forked from TrueCloudLab/neoneo-go
5bf00db2c9
The logic here is that we'll have all binary encoding/decoding done via our io package, which simplifies error handling. This functionality doesn't belong to util, so it's moved. This also expands BufBinWriter with Reset() method to fit the needs of core package.
87 lines
1.9 KiB
Go
87 lines
1.9 KiB
Go
package io
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import (
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"bytes"
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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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// NewBinReaderFromIO makes a BinReader from io.Reader.
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func NewBinReaderFromIO(ior io.Reader) *BinReader {
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return &BinReader{r: ior}
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}
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// NewBinReaderFromBuf makes a BinReader from byte buffer.
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func NewBinReaderFromBuf(b []byte) *BinReader {
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r := bytes.NewReader(b)
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return NewBinReaderFromIO(r)
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}
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// ReadLE reads from the underlying io.Reader
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// into the interface v in little-endian format
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func (r *BinReader) ReadLE(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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// ReadBE reads from the underlying io.Reader
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// into the interface v in big-endian format
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func (r *BinReader) ReadBE(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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// ReadVarUint reads a variable-length-encoded integer from the
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// underlying reader
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func (r *BinReader) ReadVarUint() uint64 {
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if r.Err != nil {
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return 0
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}
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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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// ReadBytes reads the next set of bytes from the underlying reader.
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// ReadVarUInt() is used to determine how large that slice is
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func (r *BinReader) ReadBytes() []byte {
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n := r.ReadVarUint()
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b := make([]byte, n)
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r.ReadLE(b)
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return b
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}
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// ReadString calls ReadBytes and casts the results as a string
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func (r *BinReader) ReadString() string {
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b := r.ReadBytes()
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return string(b)
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}
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