65 lines
1.1 KiB
Go
65 lines
1.1 KiB
Go
package envexp
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import (
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"bytes"
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"io"
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"os"
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)
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const (
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MinimumBufferSize = 32
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DefaultBufferSize = 4096
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)
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type Reader struct {
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exp *Expander
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in io.Reader
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buf *bytes.Buffer
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out *bytes.Buffer
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}
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func (rd *Reader) Read(b []byte) (int, error) {
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return rd.in.Read(b)
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}
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func (rd *Reader) Close() error {
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if f, ok := rd.in.(io.Closer); ok {
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return f.Close()
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}
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return nil
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}
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//
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// Constructors
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//
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func (exp *Expander) NewReaderSize(in io.Reader, size int) *Reader {
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if size < MinimumBufferSize {
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size = DefaultBufferSize
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}
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return &Reader{
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exp: exp,
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in: in,
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buf: bytes.NewBuffer(make([]byte, 0, size)),
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out: bytes.NewBuffer(make([]byte, 0, size)),
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}
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}
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func (exp *Expander) NewReader(in io.Reader) *Reader {
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return exp.NewReaderSize(in, DefaultBufferSize)
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}
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func (exp *Expander) NewReaderFileSize(filename string, size int) (*Reader, error) {
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f, err := os.Open(filename)
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if err != nil {
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return nil, err
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}
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rd := exp.NewReaderSize(f, size)
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return rd, nil
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}
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func (exp *Expander) NewReaderFile(filename string) (*Reader, error) {
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return exp.NewReaderFileSize(filename, DefaultBufferSize)
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}
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