67 lines
2.2 KiB
Java
67 lines
2.2 KiB
Java
import java.text.MessageFormat;
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import java.text.ParseException;
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public class CanonicalizeCIDR {
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public static void main(String[] args) {
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for (String test : TESTS) {
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try {
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CIDR cidr = new CIDR(test);
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System.out.printf("%-18s -> %s\n", test, cidr.toString());
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} catch (Exception ex) {
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System.err.printf("Error parsing '%s': %s\n", test, ex.getLocalizedMessage());
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}
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}
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}
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private static class CIDR {
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private CIDR(int address, int maskLength) {
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this.address = address;
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this.maskLength = maskLength;
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}
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private CIDR(String str) throws Exception {
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Object[] args = new MessageFormat(FORMAT).parse(str);
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int address = 0;
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for (int i = 0; i < 4; ++i) {
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int a = ((Number)args[i]).intValue();
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if (a < 0 || a > 255)
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throw new Exception("Invalid IP address");
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address <<= 8;
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address += a;
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}
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int maskLength = ((Number)args[4]).intValue();
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if (maskLength < 1 || maskLength > 32)
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throw new Exception("Invalid mask length");
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int mask = ~((1 << (32 - maskLength)) - 1);
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this.address = address & mask;
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this.maskLength = maskLength;
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}
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public String toString() {
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int address = this.address;
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int d = address & 0xFF;
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address >>= 8;
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int c = address & 0xFF;
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address >>= 8;
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int b = address & 0xFF;
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address >>= 8;
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int a = address & 0xFF;
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Object[] args = { a, b, c, d, maskLength };
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return new MessageFormat(FORMAT).format(args);
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}
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private int address;
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private int maskLength;
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private static final String FORMAT = "{0,number,integer}.{1,number,integer}.{2,number,integer}.{3,number,integer}/{4,number,integer}";
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};
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private static final String[] TESTS = {
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"87.70.141.1/22",
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"36.18.154.103/12",
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"62.62.197.11/29",
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"67.137.119.181/4",
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"161.214.74.21/24",
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"184.232.176.184/18"
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};
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}
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