package org.ehcache.impl.internal.store.offheap;
public class MemorySizeParser {
private static final long BYTE = 1;
private static final long KILOBYTE = 1024;
private static final long MEGABYTE = 1024 * KILOBYTE;
private static final long GIGABYTE = 1024 * MEGABYTE;
private static final long TERABYTE = 1024 * GIGABYTE;
public static long parse(String configuredMemorySize) throws IllegalArgumentException {
MemorySize size = parseIncludingUnit(configuredMemorySize);
return size.calculateMemorySizeInBytes();
}
private static MemorySize parseIncludingUnit(String configuredMemorySize) throws IllegalArgumentException {
if (configuredMemorySize == null || "".equals(configuredMemorySize)) {
return new MemorySize("0", BYTE);
}
char unit = configuredMemorySize.charAt(configuredMemorySize.length() - 1);
MemorySize memorySize;
switch (unit) {
case 'k':
case 'K':
memorySize = toMemorySize(configuredMemorySize, KILOBYTE);
break;
case 'm':
case 'M':
memorySize = toMemorySize(configuredMemorySize, MEGABYTE);
break;
case 'g':
case 'G':
memorySize = toMemorySize(configuredMemorySize, GIGABYTE);
break;
case 't':
case 'T':
memorySize = toMemorySize(configuredMemorySize, TERABYTE);
break;
default:
try {
Integer.parseInt("" + unit);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("invalid format for memory size [" + configuredMemorySize + "]");
}
memorySize = new MemorySize(configuredMemorySize, BYTE);
}
return memorySize;
}
private static MemorySize toMemorySize(String configuredMemorySize, long unitMultiplier) {
if (configuredMemorySize.length() < 2) {
throw new IllegalArgumentException("invalid format for memory size [" + configuredMemorySize + "]");
}
return new MemorySize(configuredMemorySize.substring(0, configuredMemorySize.length() - 1), unitMultiplier);
}
private static final class MemorySize {
private final String configuredMemorySizeWithoutUnit;
private final long multiplicationFactor;
private MemorySize(String configuredMemorySizeWithoutUnit, long multiplicationFactor) {
this.configuredMemorySizeWithoutUnit = configuredMemorySizeWithoutUnit;
this.multiplicationFactor = multiplicationFactor;
}
public long calculateMemorySizeInBytes() throws IllegalArgumentException {
try {
long memorySizeLong = Long.parseLong(configuredMemorySizeWithoutUnit);
long result = memorySizeLong * multiplicationFactor;
if (result < 0) {
throw new IllegalArgumentException("memory size cannot be negative");
}
return result;
} catch (NumberFormatException e) {
throw new IllegalArgumentException("invalid format for memory size");
}
}
}
}