40 lines
669 B
Go
40 lines
669 B
Go
package zlib
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import (
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"compress/flate"
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"compress/zlib"
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"io"
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)
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type Reader interface {
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io.ReadCloser
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zlib.Resetter
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}
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func zlibStreamer(r flate.Reader) (Reader, error) {
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// verify header
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h := make([]byte, 2)
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if _, err := io.ReadFull(r, h); err != nil {
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return nil, err
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}
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// verify header
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if err := verifyHeader(h); err != nil {
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return nil, err
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}
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return flate.NewReader(r).(Reader), nil
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}
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// https://golang.org/src/compress/zlib/reader.go#L35
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const zlibDeflate = 8
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func verifyHeader(scratch []byte) error {
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h := uint(scratch[0])<<8 | uint(scratch[1])
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if (scratch[0]&0x0f != zlibDeflate) || (h%31 != 0) {
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return zlib.ErrHeader
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}
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return nil
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}
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