Aditi16 / jss7

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RuleComparator bug - Infinite loop - java.lang.StackOverflowError #337

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago
What steps will reproduce the problem?
1. Add two SccpAddresses with similar patterns like "1/????" and "2/????".
2. Number of the "?" must be equal after separator "/"

What is the expected output? What do you see instead?
Expected: Rule added.
Instead: java.lang.StackOverflowError.

What version of the product are you using? On what operating system?
jSS7 2.1.0.FINAL, Windows 8.1 x64

Please provide any additional information below.
Stack trace:
Exception in thread "main" java.lang.StackOverflowError
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:135)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)
    at org.mobicents.protocols.ss7.sccp.impl.router.RuleComparator.compareQuestionMarksIndex(RuleComparator.java:144)

Found cause in method:
private int compareQuestionMarksIndex(String digits1, int fromIndex1, String 
digits2, int fromIndex2){
...
                     // Keep comparing occurrence of "?" till difference is reached
line 144:            compareQuestionMarksIndex(digits1, index1, digits2, 
index2);

Solution is to change it to:
            // Keep comparing occurrence of "?" till difference is reached
            compareQuestionMarksIndex(digits1, index1 + 1, digits2, index2 + 1);

Because:
        int index1 = digits1.indexOf(WILDCARD_SINGLE, fromIndex1);
        int index2 = digits2.indexOf(WILDCARD_SINGLE, fromIndex2);

will produce the same indexes:
        index1 = fromIndex1
and
        index2 = fromIndex2

and call of the compareQuestionMarksIndex will enter in infinite loop - 
compareQuestionMarksIndex will be called with the same index values.

After correction no exception is thrown and rule is successfully added.

Original issue reported on code.google.com by asimil...@gmail.com on 18 Feb 2015 at 1:39