a6e64aea67
* network/bitvector: Multibit set/unset + string rep * network/bitvector: Add code comments * network/bitvector: Make Unset -> Set with bool false * network/bitvector: Revert to Set/Unset * network/stream: Update to new bitvector signature
125 lines
3.1 KiB
Go
125 lines
3.1 KiB
Go
// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package bitvector
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import (
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"errors"
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)
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var errInvalidLength = errors.New("invalid length")
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// BitVector is a convenience object for manipulating and representing bit vectors
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type BitVector struct {
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len int
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b []byte
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}
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// New creates a new bit vector with the given length
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func New(l int) (bv *BitVector, err error) {
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return NewFromBytes(make([]byte, l/8+1), l)
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}
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// NewFromBytes creates a bit vector from the passed byte slice.
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//
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// Leftmost bit in byte slice becomes leftmost bit in bit vector
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func NewFromBytes(b []byte, l int) (bv *BitVector, err error) {
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if l <= 0 {
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return nil, errInvalidLength
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}
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if len(b)*8 < l {
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return nil, errInvalidLength
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}
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return &BitVector{
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len: l,
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b: b,
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}, nil
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}
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// Get gets the corresponding bit, counted from left to right
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func (bv *BitVector) Get(i int) bool {
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bi := i / 8
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return bv.b[bi]&(0x1<<uint(i%8)) != 0
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}
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// Set sets the bit corresponding to the index in the bitvector, counted from left to right
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func (bv *BitVector) set(i int, v bool) {
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bi := i / 8
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cv := bv.Get(i)
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if cv != v {
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bv.b[bi] ^= 0x1 << uint8(i%8)
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}
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}
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// Set sets the bit corresponding to the index in the bitvector, counted from left to right
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func (bv *BitVector) Set(i int) {
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bv.set(i, true)
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}
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// Unset UNSETS the corresponding bit, counted from left to right
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func (bv *BitVector) Unset(i int) {
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bv.set(i, false)
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}
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// SetBytes sets all bits in the bitvector that are set in the argument
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//
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// The argument must be the same as the bitvector length
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func (bv *BitVector) SetBytes(bs []byte) error {
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if len(bs) != bv.len {
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return errors.New("invalid length")
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}
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for i := 0; i < bv.len*8; i++ {
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bi := i / 8
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if bs[bi]&(0x01<<uint(i%8)) > 0 {
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bv.set(i, true)
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}
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}
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return nil
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}
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// UnsetBytes UNSETS all bits in the bitvector that are set in the argument
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//
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// The argument must be the same as the bitvector length
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func (bv *BitVector) UnsetBytes(bs []byte) error {
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if len(bs) != bv.len {
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return errors.New("invalid length")
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}
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for i := 0; i < bv.len*8; i++ {
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bi := i / 8
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if bs[bi]&(0x01<<uint(i%8)) > 0 {
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bv.set(i, false)
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}
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}
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return nil
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}
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// String implements Stringer interface
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func (bv *BitVector) String() (s string) {
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for i := 0; i < bv.len*8; i++ {
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if bv.Get(i) {
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s += "1"
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} else {
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s += "0"
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}
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}
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return s
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}
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// Bytes retrieves the underlying bytes of the bitvector
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func (bv *BitVector) Bytes() []byte {
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return bv.b
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}
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