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Fix conversion of ip address to int #199

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Jun 20, 2017
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Fix conversion of ip address to int #199

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b1b34ad
Fix conversion of ip address to int
Jun 19, 2017
f3abc85
More readable test
Jun 20, 2017
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2 changes: 1 addition & 1 deletion jaeger-core/src/main/java/com/uber/jaeger/utils/Utils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ public static int ipToInt(String ip) throws EmptyIpException, NotFourOctetsExcep

int intIp = 0;
for (byte octet : octets.getAddress()) {
intIp = (intIp << 8) | (octet);
intIp = (intIp << 8) | (octet & 0xFF);
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for my education, since octet is already of type byte, why does & 0xFF make a difference?

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@mabn mabn Jun 20, 2017 •
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octet is promoted to integer via binary numeric promotion (https://docs.oracle.com/javase/specs/jls/se7/html/jls-5.html#jls-5.6.2), but it's a signed integer so the mask is filled with 1s on the left for negative numbers. & 0xFF converts it to unsigned (It's a byte so no need to care about int overflow. If it mattered then it should be 0xFFL). At least that's how I understand that.

In Java 8 that would instead be: Byte.toUnsignedInt(octet)

}
return intIp;
}
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23 changes: 19 additions & 4 deletions jaeger-core/src/test/java/com/uber/jaeger/UtilsTest.java
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Expand Up @@ -22,7 +22,9 @@

package com.uber.jaeger;

import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;

import com.uber.jaeger.exceptions.EmptyIpException;
import com.uber.jaeger.exceptions.NotFourOctetsException;
Expand All @@ -49,9 +51,22 @@ public void testIpToInt32EmptyIpException() {
}

@Test
public void testIpToInt32() {
int expectedIp = (127 << 24) | 1;
int actualIp = Utils.ipToInt("127.0.0.1");
assertEquals(expectedIp, actualIp);
public void testIpToInt32_localhost() {
assertThat(Utils.ipToInt("127.0.0.1"), equalTo((127 << 24) | 1));
}

@Test
public void testIpToInt32_above127() {
assertThat(Utils.ipToInt("10.137.1.2"), equalTo((10 << 24) | (137 << 16) | (1 << 8) | 2));
}

@Test
public void testIpToInt32_zeros() {
assertThat(Utils.ipToInt("0.0.0.0"), equalTo(0));
}

@Test
public void testIpToInt32_broadcast() {
assertThat(Utils.ipToInt("255.255.255.255"), equalTo(-1));
}
}