1 files changed, 46 insertions, 0 deletions
diff --git a/core/gaspool.go b/core/gaspool.go
new file mode 100644
index 000000000..2ef07c754
--- /dev/null
+++ b/core/gaspool.go
@@ -0,0 +1,46 @@
+// Copyright 2014 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/>.
+
+package core
+
+import "math/big"
+
+// GasPool tracks the amount of gas available during
+// execution of the transactions in a block.
+// The zero value is a pool with zero gas available.
+type GasPool big.Int
+
+// AddGas makes gas available for execution.
+func (gp *GasPool) AddGas(amount *big.Int) *GasPool {
+	i := (*big.Int)(gp)
+	i.Add(i, amount)
+	return gp
+}
+
+// SubGas deducts the given amount from the pool if enough gas is
+// available and returns an error otherwise.
+func (gp *GasPool) SubGas(amount *big.Int) error {
+	i := (*big.Int)(gp)
+	if i.Cmp(amount) < 0 {
+		return &GasLimitErr{Have: new(big.Int).Set(i), Want: amount}
+	}
+	i.Sub(i, amount)
+	return nil
+}
+
+func (gp *GasPool) String() string {
+	return (*big.Int)(gp).String()
+}