54 lines
1.0 KiB
Go
54 lines
1.0 KiB
Go
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// Copyright (C) 2018 Storj Labs, Inc.
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// See LICENSE for copying information.
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package ranger
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import (
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"io"
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)
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type readerAtRanger struct {
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r io.ReaderAt
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size int64
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}
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// ReaderAtRanger converts a ReaderAt with a given size to a Ranger
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func ReaderAtRanger(r io.ReaderAt, size int64) Ranger {
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return &readerAtRanger{
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r: r,
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size: size,
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}
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}
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func (r *readerAtRanger) Size() int64 {
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return r.size
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}
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type readerAtReader struct {
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r io.ReaderAt
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offset, length int64
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}
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func (r *readerAtRanger) Range(offset, length int64) io.Reader {
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if offset < 0 {
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return FatalReader(Error.New("negative offset"))
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}
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if offset+length > r.size {
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return FatalReader(Error.New("buffer runoff"))
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}
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return &readerAtReader{r: r.r, offset: offset, length: length}
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}
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func (r *readerAtReader) Read(p []byte) (n int, err error) {
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if r.length == 0 {
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return 0, io.EOF
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}
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if int64(len(p)) > r.length {
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p = p[:r.length]
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}
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n, err = r.r.ReadAt(p, r.offset)
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r.offset += int64(n)
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r.length -= int64(n)
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return n, err
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}
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