Convert the memory size representation to a long value in bytes

Write a function that converts the human readable memory representation to a long value in bytes. Please find the below table for the inputs and outputs.

 

Input	Output (in bytes)
10K	10240
10M	10485760
10G	10737418240
10T	10995116277760
10P	11258999068426240

 

Find the below working application.

MemorySizeToLongValue.java

package com.sample.app.strings;

public class MemorySizeToLongValue {
	// Size in bytes
	private static final long KILO_BYTE = 1024;
	private static final long MEGA_BYTE = KILO_BYTE * 1024;
	private static final long GIGA_BYTE = MEGA_BYTE * 1024;
	private static final long TERA_BYTE = GIGA_BYTE * 1024;
	private static final long PETA_BYTE = TERA_BYTE * 1024;

	public static long toBytes(final String memorySize) throws Exception {
		final String inputStr = memorySize.trim();
		String memorySizeWithoutSign = null;
		long sign = 1L;
		char firstChar = memorySize.charAt(0);

		switch (firstChar) {
		case '+':
			memorySizeWithoutSign = inputStr.substring(1);
			break;
		case '-':
			sign = -1L;
			memorySizeWithoutSign = inputStr.substring(1);
			break;
		default:
			memorySizeWithoutSign = inputStr;
			break;
		}

		// last character should be K, M, G, T, P.
		long result = sign;
		char lastChar = memorySizeWithoutSign.charAt(memorySizeWithoutSign.length() - 1);

		switch (lastChar) {
		case 'K':
			result *= KILO_BYTE;
			break;
		case 'M':
			result *= MEGA_BYTE;
			break;
		case 'G':
			result *= GIGA_BYTE;
			break;
		case 'T':
			result *= TERA_BYTE;
			break;
		case 'P':
			result *= PETA_BYTE;
			break;
		default:
			throw new IllegalArgumentException("Invalid input format. Valid values are : (10K, 10M, 10G, 10T, 10P)");
		}

		memorySizeWithoutSign = memorySizeWithoutSign.substring(0, memorySizeWithoutSign.length() - 1);

		return result * Long.parseLong(memorySizeWithoutSign);

	}

	public static void main(String[] args) throws Exception {
		System.out.println("10K : " + toBytes("10K") + " bytes");
		System.out.println("10M : " + toBytes("10M") + " bytes");
		System.out.println("10G : " + toBytes("10G") + " bytes");
		System.out.println("10T : " + toBytes("10T") + " bytes");
		System.out.println("10P : " + toBytes("10P") + " bytes\n");

		System.out.println("+10K : " + toBytes("+10K") + " bytes");
		System.out.println("+10M : " + toBytes("+10M") + " bytes");
		System.out.println("+10G : " + toBytes("+10G") + " bytes");
		System.out.println("+10T : " + toBytes("+10T") + " bytes");
		System.out.println("+10P : " + toBytes("+10P") + " bytes\n");

		System.out.println("-10K : " + toBytes("-10K") + " bytes");
		System.out.println("-10M : " + toBytes("-10M") + " bytes");
		System.out.println("-10G : " + toBytes("-10G") + " bytes");
		System.out.println("-10T : " + toBytes("-10T") + " bytes");
		System.out.println("-10P : " + toBytes("-10P") + " bytes\n");
	}

}

 

Output

10K : 10240 bytes
10M : 10485760 bytes
10G : 10737418240 bytes
10T : 10995116277760 bytes
10P : 11258999068426240 bytes

+10K : 10240 bytes
+10M : 10485760 bytes
+10G : 10737418240 bytes
+10T : 10995116277760 bytes
+10P : 11258999068426240 bytes

-10K : -10240 bytes
-10M : -10485760 bytes
-10G : -10737418240 bytes
-10T : -10995116277760 bytes
-10P : -11258999068426240 bytes

 

 

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