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- #import "MMScanner.h"
-
-
- static NSString *__delimitersForCharacter(unichar character)
- {
- switch (character)
- {
- case '[':
- case ']':
- return @"[]";
- case '(':
- case ')':
- return @"()";
- case '<':
- case '>':
- return @"<>";
- case '{':
- case '}':
- return @"{}";
- default:
- [NSException raise:@"Invalid delimiter character"
- format:@"Character '%C' is not a valid delimiter", character];
- return nil;
- }
- }
-
- @interface MMScanner ()
- @property (assign, nonatomic) NSUInteger startLocation;
- @property (assign, nonatomic) NSRange currentRange;
-
- @property (assign, nonatomic, readonly) NSRange currentLineRange;
- @property (assign, nonatomic) NSUInteger rangeIndex;
- @property (strong, nonatomic, readonly) NSMutableArray *transactions;
- @end
-
- @implementation MMScanner
-
- #pragma mark - Public Methods
-
- + (id)scannerWithString:(NSString *)aString
- {
- return [[self.class alloc] initWithString:aString];
- }
-
- - (id)initWithString:(NSString *)aString
- {
- NSArray *lineRanges = [self _lineRangesForString:aString];
- return [self initWithString:aString lineRanges:lineRanges];
- }
-
- + (id)scannerWithString:(NSString *)aString lineRanges:(NSArray *)theLineRanges
- {
- return [[self.class alloc] initWithString:aString lineRanges:theLineRanges];
- }
-
- - (id)initWithString:(NSString *)aString lineRanges:(NSArray *)theLineRanges
- {
- NSParameterAssert(theLineRanges.count > 0);
-
- self = [super init];
-
- if (self)
- {
- _string = aString;
- _lineRanges = theLineRanges;
-
- _rangeIndex = 0;
- _transactions = [NSMutableArray new];
-
- self.startLocation = 0;
- self.currentRange = self.currentLineRange;
- }
-
- return self;
- }
-
- - (void)beginTransaction
- {
- NSDictionary *transaction = @{
- @"rangeIndex": @(self.rangeIndex),
- @"location": @(self.location),
- @"startLocation": @(self.startLocation),
- };
- [self.transactions addObject:transaction];
- self.startLocation = self.location;
- }
-
- - (void)commitTransaction:(BOOL)shouldSave
- {
- if (!self.transactions.count)
- [NSException raise:@"Transaction underflow" format:@"Could not commit transaction because the stack is empty"];
-
- NSDictionary *transaction = [self.transactions lastObject];
- [self.transactions removeLastObject];
-
- self.startLocation = [[transaction objectForKey:@"startLocation"] unsignedIntegerValue];
- if (!shouldSave)
- {
- self.rangeIndex = [[transaction objectForKey:@"rangeIndex"] unsignedIntegerValue];
- self.location = [[transaction objectForKey:@"location"] unsignedIntegerValue];
- }
- }
-
- - (BOOL)atBeginningOfLine
- {
- return self.location == self.currentLineRange.location;
- }
-
- - (BOOL)atEndOfLine
- {
- return self.location == NSMaxRange(self.currentLineRange);
- }
-
- - (BOOL)atEndOfString
- {
- return self.atEndOfLine && self.rangeIndex == self.lineRanges.count - 1;
- }
-
- - (unichar)previousCharacter
- {
- if (self.atBeginningOfLine)
- return '\0';
-
- return [self.string characterAtIndex:self.location - 1];
- }
-
- - (unichar)nextCharacter
- {
- if (self.atEndOfLine)
- return '\n';
- return [self.string characterAtIndex:self.location];
- }
-
- - (NSString *)previousWord
- {
- return [self previousWordWithCharactersFromSet:NSCharacterSet.alphanumericCharacterSet];
- }
-
- - (NSString *)nextWord
- {
- return [self nextWordWithCharactersFromSet:NSCharacterSet.alphanumericCharacterSet];
- }
-
- - (NSString *)previousWordWithCharactersFromSet:(NSCharacterSet *)set
- {
- NSUInteger start = MAX(self.currentLineRange.location, self.startLocation);
- NSUInteger end = self.currentRange.location;
- NSRange range = NSMakeRange(start, end-start);
-
- NSRange result = [self.string rangeOfCharacterFromSet:set.invertedSet
- options:NSBackwardsSearch
- range:range];
-
- if (result.location == NSNotFound)
- return [self.string substringWithRange:range];
-
- NSUInteger wordLocation = NSMaxRange(result);
- NSRange wordRange = NSMakeRange(wordLocation, end-wordLocation);
- return [self.string substringWithRange:wordRange];
- }
-
- - (NSString *)nextWordWithCharactersFromSet:(NSCharacterSet *)set
- {
- NSRange result = [self.string rangeOfCharacterFromSet:set.invertedSet
- options:0
- range:self.currentRange];
-
- if (result.location == NSNotFound)
- return [self.string substringWithRange:self.currentRange];
-
- NSRange wordRange = self.currentRange;
- wordRange.length = result.location - wordRange.location;
-
- return [self.string substringWithRange:wordRange];
- }
-
- - (void)advance
- {
- if (self.atEndOfLine)
- return;
- self.location += 1;
- }
-
- - (void)advanceToNextLine
- {
-
- if (self.rangeIndex == self.lineRanges.count - 1)
- {
- self.location = NSMaxRange(self.currentLineRange);
- }
-
- else
- {
- self.rangeIndex += 1;
- self.currentRange = self.currentLineRange;
- }
- }
-
- - (BOOL)matchString:(NSString *)string
- {
- if (self.currentRange.length < string.length)
- return NO;
-
- NSUInteger location = self.location;
- for (NSUInteger idx=0; idx<string.length; idx++)
- {
- if ([string characterAtIndex:idx] != [self.string characterAtIndex:location+idx])
- return NO;
- }
-
- self.location += string.length;
- return YES;
- }
-
- - (NSUInteger)skipCharactersFromSet:(NSCharacterSet *)aSet
- {
- NSRange searchRange = self.currentRange;
- NSRange range = [self.string rangeOfCharacterFromSet:[aSet invertedSet]
- options:0
- range:searchRange];
-
- NSUInteger current = self.location;
-
- if (range.location == NSNotFound)
- {
- self.currentRange = NSMakeRange(NSMaxRange(self.currentRange), 0);
- }
- else
- {
- self.currentRange = NSMakeRange(range.location, NSMaxRange(self.currentRange)-range.location);
- }
-
- return self.location - current;
- }
-
- - (NSUInteger)skipCharactersFromSet:(NSCharacterSet *)aSet max:(NSUInteger)maxToSkip
- {
- NSUInteger idx=0;
- for (; idx<maxToSkip; idx++)
- {
- unichar character = [self nextCharacter];
- if ([aSet characterIsMember:character])
- [self advance];
- else
- break;
- }
- return idx;
- }
-
- - (NSUInteger)skipEmptyLines
- {
- NSUInteger skipped = 0;
-
- while (![self atEndOfString])
- {
- [self beginTransaction];
- [self skipWhitespace];
- if (!self.atEndOfLine)
- {
- [self commitTransaction:NO];
- break;
- }
- [self commitTransaction:YES];
- [self advanceToNextLine];
- skipped++;
- }
-
- return skipped;
- }
-
- - (NSUInteger)skipIndentationUpTo:(NSUInteger)maxSpacesToSkip
- {
- NSUInteger skipped = 0;
- [self beginTransaction];
-
- while (!self.atEndOfLine && skipped < maxSpacesToSkip)
- {
- unichar character = self.nextCharacter;
-
- if (character == ' ')
- skipped += 1;
- else if (character == '\t')
- {
- skipped -= skipped % 4;
- skipped += 4;
- }
- else
- break;
-
- [self advance];
- }
-
- [self commitTransaction:skipped <= maxSpacesToSkip];
- return skipped;
- }
-
- - (NSUInteger)skipNestedBracketsWithDelimiter:(unichar)delimiter
- {
- NSString *delimiters = __delimitersForCharacter(delimiter);
-
- if (delimiters == nil)
- return 0;
-
- unichar openDelimiter = [delimiters characterAtIndex:0];
- unichar closeDelimeter = [delimiters characterAtIndex:1];
-
- if ([self nextCharacter] != openDelimiter)
- return 0;
-
- [self beginTransaction];
- NSUInteger location = self.location;
- [self advance];
-
- NSString *specialChars = [NSString stringWithFormat:@"%@\\", delimiters];
- NSCharacterSet *boringChars = [[NSCharacterSet characterSetWithCharactersInString:specialChars] invertedSet];
- NSUInteger nestingLevel = 1;
-
- while (nestingLevel > 0)
- {
- if (self.atEndOfLine)
- {
- [self commitTransaction:NO];
- return 0;
- }
-
- [self skipCharactersFromSet:boringChars];
-
- unichar nextChar = self.nextCharacter;
- [self advance];
-
- if (nextChar == openDelimiter)
- {
- nestingLevel++;
- }
- else if (nextChar == closeDelimeter)
- {
- nestingLevel--;
- }
- else if (nextChar == '\\')
- {
-
- [self advance];
- }
- }
-
- [self commitTransaction:YES];
- return self.location - location;
- }
-
- - (NSUInteger)skipToEndOfLine
- {
- NSUInteger length = self.currentRange.length;
- self.location = NSMaxRange(self.currentRange);
- return length;
- }
-
- - (NSUInteger)skipToLastCharacterOfLine
- {
- NSUInteger length = self.currentRange.length - 1;
- self.location = NSMaxRange(self.currentRange) - 1;
- return length;
- }
-
- - (NSUInteger)skipWhitespace
- {
- return [self skipCharactersFromSet:NSCharacterSet.whitespaceCharacterSet];
- }
-
- - (NSUInteger)skipWhitespaceAndNewlines
- {
- NSCharacterSet *whitespaceSet = NSCharacterSet.whitespaceCharacterSet;
- NSUInteger length = 0;
-
- while (!self.atEndOfString)
- {
- if (self.atEndOfLine)
- {
- [self advanceToNextLine];
- length++;
- }
- else
- {
- NSUInteger spaces = [self skipCharactersFromSet:whitespaceSet];
- if (spaces == 0)
- break;
-
- length += spaces;
- }
- }
-
- return length;
- }
-
-
- #pragma mark - Public Properties
-
- - (NSUInteger)location
- {
- return self.currentRange.location;
- }
-
- - (void)setLocation:(NSUInteger)location
- {
-
- if (!NSLocationInRange(location, self.currentLineRange))
- {
- __block NSUInteger index = 0;
- [self.lineRanges enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop){
- NSRange range = [obj rangeValue];
- *stop = NSLocationInRange(location, range) || location == NSMaxRange(range);
- index = idx;
- }];
- self.rangeIndex = index;
- }
-
- self.currentRange = NSMakeRange(location, NSMaxRange(self.currentLineRange)-location);
- }
-
-
- #pragma mark - Private Methods
-
- - (NSArray *)_lineRangesForString:(NSString *)aString
- {
- NSMutableArray *result = [NSMutableArray array];
-
- NSUInteger location = 0;
- NSUInteger idx;
- for (idx=0; idx<aString.length; idx++)
- {
- unichar character = [aString characterAtIndex:idx];
- if (character == '\r' || character == '\n')
- {
- NSRange range = NSMakeRange(location, idx-location);
- [result addObject:[NSValue valueWithRange:range]];
-
-
- if (character == '\r')
- {
- if (idx + 1 < aString.length && [aString characterAtIndex:idx + 1] == '\n')
- {
- idx += 1;
- }
- }
-
- location = idx + 1;
- }
- }
-
-
- if (location < aString.length)
- {
- NSRange range = NSMakeRange(location, aString.length-location);
- [result addObject:[NSValue valueWithRange:range]];
- }
-
- return result;
- }
-
- - (NSUInteger)_locationOfCharacter:(unichar)character inRange:(NSRange)range
- {
- NSString *characterString = [NSString stringWithCharacters:&character length:1];
- NSCharacterSet *characterSet = [NSCharacterSet characterSetWithCharactersInString:characterString];
- NSRange result = [self.string rangeOfCharacterFromSet:characterSet options:0 range:range];
- return result.location;
- }
-
- #pragma mark - Private Properties
-
- - (NSRange)currentLineRange
- {
- return [self.lineRanges[self.rangeIndex] rangeValue];
- }
-
- @end
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