102 lines
2.4 KiB
Go
102 lines
2.4 KiB
Go
package iconv
|
|
|
|
import (
|
|
"io"
|
|
"os"
|
|
)
|
|
|
|
type Reader struct {
|
|
source io.Reader
|
|
converter *Converter
|
|
rawBuffer []byte
|
|
rawReadPos, rawWritePos int
|
|
convertedBuffer []byte
|
|
convertedReadPos, convertedWritePos int
|
|
}
|
|
|
|
func NewReader(source io.Reader, fromEncoding string, toEncoding string) (*Reader, os.Error) {
|
|
// create a converter
|
|
converter, err := NewConverter(fromEncoding, toEncoding)
|
|
|
|
if err == nil {
|
|
return NewReaderFromConverter(source, converter), err
|
|
}
|
|
|
|
// return the error
|
|
return nil, err
|
|
}
|
|
|
|
func NewReaderFromConverter(source io.Reader, converter *Converter) (reader *Reader) {
|
|
reader = new(Reader)
|
|
|
|
// copy elements
|
|
reader.source = source
|
|
reader.converter = converter
|
|
|
|
// create 8K buffers
|
|
reader.rawBuffer = make([]byte, 8 * 1024)
|
|
reader.convertedBuffer = make([]byte, 8 * 1024)
|
|
|
|
return reader
|
|
}
|
|
|
|
func (this *Reader) fillRawBuffer() {
|
|
// slide existing data to beginning
|
|
if this.rawReadPos > 0 {
|
|
// copy current bytes
|
|
copy(this.rawBuffer, this.rawBuffer[this.rawReadPos:this.rawWritePos])
|
|
|
|
// adjust positions
|
|
this.rawWritePos -= this.rawReadPos
|
|
this.rawReadPos = 0
|
|
}
|
|
|
|
// read new data into buffer at write position
|
|
bytesRead, err := this.source.Read(this.rawBuffer[this.rawWritePos:])
|
|
|
|
// adjust write position
|
|
this.rawWritePos += bytesRead
|
|
|
|
// track source reader errors
|
|
if err != nil {
|
|
// not sure where to put this for now
|
|
}
|
|
}
|
|
|
|
func (this *Reader) fillConvertedBuffer() {
|
|
// slide existing data to beginning
|
|
if this.convertedReadPos > 0 {
|
|
// copy current bytes
|
|
copy(this.convertedBuffer, this.convertedBuffer[this.convertedReadPos:this.convertedWritePos])
|
|
|
|
// adjust positions
|
|
this.convertedWritePos -= this.convertedReadPos
|
|
this.convertedReadPos = 0
|
|
}
|
|
|
|
// use iconv to fill the converted buffer from the raw buffer
|
|
bytesRead, bytesWritten, err := this.converter.Convert(this.rawBuffer[this.rawReadPos:this.rawWritePos], this.convertedBuffer[this.convertedWritePos:])
|
|
|
|
// adjust read and write positions
|
|
this.rawReadPos += bytesRead
|
|
this.convertedWritePos += bytesWritten
|
|
|
|
// track iconv convert errors
|
|
if err != nil {
|
|
// not sure where to put this for now
|
|
}
|
|
}
|
|
|
|
// implement the io.Reader interface
|
|
func (this *Reader) Read(p []byte) (n int, err os.Error) {
|
|
this.fillRawBuffer()
|
|
this.fillConvertedBuffer()
|
|
|
|
if this.convertedWritePos - 1 > this.convertedReadPos {
|
|
// copy converted bytes into p
|
|
n = copy(p, this.convertedBuffer[this.convertedReadPos:this.convertedWritePos])
|
|
}
|
|
|
|
return
|
|
}
|