[swift-corelibs-dev] NSRegularExpression.firstMatchInString() fails on Linux

[Mamatha Busi]

Hi Tony,

Thank you for the comments.

PR  is created: 
https://github.com/apple/swift-corelibs-foundation/pull/282

Regards,
Mamatha


































From:   Tony Parker <anthony.parker at apple.com>
To:     Mamatha Busi/India/IBM at IBMIN
Cc:     Philippe Hausler <phausler at apple.com>, 
swift-corelibs-dev at swift.org
Date:   03/08/2016 11:11 PM
Subject:        Re: [swift-corelibs-dev] 
NSRegularExpression.firstMatchInString() fails  on Linux
Sent by:        anthony.parker at apple.com



Hi Mamatha,

On Mar 8, 2016, at 4:15 AM, Mamatha Busi <mamabusi at in.ibm.com> wrote:

 @Philippe Hausler, @Tony Parker: Thank you for the response. 

As per Tony's suggestions I have translated CF's kCFNotFound into an 
NSNotFound of Foundation in 'NSTextCheckingResult'  (the place where the 
ranges are being constructed). Below is the code snippet with the changes:

 _regularExpression = regularExpression
        super.init()
        let notFound = NSRange(location: NSNotFound,length: 0)
        for i in 0..<count {
            ranges[i].location == kCFNotFound ? _ranges.append(notFound) : 
_ranges.append(ranges[i])
        }

@Philippe: Request your comments on the above code changes.

TestFoundation has been run and I see no failures with the above changes.

The tests 'test_complexRegularExpressions' in the  TestNSRegularExpression 
were excluded till date. I am now running the excluded tests as well and 
there are a few test-cases here which deal with the ranges having 
NSNotFound. Along with these should there be more tests written to test 
the same? 


Sure, more tests are always a bonus.

Please open a PR on swift-corelibs-foundatation when you’re ready to get a 
review.

Thanks for tackling this!
- Tony

Regards
Mamatha


Mamatha Busi

<Mail Attachment.gif>
Java L3 Support

IBM Software Group
 
India Software Labs
 



 



 

e-mail:
mamabusi at in.ibm.com
 

Java Technology India Group
 








From:        Philippe Hausler <phausler at apple.com>
To:        Tony Parker <anthony.parker at apple.com>
Cc:        Mamatha Busi/India/IBM at IBMIN, swift-corelibs-dev at swift.org
Date:        03/04/2016 12:02 AM
Subject:        Re: [swift-corelibs-dev] 
NSRegularExpression.firstMatchInString() fails        on Linux
Sent by:        phausler at apple.com




On Mar 3, 2016, at 10:22 AM, Tony Parker via swift-corelibs-dev <
swift-corelibs-dev at swift.org> wrote:

Hi Mamatha,

On Mar 2, 2016, at 3:57 AM, Mamatha Busi via swift-corelibs-dev <
swift-corelibs-dev at swift.org> wrote:

Hello

The following test case, that currently fails on Linux,  is extracted from 
some of the excluded tests inside TestFoundation/TestNSRegularExpression. 

import Foundation

let searchStr = "123"
let testRegex = try NSRegularExpression.init(pattern: 
"a(b|c|d)(x|y|z)*|123", options: [])
let firstMatch = testRegex.firstMatchInString(searchStr, options: [], 
range: NSMakeRange(0,3))

if NSEqualRanges((firstMatch!.rangeAtIndex(1), NSMakeRange(NSNotFound,0)) 
{
   print("Test passed")
} else {
   print("First match first capture range = 
\(NSStringFromRange(firstMatch!.rangeAtIndex(1)))")
   print("Test failed")
}



In the above scenario, no capture group participates in the match. So, 
firstMatch.rangeAtIndex(1) should ideally return range {NSNotFound, 0} but 
the actual returned value is range {-1, 0}. Hence the failure.

Debugging on the CoreFoundation, it is observed that the value -1 is 
coming from 'kCFNotFound' which is defined as -1. On the Foundation side, 
'NSNotFound' is defined with the value of ‘Int.max’ (which must be 
Int32.max and Int64.max on 32 and 64 bit platforms respectively).

There are a couple of queries that I have:

-> Is 'NSNotFound' in Foundation mapped  to 'kCFNotFound'  in 
CoreFoundation?

-> If so, then why do 'NSNotFound' and 'kCFNotFound' have different values 
on the Foundation and CoreFoundation respectively?


They don’t have the same value; we translate it manually in most places.

Also, I tested by modifying the 'kCFNotFound' value in 
CoreFoundation/Base.subproj/CFBase.h  (See below code snippet):

#if TARGET_RT_64_BIT
static const CFIndex kCFNotFound = LONG_MAX;
#else
static const CFIndex kCFNotFound = INT_MAX;
#endif


With this change the above mentioned test-case passes but a lot of other 
TestFoundation tests seem to fail.

Please provide your comments on the appropriate change that is needed 
here. 

Thank you.

I think we probably just need to check the result from the CF function and 
translate it into an NSNotFound in this one particular case.

I think the problem in this case is that we fetch a buffer of CFRanges and 
pass that to the result creation.

ranges: UnsafeMutablePointer<CFRange>
...
let result = 
NSTextCheckingResult.regularExpressionCheckingResultWithRanges(NSRangePointer(ranges), 
count: count, regularExpression: matcher.regex)


Thanks,
- Tony


Regards
Mamatha


Mamatha Busi

<Mail Attachment.gif>
Java L3 Support

IBM Software Group
 
India Software Labs
 



 



 

e-mail:
mamabusi at in.ibm.com
 

Java Technology India Group
 






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