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authorDeterminant <[email protected]>2020-07-30 14:18:44 -0400
committerDeterminant <[email protected]>2020-07-30 14:18:44 -0400
commit0444e66f640999c15496066637841efcc0433934 (patch)
treec19aec2dced2e9129c880c19c52ca0f87b3d62f6 /core/vm/common.go
parentcffa0954bbdb43821d1b71d00f99fb705cecd25b (diff)
parent1f49826de2bb8bb4f5f99f69fd2beb039b1172d9 (diff)
Merge branch 'multi-coin'
Diffstat (limited to 'core/vm/common.go')
-rw-r--r--core/vm/common.go99
1 files changed, 99 insertions, 0 deletions
diff --git a/core/vm/common.go b/core/vm/common.go
new file mode 100644
index 0000000..ead30fc
--- /dev/null
+++ b/core/vm/common.go
@@ -0,0 +1,99 @@
+// 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 vm
+
+import (
+ "math/big"
+
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/common/math"
+)
+
+// calcMemSize64 calculates the required memory size, and returns
+// the size and whether the result overflowed uint64
+func calcMemSize64(off, l *big.Int) (uint64, bool) {
+ if !l.IsUint64() {
+ return 0, true
+ }
+ return calcMemSize64WithUint(off, l.Uint64())
+}
+
+// calcMemSize64WithUint calculates the required memory size, and returns
+// the size and whether the result overflowed uint64
+// Identical to calcMemSize64, but length is a uint64
+func calcMemSize64WithUint(off *big.Int, length64 uint64) (uint64, bool) {
+ // if length is zero, memsize is always zero, regardless of offset
+ if length64 == 0 {
+ return 0, false
+ }
+ // Check that offset doesn't overflow
+ if !off.IsUint64() {
+ return 0, true
+ }
+ offset64 := off.Uint64()
+ val := offset64 + length64
+ // if value < either of it's parts, then it overflowed
+ return val, val < offset64
+}
+
+// getData returns a slice from the data based on the start and size and pads
+// up to size with zero's. This function is overflow safe.
+func getData(data []byte, start uint64, size uint64) []byte {
+ length := uint64(len(data))
+ if start > length {
+ start = length
+ }
+ end := start + size
+ if end > length {
+ end = length
+ }
+ return common.RightPadBytes(data[start:end], int(size))
+}
+
+// getDataBig returns a slice from the data based on the start and size and pads
+// up to size with zero's. This function is overflow safe.
+func getDataBig(data []byte, start *big.Int, size *big.Int) []byte {
+ dlen := big.NewInt(int64(len(data)))
+
+ s := math.BigMin(start, dlen)
+ e := math.BigMin(new(big.Int).Add(s, size), dlen)
+ return common.RightPadBytes(data[s.Uint64():e.Uint64()], int(size.Uint64()))
+}
+
+// bigUint64 returns the integer casted to a uint64 and returns whether it
+// overflowed in the process.
+func bigUint64(v *big.Int) (uint64, bool) {
+ return v.Uint64(), !v.IsUint64()
+}
+
+// toWordSize returns the ceiled word size required for memory expansion.
+func toWordSize(size uint64) uint64 {
+ if size > math.MaxUint64-31 {
+ return math.MaxUint64/32 + 1
+ }
+
+ return (size + 31) / 32
+}
+
+func allZero(b []byte) bool {
+ for _, byte := range b {
+ if byte != 0 {
+ return false
+ }
+ }
+ return true
+}