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Vendor IP address calculation function
The version of AddrForNodeID we vendor preallocates memory during IP address calculation, and has a slight performance win.
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package main | ||
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import ( | ||
"github.com/yggdrasil-network/yggdrasil-go/src/address" | ||
"github.com/yggdrasil-network/yggdrasil-go/src/crypto" | ||
) | ||
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||
// AddrForNodeID is a variant of Yggdrasil's src/address.AddrForNodeID that | ||
// might be slightly optimized for performance. | ||
// | ||
// This function is a modded variant of address.AddrForNodeID from Yggdrasil. | ||
// See src/address/address.go@78b5f88e4bb734d0dd6a138ff08d34ca39dcaea3 | ||
func AddrForNodeID(nid *crypto.NodeID) *address.Address { | ||
// 128 bit address, begins with GetPrefix(), with last bit set to 0 | ||
// (indicates an address). Next 7 bits, interpreted as a uint, are the count | ||
// of leading 1s in the NodeID. Leading 1s and first leading 0 of the NodeID | ||
// are truncated off. The rest is appended to the IPv6 address (truncated to | ||
// 128 bits total). | ||
var addr address.Address | ||
temp := make([]byte, 0, len(nid)) | ||
done := false | ||
ones := byte(0) | ||
bits := byte(0) | ||
nBits := 0 | ||
for idx := 0; idx < 8*len(nid); idx++ { | ||
bit := (nid[idx/8] & (0x80 >> byte(idx%8))) >> byte(7-(idx%8)) | ||
if !done && bit != 0 { | ||
ones++ | ||
continue | ||
} | ||
if !done && bit == 0 { | ||
done = true | ||
continue | ||
} | ||
bits = (bits << 1) | bit | ||
nBits++ | ||
if nBits == 8 { | ||
nBits = 0 | ||
temp = append(temp, bits) | ||
} | ||
} | ||
prefix := address.GetPrefix() | ||
copy(addr[:], prefix[:]) | ||
addr[len(prefix)] = ones | ||
copy(addr[len(prefix)+1:], temp) | ||
return &addr | ||
} |
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