// encodeDataRaw encodes data in dataMode. The encoded data is appended to
// encoded.
func (d *dataEncoder) encodeDataRaw(data []byte, dataMode dataMode, encoded *bitset.Bitset) {
modeIndicator := d.modeIndicator(dataMode)
charCountBits := d.charCountBits(dataMode)
// Append mode indicator.
encoded.Append(modeIndicator)
// Append character count.
encoded.AppendUint32(uint32(len(data)), charCountBits)
// Append data.
switch dataMode {
case dataModeNumeric:
for i := 0; i < len(data); i += 3 {
charsRemaining := len(data) - i
var value uint32
bitsUsed := 1
for j := 0; j < charsRemaining && j < 3; j++ {
value *= 10
value += uint32(data[i+j] - 0x30)
bitsUsed += 3
}
encoded.AppendUint32(value, bitsUsed)
}
case dataModeAlphanumeric:
for i := 0; i < len(data); i += 2 {
charsRemaining := len(data) - i
var value uint32
for j := 0; j < charsRemaining && j < 2; j++ {
value *= 45
value += encodeAlphanumericCharacter(data[i+j])
}
bitsUsed := 6
if charsRemaining > 1 {
bitsUsed = 11
}
encoded.AppendUint32(value, bitsUsed)
}
case dataModeByte:
for _, b := range data {
encoded.AppendByte(b, 8)
}
}
}
// 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
}
// newGFPolyFromData returns |data| as a polynomial over GF(2^8).
//
// Each data byte becomes the coefficient of an x term.
//
// For an n byte input the polynomial is:
// data[n-1]*(x^n-1) + data[n-2]*(x^n-2) ... + data[0]*(x^0).
func newGFPolyFromData(data *bitset.Bitset) gfPoly {
numTotalBytes := data.Len() / 8
if data.Len()%8 != 0 {
numTotalBytes++
}
result := gfPoly{term: make([]gfElement, numTotalBytes)}
i := numTotalBytes - 1
for j := 0; j < data.Len(); j += 8 {
result.term[i] = gfElement(data.ByteAt(j))
i--
}
return result
}
