +-+
+// | | | +=v2304
+// b022 | +-+
+// | | +=v1856
+// b044 | | +-+
+// | | | +=v1920
+// b030 | +-+
+// | | +=v2368
+// b066 | | +-+
+// | | | +=v2432
+// b045 | +-+
+// | | +=v2496
+// b067 | +-+
+// | +=v2560
+// b013 +-+
+// | | +=v0018
+// b031 | | +-+
+// | | | | +=v0052
+// b068 | | | | +-+
+// | | | | | | +=v0640
+// b095 | | | | | +-+
+// | | | | | +=v0704
+// b046 | | | +-+
+// | | | | +=v0768
+// b096 | | | | +-+
+// | | | | | +=v0832
+// b069 | | | +-+
+// | | | +=v0055
+// b023 | | +-+
+// | | | | +=v0056
+// b070 | | | | +-+
+// | | | | | | +=v1280
+// b097 | | | | | +-+
+// | | | | | +=v1344
+// b047 | | | | +-+
+// | | | | | | +=v1408
+// b098 | | | | | | +-+
+// | | | | | | | +=v1472
+// b071 | | | | | +-+
+// | | | | | +=v0059
+// b032 | | | +-+
+// | | | | +=v0060
+// b072 | | | | +-+
+// | | | | | | +=v1536
+// b099 | | | | | +-+
+// | | | | | +=v1600
+// b048 | | | +-+
+// | | | +=v0024
+// b018 | +-+
+// | | +=v0025
+// b049 | | +-+
+// | | | | +=v1664
+// b100 | | | | +-+
+// | | | | | +=v1728
+// b073 | | | +-+
+// | | | +=v0320
+// b033 | | +-+
+// | | | | +=v0384
+// b074 | | | | +-+
+// | | | | | +=v0448
+// b050 | | | +-+
+// | | | | +=v0512
+// b101 | | | | +-+
+// | | | | | +=v0576
+// b075 | | | +-+
+// | | | +=v0053
+// b024 | +-+
+// | | +=v0054
+// b076 | | +-+
+// | | | | +=v0896
+// b102 | | | +-+
+// | | | +=v0960
+// b051 | | +-+
+// | | | | +=v1024
+// b103 | | | | +-+
+// | | | | | +=v1088
+// b077 | | | +-+
+// | | | | +=v1152
+// b104 | | | +-+
+// | | | +=v1216
+// b034 | +-+
+// | +=v0064
+// b010 +-+
+// | | +=v0013
+// b019 | | +-+
+// | | | | +=v0023
+// b052 | | | | +-+
+// | | | | | | +=v0050
+// b078 | | | | | +-+
+// | | | | | +=v0051
+// b035 | | | | +-+
+// | | | | | | +=v0044
+// b079 | | | | | | +-+
+// | | | | | | | +=v0045
+// b053 | | | | | +-+
+// | | | | | | +=v0046
+// b080 | | | | | +-+
+// | | | | | +=v0047
+// b025 | | | +-+
+// | | | | +=v0057
+// b081 | | | | +-+
+// | | | | | +=v0058
+// b054 | | | | +-+
+// | | | | | | +=v0061
+// b082 | | | | | +-+
+// | | | | | +=v0256
+// b036 | | | +-+
+// | | | +=v0016
+// b014 | +-+
+// | | +=v0017
+// b037 | | +-+
+// | | | | +=v0048
+// b083 | | | | +-+
+// | | | | | +=v0049
+// b055 | | | +-+
+// | | | | +=v0062
+// b084 | | | +-+
+// | | | +=v0063
+// b026 | | +-+
+// | | | | +=v0030
+// b085 | | | | +-+
+// | | | | | +=v0031
+// b056 | | | | +-+
+// | | | | | | +=v0032
+// b086 | | | | | +-+
+// | | | | | +=v0033
+// b038 | | | +-+
+// | | | | +=v0040
+// b087 | | | | +-+
+// | | | | | +=v0041
+// b057 | | | +-+
+// | | | +=v0022
+// b020 | +-+
+// | +=v0014
+// b008 +-+
+// | | +=v0010
+// b015 | | +-+
+// | | | +=v0011
+// b011 | +-+
+// | | +=v0015
+// b027 | | +-+
+// | | | | +=v0128
+// b088 | | | | +-+
+// | | | | | +=v0192
+// b058 | | | | +-+
+// | | | | | | +=v0026
+// b089 | | | | | +-+
+// | | | | | +=v0027
+// b039 | | | +-+
+// | | | | +=v0028
+// b090 | | | | +-+
+// | | | | | +=v0029
+// b059 | | | +-+
+// | | | +=v0019
+// b021 | | +-+
+// | | | | +=v0020
+// b060 | | | | +-+
+// | | | | | | +=v0034
+// b091 | | | | | +-+
+// | | | | | +=v0035
+// b040 | | | | +-+
+// | | | | | | +=v0036
+// b092 | | | | | | +-+
+// | | | | | | | +=v0037
+// b061 | | | | | +-+
+// | | | | | | +=v0038
+// b093 | | | | | +-+
+// | | | | | +=v0039
+// b028 | | | +-+
+// | | | | +=v0021
+// b062 | | | | +-+
+// | | | | | | +=v0042
+// b094 | | | | | +-+
+// | | | | | +=v0043
+// b041 | | | +-+
+// | | | +=v0000
+// b016 | +-+
+// | +=v0012
+// b006 +-+
+// | | +=v0009
+// b012 | | +-+
+// | | | +=v0008
+// b009 | +-+
+// | +=v0007
+// b004 +-+
+// | | +=v0006
+// b007 | +-+
+// | +=v0005
+// b002 +-+
+// | | +=v0001
+// b005 | +-+
+// | +=v0004
+// b001 +-+
+// | +=v0003
+// b003 +-+
+// +=v0002
+var blackDecodeTable = [...][2]int16{
+ 0: {0, 0},
+ 1: {2, 3},
+ 2: {4, 5},
+ 3: {^3, ^2},
+ 4: {6, 7},
+ 5: {^1, ^4},
+ 6: {8, 9},
+ 7: {^6, ^5},
+ 8: {10, 11},
+ 9: {12, ^7},
+ 10: {13, 14},
+ 11: {15, 16},
+ 12: {^9, ^8},
+ 13: {17, 18},
+ 14: {19, 20},
+ 15: {^10, ^11},
+ 16: {21, ^12},
+ 17: {0, 22},
+ 18: {23, 24},
+ 19: {^13, 25},
+ 20: {26, ^14},
+ 21: {27, 28},
+ 22: {29, 30},
+ 23: {31, 32},
+ 24: {33, 34},
+ 25: {35, 36},
+ 26: {37, 38},
+ 27: {^15, 39},
+ 28: {40, 41},
+ 29: {42, 43},
+ 30: {44, 45},
+ 31: {^18, 46},
+ 32: {47, 48},
+ 33: {49, 50},
+ 34: {51, ^64},
+ 35: {52, 53},
+ 36: {54, ^16},
+ 37: {^17, 55},
+ 38: {56, 57},
+ 39: {58, 59},
+ 40: {60, 61},
+ 41: {62, ^0},
+ 42: {^1792, 63},
+ 43: {64, 65},
+ 44: {^1856, ^1920},
+ 45: {66, 67},
+ 46: {68, 69},
+ 47: {70, 71},
+ 48: {72, ^24},
+ 49: {^25, 73},
+ 50: {74, 75},
+ 51: {76, 77},
+ 52: {^23, 78},
+ 53: {79, 80},
+ 54: {81, 82},
+ 55: {83, 84},
+ 56: {85, 86},
+ 57: {87, ^22},
+ 58: {88, 89},
+ 59: {90, ^19},
+ 60: {^20, 91},
+ 61: {92, 93},
+ 62: {^21, 94},
+ 63: {^1984, ^2048},
+ 64: {^2112, ^2176},
+ 65: {^2240, ^2304},
+ 66: {^2368, ^2432},
+ 67: {^2496, ^2560},
+ 68: {^52, 95},
+ 69: {96, ^55},
+ 70: {^56, 97},
+ 71: {98, ^59},
+ 72: {^60, 99},
+ 73: {100, ^320},
+ 74: {^384, ^448},
+ 75: {101, ^53},
+ 76: {^54, 102},
+ 77: {103, 104},
+ 78: {^50, ^51},
+ 79: {^44, ^45},
+ 80: {^46, ^47},
+ 81: {^57, ^58},
+ 82: {^61, ^256},
+ 83: {^48, ^49},
+ 84: {^62, ^63},
+ 85: {^30, ^31},
+ 86: {^32, ^33},
+ 87: {^40, ^41},
+ 88: {^128, ^192},
+ 89: {^26, ^27},
+ 90: {^28, ^29},
+ 91: {^34, ^35},
+ 92: {^36, ^37},
+ 93: {^38, ^39},
+ 94: {^42, ^43},
+ 95: {^640, ^704},
+ 96: {^768, ^832},
+ 97: {^1280, ^1344},
+ 98: {^1408, ^1472},
+ 99: {^1536, ^1600},
+ 100: {^1664, ^1728},
+ 101: {^512, ^576},
+ 102: {^896, ^960},
+ 103: {^1024, ^1088},
+ 104: {^1152, ^1216},
+}
+
+const maxCodeLength = 13
+
+// Each encodeTable is represented by an array of bitStrings.
+
+// bitString is a pair of uint32 values representing a bit code.
+// The nBits low bits of bits make up the actual bit code.
+// Eg. bitString{0x0004, 8} represents the bitcode "00000100".
+type bitString struct {
+ bits uint32
+ nBits uint32
+}
+
+// modeEncodeTable represents Table 1 and the End-of-Line code.
+var modeEncodeTable = [...]bitString{
+ 0: {0x0001, 4}, // "0001"
+ 1: {0x0001, 3}, // "001"
+ 2: {0x0001, 1}, // "1"
+ 3: {0x0003, 3}, // "011"
+ 4: {0x0003, 6}, // "000011"
+ 5: {0x0003, 7}, // "0000011"
+ 6: {0x0002, 3}, // "010"
+ 7: {0x0002, 6}, // "000010"
+ 8: {0x0002, 7}, // "0000010"
+ 9: {0x0001, 7}, // "0000001"
+}
+
+// whiteEncodeTable2 represents Table 2 for a white run.
+var whiteEncodeTable2 = [...]bitString{
+ 0: {0x0035, 8}, // "00110101"
+ 1: {0x0007, 6}, // "000111"
+ 2: {0x0007, 4}, // "0111"
+ 3: {0x0008, 4}, // "1000"
+ 4: {0x000b, 4}, // "1011"
+ 5: {0x000c, 4}, // "1100"
+ 6: {0x000e, 4}, // "1110"
+ 7: {0x000f, 4}, // "1111"
+ 8: {0x0013, 5}, // "10011"
+ 9: {0x0014, 5}, // "10100"
+ 10: {0x0007, 5}, // "00111"
+ 11: {0x0008, 5}, // "01000"
+ 12: {0x0008, 6}, // "001000"
+ 13: {0x0003, 6}, // "000011"
+ 14: {0x0034, 6}, // "110100"
+ 15: {0x0035, 6}, // "110101"
+ 16: {0x002a, 6}, // "101010"
+ 17: {0x002b, 6}, // "101011"
+ 18: {0x0027, 7}, // "0100111"
+ 19: {0x000c, 7}, // "0001100"
+ 20: {0x0008, 7}, // "0001000"
+ 21: {0x0017, 7}, // "0010111"
+ 22: {0x0003, 7}, // "0000011"
+ 23: {0x0004, 7}, // "0000100"
+ 24: {0x0028, 7}, // "0101000"
+ 25: {0x002b, 7}, // "0101011"
+ 26: {0x0013, 7}, // "0010011"
+ 27: {0x0024, 7}, // "0100100"
+ 28: {0x0018, 7}, // "0011000"
+ 29: {0x0002, 8}, // "00000010"
+ 30: {0x0003, 8}, // "00000011"
+ 31: {0x001a, 8}, // "00011010"
+ 32: {0x001b, 8}, // "00011011"
+ 33: {0x0012, 8}, // "00010010"
+ 34: {0x0013, 8}, // "00010011"
+ 35: {0x0014, 8}, // "00010100"
+ 36: {0x0015, 8}, // "00010101"
+ 37: {0x0016, 8}, // "00010110"
+ 38: {0x0017, 8}, // "00010111"
+ 39: {0x0028, 8}, // "00101000"
+ 40: {0x0029, 8}, // "00101001"
+ 41: {0x002a, 8}, // "00101010"
+ 42: {0x002b, 8}, // "00101011"
+ 43: {0x002c, 8}, // "00101100"
+ 44: {0x002d, 8}, // "00101101"
+ 45: {0x0004, 8}, // "00000100"
+ 46: {0x0005, 8}, // "00000101"
+ 47: {0x000a, 8}, // "00001010"
+ 48: {0x000b, 8}, // "00001011"
+ 49: {0x0052, 8}, // "01010010"
+ 50: {0x0053, 8}, // "01010011"
+ 51: {0x0054, 8}, // "01010100"
+ 52: {0x0055, 8}, // "01010101"
+ 53: {0x0024, 8}, // "00100100"
+ 54: {0x0025, 8}, // "00100101"
+ 55: {0x0058, 8}, // "01011000"
+ 56: {0x0059, 8}, // "01011001"
+ 57: {0x005a, 8}, // "01011010"
+ 58: {0x005b, 8}, // "01011011"
+ 59: {0x004a, 8}, // "01001010"
+ 60: {0x004b, 8}, // "01001011"
+ 61: {0x0032, 8}, // "00110010"
+ 62: {0x0033, 8}, // "00110011"
+ 63: {0x0034, 8}, // "00110100"
+}
+
+// whiteEncodeTable3 represents Table 3 for a white run.
+var whiteEncodeTable3 = [...]bitString{
+ 0: {0x001b, 5}, // "11011"
+ 1: {0x0012, 5}, // "10010"
+ 2: {0x0017, 6}, // "010111"
+ 3: {0x0037, 7}, // "0110111"
+ 4: {0x0036, 8}, // "00110110"
+ 5: {0x0037, 8}, // "00110111"
+ 6: {0x0064, 8}, // "01100100"
+ 7: {0x0065, 8}, // "01100101"
+ 8: {0x0068, 8}, // "01101000"
+ 9: {0x0067, 8}, // "01100111"
+ 10: {0x00cc, 9}, // "011001100"
+ 11: {0x00cd, 9}, // "011001101"
+ 12: {0x00d2, 9}, // "011010010"
+ 13: {0x00d3, 9}, // "011010011"
+ 14: {0x00d4, 9}, // "011010100"
+ 15: {0x00d5, 9}, // "011010101"
+ 16: {0x00d6, 9}, // "011010110"
+ 17: {0x00d7, 9}, // "011010111"
+ 18: {0x00d8, 9}, // "011011000"
+ 19: {0x00d9, 9}, // "011011001"
+ 20: {0x00da, 9}, // "011011010"
+ 21: {0x00db, 9}, // "011011011"
+ 22: {0x0098, 9}, // "010011000"
+ 23: {0x0099, 9}, // "010011001"
+ 24: {0x009a, 9}, // "010011010"
+ 25: {0x0018, 6}, // "011000"
+ 26: {0x009b, 9}, // "010011011"
+ 27: {0x0008, 11}, // "00000001000"
+ 28: {0x000c, 11}, // "00000001100"
+ 29: {0x000d, 11}, // "00000001101"
+ 30: {0x0012, 12}, // "000000010010"
+ 31: {0x0013, 12}, // "000000010011"
+ 32: {0x0014, 12}, // "000000010100"
+ 33: {0x0015, 12}, // "000000010101"
+ 34: {0x0016, 12}, // "000000010110"
+ 35: {0x0017, 12}, // "000000010111"
+ 36: {0x001c, 12}, // "000000011100"
+ 37: {0x001d, 12}, // "000000011101"
+ 38: {0x001e, 12}, // "000000011110"
+ 39: {0x001f, 12}, // "000000011111"
+}
+
+// blackEncodeTable2 represents Table 2 for a black run.
+var blackEncodeTable2 = [...]bitString{
+ 0: {0x0037, 10}, // "0000110111"
+ 1: {0x0002, 3}, // "010"
+ 2: {0x0003, 2}, // "11"
+ 3: {0x0002, 2}, // "10"
+ 4: {0x0003, 3}, // "011"
+ 5: {0x0003, 4}, // "0011"
+ 6: {0x0002, 4}, // "0010"
+ 7: {0x0003, 5}, // "00011"
+ 8: {0x0005, 6}, // "000101"
+ 9: {0x0004, 6}, // "000100"
+ 10: {0x0004, 7}, // "0000100"
+ 11: {0x0005, 7}, // "0000101"
+ 12: {0x0007, 7}, // "0000111"
+ 13: {0x0004, 8}, // "00000100"
+ 14: {0x0007, 8}, // "00000111"
+ 15: {0x0018, 9}, // "000011000"
+ 16: {0x0017, 10}, // "0000010111"
+ 17: {0x0018, 10}, // "0000011000"
+ 18: {0x0008, 10}, // "0000001000"
+ 19: {0x0067, 11}, // "00001100111"
+ 20: {0x0068, 11}, // "00001101000"
+ 21: {0x006c, 11}, // "00001101100"
+ 22: {0x0037, 11}, // "00000110111"
+ 23: {0x0028, 11}, // "00000101000"
+ 24: {0x0017, 11}, // "00000010111"
+ 25: {0x0018, 11}, // "00000011000"
+ 26: {0x00ca, 12}, // "000011001010"
+ 27: {0x00cb, 12}, // "000011001011"
+ 28: {0x00cc, 12}, // "000011001100"
+ 29: {0x00cd, 12}, // "000011001101"
+ 30: {0x0068, 12}, // "000001101000"
+ 31: {0x0069, 12}, // "000001101001"
+ 32: {0x006a, 12}, // "000001101010"
+ 33: {0x006b, 12}, // "000001101011"
+ 34: {0x00d2, 12}, // "000011010010"
+ 35: {0x00d3, 12}, // "000011010011"
+ 36: {0x00d4, 12}, // "000011010100"
+ 37: {0x00d5, 12}, // "000011010101"
+ 38: {0x00d6, 12}, // "000011010110"
+ 39: {0x00d7, 12}, // "000011010111"
+ 40: {0x006c, 12}, // "000001101100"
+ 41: {0x006d, 12}, // "000001101101"
+ 42: {0x00da, 12}, // "000011011010"
+ 43: {0x00db, 12}, // "000011011011"
+ 44: {0x0054, 12}, // "000001010100"
+ 45: {0x0055, 12}, // "000001010101"
+ 46: {0x0056, 12}, // "000001010110"
+ 47: {0x0057, 12}, // "000001010111"
+ 48: {0x0064, 12}, // "000001100100"
+ 49: {0x0065, 12}, // "000001100101"
+ 50: {0x0052, 12}, // "000001010010"
+ 51: {0x0053, 12}, // "000001010011"
+ 52: {0x0024, 12}, // "000000100100"
+ 53: {0x0037, 12}, // "000000110111"
+ 54: {0x0038, 12}, // "000000111000"
+ 55: {0x0027, 12}, // "000000100111"
+ 56: {0x0028, 12}, // "000000101000"
+ 57: {0x0058, 12}, // "000001011000"
+ 58: {0x0059, 12}, // "000001011001"
+ 59: {0x002b, 12}, // "000000101011"
+ 60: {0x002c, 12}, // "000000101100"
+ 61: {0x005a, 12}, // "000001011010"
+ 62: {0x0066, 12}, // "000001100110"
+ 63: {0x0067, 12}, // "000001100111"
+}
+
+// blackEncodeTable3 represents Table 3 for a black run.
+var blackEncodeTable3 = [...]bitString{
+ 0: {0x000f, 10}, // "0000001111"
+ 1: {0x00c8, 12}, // "000011001000"
+ 2: {0x00c9, 12}, // "000011001001"
+ 3: {0x005b, 12}, // "000001011011"
+ 4: {0x0033, 12}, // "000000110011"
+ 5: {0x0034, 12}, // "000000110100"
+ 6: {0x0035, 12}, // "000000110101"
+ 7: {0x006c, 13}, // "0000001101100"
+ 8: {0x006d, 13}, // "0000001101101"
+ 9: {0x004a, 13}, // "0000001001010"
+ 10: {0x004b, 13}, // "0000001001011"
+ 11: {0x004c, 13}, // "0000001001100"
+ 12: {0x004d, 13}, // "0000001001101"
+ 13: {0x0072, 13}, // "0000001110010"
+ 14: {0x0073, 13}, // "0000001110011"
+ 15: {0x0074, 13}, // "0000001110100"
+ 16: {0x0075, 13}, // "0000001110101"
+ 17: {0x0076, 13}, // "0000001110110"
+ 18: {0x0077, 13}, // "0000001110111"
+ 19: {0x0052, 13}, // "0000001010010"
+ 20: {0x0053, 13}, // "0000001010011"
+ 21: {0x0054, 13}, // "0000001010100"
+ 22: {0x0055, 13}, // "0000001010101"
+ 23: {0x005a, 13}, // "0000001011010"
+ 24: {0x005b, 13}, // "0000001011011"
+ 25: {0x0064, 13}, // "0000001100100"
+ 26: {0x0065, 13}, // "0000001100101"
+ 27: {0x0008, 11}, // "00000001000"
+ 28: {0x000c, 11}, // "00000001100"
+ 29: {0x000d, 11}, // "00000001101"
+ 30: {0x0012, 12}, // "000000010010"
+ 31: {0x0013, 12}, // "000000010011"
+ 32: {0x0014, 12}, // "000000010100"
+ 33: {0x0015, 12}, // "000000010101"
+ 34: {0x0016, 12}, // "000000010110"
+ 35: {0x0017, 12}, // "000000010111"
+ 36: {0x001c, 12}, // "000000011100"
+ 37: {0x001d, 12}, // "000000011101"
+ 38: {0x001e, 12}, // "000000011110"
+ 39: {0x001f, 12}, // "000000011111"
+}
+
+// COPY PASTE table.go BEGIN
+
+const (
+ modePass = iota // Pass
+ modeH // Horizontal
+ modeV0 // Vertical-0
+ modeVR1 // Vertical-Right-1
+ modeVR2 // Vertical-Right-2
+ modeVR3 // Vertical-Right-3
+ modeVL1 // Vertical-Left-1
+ modeVL2 // Vertical-Left-2
+ modeVL3 // Vertical-Left-3
+ modeExt // Extension
+)
+
+// COPY PASTE table.go END
diff --git a/vendor/golang.org/x/image/ccitt/writer.go b/vendor/golang.org/x/image/ccitt/writer.go
new file mode 100644
index 00000000..87130ab0
--- /dev/null
+++ b/vendor/golang.org/x/image/ccitt/writer.go
@@ -0,0 +1,102 @@
+// Copyright 2019 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 ccitt
+
+import (
+ "encoding/binary"
+ "io"
+)
+
+type bitWriter struct {
+ w io.Writer
+
+ // order is whether to process w's bytes LSB first or MSB first.
+ order Order
+
+ // The high nBits bits of the bits field hold encoded bits to be written to w.
+ bits uint64
+ nBits uint32
+
+ // bytes[:bw] holds encoded bytes not yet written to w.
+ // Overflow protection is ensured by using a multiple of 8 as bytes length.
+ bw uint32
+ bytes [1024]uint8
+}
+
+// flushBits copies 64 bits from b.bits to b.bytes. If b.bytes is then full, it
+// is written to b.w.
+func (b *bitWriter) flushBits() error {
+ binary.BigEndian.PutUint64(b.bytes[b.bw:], b.bits)
+ b.bits = 0
+ b.nBits = 0
+ b.bw += 8
+ if b.bw < uint32(len(b.bytes)) {
+ return nil
+ }
+ b.bw = 0
+ if b.order != MSB {
+ reverseBitsWithinBytes(b.bytes[:])
+ }
+ _, err := b.w.Write(b.bytes[:])
+ return err
+}
+
+// close finalizes a bitcode stream by writing any
+// pending bits to bitWriter's underlying io.Writer.
+func (b *bitWriter) close() error {
+ // Write any encoded bits to bytes.
+ if b.nBits > 0 {
+ binary.BigEndian.PutUint64(b.bytes[b.bw:], b.bits)
+ b.bw += (b.nBits + 7) >> 3
+ }
+
+ if b.order != MSB {
+ reverseBitsWithinBytes(b.bytes[:b.bw])
+ }
+
+ // Write b.bw bytes to b.w.
+ _, err := b.w.Write(b.bytes[:b.bw])
+ return err
+}
+
+// alignToByteBoundary rounds b.nBits up to a multiple of 8.
+// If all 64 bits are used, flush them to bitWriter's bytes.
+func (b *bitWriter) alignToByteBoundary() error {
+ if b.nBits = (b.nBits + 7) &^ 7; b.nBits == 64 {
+ return b.flushBits()
+ }
+ return nil
+}
+
+// writeCode writes a variable length bitcode to b's underlying io.Writer.
+func (b *bitWriter) writeCode(bs bitString) error {
+ bits := bs.bits
+ nBits := bs.nBits
+ if 64-b.nBits >= nBits {
+ // b.bits has sufficient room for storing nBits bits.
+ b.bits |= uint64(bits) << (64 - nBits - b.nBits)
+ b.nBits += nBits
+ if b.nBits == 64 {
+ return b.flushBits()
+ }
+ return nil
+ }
+
+ // Number of leading bits that fill b.bits.
+ i := 64 - b.nBits
+
+ // Fill b.bits then flush and write remaining bits.
+ b.bits |= uint64(bits) >> (nBits - i)
+ b.nBits = 64
+
+ if err := b.flushBits(); err != nil {
+ return err
+ }
+
+ nBits -= i
+ b.bits = uint64(bits) << (64 - nBits)
+ b.nBits = nBits
+ return nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 12:51:53 +0000