forked from mirror/go-ethereum
swarm/chunk: move chunk related declarations to chunk package (#19170)
Janoš Guljaš
6 years ago
committed by
Anton Evangelatov
parent
b7e0dec6bd
commit
f0233948d2
@ -1,5 +1,109 @@ |
||||
package chunk |
||||
|
||||
import ( |
||||
"errors" |
||||
"fmt" |
||||
|
||||
"github.com/ethereum/go-ethereum/common" |
||||
) |
||||
|
||||
const ( |
||||
DefaultSize = 4096 |
||||
DefaultSize = 4096 |
||||
MaxPO = 16 |
||||
AddressLength = 32 |
||||
) |
||||
|
||||
var ( |
||||
ErrChunkNotFound = errors.New("chunk not found") |
||||
ErrChunkInvalid = errors.New("invalid chunk") |
||||
) |
||||
|
||||
type Chunk interface { |
||||
Address() Address |
||||
Data() []byte |
||||
} |
||||
|
||||
type chunk struct { |
||||
addr Address |
||||
sdata []byte |
||||
} |
||||
|
||||
func NewChunk(addr Address, data []byte) *chunk { |
||||
return &chunk{ |
||||
addr: addr, |
||||
sdata: data, |
||||
} |
||||
} |
||||
|
||||
func (c *chunk) Address() Address { |
||||
return c.addr |
||||
} |
||||
|
||||
func (c *chunk) Data() []byte { |
||||
return c.sdata |
||||
} |
||||
|
||||
func (self *chunk) String() string { |
||||
return fmt.Sprintf("Address: %v Chunksize: %v", self.addr.Log(), len(self.sdata)) |
||||
} |
||||
|
||||
type Address []byte |
||||
|
||||
var ZeroAddr = Address(common.Hash{}.Bytes()) |
||||
|
||||
func (a Address) Hex() string { |
||||
return fmt.Sprintf("%064x", []byte(a[:])) |
||||
} |
||||
|
||||
func (a Address) Log() string { |
||||
if len(a[:]) < 8 { |
||||
return fmt.Sprintf("%x", []byte(a[:])) |
||||
} |
||||
return fmt.Sprintf("%016x", []byte(a[:8])) |
||||
} |
||||
|
||||
func (a Address) String() string { |
||||
return fmt.Sprintf("%064x", []byte(a)) |
||||
} |
||||
|
||||
func (a Address) MarshalJSON() (out []byte, err error) { |
||||
return []byte(`"` + a.String() + `"`), nil |
||||
} |
||||
|
||||
func (a *Address) UnmarshalJSON(value []byte) error { |
||||
s := string(value) |
||||
*a = make([]byte, 32) |
||||
h := common.Hex2Bytes(s[1 : len(s)-1]) |
||||
copy(*a, h) |
||||
return nil |
||||
} |
||||
|
||||
// Proximity 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 []byte) (ret int) { |
||||
b := (MaxPO-1)/8 + 1 |
||||
if b > len(one) { |
||||
b = len(one) |
||||
} |
||||
m := 8 |
||||
for i := 0; i < b; i++ { |
||||
oxo := one[i] ^ other[i] |
||||
for j := 0; j < m; j++ { |
||||
if (oxo>>uint8(7-j))&0x01 != 0 { |
||||
return i*8 + j |
||||
} |
||||
} |
||||
} |
||||
return MaxPO |
||||
} |
||||
|
||||
Loading…
Reference in new issue