76 lines
1.5 KiB
Go
76 lines
1.5 KiB
Go
// Package datamatrix can create Datamatrix barcodes
|
|
package datamatrix
|
|
|
|
import (
|
|
"errors"
|
|
|
|
"github.com/boombuler/barcode"
|
|
)
|
|
|
|
// Encode returns a Datamatrix barcode for the given content
|
|
func Encode(content string) (barcode.Barcode, error) {
|
|
data := encodeText(content)
|
|
|
|
var size *dmCodeSize
|
|
for _, s := range codeSizes {
|
|
if s.DataCodewords() >= len(data) {
|
|
size = s
|
|
break
|
|
}
|
|
}
|
|
if size == nil {
|
|
return nil, errors.New("to much data to encode")
|
|
}
|
|
data = addPadding(data, size.DataCodewords())
|
|
data = ec.calcECC(data, size)
|
|
code := render(data, size)
|
|
if code != nil {
|
|
code.content = content
|
|
return code, nil
|
|
}
|
|
return nil, errors.New("unable to render barcode")
|
|
}
|
|
|
|
func render(data []byte, size *dmCodeSize) *datamatrixCode {
|
|
cl := newCodeLayout(size)
|
|
|
|
cl.SetValues(data)
|
|
|
|
return cl.Merge()
|
|
}
|
|
|
|
func encodeText(content string) []byte {
|
|
var result []byte
|
|
input := []byte(content)
|
|
|
|
for i := 0; i < len(input); {
|
|
c := input[i]
|
|
i++
|
|
|
|
if c >= '0' && c <= '9' && i < len(input) && input[i] >= '0' && input[i] <= '9' {
|
|
// two numbers...
|
|
c2 := input[i]
|
|
i++
|
|
cw := byte(((c-'0')*10 + (c2 - '0')) + 130)
|
|
result = append(result, cw)
|
|
} else if c > 127 {
|
|
// not correct... needs to be redone later...
|
|
result = append(result, 235, c-127)
|
|
} else {
|
|
result = append(result, c+1)
|
|
}
|
|
}
|
|
return result
|
|
}
|
|
|
|
func addPadding(data []byte, toCount int) []byte {
|
|
if len(data) < toCount {
|
|
data = append(data, 129)
|
|
}
|
|
for len(data) < toCount {
|
|
R := ((149 * (len(data) + 1)) % 253) + 1
|
|
data = append(data, byte((129+R)%254))
|
|
}
|
|
return data
|
|
}
|