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Generate random strings in Objective-C
/*
* Copyright (C) 2011 Michael Dippery <mdippery@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#import <Foundation/Foundation.h>
@interface NSString (Randomized)
+ (NSString *)defaultAlphabet;
+ (id)randomizedString;
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet;
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet length:(NSUInteger)len;
- (id)initWithDefaultAlphabet;
- (id)initWithAlphabet:(NSString *)alphabet;
- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len;
@end
/*
* Copyright (C) 2011 Michael Dippery <mdippery@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#import "NSString+Random.h"
#include <stdlib.h>
#define DEFAULT_LENGTH 8
@implementation NSString (Randomized)
+ (NSString *)defaultAlphabet
{
return @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXZY0123456789";
}
+ (id)randomizedString
{
return [self randomizedStringWithAlphabet:[self defaultAlphabet]];
}
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet
{
return [self randomizedStringWithAlphabet:alphabet length:DEFAULT_LENGTH];
}
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet length:(NSUInteger)len
{
return [[[self alloc] initWithAlphabet:alphabet length:len] autorelease];
}
- (id)initWithDefaultAlphabet
{
return [self initWithAlphabet:[NSString defaultAlphabet]];
}
- (id)initWithAlphabet:(NSString *)alphabet
{
return [self initWithAlphabet:alphabet length:DEFAULT_LENGTH];
}
- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len
{
[self release];
NSMutableString *s = [NSMutableString stringWithCapacity:len];
for (NSUInteger i = 0U; i < len; i++) {
u_int32_t r = arc4random() % [alphabet length];
unichar c = [alphabet characterAtIndex:r];
[s appendFormat:@"%C", c];
}
return [NSString stringWithString:s];
}
@end
/*
* Copyright (C) 2011 Michael Dippery <mdippery@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#import <Foundation/Foundation.h>
@interface NSString (Randomized)
+ (NSString *)defaultAlphabet;
+ (id)randomizedString;
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet;
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet length:(NSUInteger)len;
- (id)initWithDefaultAlphabet;
- (id)initWithAlphabet:(NSString *)alphabet;
- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len;
@end
/*
* Copyright (C) 2011 Michael Dippery <mdippery@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#import "NSString+Random.h"
#include <stdlib.h>
#define DEFAULT_LENGTH 8
@implementation NSString (Randomized)
+ (NSString *)defaultAlphabet
{
return @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXZY0123456789";
}
+ (id)randomizedString
{
return [self randomizedStringWithAlphabet:[self defaultAlphabet]];
}
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet
{
return [self randomizedStringWithAlphabet:alphabet length:DEFAULT_LENGTH];
}
+ (id)randomizedStringWithAlphabet:(NSString *)alphabet length:(NSUInteger)len
{
return [[[self alloc] initWithAlphabet:alphabet length:len] autorelease];
}
- (id)initWithDefaultAlphabet
{
return [self initWithAlphabet:[NSString defaultAlphabet]];
}
- (id)initWithAlphabet:(NSString *)alphabet
{
return [self initWithAlphabet:alphabet length:DEFAULT_LENGTH];
}
- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len
{
[self release];
NSMutableString *s = [NSMutableString stringWithCapacity:len];
for (NSUInteger i = 0U; i < len; i++) {
u_int32_t r = arc4random() % [alphabet length];
unichar c = [alphabet characterAtIndex:r];
[s appendFormat:@"%C", c];
}
return [s copy];
}
@end
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@RSully RSully commented Nov 11, 2011

Line 67, might be better as %C since it's unichar, or am I wrong?

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@mdippery mdippery commented Nov 11, 2011

Yeah, that is better.

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@A-Zak A-Zak commented Dec 28, 2011

Line 47, I would put an autorelease there. or rename the class methods to "newRandomizedString....".
but I would definitely autorelease... :)

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@A-Zak A-Zak commented Dec 28, 2011

And why did you provide two .m files?

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@mdippery mdippery commented Dec 28, 2011

Yeah, I forgot the autorelease.

Re: the two .m files, I think that's due to a bug with gist (the "extra" one can't be deleted, and I didn't add it explicitly).

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@mdippery mdippery commented Dec 28, 2011

Correction: it can't be deleted through the web interface. ;)

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@A-Zak A-Zak commented Dec 28, 2011

Nice... :)
now how bout the .h file?

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@mdippery mdippery commented Dec 28, 2011

I can include it. I didn't before since this was just an example.

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@A-Zak A-Zak commented Dec 28, 2011

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@A-Zak A-Zak commented Dec 28, 2011

Thanks mate! :)

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@mdippery mdippery commented Dec 28, 2011

Yeah. I had used it in a project, and copy/pasted it from the project to gist to send to someone (probably on a forum or something).

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@A-Zak A-Zak commented Dec 28, 2011

fair enough... :)
now it's a complete drop in category... just like it should be... :)

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@elsurudo elsurudo commented Apr 26, 2012

You've got a memory management problem.

Replace the last method with this:

- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len- (id)initWithAlphabet:(NSString *)alphabet length:(NSUInteger)len
{
    NSMutableString *s = [[NSMutableString alloc] initWithCapacity:len];
    for (NSUInteger i = 0U; i < len; i++) {
        u_int32_t r = arc4random() % [alphabet length];
        unichar c = [alphabet characterAtIndex:r];
        [s appendFormat:@"%C", c];
    }
    return s;
}

By the way, there's no need to create an NSString at the end; just return the NSMutableString, since it's a subclass.

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@mdippery mdippery commented Apr 26, 2012

Whoops, thanks for the catch.

As for creating an NSString at the end, I prefer to return immutable objects unless a mutable one is necessary, but an NSMutableString would work, too.

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