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ThresholdNLeafs defines the threshold number of leafs in the tree that determines if AddBatch will work in memory or in disk. It is defined when calling NewTree, and if set to 0 it will work always in disk.
123 lines
3.3 KiB
Go
123 lines
3.3 KiB
Go
package arbo
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import (
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"crypto/sha256"
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"math/big"
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"github.com/iden3/go-iden3-crypto/poseidon"
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"golang.org/x/crypto/blake2b"
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)
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var (
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// TypeHashSha256 represents the label for the HashFunction of Sha256
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TypeHashSha256 = []byte("sha256")
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// TypeHashPoseidon represents the label for the HashFunction of
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// Poseidon
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TypeHashPoseidon = []byte("poseidon")
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// TypeHashBlake2b represents the label for the HashFunction of Blake2b
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TypeHashBlake2b = []byte("blake2b")
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// HashFunctionSha256 contains the HashSha256 struct which implements
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// the HashFunction interface
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HashFunctionSha256 HashSha256
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// HashFunctionPoseidon contains the HashPoseidon struct which implements
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// the HashFunction interface
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HashFunctionPoseidon HashPoseidon
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// HashFunctionBlake2b contains the HashBlake2b struct which implements
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// the HashFunction interface
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HashFunctionBlake2b HashBlake2b
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)
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// Once Generics are at Go, this will be updated (August 2021
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// https://blog.golang.org/generics-next-step)
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// HashFunction defines the interface that is expected for a hash function to be
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// used in a generic way in the Tree.
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type HashFunction interface {
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Type() []byte
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Len() int
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Hash(...[]byte) ([]byte, error)
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// CheckInput checks if the input is valid without computing the hash
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// CheckInput(...[]byte) error
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}
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// HashSha256 implements the HashFunction interface for the Sha256 hash
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type HashSha256 struct{}
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// Type returns the type of HashFunction for the HashSha256
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func (f HashSha256) Type() []byte {
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return TypeHashSha256
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}
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// Len returns the length of the Hash output
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func (f HashSha256) Len() int {
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return 32 //nolint:gomnd
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}
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// Hash implements the hash method for the HashFunction HashSha256
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func (f HashSha256) Hash(b ...[]byte) ([]byte, error) {
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var toHash []byte
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for i := 0; i < len(b); i++ {
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toHash = append(toHash, b[i]...)
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}
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h := sha256.Sum256(toHash)
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return h[:], nil
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}
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// HashPoseidon implements the HashFunction interface for the Poseidon hash
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type HashPoseidon struct{}
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// Type returns the type of HashFunction for the HashPoseidon
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func (f HashPoseidon) Type() []byte {
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return TypeHashPoseidon
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}
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// Len returns the length of the Hash output
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func (f HashPoseidon) Len() int {
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return 32 //nolint:gomnd
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}
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// Hash implements the hash method for the HashFunction HashPoseidon. It
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// expects the byte arrays to be little-endian representations of big.Int
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// values.
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func (f HashPoseidon) Hash(b ...[]byte) ([]byte, error) {
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var toHash []*big.Int
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for i := 0; i < len(b); i++ {
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bi := BytesToBigInt(b[i])
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toHash = append(toHash, bi)
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}
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h, err := poseidon.Hash(toHash)
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if err != nil {
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return nil, err
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}
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hB := BigIntToBytes(f.Len(), h)
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return hB, nil
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}
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// HashBlake2b implements the HashFunction interface for the Blake2b hash
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type HashBlake2b struct{}
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// Type returns the type of HashFunction for the HashBlake2b
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func (f HashBlake2b) Type() []byte {
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return TypeHashBlake2b
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}
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// Len returns the length of the Hash output
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func (f HashBlake2b) Len() int {
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return 32 //nolint:gomnd
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}
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// Hash implements the hash method for the HashFunction HashBlake2b
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func (f HashBlake2b) Hash(b ...[]byte) ([]byte, error) {
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hasher, err := blake2b.New256(nil)
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if err != nil {
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return nil, err
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}
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for i := 0; i < len(b); i++ {
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if _, err = hasher.Write(b[i]); err != nil {
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return nil, err
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}
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}
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return hasher.Sum(nil), nil
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}
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