//
//  NSDataEx.m
//  iX3.0
//
//  Created by Feng Huajun on 09-4-16.
//  Copyright 2009 Infothinker. All rights reserved.
//

#import "NSDataEx.h"

static char encodingTable[64] = {
'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/' };

@implementation NSData (NSDataBase64Additions)

+ (NSData *) dataWithBase64EncodedString:(NSString *) string {
    NSData *result = [[NSData alloc] initWithBase64EncodedString:string];
    return result;
}

- (id) initWithBase64EncodedString:(NSString *) string {
    NSMutableData *mutableData = nil;
    
    if( string ) {
        unsigned long ixtext = 0;
        unsigned long lentext = 0;
        unsigned char ch = 0;
        unsigned char inbuf[4], outbuf[3];
        short i = 0, ixinbuf = 0;
        BOOL flignore = NO;
        BOOL flendtext = NO;
        NSData *base64Data = nil;
        const unsigned char *base64Bytes = nil;
        
        // Convert the string to ASCII data.
        base64Data = [string dataUsingEncoding:NSASCIIStringEncoding];
        base64Bytes = [base64Data bytes];
        mutableData = [NSMutableData dataWithCapacity:[base64Data length]];
        lentext = [base64Data length];
        
        while( YES ) {
            if( ixtext >= lentext ) break;
            ch = base64Bytes[ixtext++];
            flignore = NO;
            
            if( ( ch >= 'A' ) && ( ch <= 'Z' ) ) ch = ch - 'A';
            else if( ( ch >= 'a' ) && ( ch <= 'z' ) ) ch = ch - 'a' + 26;
            else if( ( ch >= '0' ) && ( ch <= '9' ) ) ch = ch - '0' + 52;
            else if( ch == '+' ) ch = 62;
            else if( ch == '=' ) flendtext = YES;
            else if( ch == '/' ) ch = 63;
            else flignore = YES; 
            
            if( ! flignore ) {
                short ctcharsinbuf = 3;
                BOOL flbreak = NO;
                
                if( flendtext ) {
                    if( ! ixinbuf ) break;
                    if( ( ixinbuf == 1 ) || ( ixinbuf == 2 ) ) ctcharsinbuf = 1;
                    else ctcharsinbuf = 2;
                    ixinbuf = 3;
                    flbreak = YES;
                }
                
                inbuf [ixinbuf++] = ch;
                
                if( ixinbuf == 4 ) {
                    ixinbuf = 0;
                    outbuf [0] = ( inbuf[0] << 2 ) | ( ( inbuf[1] & 0x30) >> 4 );
                    outbuf [1] = ( ( inbuf[1] & 0x0F ) << 4 ) | ( ( inbuf[2] & 0x3C ) >> 2 );
                    outbuf [2] = ( ( inbuf[2] & 0x03 ) << 6 ) | ( inbuf[3] & 0x3F );
                    
                    for( i = 0; i < ctcharsinbuf; i++ ) 
                        [mutableData appendBytes:&outbuf[i] length:1];
                }
                
                if( flbreak )  break;
            }
        }
    }
    
    self = [self initWithData:mutableData];
    return self;
}

#pragma mark -

- (NSString *) base64Encoding {
    return [self base64EncodingWithLineLength:0];
}

- (NSString *) base64EncodingWithLineLength:(unsigned int) lineLength {
    const unsigned char    *bytes = [self bytes];
    NSMutableString *result = [NSMutableString stringWithCapacity:[self length]];
    unsigned long ixtext = 0;
    unsigned long lentext = [self length];
    long ctremaining = 0;
    unsigned char inbuf[3], outbuf[4];
    short i = 0;
    short charsonline = 0, ctcopy = 0;
    unsigned long ix = 0;
    
    while( YES ) {
        ctremaining = lentext - ixtext;
        if( ctremaining <= 0 ) break;
        
        for( i = 0; i < 3; i++ ) {
            ix = ixtext + i;
            if( ix < lentext ) inbuf[i] = bytes[ix];
            else inbuf [i] = 0;
        }
        
        outbuf [0] = (inbuf [0] & 0xFC) >> 2;
        outbuf [1] = ((inbuf [0] & 0x03) << 4) | ((inbuf [1] & 0xF0) >> 4);
        outbuf [2] = ((inbuf [1] & 0x0F) << 2) | ((inbuf [2] & 0xC0) >> 6);
        outbuf [3] = inbuf [2] & 0x3F;
        ctcopy = 4;
        
        switch( ctremaining ) {
            case 1: 
                ctcopy = 2; 
                break;
            case 2: 
                ctcopy = 3; 
                break;
        }
        
        for( i = 0; i < ctcopy; i++ )
            [result appendFormat:@"%c", encodingTable[outbuf[i]]];
        
        for( i = ctcopy; i < 4; i++ )
            [result appendFormat:@"%c",'='];
        
        ixtext += 3;
        charsonline += 4;
        
        if( lineLength > 0 ) {
            if (charsonline >= lineLength) {
                charsonline = 0;
                [result appendString:@"\n"];
            }
        }
    }
    
    return result;
}



//- (NSString*) urlEncodedString
//{
//	char *hex = "0123456789ABCDEF";
//	unsigned char* data = (unsigned char*)[self bytes];
//	int len = [self length];
//	//NSLog(@"len = %d", len);
//	NSMutableString* s = [NSMutableString string];
//	for(int i = 0;i<len;i++){
//		unsigned char c = data[i];
//		if( ('a' <= c && c <= 'z')
//		   || ('A' <= c && c <= 'Z')
//		   || ('0' <= c && c <= '9') ){
//			NSString* ts = [[NSString alloc] initWithCString:(char *)&c length:1];
//			
//			[s appendString:ts];
//			[ts release];
//		} else {
//			[s appendString:@"%"];
//			char ts1 = hex[c >> 4];
//		//	NSLog(@"ts = %c", ts1);
//			NSString* ts = [[NSString alloc] initWithCString:&ts1 length:1];
//			[s appendString:ts];
//			[ts release];
//			char ts2 = hex[c & 15];
//			ts = [[NSString alloc] initWithCString:&ts2 length:1];
//			[s appendString:ts];
//			[ts release];
//			
//		}
//	}
//	return s;
//}

@end