64 lines
1.3 KiB
Go
64 lines
1.3 KiB
Go
|
package zim
|
||
|
|
|
||
|
|
import (
|
||
|
|
"io"
|
||
|
|
|
||
|
|
"github.com/pkg/errors"
|
||
|
|
)
|
||
|
|
|
||
|
|
type UncompressedBlobReader struct {
|
||
|
|
reader *Reader
|
||
|
|
blobStartOffset uint64
|
||
|
|
blobEndOffset uint64
|
||
|
|
blobSize int
|
||
|
|
readOffset uint64
|
||
|
|
}
|
||
|
|
|
||
|
|
// Size implements BlobReader.
|
||
|
|
func (r *UncompressedBlobReader) Size() (int64, error) {
|
||
|
|
return int64(r.blobEndOffset - r.blobStartOffset), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Close implements io.ReadCloser.
|
||
|
|
func (*UncompressedBlobReader) Close() error {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Read implements io.ReadCloser.
|
||
|
|
func (r *UncompressedBlobReader) Read(p []byte) (n int, err error) {
|
||
|
|
len := len(p)
|
||
|
|
remaining := int(r.blobEndOffset - (r.blobStartOffset + r.readOffset))
|
||
|
|
if len > remaining {
|
||
|
|
len = remaining
|
||
|
|
}
|
||
|
|
|
||
|
|
data := make([]byte, len)
|
||
|
|
|
||
|
|
err = r.reader.readRange(int64(r.blobStartOffset+r.readOffset), data)
|
||
|
|
if err != nil {
|
||
|
|
return len, errors.WithStack(err)
|
||
|
|
}
|
||
|
|
|
||
|
|
r.readOffset += uint64(len)
|
||
|
|
|
||
|
|
copy(p, data)
|
||
|
|
|
||
|
|
if len == remaining {
|
||
|
|
return len, io.EOF
|
||
|
|
}
|
||
|
|
|
||
|
|
return len, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func NewUncompressedBlobReader(reader *Reader, blobStartOffset, blobEndOffset uint64, blobSize int) *UncompressedBlobReader {
|
||
|
|
return &UncompressedBlobReader{
|
||
|
|
reader: reader,
|
||
|
|
blobStartOffset: blobStartOffset,
|
||
|
|
blobEndOffset: blobEndOffset,
|
||
|
|
blobSize: blobSize,
|
||
|
|
readOffset: 0,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
var _ BlobReader = &UncompressedBlobReader{}
|