1 files changed, 459 insertions, 0 deletions
diff --git a/vendor/github.com/skip2/go-qrcode/qrcode.go b/vendor/github.com/skip2/go-qrcode/qrcode.go
new file mode 100644
index 0000000..49f8b4b
--- /dev/null
+++ b/vendor/github.com/skip2/go-qrcode/qrcode.go
@@ -0,0 +1,459 @@
+// go-qrcode
+// Copyright 2014 Tom Harwood
+
+/*
+Package qrcode implements a QR Code encoder.
+
+A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be
+encoded.
+
+A QR Code contains error recovery information to aid reading damaged or
+obscured codes. There are four levels of error recovery: qrcode.{Low, Medium,
+High, Highest}. QR Codes with a higher recovery level are more robust to damage,
+at the cost of being physically larger.
+
+Two functions cover most use cases:
+
+- Create a PNG image:
+
+	var png []byte
+	png, err := qrcode.Encode("https://example.org", qrcode.Medium, 256)
+
+- Create a PNG image and write to a file:
+
+	err := qrcode.WriteFile("https://example.org", qrcode.Medium, 256, "qr.png")
+
+Both examples use the qrcode.Medium error Recovery Level and create a 256x256
+pixel, black on white QR Code.
+
+The maximum capacity of a QR Code varies according to the content encoded and
+the error recovery level. The maximum capacity is 2,953 bytes, 4,296
+alphanumeric characters, 7,089 numeric digits, or a combination of these.
+
+This package implements a subset of QR Code 2005, as defined in ISO/IEC
+18004:2006.
+*/
+package qrcode
+
+import (
+	"bytes"
+	"errors"
+	"image"
+	"image/color"
+	"image/png"
+	"io/ioutil"
+	"log"
+	"os"
+
+	bitset "github.com/skip2/go-qrcode/bitset"
+	reedsolomon "github.com/skip2/go-qrcode/reedsolomon"
+)
+
+// Encode a QR Code and return a raw PNG image.
+//
+// size is both the image width and height in pixels. If size is too small then
+// a larger image is silently returned.
+//
+// To serve over HTTP, remember to send a Content-Type: image/png header.
+func Encode(content string, level RecoveryLevel, size int) ([]byte, error) {
+	var q *QRCode
+
+	q, err := New(content, level)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return q.PNG(size)
+}
+
+// WriteFile encodes, then writes a QR Code to the given filename in PNG format.
+//
+// size is both the width and height in pixels. If size is too small then a
+// larger image is silently written.
+func WriteFile(content string, level RecoveryLevel, size int, filename string) error {
+	var q *QRCode
+
+	q, err := New(content, level)
+
+	if err != nil {
+		return err
+	}
+
+	return q.WriteFile(size, filename)
+}
+
+// A QRCode represents a valid encoded QRCode.
+type QRCode struct {
+	// Original content encoded.
+	Content string
+
+	// QR Code type.
+	Level         RecoveryLevel
+	VersionNumber int
+
+	// User settable drawing options.
+	ForegroundColor color.Color
+	BackgroundColor color.Color
+
+	encoder *dataEncoder
+	version qrCodeVersion
+
+	data   *bitset.Bitset
+	symbol *symbol
+	mask   int
+}
+
+// New constructs a QRCode.
+//
+//	var q *qrcode.QRCode
+//	q, err := qrcode.New("my content", qrcode.Medium)
+//
+// An error occurs if the content is too long.
+func New(content string, level RecoveryLevel) (*QRCode, error) {
+	encoders := []dataEncoderType{dataEncoderType1To9, dataEncoderType10To26,
+		dataEncoderType27To40}
+
+	var encoder *dataEncoder
+	var encoded *bitset.Bitset
+	var chosenVersion *qrCodeVersion
+	var err error
+
+	for _, t := range encoders {
+		encoder = newDataEncoder(t)
+		encoded, err = encoder.encode([]byte(content))
+
+		if err != nil {
+			continue
+		}
+
+		chosenVersion = chooseQRCodeVersion(level, encoder, encoded.Len())
+
+		if chosenVersion != nil {
+			break
+		}
+	}
+
+	if err != nil {
+		return nil, err
+	} else if chosenVersion == nil {
+		return nil, errors.New("content too long to encode")
+	}
+
+	q := &QRCode{
+		Content: content,
+
+		Level:         level,
+		VersionNumber: chosenVersion.version,
+
+		ForegroundColor: color.Black,
+		BackgroundColor: color.White,
+
+		encoder: encoder,
+		data:    encoded,
+		version: *chosenVersion,
+	}
+
+	q.encode(chosenVersion.numTerminatorBitsRequired(encoded.Len()))
+
+	return q, nil
+}
+
+func newWithForcedVersion(content string, version int, level RecoveryLevel) (*QRCode, error) {
+	var encoder *dataEncoder
+
+	switch {
+	case version >= 1 && version <= 9:
+		encoder = newDataEncoder(dataEncoderType1To9)
+	case version >= 10 && version <= 26:
+		encoder = newDataEncoder(dataEncoderType10To26)
+	case version >= 27 && version <= 40:
+		encoder = newDataEncoder(dataEncoderType27To40)
+	default:
+		log.Fatalf("Invalid version %d (expected 1-40 inclusive)", version)
+	}
+
+	var encoded *bitset.Bitset
+	encoded, err := encoder.encode([]byte(content))
+
+	if err != nil {
+		return nil, err
+	}
+
+	chosenVersion := getQRCodeVersion(level, version)
+
+	if chosenVersion == nil {
+		return nil, errors.New("cannot find QR Code version")
+	}
+
+	q := &QRCode{
+		Content: content,
+
+		Level:         level,
+		VersionNumber: chosenVersion.version,
+
+		ForegroundColor: color.Black,
+		BackgroundColor: color.White,
+
+		encoder: encoder,
+		data:    encoded,
+		version: *chosenVersion,
+	}
+
+	q.encode(chosenVersion.numTerminatorBitsRequired(encoded.Len()))
+
+	return q, nil
+}
+
+// Bitmap returns the QR Code as a 2D array of 1-bit pixels.
+//
+// bitmap[y][x] is true if the pixel at (x, y) is set.
+//
+// The bitmap includes the required "quiet zone" around the QR Code to aid
+// decoding.
+func (q *QRCode) Bitmap() [][]bool {
+	return q.symbol.bitmap()
+}
+
+// Image returns the QR Code as an image.Image.
+//
+// size is both the width and height in pixels.
+func (q *QRCode) Image(size int) image.Image {
+	// Minimum pixels (both width and height) required.
+	realSize := q.symbol.size
+
+	// Actual pixels available to draw the symbol. Automatically increase the
+	// image size if it's not large enough.
+	if size < realSize {
+		size = realSize
+	}
+
+	// Size of each module drawn.
+	pixelsPerModule := size / realSize
+
+	// Center the symbol within the image.
+	offset := (size - realSize*pixelsPerModule) / 2
+
+	rect := image.Rectangle{Min: image.Point{0, 0}, Max: image.Point{size, size}}
+	img := image.NewRGBA(rect)
+
+	for i := 0; i < size; i++ {
+		for j := 0; j < size; j++ {
+			img.Set(i, j, q.BackgroundColor)
+		}
+	}
+
+	bitmap := q.symbol.bitmap()
+	for y, row := range bitmap {
+		for x, v := range row {
+			if v {
+				startX := x*pixelsPerModule + offset
+				startY := y*pixelsPerModule + offset
+				for i := startX; i < startX+pixelsPerModule; i++ {
+					for j := startY; j < startY+pixelsPerModule; j++ {
+						img.Set(i, j, q.ForegroundColor)
+					}
+				}
+			}
+		}
+	}
+
+	return img
+}
+
+// PNG returns the QR Code as a PNG image.
+//
+// size is both the image width and height in pixels. If size is too small then
+// a larger image is silently returned.
+func (q *QRCode) PNG(size int) ([]byte, error) {
+	img := q.Image(size)
+
+	var b bytes.Buffer
+	err := png.Encode(&b, img)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return b.Bytes(), nil
+}
+
+// WriteFile writes the QR Code as a PNG image to the specified file.
+//
+// size is both the image width and height in pixels. If size is too small then
+// a larger image is silently written.
+func (q *QRCode) WriteFile(size int, filename string) error {
+	var png []byte
+
+	png, err := q.PNG(size)
+
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(filename, png, os.FileMode(0644))
+}
+
+// encode completes the steps required to encode the QR Code. These include
+// adding the terminator bits and padding, splitting the data into blocks and
+// applying the error correction, and selecting the best data mask.
+func (q *QRCode) encode(numTerminatorBits int) {
+	q.addTerminatorBits(numTerminatorBits)
+	q.addPadding()
+
+	encoded := q.encodeBlocks()
+
+	const numMasks int = 8
+	penalty := 0
+
+	for mask := 0; mask < numMasks; mask++ {
+		var s *symbol
+		var err error
+
+		s, err = buildRegularSymbol(q.version, mask, encoded)
+
+		if err != nil {
+			log.Panic(err.Error())
+		}
+
+		numEmptyModules := s.numEmptyModules()
+		if numEmptyModules != 0 {
+			log.Panicf("bug: numEmptyModules is %d (expected 0) (version=%d)",
+				numEmptyModules, q.VersionNumber)
+		}
+
+		p := s.penaltyScore()
+
+		//log.Printf("mask=%d p=%3d p1=%3d p2=%3d p3=%3d p4=%d\n", mask, p, s.penalty1(), s.penalty2(), s.penalty3(), s.penalty4())
+
+		if q.symbol == nil || p < penalty {
+			q.symbol = s
+			q.mask = mask
+			penalty = p
+		}
+	}
+}
+
+// addTerminatorBits adds final terminator bits to the encoded data.
+//
+// The number of terminator bits required is determined when the QR Code version
+// is chosen (which itself depends on the length of the data encoded). The
+// terminator bits are thus added after the QR Code version
+// is chosen, rather than at the data encoding stage.
+func (q *QRCode) addTerminatorBits(numTerminatorBits int) {
+	q.data.AppendNumBools(numTerminatorBits, false)
+}
+
+// encodeBlocks takes the completed (terminated & padded) encoded data, splits
+// the data into blocks (as specified by the QR Code version), applies error
+// correction to each block, then interleaves the blocks together.
+//
+// The QR Code's final data sequence is returned.
+func (q *QRCode) encodeBlocks() *bitset.Bitset {
+	// Split into blocks.
+	type dataBlock struct {
+		data          *bitset.Bitset
+		ecStartOffset int
+	}
+
+	block := make([]dataBlock, q.version.numBlocks())
+
+	start := 0
+	end := 0
+	blockID := 0
+
+	for _, b := range q.version.block {
+		for j := 0; j < b.numBlocks; j++ {
+			start = end
+			end = start + b.numDataCodewords*8
+
+			// Apply error correction to each block.
+			numErrorCodewords := b.numCodewords - b.numDataCodewords
+			block[blockID].data = reedsolomon.Encode(q.data.Substr(start, end), numErrorCodewords)
+			block[blockID].ecStartOffset = end - start
+
+			blockID++
+		}
+	}
+
+	// Interleave the blocks.
+
+	result := bitset.New()
+
+	// Combine data blocks.
+	working := true
+	for i := 0; working; i += 8 {
+		working = false
+
+		for j, b := range block {
+			if i >= block[j].ecStartOffset {
+				continue
+			}
+
+			result.Append(b.data.Substr(i, i+8))
+
+			working = true
+		}
+	}
+
+	// Combine error correction blocks.
+	working = true
+	for i := 0; working; i += 8 {
+		working = false
+
+		for j, b := range block {
+			offset := i + block[j].ecStartOffset
+			if offset >= block[j].data.Len() {
+				continue
+			}
+
+			result.Append(b.data.Substr(offset, offset+8))
+
+			working = true
+		}
+	}
+
+	// Append remainder bits.
+	result.AppendNumBools(q.version.numRemainderBits, false)
+
+	return result
+}
+
+// max returns the maximum of a and b.
+func max(a int, b int) int {
+	if a > b {
+		return a
+	}
+
+	return b
+}
+
+// addPadding pads the encoded data upto the full length required.
+func (q *QRCode) addPadding() {
+	numDataBits := q.version.numDataBits()
+
+	if q.data.Len() == numDataBits {
+		return
+	}
+
+	// Pad to the nearest codeword boundary.
+	q.data.AppendNumBools(q.version.numBitsToPadToCodeword(q.data.Len()), false)
+
+	// Pad codewords 0b11101100 and 0b00010001.
+	padding := [2]*bitset.Bitset{
+		bitset.New(true, true, true, false, true, true, false, false),
+		bitset.New(false, false, false, true, false, false, false, true),
+	}
+
+	// Insert pad codewords alternately.
+	i := 0
+	for numDataBits-q.data.Len() >= 8 {
+		q.data.Append(padding[i])
+
+		i = 1 - i // Alternate between 0 and 1.
+	}
+
+	if q.data.Len() != numDataBits {
+		log.Panicf("BUG: got len %d, expected %d", q.data.Len(), numDataBits)
+	}
+}