45 lines
1000 B
Go
45 lines
1000 B
Go
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package multiaddr
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import (
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"encoding/binary"
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"fmt"
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"math/bits"
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)
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// VarintSize returns the size (in bytes) of `num` encoded as a varint.
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func VarintSize(num int) int {
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bits := bits.Len(uint(num))
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q, r := bits/7, bits%7
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size := q
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if r > 0 || size == 0 {
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size++
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}
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return size
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}
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// CodeToVarint converts an integer to a varint-encoded []byte
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func CodeToVarint(num int) []byte {
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buf := make([]byte, VarintSize(num))
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n := binary.PutUvarint(buf, uint64(num))
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return buf[:n]
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}
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// VarintToCode converts a varint-encoded []byte to an integer protocol code
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func VarintToCode(buf []byte) int {
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num, _, err := ReadVarintCode(buf)
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if err != nil {
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panic(err)
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}
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return num
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}
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// ReadVarintCode reads a varint code from the beginning of buf.
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// returns the code, and the number of bytes read.
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func ReadVarintCode(buf []byte) (int, int, error) {
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num, n := binary.Uvarint(buf)
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if n < 0 {
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return 0, 0, fmt.Errorf("varints larger than uint64 not yet supported")
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}
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return int(num), n, nil
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}
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