prysm-pulse/consensus/ethash/algorithm_go1.7.go
Raul Jordan da20785685 Merge branch 'master' into gitter-badge-1
Former-commit-id: 23f542f43b4b493e38f5aa4c29788ed93a63b43b [formerly 71b23a6a28eb045fcfeab6329de69f1e5455486b]
Former-commit-id: d12b3a6decc876f010a71f98e11df7387c1aaf2a
2018-01-13 17:31:28 -05:00

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Go

// Copyright 2017 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/>.
// +build !go1.8
package ethash
// cacheSize calculates and returns the size of the ethash verification cache that
// belongs to a certain block number. The cache size grows linearly, however, we
// always take the highest prime below the linearly growing threshold in order to
// reduce the risk of accidental regularities leading to cyclic behavior.
func cacheSize(block uint64) uint64 {
// If we have a pre-generated value, use that
epoch := int(block / epochLength)
if epoch < len(cacheSizes) {
return cacheSizes[epoch]
}
// We don't have a way to verify primes fast before Go 1.8
panic("fast prime testing unsupported in Go < 1.8")
}
// datasetSize calculates and returns the size of the ethash mining dataset that
// belongs to a certain block number. The dataset size grows linearly, however, we
// always take the highest prime below the linearly growing threshold in order to
// reduce the risk of accidental regularities leading to cyclic behavior.
func datasetSize(block uint64) uint64 {
// If we have a pre-generated value, use that
epoch := int(block / epochLength)
if epoch < len(datasetSizes) {
return datasetSizes[epoch]
}
// We don't have a way to verify primes fast before Go 1.8
panic("fast prime testing unsupported in Go < 1.8")
}