mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 01:52:46 +00:00
208 lines
4.3 KiB
Go
208 lines
4.3 KiB
Go
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// Copyright (c) 2014 The mathutil Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package mathutil // import "modernc.org/mathutil"
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import (
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"math/big"
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)
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// BitLenByte returns the bit width of the non zero part of n.
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func BitLenByte(n byte) int {
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return log2[n] + 1
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}
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// BitLenUint16 returns the bit width of the non zero part of n.
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func BitLenUint16(n uint16) int {
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if b := n >> 8; b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[n] + 1
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}
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// BitLenUint32 returns the bit width of the non zero part of n.
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func BitLenUint32(n uint32) int {
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if b := n >> 24; b != 0 {
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return log2[b] + 24 + 1
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}
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if b := n >> 16; b != 0 {
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return log2[b] + 16 + 1
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}
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if b := n >> 8; b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[n] + 1
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}
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// BitLen returns the bit width of the non zero part of n.
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func BitLen(n int) int { // Should handle correctly [future] 64 bit Go ints
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if IntBits == 64 {
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return BitLenUint64(uint64(n))
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}
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if b := byte(n >> 24); b != 0 {
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return log2[b] + 24 + 1
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}
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if b := byte(n >> 16); b != 0 {
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return log2[b] + 16 + 1
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}
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if b := byte(n >> 8); b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[byte(n)] + 1
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}
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// BitLenUint returns the bit width of the non zero part of n.
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func BitLenUint(n uint) int { // Should handle correctly [future] 64 bit Go uints
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if IntBits == 64 {
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return BitLenUint64(uint64(n))
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}
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if b := n >> 24; b != 0 {
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return log2[b] + 24 + 1
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}
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if b := n >> 16; b != 0 {
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return log2[b] + 16 + 1
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}
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if b := n >> 8; b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[n] + 1
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}
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// BitLenUint64 returns the bit width of the non zero part of n.
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func BitLenUint64(n uint64) int {
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if b := n >> 56; b != 0 {
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return log2[b] + 56 + 1
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}
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if b := n >> 48; b != 0 {
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return log2[b] + 48 + 1
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}
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if b := n >> 40; b != 0 {
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return log2[b] + 40 + 1
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}
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if b := n >> 32; b != 0 {
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return log2[b] + 32 + 1
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}
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if b := n >> 24; b != 0 {
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return log2[b] + 24 + 1
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}
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if b := n >> 16; b != 0 {
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return log2[b] + 16 + 1
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}
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if b := n >> 8; b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[n] + 1
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}
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// BitLenUintptr returns the bit width of the non zero part of n.
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func BitLenUintptr(n uintptr) int {
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if b := n >> 56; b != 0 {
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return log2[b] + 56 + 1
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}
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if b := n >> 48; b != 0 {
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return log2[b] + 48 + 1
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}
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if b := n >> 40; b != 0 {
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return log2[b] + 40 + 1
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}
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if b := n >> 32; b != 0 {
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return log2[b] + 32 + 1
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}
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if b := n >> 24; b != 0 {
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return log2[b] + 24 + 1
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}
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if b := n >> 16; b != 0 {
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return log2[b] + 16 + 1
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}
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if b := n >> 8; b != 0 {
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return log2[b] + 8 + 1
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}
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return log2[n] + 1
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}
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// PopCountByte returns population count of n (number of bits set in n).
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func PopCountByte(n byte) int {
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return int(popcnt[n])
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}
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// PopCountUint16 returns population count of n (number of bits set in n).
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func PopCountUint16(n uint16) int {
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return int(popcnt[byte(n>>8)]) + int(popcnt[byte(n)])
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}
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// PopCountUint32 returns population count of n (number of bits set in n).
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func PopCountUint32(n uint32) int {
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return int(popcnt[byte(n>>24)]) + int(popcnt[byte(n>>16)]) +
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int(popcnt[byte(n>>8)]) + int(popcnt[byte(n)])
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}
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// PopCount returns population count of n (number of bits set in n).
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func PopCount(n int) int { // Should handle correctly [future] 64 bit Go ints
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if IntBits == 64 {
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return PopCountUint64(uint64(n))
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}
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return PopCountUint32(uint32(n))
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}
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// PopCountUint returns population count of n (number of bits set in n).
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func PopCountUint(n uint) int { // Should handle correctly [future] 64 bit Go uints
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if IntBits == 64 {
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return PopCountUint64(uint64(n))
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}
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return PopCountUint32(uint32(n))
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}
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// PopCountUintptr returns population count of n (number of bits set in n).
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func PopCountUintptr(n uintptr) int {
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if UintPtrBits == 64 {
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return PopCountUint64(uint64(n))
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}
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return PopCountUint32(uint32(n))
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}
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// PopCountUint64 returns population count of n (number of bits set in n).
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func PopCountUint64(n uint64) int {
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return int(popcnt[byte(n>>56)]) + int(popcnt[byte(n>>48)]) +
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int(popcnt[byte(n>>40)]) + int(popcnt[byte(n>>32)]) +
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int(popcnt[byte(n>>24)]) + int(popcnt[byte(n>>16)]) +
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int(popcnt[byte(n>>8)]) + int(popcnt[byte(n)])
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}
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// PopCountBigInt returns population count of |n| (number of bits set in |n|).
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func PopCountBigInt(n *big.Int) (r int) {
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for _, v := range n.Bits() {
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r += PopCountUintptr(uintptr(v))
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}
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return
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}
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