diff options
Diffstat (limited to 'swarm/pot/address.go')
| -rw-r--r-- | swarm/pot/address.go | 40 |
1 files changed, 0 insertions, 40 deletions
diff --git a/swarm/pot/address.go b/swarm/pot/address.go index 3974ebcaa..728dac14e 100644 --- a/swarm/pot/address.go +++ b/swarm/pot/address.go @@ -79,46 +79,6 @@ func (a Address) Bytes() []byte { return a[:] } -/* -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 an 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, eq bool) { - return posProximity(one, other, 0) -} - -// posProximity(a, b, pos) returns proximity order of b wrt a (symmetric) pretending -// the first pos bits match, checking only bits index >= pos -func posProximity(one, other Address, pos int) (ret int, eq bool) { - for i := pos / 8; i < len(one); i++ { - if one[i] == other[i] { - continue - } - oxo := one[i] ^ other[i] - start := 0 - if i == pos/8 { - start = pos % 8 - } - for j := start; j < 8; j++ { - if (oxo>>uint8(7-j))&0x01 != 0 { - return i*8 + j, false - } - } - } - return len(one) * 8, true -} - // 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. |