mirror of
https://github.com/ethereum/go-ethereum.git
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584 lines
18 KiB
Go
584 lines
18 KiB
Go
// Copyright 2026 The go-ethereum Authors
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// This file is part of go-ethereum.
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//
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// go-ethereum is free software: you can redistribute it and/or modify
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// it under the terms of the GNU 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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// go-ethereum 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 General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
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package bintrie
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import (
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"encoding/binary"
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"encoding/hex"
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"fmt"
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"math"
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)
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const (
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maxUint64 = uint64(math.MaxUint64) // 0xFFFFFFFFFFFFFFFF
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maxUint8 = uint8(math.MaxUint8)
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)
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var emptyBitArray = new(BitArray)
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// BitArray represents a bit array with length representing the number of used bits.
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// It uses a little endian representation to do bitwise operations of the words efficiently.
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// For example, if len is 10, it means that the 2^9, 2^8, ..., 2^0 bits are used.
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// The max length is 255 bits (uint8), because our use case only need up to 248 bits for a given trie key.
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// Although words can be used to represent 256 bits, we don't want to add an additional byte for the length.
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type BitArray struct {
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len uint8 // number of used bits
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words [4]uint64 // little endian (i.e. words[0] is the least significant)
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}
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// NewBitArray creates a new bit array with the given length and value.
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func NewBitArray(length uint8, val uint64) BitArray {
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var b BitArray
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b.SetUint64(length, val)
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return b
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}
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func (b *BitArray) Len() uint8 {
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return b.len
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}
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// Bytes returns the bytes representation of the bit array in big endian format
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func (b *BitArray) Bytes() [32]byte {
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var res [32]byte
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binary.BigEndian.PutUint64(res[0:8], b.words[3])
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binary.BigEndian.PutUint64(res[8:16], b.words[2])
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binary.BigEndian.PutUint64(res[16:24], b.words[1])
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binary.BigEndian.PutUint64(res[24:32], b.words[0])
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return res
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}
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// Append sets the bit array to the concatenation of x and y and returns the bit array.
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// For example:
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//
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// x = 000 (len=3)
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// y = 111 (len=3)
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// Append(x,y) = 000111 (len=6)
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func (b *BitArray) Append(x, y *BitArray) *BitArray {
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if x.len == 0 {
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return b.Set(y)
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}
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if y.len == 0 {
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return b.Set(x)
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}
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if x.len > maxUint8-y.len {
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panic("error on bitarray append: result would exceed maximum length of 255 bits")
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}
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// Shift left by y's length and OR with y
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return b.lsh(x, y.len).or(b, y)
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}
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// AppendBit sets the bit array to the concatenation of x and a single bit.
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// Equivalent to Append(x, {bit}) but avoids allocating a temporary BitArray.
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func (b *BitArray) AppendBit(x *BitArray, bit uint8) *BitArray {
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if x.len == 0 {
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return b.SetBit(bit)
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}
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b.lsh(x, 1)
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b.words[0] |= uint64(bit & 1)
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return b
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}
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// MSBs sets the bit array to the most significant 'n' bits of x, that is position 0 to n (exclusive).
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// If n >= x.len, the bit array is an exact copy of x.
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// Think of this method as array[0:n]
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// For example:
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//
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// x = 11001011 (len=8)
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// MSBs(x, 4) = 1100 (len=4)
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// MSBs(x, 10) = 11001011 (len=8, original x)
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// MSBs(x, 0) = 0 (len=0)
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func (b *BitArray) MSBs(x *BitArray, n uint8) *BitArray {
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if n >= x.len {
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return b.Set(x)
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}
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return b.rsh(x, x.len-n)
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}
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// Equal checks if two bit arrays are equal
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func (b *BitArray) Equal(x *BitArray) bool {
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if b == nil || x == nil {
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panic("bit array is nil")
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}
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return b.len == x.len && b.words == x.words
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}
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// SetBytes interprets the data as the big-endian bytes, sets the bit array to that value and returns it.
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// If the data is larger than 32 bytes, only the first 32 bytes are used.
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func (b *BitArray) SetBytes(length uint8, data []byte) *BitArray {
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switch l := len(data); l {
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case 0:
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b.clear()
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case 1:
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, uint64(data[0])
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case 2:
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_ = data[1]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, uint64(binary.BigEndian.Uint16(data[0:2]))
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case 3:
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_ = data[2]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, uint64(binary.BigEndian.Uint16(data[1:3]))|uint64(data[0])<<16
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case 4:
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_ = data[3]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, uint64(binary.BigEndian.Uint32(data[0:4]))
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case 5:
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_ = data[4]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, bigEndianUint40(data[0:5])
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case 6:
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_ = data[5]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, bigEndianUint48(data[0:6])
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case 7:
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_ = data[6]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, bigEndianUint56(data[0:7])
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case 8:
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_ = data[7]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, binary.BigEndian.Uint64(data[0:8])
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case 9:
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_ = data[8]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, uint64(data[0]), binary.BigEndian.Uint64(data[1:9])
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case 10:
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_ = data[9]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, uint64(binary.BigEndian.Uint16(data[0:2])), binary.BigEndian.Uint64(data[2:10])
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case 11:
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_ = data[10]
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b.words[3], b.words[2] = 0, 0
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b.words[1], b.words[0] = uint64(binary.BigEndian.Uint16(data[1:3]))|uint64(data[0])<<16, binary.BigEndian.Uint64(data[3:11])
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case 12:
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_ = data[11]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, uint64(binary.BigEndian.Uint32(data[0:4])), binary.BigEndian.Uint64(data[4:12])
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case 13:
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_ = data[12]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, bigEndianUint40(data[0:5]), binary.BigEndian.Uint64(data[5:13])
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case 14:
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_ = data[13]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, bigEndianUint48(data[0:6]), binary.BigEndian.Uint64(data[6:14])
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case 15:
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_ = data[14]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, bigEndianUint56(data[0:7]), binary.BigEndian.Uint64(data[7:15])
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case 16:
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_ = data[15]
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b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, binary.BigEndian.Uint64(data[0:8]), binary.BigEndian.Uint64(data[8:16])
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case 17:
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_ = data[16]
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b.words[3], b.words[2] = 0, uint64(data[0])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[1:9]), binary.BigEndian.Uint64(data[9:17])
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case 18:
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_ = data[17]
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b.words[3], b.words[2] = 0, uint64(binary.BigEndian.Uint16(data[0:2]))
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[2:10]), binary.BigEndian.Uint64(data[10:18])
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case 19:
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_ = data[18]
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b.words[3], b.words[2] = 0, uint64(binary.BigEndian.Uint16(data[1:3]))|uint64(data[0])<<16
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[3:11]), binary.BigEndian.Uint64(data[11:19])
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case 20:
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_ = data[19]
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b.words[3], b.words[2] = 0, uint64(binary.BigEndian.Uint32(data[0:4]))
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[4:12]), binary.BigEndian.Uint64(data[12:20])
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case 21:
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_ = data[20]
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b.words[3], b.words[2] = 0, bigEndianUint40(data[0:5])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[5:13]), binary.BigEndian.Uint64(data[13:21])
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case 22:
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_ = data[21]
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b.words[3], b.words[2] = 0, bigEndianUint48(data[0:6])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[6:14]), binary.BigEndian.Uint64(data[14:22])
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case 23:
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_ = data[22]
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b.words[3], b.words[2] = 0, bigEndianUint56(data[0:7])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[7:15]), binary.BigEndian.Uint64(data[15:23])
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case 24:
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_ = data[23]
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b.words[3], b.words[2] = 0, binary.BigEndian.Uint64(data[0:8])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[8:16]), binary.BigEndian.Uint64(data[16:24])
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case 25:
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_ = data[24]
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b.words[3], b.words[2] = uint64(data[0]), binary.BigEndian.Uint64(data[1:9])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[9:17]), binary.BigEndian.Uint64(data[17:25])
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case 26:
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_ = data[25]
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b.words[3], b.words[2] = uint64(binary.BigEndian.Uint16(data[0:2])), binary.BigEndian.Uint64(data[2:10])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[10:18]), binary.BigEndian.Uint64(data[18:26])
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case 27:
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_ = data[26]
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b.words[3] = uint64(binary.BigEndian.Uint16(data[1:3])) | uint64(data[0])<<16
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b.words[2] = binary.BigEndian.Uint64(data[3:11])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[11:19]), binary.BigEndian.Uint64(data[19:27])
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case 28:
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_ = data[27]
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b.words[3], b.words[2] = uint64(binary.BigEndian.Uint32(data[0:4])), binary.BigEndian.Uint64(data[4:12])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[12:20]), binary.BigEndian.Uint64(data[20:28])
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case 29:
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_ = data[28]
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b.words[3], b.words[2] = bigEndianUint40(data[0:5]), binary.BigEndian.Uint64(data[5:13])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[13:21]), binary.BigEndian.Uint64(data[21:29])
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case 30:
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_ = data[29]
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b.words[3], b.words[2] = bigEndianUint48(data[0:6]), binary.BigEndian.Uint64(data[6:14])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[14:22]), binary.BigEndian.Uint64(data[22:30])
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case 31:
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_ = data[30]
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b.words[3], b.words[2] = bigEndianUint56(data[0:7]), binary.BigEndian.Uint64(data[7:15])
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b.words[1], b.words[0] = binary.BigEndian.Uint64(data[15:23]), binary.BigEndian.Uint64(data[23:31])
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default:
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b.setBytes32(data)
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}
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b.len = length
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b.truncateToLength()
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return b
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}
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// SetUint64 sets the bit array to the uint64 representation of a bit array.
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func (b *BitArray) SetUint64(length uint8, data uint64) *BitArray {
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b.words[0] = data
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b.words[1], b.words[2], b.words[3] = 0, 0, 0
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b.len = length
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b.truncateToLength()
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return b
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}
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// SetBit sets the bit array to a single bit.
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func (b *BitArray) SetBit(bit uint8) *BitArray {
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b.len = 1
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b.words[0] = uint64(bit & 1)
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b.words[1], b.words[2], b.words[3] = 0, 0, 0
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return b
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}
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// Copy returns a deep copy of the bit array.
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func (b *BitArray) Copy() BitArray {
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var res BitArray
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res.Set(b)
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return res
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}
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// String returns a string representation of the bit array.
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// This is typically used for logging or debugging.
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func (b *BitArray) String() string {
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bt := b.Bytes()
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return fmt.Sprintf("(%d) %s", b.len, hex.EncodeToString(bt[:]))
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}
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// Bit returns the bit value at position n, where n = 0 is MSB.
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// If n is out of bounds, returns 0.
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func (b *BitArray) Bit(n uint8) uint8 {
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if n >= b.Len() {
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return 0
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}
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return b.bitFromLSB(b.Len() - n - 1)
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}
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// Set sets the bit array to the same value as x.
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func (b *BitArray) Set(x *BitArray) *BitArray {
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b.len = x.len
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b.words[0] = x.words[0]
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b.words[1] = x.words[1]
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b.words[2] = x.words[2]
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b.words[3] = x.words[3]
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return b
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}
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// ActiveBytes returns a slice containing only the bytes that are actually used by the bit array,
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// as specified by the length. The returned slice is in big-endian order.
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//
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// Example:
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//
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// len = 10, words = [0x3FF, 0, 0, 0] -> [0x03, 0xFF]
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func (b *BitArray) ActiveBytes() []byte {
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wordsBytes := b.Bytes()
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return wordsBytes[32-b.byteCount():]
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}
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// PutActiveBytes writes the active bytes into dst (which must be at least 32 bytes)
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// and returns the populated sub-slice. No heap allocation occurs because the
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// backing array is owned by the caller.
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func (b *BitArray) PutActiveBytes(dst *[32]byte) []byte {
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binary.BigEndian.PutUint64(dst[0:8], b.words[3])
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binary.BigEndian.PutUint64(dst[8:16], b.words[2])
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binary.BigEndian.PutUint64(dst[16:24], b.words[1])
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binary.BigEndian.PutUint64(dst[24:32], b.words[0])
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return dst[32-b.byteCount():]
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}
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// bitFromLSB returns the bit value at position n, where n = 0 is LSB.
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// If n is out of bounds, returns 0.
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func (b *BitArray) bitFromLSB(n uint8) uint8 {
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if n >= b.len {
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return 0
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}
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if (b.words[n/64] & (1 << (n % 64))) != 0 {
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return 1
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}
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return 0
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}
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// copyLsb sets the bit array to the least significant 'n' bits of x.
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// n is counted from the least significant bit, starting at 0.
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// If length >= x.len, the bit array is an exact copy of x.
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// For example:
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//
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// x = 11001011 (len=8)
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// copyLsb(x, 4) = 1011 (len=4)
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// copyLsb(x, 10) = 11001011 (len=8, original x)
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// copyLsb(x, 0) = 0 (len=0)
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func (b *BitArray) copyLsb(x *BitArray, n uint8) *BitArray {
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if n >= x.len {
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return b.Set(x)
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}
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b.len = n
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switch {
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case n == 0:
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b.words = [4]uint64{0, 0, 0, 0}
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case n <= 64:
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b.words[0] = x.words[0] & (maxUint64 >> (64 - n))
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b.words[1], b.words[2], b.words[3] = 0, 0, 0
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case n <= 128:
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b.words[0] = x.words[0]
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b.words[1] = x.words[1] & (maxUint64 >> (128 - n))
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b.words[2], b.words[3] = 0, 0
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case n <= 192:
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b.words[0] = x.words[0]
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b.words[1] = x.words[1]
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b.words[2] = x.words[2] & (maxUint64 >> (192 - n))
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b.words[3] = 0
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default:
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b.words[0] = x.words[0]
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b.words[1] = x.words[1]
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b.words[2] = x.words[2]
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b.words[3] = x.words[3] & (maxUint64 >> (256 - uint16(n)))
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}
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return b
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}
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// lsb returns the least significant bits of `x` with `n` counted from the most significant bit, starting at 0.
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// Think of this method as array[n:]
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// For example:
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//
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// x = 11001011 (len=8)
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// lsb(x, 1) = 1001011 (len=7)
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// lsb(x, 10) = 0 (len=0)
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// lsb(x, 0) = 11001011 (len=8, original x)
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func (b *BitArray) lsb(x *BitArray, n uint8) *BitArray {
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if n == 0 {
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return b.Set(x)
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}
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if n > x.Len() {
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return b.clear()
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}
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return b.copyLsb(x, x.Len()-n)
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}
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// or sets the bit array to x | y and returns the bit array.
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func (b *BitArray) or(x, y *BitArray) *BitArray {
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b.words[0] = x.words[0] | y.words[0]
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b.words[1] = x.words[1] | y.words[1]
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b.words[2] = x.words[2] | y.words[2]
|
|
b.words[3] = x.words[3] | y.words[3]
|
|
b.len = x.len
|
|
return b
|
|
}
|
|
|
|
// rsh sets the bit array to x >> n and returns the bit array.
|
|
func (b *BitArray) rsh(x *BitArray, n uint8) *BitArray {
|
|
if x.len == 0 {
|
|
return b.Set(x)
|
|
}
|
|
|
|
if n >= x.len {
|
|
return b.clear()
|
|
}
|
|
|
|
switch {
|
|
case n == 0:
|
|
return b.Set(x)
|
|
case n >= 192:
|
|
b.rsh192(x)
|
|
b.len = x.len - n
|
|
n -= 192
|
|
b.words[0] >>= n
|
|
case n >= 128:
|
|
b.rsh128(x)
|
|
b.len = x.len - n
|
|
n -= 128
|
|
b.words[0] = (b.words[0] >> n) | (b.words[1] << (64 - n))
|
|
b.words[1] >>= n
|
|
case n >= 64:
|
|
b.rsh64(x)
|
|
b.len = x.len - n
|
|
n -= 64
|
|
b.words[0] = (b.words[0] >> n) | (b.words[1] << (64 - n))
|
|
b.words[1] = (b.words[1] >> n) | (b.words[2] << (64 - n))
|
|
b.words[2] >>= n
|
|
default:
|
|
b.Set(x)
|
|
b.len -= n
|
|
b.words[0] = (b.words[0] >> n) | (b.words[1] << (64 - n))
|
|
b.words[1] = (b.words[1] >> n) | (b.words[2] << (64 - n))
|
|
b.words[2] = (b.words[2] >> n) | (b.words[3] << (64 - n))
|
|
b.words[3] >>= n
|
|
}
|
|
|
|
b.truncateToLength()
|
|
return b
|
|
}
|
|
|
|
// lsh sets the bit array to x << n and returns the bit array.
|
|
func (b *BitArray) lsh(x *BitArray, n uint8) *BitArray {
|
|
if x.len == 0 || n == 0 {
|
|
return b.Set(x)
|
|
}
|
|
|
|
// If the result will overflow, we set the length to the max length
|
|
// but we still shift `n` bits
|
|
if n > maxUint8-x.len {
|
|
b.len = maxUint8
|
|
} else {
|
|
b.len = x.len + n
|
|
}
|
|
|
|
switch {
|
|
case n >= 192:
|
|
b.lsh192(x)
|
|
n -= 192
|
|
b.words[3] <<= n
|
|
case n >= 128:
|
|
b.lsh128(x)
|
|
n -= 128
|
|
b.words[3] = (b.words[3] << n) | (b.words[2] >> (64 - n))
|
|
b.words[2] <<= n
|
|
case n >= 64:
|
|
b.lsh64(x)
|
|
n -= 64
|
|
b.words[3] = (b.words[3] << n) | (b.words[2] >> (64 - n))
|
|
b.words[2] = (b.words[2] << n) | (b.words[1] >> (64 - n))
|
|
b.words[1] <<= n
|
|
default:
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = x.words[3], x.words[2], x.words[1], x.words[0]
|
|
b.words[3] = (b.words[3] << n) | (b.words[2] >> (64 - n))
|
|
b.words[2] = (b.words[2] << n) | (b.words[1] >> (64 - n))
|
|
b.words[1] = (b.words[1] << n) | (b.words[0] >> (64 - n))
|
|
b.words[0] <<= n
|
|
}
|
|
|
|
b.truncateToLength()
|
|
return b
|
|
}
|
|
|
|
func (b *BitArray) setBytes32(data []byte) {
|
|
_ = data[31] // bound check hint, see https://golang.org/issue/14808
|
|
b.words[3] = binary.BigEndian.Uint64(data[0:8])
|
|
b.words[2] = binary.BigEndian.Uint64(data[8:16])
|
|
b.words[1] = binary.BigEndian.Uint64(data[16:24])
|
|
b.words[0] = binary.BigEndian.Uint64(data[24:32])
|
|
}
|
|
|
|
// byteCount returns the minimum number of bytes needed to represent the bit array.
|
|
// It rounds up to the nearest byte.
|
|
func (b *BitArray) byteCount() uint {
|
|
const bits8 = 8
|
|
return (uint(b.len) + (bits8 - 1)) / uint(bits8)
|
|
}
|
|
|
|
func (b *BitArray) rsh64(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = 0, x.words[3], x.words[2], x.words[1]
|
|
}
|
|
|
|
func (b *BitArray) rsh128(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, x.words[3], x.words[2]
|
|
}
|
|
|
|
func (b *BitArray) rsh192(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = 0, 0, 0, x.words[3]
|
|
}
|
|
|
|
func (b *BitArray) lsh64(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = x.words[2], x.words[1], x.words[0], 0
|
|
}
|
|
|
|
func (b *BitArray) lsh128(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = x.words[1], x.words[0], 0, 0
|
|
}
|
|
|
|
func (b *BitArray) lsh192(x *BitArray) {
|
|
b.words[3], b.words[2], b.words[1], b.words[0] = x.words[0], 0, 0, 0
|
|
}
|
|
|
|
func (b *BitArray) clear() *BitArray {
|
|
b.len = 0
|
|
b.words[0], b.words[1], b.words[2], b.words[3] = 0, 0, 0, 0
|
|
return b
|
|
}
|
|
|
|
// truncateToLength truncates the bit array to the specified length, ensuring that any unused bits are all zeros.
|
|
//
|
|
// Example:
|
|
//
|
|
// b := &BitArray{
|
|
// len: 5,
|
|
// words: [4]uint64{
|
|
// 0xFFFFFFFFFFFFFFFF, // Before: all bits are 1
|
|
// 0x0, 0x0, 0x0,
|
|
// },
|
|
// }
|
|
// b.truncateToLength()
|
|
// // After: only first 5 bits remain
|
|
// // words[0] = 0x000000000000001F
|
|
// // words[1..3] = 0x0
|
|
func (b *BitArray) truncateToLength() {
|
|
switch {
|
|
case b.len == 0:
|
|
b.words = [4]uint64{0, 0, 0, 0}
|
|
case b.len <= 64:
|
|
b.words[0] &= maxUint64 >> (64 - b.len)
|
|
b.words[1], b.words[2], b.words[3] = 0, 0, 0
|
|
case b.len <= 128:
|
|
b.words[1] &= maxUint64 >> (128 - b.len)
|
|
b.words[2], b.words[3] = 0, 0
|
|
case b.len <= 192:
|
|
b.words[2] &= maxUint64 >> (192 - b.len)
|
|
b.words[3] = 0
|
|
default:
|
|
b.words[3] &= maxUint64 >> (256 - uint16(b.len))
|
|
}
|
|
}
|
|
|
|
func bigEndianUint40(b []byte) uint64 {
|
|
_ = b[4] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[4]) | uint64(b[3])<<8 | uint64(b[2])<<16 | uint64(b[1])<<24 |
|
|
uint64(b[0])<<32
|
|
}
|
|
|
|
func bigEndianUint48(b []byte) uint64 {
|
|
_ = b[5] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[5]) | uint64(b[4])<<8 | uint64(b[3])<<16 | uint64(b[2])<<24 |
|
|
uint64(b[1])<<32 | uint64(b[0])<<40
|
|
}
|
|
|
|
func bigEndianUint56(b []byte) uint64 {
|
|
_ = b[6] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[6]) | uint64(b[5])<<8 | uint64(b[4])<<16 | uint64(b[3])<<24 |
|
|
uint64(b[2])<<32 | uint64(b[1])<<40 | uint64(b[0])<<48
|
|
}
|