CSRegex.m

//
//  CSRegex.m
//
//  http://www.cocoadev.com/index.pl?CSRegex
//

#import "CSRegex.h"

static NSString *nullstring=nil;

@implementation CSRegex

- (id) initWithPattern:(NSString *)pattern options:(int)options
{
	if (self=[super init]) {
		int err=regcomp(&preg,[pattern UTF8String],options|REG_EXTENDED);
		if (err) {
			char errbuf[256];
			regerror(err,&preg,errbuf,sizeof(errbuf));
			[NSException raise:@"CSRegexException"
                  format:@"Could not compile regex \"%@\": %s",pattern,errbuf];
		}
	}
	return self;
}

- (void) dealloc
{
	regfree(&preg);
	[super dealloc];
}

- (BOOL) matchesString:(NSString *)string
{
	if (regexec(&preg,[string UTF8String],0,NULL,0) == 0)
    return YES;
  
	return NO;
}

- (NSString *) matchedSubstringOfString:(NSString *)string
{
	const char *cstr=[string UTF8String];
	regmatch_t match;
	if (regexec(&preg,cstr,1,&match,0) == 0) {
		return [[[NSString alloc] initWithBytes:cstr+match.rm_so
                                     length:match.rm_eo-match.rm_so encoding:NSUTF8StringEncoding] autorelease];
	}
  
	return nil;
}

- (NSArray *) capturedSubstringsOfString:(NSString *)string
{
	const char *cstr = [string UTF8String];
	int num = preg.re_nsub+1;
	regmatch_t *matches = calloc(sizeof(regmatch_t),num);
  
	if (regexec(&preg,cstr,num,matches,0) == 0)	{
		NSMutableArray *array=[NSMutableArray arrayWithCapacity:num];
    
		int i;
		for (i=0;i<num;i++)	{
			NSString *str;
      
			if(matches[i].rm_so == -1 && matches[i].rm_eo == -1)
        str=nullstring;
			else
        str=[[[NSString alloc] initWithBytes:cstr+matches[i].rm_so
                                      length:matches[i].rm_eo-matches[i].rm_so encoding:NSUTF8StringEncoding] autorelease];
      
			[array addObject:str];
		}
    
		free(matches);
    
		return [NSArray arrayWithArray:array];
	}
  
	free(matches);

	return nil;
}

+ (CSRegex *) regexWithPattern:(NSString *)pattern options:(int)options
{
  return [[[CSRegex alloc] initWithPattern:pattern options:options] autorelease];
}

+ (CSRegex *) regexWithPattern:(NSString *)pattern
{
  return [[[CSRegex alloc] initWithPattern:pattern options:0] autorelease];
}

+ (NSString *) null
{
  return nullstring;
}

+ (void) initialize
{
	if (!nullstring)
    nullstring=[[NSString alloc] initWithString:@""];
}

@end

@implementation NSString (CSRegex)

- (BOOL) matchedByPattern:(NSString *)pattern options:(int)options
{
	CSRegex *re=[CSRegex regexWithPattern:pattern options:options|REG_NOSUB];
	return [re matchesString:self];
}

- (BOOL) matchedByPattern:(NSString *)pattern
{
  return [self matchedByPattern:pattern options:0];
}

- (NSString *) substringMatchedByPattern:(NSString *)pattern options:(int)options
{
	CSRegex *re=[CSRegex regexWithPattern:pattern options:options];
  return [re matchedSubstringOfString:self];
}

- (NSString *) substringMatchedByPattern:(NSString *)pattern
{
  return [self substringMatchedByPattern:pattern options:0];
}

- (NSArray *) substringsCapturedByPattern:(NSString *)pattern options:(int)options
{
	CSRegex *re=[CSRegex regexWithPattern:pattern options:options];
	return [re capturedSubstringsOfString:self];
}

- (NSArray *) substringsCapturedByPattern:(NSString *)pattern
{
  return [self substringsCapturedByPattern:pattern options:0];
}

- (NSString *) escapedPattern
{
	int len=[self length];
	NSMutableString *escaped=[NSMutableString stringWithCapacity:len];
  
  int i;
	for (i=0;i<len;i++) {
		unichar c=[self characterAtIndex:i];
		if(c=='^'||c=='.'||c=='['||c=='$'||c=='('||c==')'
       ||c=='|'||c=='*'||c=='+'||c=='?'||c=='{'||c=='\\')
      [escaped appendFormat:@"\\%C",c];
		else
      [escaped appendFormat:@"%C",c];
	}
	return [NSString stringWithString:escaped];
}

@end