Hello everyone
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];
//below are to change the sequence of char in h
// txt.edcba -> abcde.txt
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
