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Diffstat (limited to 'swarm/network/kademlia/address.go')
| -rw-r--r-- | swarm/network/kademlia/address.go | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/swarm/network/kademlia/address.go b/swarm/network/kademlia/address.go deleted file mode 100644 index ef82d2e8b..000000000 --- a/swarm/network/kademlia/address.go +++ /dev/null @@ -1,173 +0,0 @@ -// Copyright 2016 The go-ethereum Authors -// This file is part of the go-ethereum library. -// -// The go-ethereum library is free software: you can redistribute it and/or modify -// it under the terms of the GNU Lesser General Public License as published by -// the Free Software Foundation, either version 3 of the License, or -// (at your option) any later version. -// -// The go-ethereum library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU Lesser General Public License for more details. -// -// You should have received a copy of the GNU Lesser General Public License -// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. - -package kademlia - -import ( - "fmt" - "math/rand" - "strings" - - "github.com/ethereum/go-ethereum/common" -) - -type Address common.Hash - -func (a Address) String() string { - return fmt.Sprintf("%x", a[:]) -} - -func (a *Address) MarshalJSON() (out []byte, err error) { - return []byte(`"` + a.String() + `"`), nil -} - -func (a *Address) UnmarshalJSON(value []byte) error { - *a = Address(common.HexToHash(string(value[1 : len(value)-1]))) - return nil -} - -// the string form of the binary representation of an address (only first 8 bits) -func (a Address) Bin() string { - var bs []string - for _, b := range a[:] { - bs = append(bs, fmt.Sprintf("%08b", b)) - } - return strings.Join(bs, "") -} - -/* -Proximity(x, y) returns the proximity order of the MSB distance between x and y - -The distance metric MSB(x, y) of two equal length byte sequences x and y is the -value of the binary integer cast of the x^y, ie., x and y bitwise xor-ed. -the binary cast is big endian: most significant bit first (=MSB). - -Proximity(x, y) is a discrete logarithmic scaling of the MSB distance. -It is defined as the reverse rank of the integer part of the base 2 -logarithm of the distance. -It is calculated by counting the number of common leading zeros in the (MSB) -binary representation of the x^y. - -(0 farthest, 255 closest, 256 self) -*/ -func proximity(one, other Address) (ret int) { - for i := 0; i < len(one); i++ { - oxo := one[i] ^ other[i] - for j := 0; j < 8; j++ { - if (oxo>>uint8(7-j))&0x01 != 0 { - return i*8 + j - } - } - } - return len(one) * 8 -} - -// Address.ProxCmp compares the distances a->target and b->target. -// Returns -1 if a is closer to target, 1 if b is closer to target -// and 0 if they are equal. -func (target Address) ProxCmp(a, b Address) int { - for i := range target { - da := a[i] ^ target[i] - db := b[i] ^ target[i] - if da > db { - return 1 - } else if da < db { - return -1 - } - } - return 0 -} - -// randomAddressAt(address, prox) generates a random address -// at proximity order prox relative to address -// if prox is negative a random address is generated -func RandomAddressAt(self Address, prox int) (addr Address) { - addr = self - var pos int - if prox >= 0 { - pos = prox / 8 - trans := prox % 8 - transbytea := byte(0) - for j := 0; j <= trans; j++ { - transbytea |= 1 << uint8(7-j) - } - flipbyte := byte(1 << uint8(7-trans)) - transbyteb := transbytea ^ byte(255) - randbyte := byte(rand.Intn(255)) - addr[pos] = ((addr[pos] & transbytea) ^ flipbyte) | randbyte&transbyteb - } - for i := pos + 1; i < len(addr); i++ { - addr[i] = byte(rand.Intn(255)) - } - - return -} - -// KeyRange(a0, a1, proxLimit) returns the address inclusive address -// range that contain addresses closer to one than other -func KeyRange(one, other Address, proxLimit int) (start, stop Address) { - prox := proximity(one, other) - if prox >= proxLimit { - prox = proxLimit - } - start = CommonBitsAddrByte(one, other, byte(0x00), prox) - stop = CommonBitsAddrByte(one, other, byte(0xff), prox) - return -} - -func CommonBitsAddrF(self, other Address, f func() byte, p int) (addr Address) { - prox := proximity(self, other) - var pos int - if p <= prox { - prox = p - } - pos = prox / 8 - addr = self - trans := byte(prox % 8) - var transbytea byte - if p > prox { - transbytea = byte(0x7f) - } else { - transbytea = byte(0xff) - } - transbytea >>= trans - transbyteb := transbytea ^ byte(0xff) - addrpos := addr[pos] - addrpos &= transbyteb - if p > prox { - addrpos ^= byte(0x80 >> trans) - } - addrpos |= transbytea & f() - addr[pos] = addrpos - for i := pos + 1; i < len(addr); i++ { - addr[i] = f() - } - - return -} - -func CommonBitsAddr(self, other Address, prox int) (addr Address) { - return CommonBitsAddrF(self, other, func() byte { return byte(rand.Intn(255)) }, prox) -} - -func CommonBitsAddrByte(self, other Address, b byte, prox int) (addr Address) { - return CommonBitsAddrF(self, other, func() byte { return b }, prox) -} - -// randomAddressAt() generates a random address -func RandomAddress() Address { - return RandomAddressAt(Address{}, -1) -} |