Crash when scrolling to the top

[Ricardo1980]

Sometimes, when I scroll the table (more than necessary) to see the header, the app stops for 60 seconds, and then after that it crashes giving this message. Probably it is a buffer overflow but I don't know where exactly.
Note that this happens when I scroll the table in a way that the index bar is resized to a very small size, I would say this is related.
I relayout the index bar when scrolling, because I want it below the headerview.
Currently I am using version 0.3.5

A workaround is to limit scrolling, like this:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    [self.indexView setNeedsLayout];

    // to avoid a weird crash
    if (scrollView.contentOffset.y < kTableViewScrollLimit) {
        scrollView.contentOffset = CGPointMake(0.0f, kTableViewScrollLimit);
    }
}

2016-01-29 10:57:08.858 BLABLA[87354:2740121] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM setObject:atIndex:]: index 18446744071562067968 beyond bounds [0 .. 2147483647]'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000112edee65 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x0000000112957deb objc_exception_throw + 48
    2   CoreFoundation                      0x0000000112e32454 -[__NSArrayM setObject:atIndex:] + 452
    3   GDIIndexBar                         0x000000010fbf0338 -[GDIIndexBar updateDisplayedIndexStrings] + 904
    4   GDIIndexBar                         0x000000010fbf1a69 -[GDIIndexBar drawRect:] + 121
    5   UIKit                               0x000000011098ff08 -[UIView(CALayerDelegate) drawLayer:inContext:] + 495
    6   QuartzCore                          0x000000011047b183 -[CALayer drawInContext:] + 257
    7   QuartzCore                          0x000000011037033d CABackingStoreUpdate_ + 2688
    8   QuartzCore                          0x000000011047b002 ___ZN2CA5Layer8display_Ev_block_invoke + 59
    9   QuartzCore                          0x000000011047ae80 _ZN2CA5Layer8display_Ev + 1460
    10  QuartzCore                          0x000000011046fc69 _ZN2CA5Layer17display_if_neededEPNS_11TransactionE + 293
    11  QuartzCore                          0x000000011046fcf9 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 35
    12  QuartzCore                          0x0000000110464475 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 277
    13  QuartzCore                          0x0000000110491c0a _ZN2CA11Transaction6commitEv + 486
    14  QuartzCore                          0x00000001104a09f4 _ZN2CA7Display11DisplayLink14dispatch_itemsEyyy + 576
    15  CoreFoundation                      0x0000000112e3ec84 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
    16  CoreFoundation                      0x0000000112e3e831 __CFRunLoopDoTimer + 1089
    17  CoreFoundation                      0x0000000112e00241 __CFRunLoopRun + 1937
    18  CoreFoundation                      0x0000000112dff828 CFRunLoopRunSpecific + 488
    19  GraphicsServices                    0x0000000115bcead2 GSEventRunModal + 161
    20  UIKit                               0x00000001108d9610 UIApplicationMain + 171
    21  WorkAngel                           0x000000010d5611a3 main + 147
    22  libdyld.dylib                       0x000000011388e92d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException