size

README

size - calculates variable's memory consumption at runtime

Part of the Transflow Project

Sometimes you may need a tool to measure the size of object in your Go program at runtime. This package makes an attempt to do so. Package based on binary.Size() from Go standard library.

Features:

• supports non-fixed size variables and struct fields: struct, int, slice, string, map;
• supports complex types including structs with non-fixed size fields;
• supports all basic types (numbers, bool);
• supports chan and interface;
• supports pointers;
• implements infinite recursion detection (i.e. pointer inside struct field references to parent struct).

Usage example

package main

import (
	"fmt"

	// Use latest tag.
	"github.com/DmitriyVTitov/size"
)

func main() {
	a := struct {
		a int
		b string
		c bool
		d int32
		e []byte
		f [3]int64
	}{
		a: 10,                    // 8 bytes
		b: "Text",                // 16 (string itself) + 4 = 20 bytes
		c: true,                  // 1 byte
		d: 25,                    // 4 bytes
		e: []byte{'c', 'd', 'e'}, // 24 (slice itself) + 3 = 27 bytes
		f: [3]int64{1, 2, 3},     // 3 * 8 = 24 bytes
	} // 84 + 3 (padding) = 87 bytes

	fmt.Println(size.Of(a))
}

// Output: 87

Documentation

Overview

Package size implements run-time calculation of size of the variable. Source code is based on "binary.Size()" function from Go standard library. size.Of() omits size of slices, arrays and maps containers itself (24, 24 and 8 bytes). When counting maps separate calculations are done for keys and values.

Index

• func Of(v interface{}) int

Functions

func Of

func Of(v interface{}) int

Of returns the size of 'v' in bytes. If there is an error during calculation, Of returns -1.