diff options
Diffstat (limited to 'core/database_util.go')
| -rw-r--r-- | core/database_util.go | 69 |
1 files changed, 0 insertions, 69 deletions
diff --git a/core/database_util.go b/core/database_util.go index 2dc113e29..fd2b4c312 100644 --- a/core/database_util.go +++ b/core/database_util.go @@ -27,7 +27,6 @@ import ( "github.com/ethereum/go-ethereum/ethdb" "github.com/ethereum/go-ethereum/logger" "github.com/ethereum/go-ethereum/logger/glog" - "github.com/ethereum/go-ethereum/params" "github.com/ethereum/go-ethereum/rlp" ) @@ -50,77 +49,9 @@ var ( mipmapPre = []byte("mipmap-log-bloom-") MIPMapLevels = []uint64{1000000, 500000, 100000, 50000, 1000} - ExpDiffPeriod = big.NewInt(100000) blockHashPrefix = []byte("block-hash-") // [deprecated by the header/block split, remove eventually] ) -// CalcDifficulty is the difficulty adjustment algorithm. It returns -// the difficulty that a new block b should have when created at time -// given the parent block's time and difficulty. -func CalcDifficulty(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int { - diff := new(big.Int) - adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor) - bigTime := new(big.Int) - bigParentTime := new(big.Int) - - bigTime.SetUint64(time) - bigParentTime.SetUint64(parentTime) - - if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 { - diff.Add(parentDiff, adjust) - } else { - diff.Sub(parentDiff, adjust) - } - if diff.Cmp(params.MinimumDifficulty) < 0 { - diff = params.MinimumDifficulty - } - - periodCount := new(big.Int).Add(parentNumber, common.Big1) - periodCount.Div(periodCount, ExpDiffPeriod) - if periodCount.Cmp(common.Big1) > 0 { - // diff = diff + 2^(periodCount - 2) - expDiff := periodCount.Sub(periodCount, common.Big2) - expDiff.Exp(common.Big2, expDiff, nil) - diff.Add(diff, expDiff) - diff = common.BigMax(diff, params.MinimumDifficulty) - } - - return diff -} - -// CalcGasLimit computes the gas limit of the next block after parent. -// The result may be modified by the caller. -// This is miner strategy, not consensus protocol. -func CalcGasLimit(parent *types.Block) *big.Int { - // contrib = (parentGasUsed * 3 / 2) / 1024 - contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3)) - contrib = contrib.Div(contrib, big.NewInt(2)) - contrib = contrib.Div(contrib, params.GasLimitBoundDivisor) - - // decay = parentGasLimit / 1024 -1 - decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor) - decay.Sub(decay, big.NewInt(1)) - - /* - strategy: gasLimit of block-to-mine is set based on parent's - gasUsed value. if parentGasUsed > parentGasLimit * (2/3) then we - increase it, otherwise lower it (or leave it unchanged if it's right - at that usage) the amount increased/decreased depends on how far away - from parentGasLimit * (2/3) parentGasUsed is. - */ - gl := new(big.Int).Sub(parent.GasLimit(), decay) - gl = gl.Add(gl, contrib) - gl.Set(common.BigMax(gl, params.MinGasLimit)) - - // however, if we're now below the target (GenesisGasLimit) we increase the - // limit as much as we can (parentGasLimit / 1024 -1) - if gl.Cmp(params.GenesisGasLimit) < 0 { - gl.Add(parent.GasLimit(), decay) - gl.Set(common.BigMin(gl, params.GenesisGasLimit)) - } - return gl -} - // GetCanonicalHash retrieves a hash assigned to a canonical block number. func GetCanonicalHash(db ethdb.Database, number uint64) common.Hash { data, _ := db.Get(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...)) |