Example: Calculate circulating supply for geth private network

circulating_supply.go

/**
 * Go playground: https://play.golang.org/p/DaCCAm2KGZ6
 */

package main

import (
	"fmt"
	"math/big"
)

type BlockRange struct {
	lastBlockNumber *big.Int
	reward          *big.Int
}

func main() {

	blockRanges := []BlockRange{
		BlockRange{
			lastBlockNumber: big.NewInt(500),
			reward:          big.NewInt(2e+18),
		},
		BlockRange{
			lastBlockNumber: big.NewInt(1000),
			reward:          big.NewInt(1e+18),
		},
		BlockRange{
			lastBlockNumber: big.NewInt(1500),
			reward:          big.NewInt(5e+17),
		},
	}

	currentBlockNumber := big.NewInt(1357)
	circulatingSupply := big.NewInt(0)

	for i, blockRange := range blockRanges {

		lastBlockNumber := blockRange.lastBlockNumber
		addReward := big.NewInt(0)
		multiplier := big.NewInt(0)

		if i == 0 {
			multiplier = lastBlockNumber
		} else if currentBlockNumber.Cmp(lastBlockNumber) >= 0 {
			multiplier.Sub(lastBlockNumber, blockRanges[i-1].lastBlockNumber)
		} else {
			multiplier.Sub(lastBlockNumber, currentBlockNumber)
		}

		addReward.Mul(multiplier, blockRange.reward)
		circulatingSupply.Add(circulatingSupply, addReward)
	}

	fmt.Println("Circulating supply: ", circulatingSupply)
}