//
//  CSRegex.m
//
//  Created by Dag Ågren.
//  Public domain.
//  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];
	
	for(int 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