function to get the file name of an URL

Question

I have some source code to get the file name of an url

for example:

http://www.google.com/a.pdf

I hope to get a.pdf

because the way to join 2 NSStrings I can get is 'appendString' which only for adding a string at right side, so I planned to check each char one by one from the right side of string 'http://www.google.com/a.pdf', when it reach at the char '/', stop the checking, return string fdp.a , after that I change fdp.a to a.pdf

source codes are below

-(NSMutableString *) getSubStringAfterH :  originalString:(NSString *)s0  {     NSInteger i,l;     l=[s0 length];     NSMutableString *h=[[NSMutableString alloc] init];      NSMutableString *ttt=[[NSMutableString alloc] init  ];      for(i=l-1;i>=0;i--) //check each char one by one from the right side of string 'http://www.google.com/a.pdf', when it reach at the char '/', stop     {         ttt=[s0 substringWithRange:NSMakeRange(i, 1)];          if([ttt isEqualToString:@"/"])          {              break;         }             else         {              [h appendString:ttt];         }       }      [ttt release];      NSMutableString *h1=[[[NSMutableString alloc] initWithFormat:@""] autorelease];      for (i=[h length]-1;i>=0;i--)     {             NSMutableString *t1=[[NSMutableString alloc] init ];         t1=[h substringWithRange:NSMakeRange(i, 1)];         [h1 appendString:t1];             [t1 release];     }      [h release];     return h1; } 

h1 can reuturn the coorect string a.pdf, but if it returns to the codes where it was called, after a while system reports 'double free *** set a breakpoint in malloc_error_break to debug'

I checked a long time and foudn that if I removed the code

ttt=[s0 substringWithRange:NSMakeRange(i, 1)];

everything will be Ok (of course getSubStringAfterH can not returns the corrent result I expected.), no error reported.

I try to fix the bug a few hours, but still no clue.

Welcome any comment

Thanks interdev

Answer 1

The following line does the job if url is a NSString:

NSString *filename = [url lastPathComponent]; 

If url is a NSURL, then the following does the job:

NSString *filename = [[url path] lastPathComponent];