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matrix_util.go
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matrix_util.go
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package encoder
import (
"math/bits"
errors "golang.org/x/xerrors"
"github.com/kaxap/gozxing"
"github.com/kaxap/gozxing/qrcode/decoder"
)
var (
matrixUtil_POSITION_DETECTION_PATTERN = [][]int8{
{1, 1, 1, 1, 1, 1, 1},
{1, 0, 0, 0, 0, 0, 1},
{1, 0, 1, 1, 1, 0, 1},
{1, 0, 1, 1, 1, 0, 1},
{1, 0, 1, 1, 1, 0, 1},
{1, 0, 0, 0, 0, 0, 1},
{1, 1, 1, 1, 1, 1, 1},
}
matrixUtil_POSITION_ADJUSTMENT_PATTERN = [][]int8{
{1, 1, 1, 1, 1},
{1, 0, 0, 0, 1},
{1, 0, 1, 0, 1},
{1, 0, 0, 0, 1},
{1, 1, 1, 1, 1},
}
// From Appendix E. Table 1, JIS0510X:2004 (p 71). The table was double-checked by komatsu.
matrixUtil_POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE = [][]int{
{-1, -1, -1, -1, -1, -1, -1}, // Version 1
{6, 18, -1, -1, -1, -1, -1}, // Version 2
{6, 22, -1, -1, -1, -1, -1}, // Version 3
{6, 26, -1, -1, -1, -1, -1}, // Version 4
{6, 30, -1, -1, -1, -1, -1}, // Version 5
{6, 34, -1, -1, -1, -1, -1}, // Version 6
{6, 22, 38, -1, -1, -1, -1}, // Version 7
{6, 24, 42, -1, -1, -1, -1}, // Version 8
{6, 26, 46, -1, -1, -1, -1}, // Version 9
{6, 28, 50, -1, -1, -1, -1}, // Version 10
{6, 30, 54, -1, -1, -1, -1}, // Version 11
{6, 32, 58, -1, -1, -1, -1}, // Version 12
{6, 34, 62, -1, -1, -1, -1}, // Version 13
{6, 26, 46, 66, -1, -1, -1}, // Version 14
{6, 26, 48, 70, -1, -1, -1}, // Version 15
{6, 26, 50, 74, -1, -1, -1}, // Version 16
{6, 30, 54, 78, -1, -1, -1}, // Version 17
{6, 30, 56, 82, -1, -1, -1}, // Version 18
{6, 30, 58, 86, -1, -1, -1}, // Version 19
{6, 34, 62, 90, -1, -1, -1}, // Version 20
{6, 28, 50, 72, 94, -1, -1}, // Version 21
{6, 26, 50, 74, 98, -1, -1}, // Version 22
{6, 30, 54, 78, 102, -1, -1}, // Version 23
{6, 28, 54, 80, 106, -1, -1}, // Version 24
{6, 32, 58, 84, 110, -1, -1}, // Version 25
{6, 30, 58, 86, 114, -1, -1}, // Version 26
{6, 34, 62, 90, 118, -1, -1}, // Version 27
{6, 26, 50, 74, 98, 122, -1}, // Version 28
{6, 30, 54, 78, 102, 126, -1}, // Version 29
{6, 26, 52, 78, 104, 130, -1}, // Version 30
{6, 30, 56, 82, 108, 134, -1}, // Version 31
{6, 34, 60, 86, 112, 138, -1}, // Version 32
{6, 30, 58, 86, 114, 142, -1}, // Version 33
{6, 34, 62, 90, 118, 146, -1}, // Version 34
{6, 30, 54, 78, 102, 126, 150}, // Version 35
{6, 24, 50, 76, 102, 128, 154}, // Version 36
{6, 28, 54, 80, 106, 132, 158}, // Version 37
{6, 32, 58, 84, 110, 136, 162}, // Version 38
{6, 26, 54, 82, 110, 138, 166}, // Version 39
{6, 30, 58, 86, 114, 142, 170}, // Version 40
}
// Type info cells at the left top corner.
matrixUtil_TYPE_INFO_COORDINATES = [][]int{
{8, 0},
{8, 1},
{8, 2},
{8, 3},
{8, 4},
{8, 5},
{8, 7},
{8, 8},
{7, 8},
{5, 8},
{4, 8},
{3, 8},
{2, 8},
{1, 8},
{0, 8},
}
// From Appendix D in JISX0510:2004 (p. 67)
matrixUtil_VERSION_INFO_POLY = 0x1f25 // 1 1111 0010 0101
// From Appendix C in JISX0510:2004 (p.65).
matrixUtil_TYPE_INFO_POLY = 0x537
matrixUtil_TYPE_INFO_MASK_PATTERN = 0x5412
)
// MatrixUtil_clearMatrix Set all cells to -1.
// -1 means that the cell is empty (not set yet).
func clearMatrix(matrix *ByteMatrix) {
matrix.Clear(-1)
}
// MatrixUtil_buildMatrix Build 2D matrix of QR Code from
// "dataBits" with "ecLevel", "version" and "getMaskPattern".
// On success, store the result in "matrix" and return true.
func MatrixUtil_buildMatrix(
dataBits *gozxing.BitArray,
ecLevel decoder.ErrorCorrectionLevel,
version *decoder.Version,
maskPattern int,
matrix *ByteMatrix) error {
clearMatrix(matrix)
e := embedBasicPatterns(version, matrix)
if e == nil {
// Type information appear with any version.
e = embedTypeInfo(ecLevel, maskPattern, matrix)
}
if e == nil {
// Version info appear if version >= 7.
e = maybeEmbedVersionInfo(version, matrix)
}
if e == nil {
// Data should be embedded at end.
e = embedDataBits(dataBits, maskPattern, matrix)
}
return e
}
// embedBasicPatterns Embed basic patterns. On success, modify the matrix and return true.
// The basic patterns are:
// - Position detection patterns
// - Timing patterns
// - Dark dot at the left bottom corner
// - Position adjustment patterns, if need be
func embedBasicPatterns(version *decoder.Version, matrix *ByteMatrix) gozxing.WriterException {
// Let's get started with embedding big squares at corners.
e := embedPositionDetectionPatternsAndSeparators(matrix)
if e != nil {
return e
}
// Then, embed the dark dot at the left bottom corner.
e = embedDarkDotAtLeftBottomCorner(matrix)
if e != nil {
return e
}
// Position adjustment patterns appear if version >= 2.
maybeEmbedPositionAdjustmentPatterns(version, matrix)
// Timing patterns should be embedded after position adj. patterns.
embedTimingPatterns(matrix)
return nil
}
// embedTypeInfo Embed type information. On success, modify the matrix.
func embedTypeInfo(ecLevel decoder.ErrorCorrectionLevel, maskPattern int, matrix *ByteMatrix) gozxing.WriterException {
typeInfoBits := gozxing.NewEmptyBitArray()
e := makeTypeInfoBits(ecLevel, maskPattern, typeInfoBits)
if e != nil {
return e
}
for i := 0; i < typeInfoBits.GetSize(); i++ {
// Place bits in LSB to MSB order. LSB (least significant bit) is the last value in
// "typeInfoBits".
bit := typeInfoBits.Get(typeInfoBits.GetSize() - 1 - i)
// Type info bits at the left top corner. See 8.9 of JISX0510:2004 (p.46).
coordinates := matrixUtil_TYPE_INFO_COORDINATES[i]
x1 := coordinates[0]
y1 := coordinates[1]
matrix.SetBool(x1, y1, bit)
if i < 8 {
// Right top corner.
x2 := matrix.GetWidth() - i - 1
y2 := 8
matrix.SetBool(x2, y2, bit)
} else {
// Left bottom corner.
x2 := 8
y2 := matrix.GetHeight() - 7 + (i - 8)
matrix.SetBool(x2, y2, bit)
}
}
return nil
}
// maybeEmbedVersionInfo Embed version information if need be.
// On success, modify the matrix and return true.
// See 8.10 of JISX0510:2004 (p.47) for how to embed version information.
func maybeEmbedVersionInfo(version *decoder.Version, matrix *ByteMatrix) gozxing.WriterException {
if version.GetVersionNumber() < 7 { // Version info is necessary if version >= 7.
return nil // Don't need version info.
}
versionInfoBits := gozxing.NewEmptyBitArray()
e := makeVersionInfoBits(version, versionInfoBits)
if e != nil {
return e
}
bitIndex := 6*3 - 1 // It will decrease from 17 to 0.
for i := 0; i < 6; i++ {
for j := 0; j < 3; j++ {
// Place bits in LSB (least significant bit) to MSB order.
bit := versionInfoBits.Get(bitIndex)
bitIndex--
// Left bottom corner.
matrix.SetBool(i, matrix.GetHeight()-11+j, bit)
// Right bottom corner.
matrix.SetBool(matrix.GetHeight()-11+j, i, bit)
}
}
return nil
}
// embedDataBits Embed "dataBits" using "getMaskPattern".
// On success, modify the matrix and return true.
// For debugging purposes, it skips masking process if "getMaskPattern" is -1.
// See 8.7 of JISX0510:2004 (p.38) for how to embed data bits.
func embedDataBits(dataBits *gozxing.BitArray, maskPattern int, matrix *ByteMatrix) gozxing.WriterException {
bitIndex := 0
direction := -1
// Start from the right bottom cell.
x := matrix.GetWidth() - 1
y := matrix.GetHeight() - 1
for x > 0 {
// Skip the vertical timing pattern.
if x == 6 {
x -= 1
}
for y >= 0 && y < matrix.GetHeight() {
for i := 0; i < 2; i++ {
xx := x - i
// Skip the cell if it's not empty.
if !isEmpty(matrix.Get(xx, y)) {
continue
}
var bit bool
if bitIndex < dataBits.GetSize() {
bit = dataBits.Get(bitIndex)
bitIndex++
} else {
// Padding bit. If there is no bit left, we'll fill the left cells with 0, as described
// in 8.4.9 of JISX0510:2004 (p. 24).
bit = false
}
// Skip masking if mask_pattern is -1.
if maskPattern != -1 {
maskBit, e := MaskUtil_getDataMaskBit(maskPattern, xx, y)
if e != nil {
return gozxing.WrapWriterException(e)
}
if maskBit {
bit = !bit
}
}
matrix.SetBool(xx, y, bit)
}
y += direction
}
direction = -direction // Reverse the direction.
y += direction
x -= 2 // Move to the left.
}
// All bits should be consumed.
if bitIndex != dataBits.GetSize() {
return gozxing.NewWriterException(
"Not all bits consumed: %v/%v", bitIndex, dataBits.GetSize())
}
return nil
}
// findMSBSet Return the position of the most significant bit set (to one) in the "value".
// The most significant bit is position 32. If there is no bit set, return 0. Examples:
// - findMSBSet(0) => 0
// - findMSBSet(1) => 1
// - findMSBSet(255) => 8
func findMSBSet(value int) int {
return 32 - bits.LeadingZeros32(uint32(value))
}
// calculateBCHCode Calculate BCH (Bose-Chaudhuri-Hocquenghem) code for "value" using polynomial "poly".
// The BCH code is used for encoding type information and version information.
// Example: Calculation of version information of 7.
// f(x) is created from 7.
// - 7 = 000111 in 6 bits
// - f(x) = x^2 + x^1 + x^0
// g(x) is given by the standard (p. 67)
// - g(x) = x^12 + x^11 + x^10 + x^9 + x^8 + x^5 + x^2 + 1
// Multiply f(x) by x^(18 - 6)
// - f'(x) = f(x) * x^(18 - 6)
// - f'(x) = x^14 + x^13 + x^12
// Calculate the remainder of f'(x) / g(x)
// x^2
// __________________________________________________
// g(x) )x^14 + x^13 + x^12
// x^14 + x^13 + x^12 + x^11 + x^10 + x^7 + x^4 + x^2
// --------------------------------------------------
// x^11 + x^10 + x^7 + x^4 + x^2
//
// The remainder is x^11 + x^10 + x^7 + x^4 + x^2
// Encode it in binary: 110010010100
// The return value is 0xc94 (1100 1001 0100)
//
// Since all coefficients in the polynomials are 1 or 0, we can do the calculation by bit
// operations. We don't care if coefficients are positive or negative.
func calculateBCHCode(value, poly int) (int, error) {
if poly == 0 {
return 0, errors.New("IllegalArgumentException: 0 polynomial")
}
// If poly is "1 1111 0010 0101" (version info poly), msbSetInPoly is 13. We'll subtract 1
// from 13 to make it 12.
msbSetInPoly := findMSBSet(poly)
value <<= uint(msbSetInPoly - 1)
// Do the division business using exclusive-or operations.
for findMSBSet(value) >= msbSetInPoly {
value ^= poly << uint(findMSBSet(value)-msbSetInPoly)
}
// Now the "value" is the remainder (i.e. the BCH code)
return value, nil
}
// maskTypeInfoBits Make bit vector of type information.
// On success, store the result in "bits" and return true.
// Encode error correction level and mask pattern. See 8.9 of JISX0510:2004 (p.45) for details.
func makeTypeInfoBits(ecLevel decoder.ErrorCorrectionLevel, maskPattern int, bits *gozxing.BitArray) gozxing.WriterException {
if !QRCode_IsValidMaskPattern(maskPattern) {
return gozxing.NewWriterException("Invalid mask pattern")
}
typeInfo := (ecLevel.GetBits() << 3) | maskPattern
bits.AppendBits(typeInfo, 5)
bchCode, _ := calculateBCHCode(typeInfo, matrixUtil_TYPE_INFO_POLY)
bits.AppendBits(bchCode, 10)
maskBits := gozxing.NewEmptyBitArray()
maskBits.AppendBits(matrixUtil_TYPE_INFO_MASK_PATTERN, 15)
bits.Xor(maskBits)
if bits.GetSize() != 15 { // Just in case.
return gozxing.NewWriterException(
"should not happen but we got: %v", bits.GetSize())
}
return nil
}
// makeVersionInfoBits Make bit vector of version information.
// On success, store the result in "bits" and return true.
// See 8.10 of JISX0510:2004 (p.45) for details.
func makeVersionInfoBits(version *decoder.Version, bits *gozxing.BitArray) gozxing.WriterException {
bits.AppendBits(version.GetVersionNumber(), 6)
bchCode, _ := calculateBCHCode(version.GetVersionNumber(), matrixUtil_VERSION_INFO_POLY)
bits.AppendBits(bchCode, 12)
if bits.GetSize() != 18 { // Just in case.
return gozxing.NewWriterException(
"should not happen but we got: %v", bits.GetSize())
}
return nil
}
// isEmpty Check if "value" is empty.
func isEmpty(value int8) bool {
return value == -1
}
func embedTimingPatterns(matrix *ByteMatrix) {
// -8 is for skipping position detection patterns (size 7), and two horizontal/vertical
// separation patterns (size 1). Thus, 8 = 7 + 1.
for i := 8; i < matrix.GetWidth()-8; i++ {
bit := int8((i + 1) % 2)
// Horizontal line.
if isEmpty(matrix.Get(i, 6)) {
matrix.Set(i, 6, bit)
}
// Vertical line.
if isEmpty(matrix.Get(6, i)) {
matrix.Set(6, i, bit)
}
}
}
// embedDarkDotAtLeftBottomCorner Embed the lonely dark dot at left bottom corner. JISX0510:2004 (p.46)
func embedDarkDotAtLeftBottomCorner(matrix *ByteMatrix) gozxing.WriterException {
if matrix.Get(8, matrix.GetHeight()-8) == 0 {
return gozxing.NewWriterException("embedDarkDotAtLeftBottomCorner")
}
matrix.Set(8, matrix.GetHeight()-8, 1)
return nil
}
func embedHorizontalSeparationPattern(xStart, yStart int, matrix *ByteMatrix) gozxing.WriterException {
for x := 0; x < 8; x++ {
if !isEmpty(matrix.Get(xStart+x, yStart)) {
return gozxing.NewWriterException(
"embedHorizontalSeparationPattern(%d, %d)", xStart, yStart)
}
matrix.Set(xStart+x, yStart, 0)
}
return nil
}
func embedVerticalSeparationPattern(xStart, yStart int, matrix *ByteMatrix) gozxing.WriterException {
for y := 0; y < 7; y++ {
if !isEmpty(matrix.Get(xStart, yStart+y)) {
return gozxing.NewWriterException(
"embedVerticalSeparationPattern(%d, %d)", xStart, yStart)
}
matrix.Set(xStart, yStart+y, 0)
}
return nil
}
func embedPositionAdjustmentPattern(xStart, yStart int, matrix *ByteMatrix) {
for y := 0; y < 5; y++ {
patternY := matrixUtil_POSITION_ADJUSTMENT_PATTERN[y]
for x := 0; x < 5; x++ {
matrix.Set(xStart+x, yStart+y, patternY[x])
}
}
}
func embedPositionDetectionPattern(xStart, yStart int, matrix *ByteMatrix) {
for y := 0; y < 7; y++ {
patternY := matrixUtil_POSITION_DETECTION_PATTERN[y]
for x := 0; x < 7; x++ {
matrix.Set(xStart+x, yStart+y, patternY[x])
}
}
}
// embedPositionDetectionPatternsAndSeparators Embed position detection patterns and
// surrounding vertical/horizontal separators.
func embedPositionDetectionPatternsAndSeparators(matrix *ByteMatrix) gozxing.WriterException {
// Embed three big squares at corners.
pdpWidth := len(matrixUtil_POSITION_DETECTION_PATTERN[0])
// Left top corner.
embedPositionDetectionPattern(0, 0, matrix)
// Right top corner.
embedPositionDetectionPattern(matrix.GetWidth()-pdpWidth, 0, matrix)
// Left bottom corner.
embedPositionDetectionPattern(0, matrix.GetWidth()-pdpWidth, matrix)
// Embed horizontal separation patterns around the squares.
hspWidth := 8
// Left top corner.
e := embedHorizontalSeparationPattern(0, hspWidth-1, matrix)
if e == nil {
// Right top corner.
e = embedHorizontalSeparationPattern(matrix.GetWidth()-hspWidth, hspWidth-1, matrix)
}
if e == nil {
// Left bottom corner.
e = embedHorizontalSeparationPattern(0, matrix.GetWidth()-hspWidth, matrix)
}
// Embed vertical separation patterns around the squares.
vspSize := 7
if e == nil {
// Left top corner.
e = embedVerticalSeparationPattern(vspSize, 0, matrix)
}
if e == nil {
// Right top corner.
e = embedVerticalSeparationPattern(matrix.GetHeight()-vspSize-1, 0, matrix)
}
if e == nil {
// Left bottom corner.
e = embedVerticalSeparationPattern(vspSize, matrix.GetHeight()-vspSize, matrix)
}
return e
}
// maybeEmbedPositionAdjustmentPatterns Embed position adjustment patterns if need be.
func maybeEmbedPositionAdjustmentPatterns(version *decoder.Version, matrix *ByteMatrix) {
if version.GetVersionNumber() < 2 { // The patterns appear if version >= 2
return
}
index := version.GetVersionNumber() - 1
coordinates := matrixUtil_POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index]
for _, y := range coordinates {
if y >= 0 {
for _, x := range coordinates {
if x >= 0 && isEmpty(matrix.Get(x, y)) {
// If the cell is unset, we embed the position adjustment pattern here.
// -2 is necessary since the x/y coordinates point to the center of the pattern, not the
// left top corner.
embedPositionAdjustmentPattern(x-2, y-2, matrix)
}
}
}
}
}