Golang 中的 bits 包

Go 语言在 bits 包的帮助下为预先声明的无符号整数类型提供了对位计数和操作函数的内置支持。

Function	Description
Add	This function returns the sum with carry of a, b and carry: sum = a + b + carry.
Add32	This function returns the sum with carry of a, b and carry: sum = a + b + carry.
Add64	This function returns the sum with carry of a, b and carry: sum = a + b + carry.
Div	This function returns the quotient and remainder of (h, l) divided by x: quo = (h, l)/x, rem = (hi, lo)%x with the dividend bits’ upper half in parameter h and the lower half in parameter l.
Div32	This function returns the quotient and remainder of (h, l) divided by x: quo = (h, l)/x, rem = (h, l)%x with the dividend bits’ upper half in parameter h and the lower half in parameter l.
Div64	This function returns the quotient and remainder of (h, l) divided by x: quo = (h, l)/x, rem = (h, l)%x with the dividend bits’ upper half in parameter h and the lower half in parameter l.
LeadingZeros	This function returns the number of leading zero bits in y. The result is UintSize for x == 0.
LeadingZeros16	This function returns the number of leading zero bits in y. The result is 16 for y == 0.
LeadingZeros32	This function returns the number of leading zero bits in y. The result is 32 for y == 0.
LeadingZeros64	This function returns the number of leading zero bits in y. The result is 64 for y == 0.
LeadingZeros8	This function returns the number of leading zero bits in y. The result is 8 for y == 0.
Len	This function returns the minimum number of bits required to represent y. The result is 0 for y == 0.
Len16	This function returns the minimum number of bits required to represent y. The result is 0 for y == 0.
Len32	This function returns the minimum number of bits required to represent y. The result is 0 for y == 0.
Len64	This function returns the minimum number of bits required to represent y. The result is 0 for y == 0.
Len8	This function returns the minimum number of bits required to represent y. the result is 0 for y == 0.
Mul	This function is used to return the full-width product of a and b, i.e., (hi, lo) = a * b with the product bits’ upper half returned in hi and the lower half returned in lo.
Mul32	This function is used to return the 64-bit product of a and b, i.e., (hi, lo) = a * b with the product bits’ upper half returned in hi and the lower half returned in lo.
Mul64	This function is used to return the 128-bit product of a and b, i.e., (hi, lo) = a * b with the product bits’ upper half returned in hi and the lower half returned in lo.
OnesCount	This function returns the number of one bits (“population count”) in y.
OnesCount16	This function returns the number of one bits (“population count”) in y.
OnesCount32	This function returns the number of one bits (“population count”) in y.
OnesCount64	This function returns the number of one bits (“population count”) in y.
OnesCount8	This function returns the number of one bits (“population count”) in y.
Rem	This function returns the remainder of (hi, lo) divided by x.
Rem32	This function returns the remainder of (hi, lo) divided by x.
Rem64	This function returns the remainder of (hi, lo) divided by x.
Reverse	This function returns the value of y with its bits in reversed order.
Reverse16	This function returns the value of y with its bits in reversed order.
Reverse32	This function returns the value of y with its bits in reversed order.
Reverse64	This function returns the value of y with its bits in reversed order.
Reverse8	This function returns the value of y with its bits in reversed order.
ReverseBytes	This function returns the value of x with its bytes in reversed order.
ReverseBytes16	This function returns the value of x with its bytes in reversed order.
ReverseBytes32	This function returns the value of x with its bytes in reversed order.
ReverseBytes64	This function returns the value of x with its bytes in reversed order.
RotateLeft	This function returns the value of y rotated left by (j mod UintSize) bits.
RotateLeft16	This function returns the value of y rotated left by (j mod 16) bits.
RotateLeft32	This function returns the value of y rotated left by (j mod 32) bits.
RotateLeft64	This function returns the value of y rotated left by (j mod 64) bits.
RotateLeft8	This function returns the value of y rotated left by (j mod 8) bits.
Sub	This function returns the difference of a, b and borrow: diff = a – b – borrow.
Sub32	This function returns the difference of a, b and borrow: diff = a – b – borrow.
Sub64	This function returns the difference of a, b and borrow: diff = a – b – borrow.
TrailingZeros	This function returns the number of trailing zero bits in y. The result is UintSize for y == 0.
TrailingZeros16	This function returns the number of trailing zero bits in y. The result is 16 for y == 0.
TrailingZeros32	This function returns the number of trailing zero bits in y. The result is 32 for y == 0.
TrailingZeros64	This function returns the number of trailing zero bits in y. The result is 64 for y == 0.
TrailingZeros8	This function returns the number of trailing zero bits in y. The result is 8 for y == 0.

示例 1：

// Golang program to illustrate bits.Sub() Function
package main
  
import (
    "fmt"
    "math/bits"
)
  
// Main function
func main() {
  
    // Finding diff and borrowOu
    // of the specified numbers
    // Using Sub() function
    nvalue_1, borrowOut := bits.Sub(4, 3, 0)
    fmt.Println("Diff:", nvalue_1)
    fmt.Println("BorrowOut :", borrowOut)
}

输出：

Diff: 1
BorrowOut : 0

示例 2：

// Golang program to illustrate bits.TrailingZeros64() Function
package main
  
import (
    "fmt"
    "math/bits"
)
  
// Main function
func main() {
  
    // Using TrailingZeros64() function
    a := bits.TrailingZeros64(15)
    fmt.Printf("Total number of trailing"+
            " zero bits in %d: %d", 15, a)
}

输出：

Total number of trailing zero bits in 15: 0