59 lines
1.0 KiB
Go
59 lines
1.0 KiB
Go
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package main
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import (
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"bytes"
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"io"
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"errors"
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)
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type FakeFile struct {
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reader *bytes.Reader
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buffer *bytes.Buffer
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offset int64
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}
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func (f *FakeFile) Read(p []byte) (n int, err error) {
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n, err = f.reader.ReadAt(p, f.offset)
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f.offset += int64(n)
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return n, err
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}
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func (f *FakeFile) Write(p []byte) (n int, err error) {
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n, err = f.buffer.Write(p)
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f.offset += int64(n)
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f.reader.Reset(f.buffer.Bytes())
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return n, err
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}
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func (f *FakeFile) Seek(offset int64, whence int) (int64, error) {
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newOffset := f.offset
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switch whence {
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case io.SeekStart:
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newOffset = offset
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case io.SeekCurrent:
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newOffset += offset
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case io.SeekEnd:
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newOffset = int64(f.buffer.Len()) + offset
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default:
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return 0, errors.New("Seek: whence not at start,current or end")
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}
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// never can get here right?
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if newOffset < 0 {
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return 0, errors.New("Seek: offset < 0")
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}
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f.offset = newOffset
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return f.offset, nil
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}
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func NewFakeFile() *FakeFile {
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buf := &bytes.Buffer{}
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return &FakeFile{
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reader: bytes.NewReader(buf.Bytes()),
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buffer: buf,
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offset: 0,
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}
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}
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