You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

49 lines
787 B

package pdf
import (
"io"
)
type alphaReader struct {
reader io.Reader
}
func newAlphaReader(reader io.Reader) *alphaReader {
return &alphaReader{reader: reader}
}
func checkASCII85(r byte) byte {
if r >= '!' && r <= 'u' { // 33 <= ascii85 <=117
return r
}
if r == '~' {
return 1 // for marking possible end of data
}
return 0 // if non-ascii85
}
func (a *alphaReader) Read(p []byte) (int, error) {
n, err := a.reader.Read(p)
if err == io.EOF {
}
if err != nil {
return n, err
}
buf := make([]byte, n)
tilda := false
for i := 0; i < n; i++ {
char := checkASCII85(p[i])
if char == '>' && tilda { // end of data
break
}
if char > 1 {
buf[i] = char
}
if char == 1 {
tilda = true // possible end of data
}
}
copy(p, buf)
return n, nil
}