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Re: Reading in dictionary from txt file: options for speed
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Re: Reading in dictionary from txt file: options for speed


  • Subject: Re: Reading in dictionary from txt file: options for speed
  • From: Miles <email@hidden>
  • Date: Thu, 16 Apr 2009 17:09:13 -0700

I'm all for just a little guidance, and thank you for it. Everything you
said makes sense now, and I have it working:

    NSString *searchStr        = @"\nJOY\n";
    const char *cString         = [searchStr UTF8String];
    const char *fileBytes      = [stringFileContents bytes];
    char *ptr                        = strstr(fileBytes, cString);

Thanks again




On Thu, Apr 16, 2009 at 4:43 PM, Greg Guerin <email@hidden> wrote:

> Miles wrote:
>
>     NSString *searchStr        = @"\njoy\n";
>>    NSData *strData            = [searchStr
>> dataUsingEncoding:NSUTF8StringEncoding];
>>    const char *strBytes    = [strData bytes];
>>
>
> Think about what you're doing here, then look at the NSString method
> -UTF8String.
>
> Also, think about whether dataUsingEncoding: includes or excludes a
> terminating null.  For example, if searchStr were assigned @"", what is the
> length of the resulting strData, and exactly what does [strData bytes]
> return?  A combination of referring to reference docs and some experimenting
> is the usual approach here.
>
> Next, consider the above in light of the args to strstr(), which are
> expected to be null-terminated C-style strings.
>
> Finally, consider what happens if searchStr isn't found.  I urge you to try
> it with a searchStr assigned a misspelled word like @"spelchek".
>
> If it seems like I'm asking you to debug and understand your own code
> without asking the list for the complete answer, you're right.  This is a
> pretty elementary example to work on, and there's no substitute for being
> able to figure it out for yourself.  If you can't debug this one without
> direct assistance, you will be lost at sea when the debugging gets harder
> (and it WILL get harder).
>
>  -- GG
>
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  • Follow-Ups:
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 >Re: Reading in dictionary from txt file: options for speed (From: Greg Guerin <email@hidden>)

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