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// 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
}
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