// 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
}