Is there a fast and efficient Go equivalent to C 's memset?

Is there a Go equivalent for the C memset function?

In C , memset allows for the initialization of an array with a specific value. This function is particularly efficient. In Go, initializing an array or slice with all zeros is straightforward using make([]int, 1000000); however, this does not provide the option to initialize with non-zero values.

While a loop can be used for manual initialization, it lacks the efficiency of memset.

memset Analogs in Go:

1. Loop-Based Approach:

func memsetLoop(a []int, v int) {
    for i := range a {
        a[i] = v
    }
}

2. copy()-Based Approach (Recommended):

The copy() function is highly optimized and can be utilized for memset-like operations.

func memsetRepeat(a []int, v int) {
    if len(a) == 0 {
        return
    }
    a[0] = v
    for bp := 1; bp < len(a); bp *= 2 {
        copy(a[bp:], a[:bp])
    }
}

This solution sets the first element manually and copies the already set parts to the unset parts using copy(). The algorithm uses a doubling approach to reduce the number of iterations to log(n).

Benchmarking:

Benchmarking memsetRepeat() against memsetLoop() shows a noticeable performance advantage for memsetRepeat() as the number of elements increases, particularly around 3800-4000 elements.

Additional Note:

For small slices, memsetLoop() may perform slightly better. However, memsetRepeat() offers significantly better performance for larger slices.

The above is the detailed content of Is there a fast and efficient Go equivalent to C 's memset?. For more information, please follow other related articles on the PHP Chinese website!