Documentation
¶
Index ¶
- Constants
- Variables
- func LengthToSpan(length int64) []byte
- type BaseHasherFunc
- type Hasher
- func (h *Hasher) BlockSize() int
- func (h *Hasher) Capacity() int
- func (h *Hasher) GetZeroHash() []byte
- func (h *Hasher) Reset()
- func (h *Hasher) SetSpan(length int64) error
- func (h *Hasher) Size() int
- func (h *Hasher) Sum(b []byte) (s []byte)
- func (h *Hasher) Write(b []byte) (int, error)
- func (h *Hasher) WriteSection(idx int, data []byte) error
- type TreePool
Constants ¶
const ( // PoolSize is the maximum number of bmt trees used by the hashers, i.e, // the maximum number of concurrent BMT hashing operations performed by the same hasher PoolSize = 8 )
Variables ¶
var (
ZeroSpan = make([]byte, 8)
)
Functions ¶
func LengthToSpan ¶
LengthToSpan creates a binary data span size representation. It is required for calculating the BMT hash.
Types ¶
type BaseHasherFunc ¶
BaseHasherFunc is a hash.Hash constructor function used for the base hash of the BMT. implemented by Keccak256 SHA3 sha3.NewLegacyKeccak256
type Hasher ¶
type Hasher struct {
// contains filtered or unexported fields
}
Hasher a reusable hasher for fixed maximum size chunks representing a BMT It reuses a pool of trees for amortised memory allocation and resource control, and supports order-agnostic concurrent segment writes and section (double segment) writes as well as sequential read and write.
The same hasher instance must not be called concurrently on more than one chunk.
The same hasher instance is synchronously reuseable.
Sum gives back the tree to the pool and guaranteed to leave the tree and itself in a state reusable for hashing a new chunk.
func New ¶
New creates a reusable BMT Hasher that pulls a new tree from a resource pool for hashing each chunk.
func (*Hasher) Capacity ¶
Count returns the maximum amount of bytes that will be processed by this hasher implementation.
func (*Hasher) GetZeroHash ¶
GetZeroHash returns the zero hash of the full depth of the Hasher instance.
func (*Hasher) Sum ¶
Sum returns the BMT root hash of the buffer using Sum presupposes sequential synchronous writes (io.Writer interface).
type TreePool ¶
type TreePool struct {
SegmentSize int // size of leaf segments, stipulated to be = hash size
SegmentCount int // the number of segments on the base level of the BMT
Capacity int // pool capacity, controls concurrency
Depth int // depth of the bmt trees = int(log2(segmentCount))+1
Size int // the total length of the data (count * size)
// contains filtered or unexported fields
}
TreePool provides a pool of trees used as resources by the BMT Hasher. A tree popped from the pool is guaranteed to have a clean state ready for hashing a new chunk.
func NewTreePool ¶
func NewTreePool(hasher BaseHasherFunc, segmentCount, capacity int) *TreePool
NewTreePool creates a tree pool with hasher, segment size, segment count and capacity on Hasher.getTree it reuses free trees or creates a new one if capacity is not reached.
Source Files