What is the use of NSMakeRange in Objective-C? - objective-c

I am new in Objective-C and have been using NSRange most of the time in my code.
I have just came to know that there is NSMakeRange. So, I just want to know - what is the use of NSMakeRange?

It's a convenience inline function, used to create an NSRange struct, populate it and return it:
(from .../Foundation.framework/Headers/NSRange.h)
NS_INLINE NSRange NSMakeRange(NSUInteger loc, NSUInteger len) {
NSRange r;
r.location = loc;
r.length = len;
return r;
}
It makes it simpler to create ranges; compare:
unichar buffer[8];
[someString getCharacters:buffer range:NSMakeRange(2, 8)];
to:
unichar buffer[8];
NSRange range = { 2, 8 };
[someString getCharacters:buffer range:range];

It's just a convenience function. It allows you to replace this:
NSRange r;
r.location = 1;
r.length = 2;
DoSomething(r);
with this:
DoSomething(NSMakeRange(1, 2));

NSMakeRange(5, 1) creates a range with location 5 and length 1. See the documentation for further information and related functions.
Alt-click the function name in Xcode, you’ll get a reference.

Well, it's to make range with specified two values. Some of the Objective-C APIs will require you to use this.

From Apple's documentation:
A structure used to describe a portion of a series—such as characters
in a string or objects in an NSArray object.
typedef struct _NSRange {
NSUInteger location;
NSUInteger length; } NSRange;
There are many ways of creating a NSRange object,
1 - using NSMakeRange
NSRange range = NSMakeRange(10, 50);
2 - By specifying within {}
NSRange range = {10,50};
3 - By properties
NSRange range;
range.location = 10;
range.length = 50;
Using either won't make much difference, but using NSMakeRange will definitely make your code more readable.

Related

Enumerate NSString characters via pointer

How can I enumerate NSString by pulling each unichar out of it? I can use characterAtIndex but that is slower than doing it by an incrementing unichar*. I didn't see anything in Apple's documentation that didn't require copying the string into a second buffer.
Something like this would be ideal:
for (unichar c in string) { ... }
or
unichar* ptr = (unichar*)string;
You can speed up -characterAtIndex: by converting it to it's IMP form first:
NSString *str = #"This is a test";
NSUInteger len = [str length]; // only calling [str length] once speeds up the process as well
SEL sel = #selector(characterAtIndex:);
// using typeof to save my fingers from typing more
unichar (*charAtIdx)(id, SEL, NSUInteger) = (typeof(charAtIdx)) [str methodForSelector:sel];
for (int i = 0; i < len; i++) {
unichar c = charAtIdx(str, sel, i);
// do something with C
NSLog(#"%C", c);
}
EDIT: It appears that the CFString Reference contains the following method:
const UniChar *CFStringGetCharactersPtr(CFStringRef theString);
This means you can do the following:
const unichar *chars = CFStringGetCharactersPtr((__bridge CFStringRef) theString);
while (*chars)
{
// do something with *chars
chars++;
}
If you don't want to allocate memory for coping the buffer, this is the way to go.
Your only option is to copy the characters into a new buffer. This is because the NSString class does not guarantee that there is an internal buffer you can use. The best way to do this is to use the getCharacters:range: method.
NSUInteger i, length = [string length];
unichar *buffer = malloc(sizeof(unichar) * length);
NSRange range = {0,length};
[string getCharacters:buffer range:range];
for(i = 0; i < length; ++i) {
unichar c = buffer[i];
}
If you are using potentially very long strings, it would be better to allocate a fixed size buffer and enumerate the string in chunks (this is actually how fast enumeration works).
I created a block-style enumeration method that uses getCharacters:range: with a fixed-size buffer, as per ughoavgfhw's suggestion in his answer. It avoids the situation where CFStringGetCharactersPtr returns null and it doesn't have to malloc a large buffer. You can drop it into an NSString category, or modify it to take a string as a parameter if you like.
-(void)enumerateCharactersWithBlock:(void (^)(unichar, NSUInteger, BOOL *))block
{
const NSInteger bufferSize = 16;
const NSInteger length = [self length];
unichar buffer[bufferSize];
NSInteger bufferLoops = (length - 1) / bufferSize + 1;
BOOL stop = NO;
for (int i = 0; i < bufferLoops; i++) {
NSInteger bufferOffset = i * bufferSize;
NSInteger charsInBuffer = MIN(length - bufferOffset, bufferSize);
[self getCharacters:buffer range:NSMakeRange(bufferOffset, charsInBuffer)];
for (int j = 0; j < charsInBuffer; j++) {
block(buffer[j], j + bufferOffset, &stop);
if (stop) {
return;
}
}
}
}
The fastest reliable way to enumerate characters in an NSString I know of is to use this relatively little-known Core Foundation gem hidden in plain sight (CFString.h).
NSString *string = <#initialize your string#>
NSUInteger stringLength = string.length;
CFStringInlineBuffer buf;
CFStringInitInlineBuffer((__bridge CFStringRef) string, &buf, (CFRange) { 0, stringLength });
for (NSUInteger charIndex = 0; charIndex < stringLength; charIndex++) {
unichar c = CFStringGetCharacterFromInlineBuffer(&buf, charIndex);
}
If you look at the source code of these inline functions, CFStringInitInlineBuffer() and CFStringGetCharacterFromInlineBuffer(), you'll see that they handle all the nasty details like CFStringGetCharactersPtr() returning NULL, CFStringGetCStringPtr() returning NULL, defaulting to slower CFStringGetCharacters() and caching the characters in a C array for fastest access possible. This API really deserves more publicity.
The caveat is that if you initialize the CFStringInlineBuffer at a non-zero offset, you should pass a relative character index to CFStringInlineBuffer(), as stated in the header comments:
The next two functions allow fast access to the contents of a string, assuming you are doing sequential or localized accesses. To use, call CFStringInitInlineBuffer() with a CFStringInlineBuffer (on the stack, say), and a range in the string to look at. Then call CFStringGetCharacterFromInlineBuffer() as many times as you want, with a index into that range (relative to the start of that range). These are INLINE functions and will end up calling CFString only once in a while, to fill a buffer. CFStringGetCharacterFromInlineBuffer() returns 0 if a location outside the original range is specified.
I don't think you can do this. NSString is an abstract interface to a multitude of classes that make no guarantees about the internal storage of the character data, so it's entirely possible there is no character array to get a pointer to.
If neither of the options mentioned in your question are suitable for your app, I'd recommend either creating your own string class for this purpose, or using raw malloc'ed unichar arrays instead of string objects.
This will work:
char *s = [string UTF8String];
for (char *t = s; *t; t++)
/* use as */ *t;
[Edit] And if you really need unicode characters then you have no option but to use length and characterAtIndex. From the documentation:
The NSString class has two primitive methods—length and characterAtIndex:—that provide the basis for all other methods in its interface. The length method returns the total number of Unicode characters in the string. characterAtIndex: gives access to each character in the string by index, with index values starting at 0.
So your code would be:
for (int index = 0; index < string.length; index++)
{
unichar c = [string characterAtIndex: index];
/* ... */
}
[edit 2]
Also, don't forget that NSString is 'toll-free bridged' to CFString and thus all the non-Objective-C, straight C-code interface functions are usable. The relevant one would be CFStringGetCharacterAtIndex

Looping using NSRange

I'm trying to use NSRange to hold a range of years, such as
NSRange years = NSMakeRange(2011, 5);
I know NSRange is used mostly for filtering, however I want to loop over the elements in the range. Is that possible without converting the NSRange into a NSArray?
It kind of sounds like you're expecting NSRange to be like a Python range object. It's not; NSRange is simply a struct
typedef struct _NSRange {
NSUInteger location;
NSUInteger length;
} NSRange;
not an object. Once you've created one, you can use its members in a plain old for loop:
NSUInteger year;
for(year = years.location; year < NSMaxRange(years); year++ ){
// Do your thing.
}
(Still working on the assumption that you're thinking about Python.) There's syntax in ObjC called fast enumeration for iterating over the contents of an NSArray that is pleasantly similar to a Python for loop, but since literal and primitive numbers can't be put into an NSArray, you can't go directly from an NSRange to a Cocoa array.
A category could make that easier, though:
#implementation NSArray (WSSRangeArray)
+ (id)WSSArrayWithNumbersInRange:(NSRange)range
{
NSMutableArray * arr = [NSMutableArray array];
NSUInteger i;
for( i = range.location; i < NSMaxRange(range); i++ ){
[arr addObject:[NSNumber numberWithUnsignedInteger:i]];
}
return arr;
}
Then you can create an array and use fast enumeration:
NSArray * years = [NSArray WSSArrayWithNumbersInRange:NSMakeRange(2011, 5)];
for( NSNumber * yearNum in years ){
NSUInteger year = [yearNum unsignedIntegerValue];
// and so on...
}
Remember that a NSRange is a structure holding two integers, representing the start and length of the range. You can easily loop over all of the contained integers using a for loop.
NSRange years = NSMakeRange(2011, 5);
NSUInteger year;
for(year = years.location; year < years.location + years.length; ++year) {
// Use the year variable here
}
This is a bit of an old question, but an alternative to using an NSArray would be to create an NSIndexSet with the desired range (using indexWithIndexesInRange: or initWithIndexesInRange:) and then using block enumeration as in https://stackoverflow.com/a/4209289/138772. (Seemed relevant as I was just checking on this myself.)
My alternate solution for this, was to define a macro just to make shorthand quicker.
#define NSRangeEnumerate(i, range) for(i = range.location; i < NSMaxRange(range); ++i)
To call it you do:
NSArray *array = #[]; // must contain at least the following range...
NSRange range = NSMakeRange(2011, 5);
NSUInteger i;
NSRangeEnumerate(i, range) {
id item = array[i];
// do your thing
}
personally I am still trying to figure out how I can write the macro so I can just call it like:
NSRangeEnumerate(NSUInteger i, range) {
}
which is not supported just yet... hope that helps or makes typing your program quicker

Passing NSArray to a cpp function

I need to call a cpp function like
void myFunc(float **array2D, int rows, int cols)
{
}
within an objective-c object. Basically, the array is created in my objective-c code as I create an NSArray object. Now, the problem is how to pass this array to my cpp function.
I am a bit new to these mixed c++/objective-c stuffs so any hint will be highly appreciated.
Thanks
I guess you have to convert the NSArray to a plain C array.
Something like:
NSArray *myNSArray; // your NSArray
int count = [myNSArray count];
float *array = new float[count];
for(int i=0; i<count; i++) {
array[i] = [[myNSArray objectAtIndex:i] floatValue];
}
or, as a commenter suggested (assuming your NSArray contains NSNumbers):
NSArray *myNSArray; // your NSArray
int count = [myNSArray count];
float *array = new float[count];
int i = 0;
for(NSNumber *number in myNSArray) {
array[i++] = [number floatValue];
}
Look at this post.
Check out the answer that mentions using [NSArray getObjects] to create a c-style array.
Here's the code that the poster put in there:
NSArray *someArray = /* .... */;
NSRange copyRange = NSMakeRange(0, [someArray count]);
id *cArray = malloc(sizeof(id *) * copyRange.length);
[someArray getObjects:cArray range:copyRange];
/* use cArray somewhere */
free(cArray);
Alternately, since CFArray is toll-free bridged to NSArray, could you call those C functions from your C++ function? I'd look around, wouldn't be surprised if there weren't a C++ wrapper to give similar semantics, or one could be written easily enough.

Most efficient way to iterate over all the chars in an NSString

What's the best way to iterate over all the chars in an NSString? Would you want to loop over the length of the string and use the method.
[aNSString characterAtIndex:index];
or would you want to user a char buffer based on the NSString?
I think it's important that people understand how to deal with unicode, so I ended up writing a monster answer, but in the spirit of tl;dr I will start with a snippet that should work fine. If you want to know details (which you should!), please continue reading after the snippet.
NSUInteger len = [str length];
unichar buffer[len+1];
[str getCharacters:buffer range:NSMakeRange(0, len)];
NSLog(#"getCharacters:range: with unichar buffer");
for(int i = 0; i < len; i++) {
NSLog(#"%C", buffer[i]);
}
Still with me? Good!
The current accepted answer seem to be confusing bytes with characters/letters. This is a common problem when encountering unicode, especially from a C background. Strings in Objective-C are represented as unicode characters (unichar) which are much bigger than bytes and shouldn't be used with standard C string manipulation functions.
(Edit: This is not the full story! To my great shame, I'd completely forgotten to account for composable characters, where a "letter" is made up of multiple unicode codepoints. This gives you a situation where you can have one "letter" resolving to multiple unichars, which in turn are multiple bytes each. Hoo boy. Please refer to this great answer for the details on that.)
The proper answer to the question depends on whether you want to iterate over the characters/letters (as distinct from the type char) or the bytes of the string (what the type char actually means). In the spirit of limiting confusion, I will use the terms byte and letter from now on, avoiding the possibly ambigious term character.
If you want to do the former and iterate over the letters in the string, you need to exclusively deal with unichars (sorry, but we're in the future now, you can't ignore it anymore). Finding the amount of letters is easy, it's the string's length property. An example snippet is as such (same as above):
NSUInteger len = [str length];
unichar buffer[len+1];
[str getCharacters:buffer range:NSMakeRange(0, len)];
NSLog(#"getCharacters:range: with unichar buffer");
for(int i = 0; i < len; i++) {
NSLog(#"%C", buffer[i]);
}
If, on the other hand, you want to iterate over the bytes in a string, it starts getting complicated and the result will depend entirely upon the encoding you choose to use. The decent default choice is UTF8, so that's what I will show.
Doing this you have to figure out how many bytes the resulting UTF8 string will be, a step where it's easy to go wrong and use the string's -length. One main reason this very easy to do wrong, especially for a US developer, is that a string with letters falling into the 7-bit ASCII spectrum will have equal byte and letter lengths. This is because UTF8 encodes 7-bit ASCII letters with a single byte, so a simple test string and basic english text might work perfectly fine.
The proper way to do this is to use the method -lengthOfBytesUsingEncoding:NSUTF8StringEncoding (or other encoding), allocate a buffer with that length, then convert the string to the same encoding with -cStringUsingEncoding: and copy it into that buffer. Example code here:
NSUInteger byteLength = [str lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
char proper_c_buffer[byteLength+1];
strncpy(proper_c_buffer, [str cStringUsingEncoding:NSUTF8StringEncoding], byteLength);
NSLog(#"strncpy with proper length");
for(int i = 0; i < byteLength; i++) {
NSLog(#"%c", proper_c_buffer[i]);
}
Just to drive the point home as to why it's important to keep things straight, I will show example code that handles this iteration in four different ways, two wrong and two correct. This is the code:
#import <Foundation/Foundation.h>
int main() {
NSString *str = #"буква";
NSUInteger len = [str length];
// Try to store unicode letters in a char array. This will fail horribly
// because getCharacters:range: takes a unichar array and will probably
// overflow or do other terrible things. (the compiler will warn you here,
// but warnings get ignored)
char c_buffer[len+1];
[str getCharacters:c_buffer range:NSMakeRange(0, len)];
NSLog(#"getCharacters:range: with char buffer");
for(int i = 0; i < len; i++) {
NSLog(#"Byte %d: %c", i, c_buffer[i]);
}
// Copy the UTF string into a char array, but use the amount of letters
// as the buffer size, which will truncate many non-ASCII strings.
strncpy(c_buffer, [str UTF8String], len);
NSLog(#"strncpy with UTF8String");
for(int i = 0; i < len; i++) {
NSLog(#"Byte %d: %c", i, c_buffer[i]);
}
// Do It Right (tm) for accessing letters by making a unichar buffer with
// the proper letter length
unichar buffer[len+1];
[str getCharacters:buffer range:NSMakeRange(0, len)];
NSLog(#"getCharacters:range: with unichar buffer");
for(int i = 0; i < len; i++) {
NSLog(#"Letter %d: %C", i, buffer[i]);
}
// Do It Right (tm) for accessing bytes, by using the proper
// encoding-handling methods
NSUInteger byteLength = [str lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
char proper_c_buffer[byteLength+1];
const char *utf8_buffer = [str cStringUsingEncoding:NSUTF8StringEncoding];
// We copy here because the documentation tells us the string can disappear
// under us and we should copy it. Just to be safe
strncpy(proper_c_buffer, utf8_buffer, byteLength);
NSLog(#"strncpy with proper length");
for(int i = 0; i < byteLength; i++) {
NSLog(#"Byte %d: %c", i, proper_c_buffer[i]);
}
return 0;
}
Running this code will output the following (with NSLog cruft trimmed out), showing exactly HOW different the byte and letter representations can be (the two last outputs):
getCharacters:range: with char buffer
Byte 0: 1
Byte 1:
Byte 2: C
Byte 3:
Byte 4: :
strncpy with UTF8String
Byte 0: Ð
Byte 1: ±
Byte 2: Ñ
Byte 3:
Byte 4: Ð
getCharacters:range: with unichar buffer
Letter 0: б
Letter 1: у
Letter 2: к
Letter 3: в
Letter 4: а
strncpy with proper length
Byte 0: Ð
Byte 1: ±
Byte 2: Ñ
Byte 3:
Byte 4: Ð
Byte 5: º
Byte 6: Ð
Byte 7: ²
Byte 8: Ð
Byte 9: °
While Daniel's solution will probably work most of the time, I think the solution is dependent on the context. For example, I have a spelling app and need to iterate over each character as it appears onscreen which may not correspond to the way it is represented in memory. This is especially true for text provided by the user.
Using something like this category on NSString:
- (void) dumpChars
{
NSMutableArray *chars = [NSMutableArray array];
NSUInteger len = [self length];
unichar buffer[len+1];
[self getCharacters: buffer range: NSMakeRange(0, len)];
for (int i=0; i<len; i++) {
[chars addObject: [NSString stringWithFormat: #"%C", buffer[i]]];
}
NSLog(#"%# = %#", self, [chars componentsJoinedByString: #", "]);
}
And feeding it a word like mañana might produce:
mañana = m, a, ñ, a, n, a
But it could just as easily produce:
mañana = m, a, n, ̃, a, n, a
The former will be produced if the string is in precomposed unicode form and the later if it's in decomposed form.
You might think this could be avoided by using the result of NSString's precomposedStringWithCanonicalMapping or precomposedStringWithCompatibilityMapping, but this is not necessarily the case as Apple warns in Technical Q&A 1225. For example a string like e̊gâds (which I totally made up) still produces the following even after converting to a precomposed form.
e̊gâds = e, ̊, g, â, d, s
The solution for me is to use NSString's enumerateSubstringsInRange passing NSStringEnumerationByComposedCharacterSequences as the enumeration option. Rewriting the earlier example to look like this:
- (void) dumpSequences
{
NSMutableArray *chars = [NSMutableArray array];
[self enumerateSubstringsInRange: NSMakeRange(0, [self length]) options: NSStringEnumerationByComposedCharacterSequences
usingBlock: ^(NSString *inSubstring, NSRange inSubstringRange, NSRange inEnclosingRange, BOOL *outStop) {
[chars addObject: inSubstring];
}];
NSLog(#"%# = %#", self, [chars componentsJoinedByString: #", "]);
}
If we feed this version e̊gâds then we get
e̊gâds = e̊, g, â, d, s
as expected, which is what I want.
The section of documentation on Characters and Grapheme Clusters may also be helpful in explaining some of this.
Note: Looks like some of the unicode strings I used are tripping up SO when formatted as code. The strings I used are mañana, and e̊gâds.
Neither. The "Optimize Your Text Manipulations" section of the "Cocoa Performance Guidelines" in the Xcode Documentation recommends:
If you want to iterate over the
characters of a string, one of the
things you should not do is use the
characterAtIndex: method to retrieve
each character separately. This method
is not designed for repeated access.
Instead, consider fetching the
characters all at once using the
getCharacters:range: method and
iterating over the bytes directly.
If you want to search a string for
specific characters or substrings, do
not iterate through the characters one
by one. Instead, use higher level
methods such as rangeOfString:,
rangeOfCharacterFromSet:, or
substringWithRange:, which are
optimized for searching the NSString
characters.
See this Stack Overflow answer on How to remove whitespace from right end of NSString for an example of how to let rangeOfCharacterFromSet: iterate over the characters of the string instead of doing it yourself.
I would definitely get a char buffer first, then iterate over that.
NSString *someString = ...
unsigned int len = [someString length];
char buffer[len];
//This way:
strncpy(buffer, [someString UTF8String]);
//Or this way (preferred):
[someString getCharacters:buffer range:NSMakeRange(0, len)];
for(int i = 0; i < len; ++i) {
char current = buffer[i];
//do something with current...
}
try enum string with blocks
Create Category of NSString
.h
#interface NSString (Category)
- (void)enumerateCharactersUsingBlock:(void (^)(NSString *character, NSInteger idx, bool *stop))block;
#end
.m
#implementation NSString (Category)
- (void)enumerateCharactersUsingBlock:(void (^)(NSString *character, NSInteger idx, bool *stop))block
{
bool _stop = NO;
for(NSInteger i = 0; i < [self length] && !_stop; i++)
{
NSString *character = [self substringWithRange:NSMakeRange(i, 1)];
block(character, i, &_stop);
}
}
#end
example
NSString *string = #"Hello World";
[string enumerateCharactersUsingBlock:^(NSString *character, NSInteger idx, bool *stop) {
NSLog(#"char %#, i: %li",character, (long)idx);
}];
This is little different solution for the question but I thought maybe this will be useful for someone. What I wanted was to actually iterate as actual unicode character in NSString. So, I found this solution:
NSString * str = #"hello 🤠💩";
NSRange range = NSMakeRange(0, str.length);
[str enumerateSubstringsInRange:range
options:NSStringEnumerationByComposedCharacterSequences
usingBlock:^(NSString *substring, NSRange substringRange,
NSRange enclosingRange, BOOL *stop)
{
NSLog(#"%#", substring);
}];
Although you would technically be getting individual NSString values, here is an alternative approach:
NSRange range = NSMakeRange(0, 1);
for (__unused int i = range.location; range.location < [starring length]; range.location++) {
NSLog(#"%#", [aNSString substringWithRange:range]);
}
(The __unused int i bit is necessary to silence the compiler warning.)
You should not use
NSUInteger len = [str length];
unichar buffer[len+1];
you should use memory allocation
NSUInteger len = [str length];
unichar* buffer = (unichar*) malloc (len+1)*sizeof(unichar);
and in the end use
free(buffer);
in order to avoid memory problems.

Is there a way to get an NSArray of NSRanges for an occurrence of an NSString inside of another NSString?

I have been recently working on an easy to use Syntax Highlighting system for a personal project. So far, I have everything working properly by finding the range of specific strings and highlighting that range in the NSTextView. Everything works until you try to type a highlighted word twice, which causes the error demonstrated below:
<div class="container">
<div> <!-- This <div> would not get highlighted -->
Hello World
</div>
</div> <!-- this </div> would not get highlighted -->
I believe this is occurring because I am only getting the first occurrence of an NSString using the rangeOfString method, and for that reason, only the first highlighted item is being highlighted.
Sorry for the long explanation! Anyway, I was wondering if there was an rangesOfString method or something similar that can give me an NSArray of NSRanges for each occurrence of an NSString inside of another NSString. Below is the line of code I am using to get my range currently:
NSString *textViewString = [textView string];
NSString *textToHighlight = #"<div>";
NSRange area;
area.location = 0;
area.length = [textViewString length];
NSRange range = [textViewString rangeOfString: textToHighlight
options: NSCaseInsensitiveSearch
range: area];
What I would like is something like this:
NSString *textViewString = [textView string];
NSString *textToHighlight = #"<div>";
NSRange area;
area.location = 0;
area.length = [textViewString length];
NSArray *ranges = [textViewString rangesOfString: textToHighlight
options: NSCaseInsensitiveSearch
range: area];
int i;
int total = [ranges count];
for (i = 0; i < total; i++) {
NSRange occurrence = [ranges objectAtIndex: i];
// Apply color highlighting here
}
If this is not possible, could someone please point me in the right direction or suggest an alternative way of doing syntax highlighting? Thank you!
There is no such method. You can use rangeOfSubstring:options:range: to get each match, and narrow down the range as you go: After each match, you change the search range's location to the character after (location + length of) the match range and reduce the search range's length by the difference.
In the modern block-based world, it's not that hard to write an “enumerate substrings that match…” method that does the above as its implementation. Here's what that looks like:
- (NSUInteger) enumerateSubstringsMatchingString_PRH:(NSString *)stringToFind
options:(NSStringCompareOptions)mask
usingBlock:(void (^)(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop))block
{
NSUInteger count = 0;
NSUInteger selfLength = self.length;
NSRange searchRange = { 0, selfLength };
NSRange foundRange;
BOOL stop = NO;
while (( ! stop ) && (foundRange = [self rangeOfString:stringToFind options:mask range:searchRange]).location != NSNotFound) {
++count;
if (block != NULL) {
#autoreleasepool {
NSString *substring = [self substringWithRange:foundRange];
block(substring, foundRange, /*TODO include terminators and separators in enclosingRange as described in enumerateSubstringsWithOptions:: docs*/ foundRange, &stop);
}
}
searchRange.location = NSMaxRange(foundRange);
if (searchRange.location >= self.length)
break;
searchRange.length = selfLength - searchRange.location;
}
return count;
}
The Gist I linked above gives a few obvious test cases.
NSRange is not an object, so you need to put it in one. Look at NSValues +valueWithRange: class method.