mindoc/vendor/github.com/boombuler/barcode/qr/alphanumeric.go

67 lines
1.4 KiB
Go

package qr
import (
"errors"
"fmt"
"strings"
"github.com/boombuler/barcode/utils"
)
const charSet string = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"
func stringToAlphaIdx(content string) <-chan int {
result := make(chan int)
go func() {
for _, r := range content {
idx := strings.IndexRune(charSet, r)
result <- idx
if idx < 0 {
break
}
}
close(result)
}()
return result
}
func encodeAlphaNumeric(content string, ecl ErrorCorrectionLevel) (*utils.BitList, *versionInfo, error) {
contentLenIsOdd := len(content)%2 == 1
contentBitCount := (len(content) / 2) * 11
if contentLenIsOdd {
contentBitCount += 6
}
vi := findSmallestVersionInfo(ecl, alphaNumericMode, contentBitCount)
if vi == nil {
return nil, nil, errors.New("To much data to encode")
}
res := new(utils.BitList)
res.AddBits(int(alphaNumericMode), 4)
res.AddBits(len(content), vi.charCountBits(alphaNumericMode))
encoder := stringToAlphaIdx(content)
for idx := 0; idx < len(content)/2; idx++ {
c1 := <-encoder
c2 := <-encoder
if c1 < 0 || c2 < 0 {
return nil, nil, fmt.Errorf("\"%s\" can not be encoded as %s", content, AlphaNumeric)
}
res.AddBits(c1*45+c2, 11)
}
if contentLenIsOdd {
c := <-encoder
if c < 0 {
return nil, nil, fmt.Errorf("\"%s\" can not be encoded as %s", content, AlphaNumeric)
}
res.AddBits(c, 6)
}
addPaddingAndTerminator(res, vi)
return res, vi, nil
}