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integer.go
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integer.go
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// Copyright 2017 The lemochain-core Authors
// This file is part of the lemochain-core library.
//
// The lemochain-core 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 lemochain-core 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 lemochain-core library. If not, see <http://www.gnu.org/licenses/>.
package math
const (
// Integer limit values.
MaxInt8 = 1<<7 - 1
MinInt8 = -1 << 7
MaxInt16 = 1<<15 - 1
MinInt16 = -1 << 15
MaxInt32 = 1<<31 - 1
MinInt32 = -1 << 31
MaxInt64 = 1<<63 - 1
MinInt64 = -1 << 63
MaxUint8 = 1<<8 - 1
MaxUint16 = 1<<16 - 1
MaxUint32 = 1<<32 - 1
MaxUint64 = 1<<64 - 1
)
// NOTE: The following methods need to be optimised using either bit checking or asm
// SafeSub returns subtraction result and whether overflow occurred.
func SafeSub(x, y uint64) (uint64, bool) {
return x - y, x < y
}
// SafeAdd returns the result and whether overflow occurred.
func SafeAdd(x, y uint64) (uint64, bool) {
return x + y, y > MaxUint64-x
}
// SafeMul returns multiplication result and whether overflow occurred.
func SafeMul(x, y uint64) (uint64, bool) {
if x == 0 || y == 0 {
return 0, false
}
return x * y, y > MaxUint64/x
}