71 lines
1.5 KiB
Go
71 lines
1.5 KiB
Go
package util
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import (
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"encoding/binary"
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"io"
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)
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//BinReader is a convenient wrapper around a io.Reader and err object
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// Used to simplify error handling when reading into a struct with many fields
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type BinReader struct {
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R io.Reader
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Err error
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}
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// Read reads from the underlying io.Reader
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// into the interface v in LE
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func (r *BinReader) Read(v interface{}) {
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if r.Err != nil {
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return
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}
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r.Err = binary.Read(r.R, binary.LittleEndian, v)
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}
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// ReadBigEnd reads from the underlying io.Reader
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// into the interface v in BE
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func (r *BinReader) ReadBigEnd(v interface{}) {
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if r.Err != nil {
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return
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}
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r.Err = binary.Read(r.R, binary.BigEndian, v)
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}
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//VarUint reads a variable integer from the
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// underlying reader
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func (r *BinReader) VarUint() uint64 {
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var b uint8
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r.Err = binary.Read(r.R, binary.LittleEndian, &b)
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if b == 0xfd {
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var v uint16
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r.Err = binary.Read(r.R, binary.LittleEndian, &v)
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return uint64(v)
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}
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if b == 0xfe {
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var v uint32
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r.Err = binary.Read(r.R, binary.LittleEndian, &v)
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return uint64(v)
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}
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if b == 0xff {
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var v uint64
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r.Err = binary.Read(r.R, binary.LittleEndian, &v)
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return v
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}
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return uint64(b)
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}
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// VarBytes reads the next set of bytes from the underlying reader.
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// VarUInt is used to determine how large that slice is
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func (r *BinReader) VarBytes() []byte {
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n := r.VarUint()
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b := make([]byte, n)
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r.Read(b)
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return b
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}
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// VarString calls VarBytes and casts the results as a string
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func (r *BinReader) VarString() string {
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b := r.VarBytes()
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return string(b)
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}
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