all: switch gas limits from big.Int to uint64

1 files changed, 16 insertions, 20 deletions

diff --git a/core/block_validator.go b/core/block_validator.go
index e9cfd0482..143728bb8 100644
--- a/core/block_validator.go
+++ b/core/block_validator.go
@@ -18,9 +18,7 @@ package core
 
 import (
 	"fmt"
-	"math/big"
 
-	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -76,10 +74,10 @@ func (v *BlockValidator) ValidateBody(block *types.Block) error {
 // transition, such as amount of used gas, the receipt roots and the state root
 // itself. ValidateState returns a database batch if the validation was a success
 // otherwise nil and an error is returned.
-func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas *big.Int) error {
+func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas uint64) error {
 	header := block.Header()
-	if block.GasUsed().Cmp(usedGas) != 0 {
-		return fmt.Errorf("invalid gas used (remote: %v local: %v)", block.GasUsed(), usedGas)
+	if block.GasUsed() != usedGas {
+		return fmt.Errorf("invalid gas used (remote: %d local: %d)", block.GasUsed(), usedGas)
 	}
 	// Validate the received block's bloom with the one derived from the generated receipts.
 	// For valid blocks this should always validate to true.
@@ -101,17 +99,13 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat
 }
 
 // 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 {
+func CalcGasLimit(parent *types.Block) uint64 {
 	// 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)
+	contrib := (parent.GasUsed() + parent.GasUsed()/2) / params.GasLimitBoundDivisor
 
 	// decay = parentGasLimit / 1024 -1
-	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
-	decay.Sub(decay, big.NewInt(1))
+	decay := parent.GasLimit()/params.GasLimitBoundDivisor - 1
 
 	/*
 		strategy: gasLimit of block-to-mine is set based on parent's
@@ -120,15 +114,17 @@ func CalcGasLimit(parent *types.Block) *big.Int {
 		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(math.BigMax(gl, params.MinGasLimit))
-
+	limit := parent.GasLimit() - decay + contrib
+	if limit < params.MinGasLimit {
+		limit = params.MinGasLimit
+	}
 	// however, if we're now below the target (TargetGasLimit) we increase the
 	// limit as much as we can (parentGasLimit / 1024 -1)
-	if gl.Cmp(params.TargetGasLimit) < 0 {
-		gl.Add(parent.GasLimit(), decay)
-		gl.Set(math.BigMin(gl, params.TargetGasLimit))
+	if limit < params.TargetGasLimit {
+		limit = parent.GasLimit() + decay
+		if limit > params.TargetGasLimit {
+			limit = params.TargetGasLimit
+		}
 	}
-	return gl
+	return limit
 }