NSData_SKExtensions.m

//
//  NSData_SKExtensions.m
//  Skim
//
//  Created by Christiaan Hofman on 9/8/07.
/*
 This software is Copyright (c) 2007
 Christiaan Hofman. All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

 - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

 - Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in
    the documentation and/or other materials provided with the
    distribution.

 - Neither the name of Christiaan Hofman nor the names of any
    contributors may be used to endorse or promote products derived
    from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

// For base 64 encoding/decoding:
//
//  Created by Matt Gallagher on 2009/06/03.
//  Copyright 2009 Matt Gallagher. All rights reserved.
//
//  Permission is given to use this source code file, free of charge, in any
//  project, commercial or otherwise, entirely at your risk, with the condition
//  that any redistribution (in part or whole) of source code must retain
//  this copyright and permission notice. Attribution in compiled projects is
//  appreciated but not required.
//

#import "NSData_SKExtensions.h"
#import "NSGeometry_SKExtensions.h"
#import <CommonCrypto/CommonDigest.h>

@implementation NSData (SKExtensions)

// Mapping from 4 bit pattern to ASCII character.
static unsigned char hexEncodeTable[17] = "0123456789ABCDEF";

// Definition for "masked-out" areas of the hexDecodeTable mapping
#define xx 0xFF

// Mapping from ASCII character to 4 bit pattern.
static unsigned char hexDecodeTable[256] =
{
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
     0,  1,  2,  3,  4,  5,  6,  7,  8,  9, xx, xx, xx, xx, xx, xx, 
    xx, 10, 11, 12, 13, 14, 15, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, 10, 11, 12, 13, 14, 15, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 
};

- (instancetype)initWithHexString:(NSString *)hexString {
    NSData *data = [hexString dataUsingEncoding:NSASCIIStringEncoding];
    size_t length = [data length];
    const unsigned char *inputBuffer = (const unsigned char *)[data bytes];
    size_t outputBufferSize = length / 2;
    unsigned char *outputBuffer = (unsigned char *)malloc(outputBufferSize);
    
    size_t i = 0, j = 0;
    while (i < length) {
		// Accumulate 2 valid characters (ignore everything else)
        unsigned char accumulated[2] = {0, 0};
		size_t accumulateIndex = 0;
		while (i < length) {
			unsigned char decode = hexDecodeTable[inputBuffer[i++]];
			if (decode != xx) {
				accumulated[accumulateIndex] = decode;
				accumulateIndex++;
				
				if (accumulateIndex == 2)
					break;
			}
		}
		
		// Store the 8 bits from each of the 2 characters as 1 byte
		outputBuffer[j++] = (accumulated[0] << 4) | (accumulated[1]);
    }
    
    NSData *result = [self initWithBytes:outputBuffer length:j];
    
    free(outputBuffer);
    
    return result;
}

- (NSString *)hexString {
    size_t length = [self length];
    const unsigned char *inputBuffer = (const unsigned char *)[self bytes];
    char *outputBuffer = (char *)malloc(length * 2);
    if (outputBuffer == NULL)
		return nil;

    size_t i = 0;
    size_t j = 0;
    
    for (i = 0; i < length; i++) {
		outputBuffer[j++] = hexEncodeTable[(inputBuffer[i] & 0xF0) >> 4];
		outputBuffer[j++] = hexEncodeTable[(inputBuffer[i] & 0x0F)];
    }
    
    NSString *result = [[NSString alloc] initWithBytes:outputBuffer length:j encoding:NSASCIIStringEncoding];
    
    free(outputBuffer);
    
    return result;
}

- (NSString *)md5String {
    CC_MD5_CTX md5context;
    NSUInteger signatureLength = CC_MD5_DIGEST_LENGTH;
    unsigned char signature[signatureLength];
    unsigned char hexSignature[signatureLength * 2 + 1];
    NSUInteger blockSize = 4096;
    char buffer[blockSize];
    NSUInteger length = [self length];
    NSRange range = NSMakeRange(0, MIN(blockSize, length));
    
    CC_MD5_Init(&md5context);
    while (range.length > 0) {
        [self getBytes:buffer range:range];
        CC_MD5_Update(&md5context, (const void *)buffer, (CC_LONG)range.length);
        range.location = NSMaxRange(range);
        range.length = MIN(blockSize, length - range.location);
    }
    CC_MD5_Final(signature, &md5context);
    
    NSUInteger i, j = 0;
    
    for (i = 0; i < signatureLength; i++) {
		hexSignature[j++] = hexEncodeTable[(signature[i] & 0xF0) >> 4];
		hexSignature[j++] = hexEncodeTable[(signature[i] & 0x0F)];
    }
    hexSignature[j] = 0;
    
    return [[NSString alloc] initWithBytes:hexSignature length:j encoding:NSASCIIStringEncoding];
}

#pragma mark Templating support

- (NSString *)xmlString {
    return [self base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength | NSDataBase64EncodingEndLineWithLineFeed];
}

#pragma mark Scripting support

+ (NSData *)dataWithPointAsQDPoint:(NSPoint)point {
    Point qdPoint = SKQDPointFromNSPoint(point);
    return [self dataWithBytes:&qdPoint length:sizeof(Point)];
}

+ (NSData *)dataWithRectAsQDRect:(NSRect)rect {
    Rect qdRect = SKQDRectFromNSRect(rect);
    return [self dataWithBytes:&qdRect length:sizeof(Rect)];
}

- (NSPoint)pointValueAsQDPoint {
    NSPoint point = NSZeroPoint;
    if ([self length] == sizeof(Point)) {
        const Point *qdPoint = (const Point *)[self bytes];
        point = SKNSPointFromQDPoint(*qdPoint);
    }
    return point;
}

- (NSRect)rectValueAsQDRect {
    NSRect rect = NSZeroRect;
    if ([self length] == sizeof(Rect)) {
        const Rect *qdRect = (const Rect *)[self bytes];
        rect = SKNSRectFromQDRect(*qdRect);
    }
    return rect;
}

+ (instancetype)scriptingPdfWithDescriptor:(NSAppleEventDescriptor *)descriptor {
    return [descriptor data];
}

- (NSAppleEventDescriptor *)scriptingPdfDescriptor {
    return [NSAppleEventDescriptor descriptorWithDescriptorType:'PDF ' data:self];
} 

+ (instancetype)scriptingTiffPictureWithDescriptor:(NSAppleEventDescriptor *)descriptor {
    return [descriptor data];
}

- (NSAppleEventDescriptor *)scriptingTiffPictureDescriptor {
    return [NSAppleEventDescriptor descriptorWithDescriptorType:'TIFF' data:self];
}

+ (instancetype)scriptingRtfWithDescriptor:(NSAppleEventDescriptor *)descriptor {
    return [descriptor data];
}

- (NSAppleEventDescriptor *)scriptingRtfDescriptor {
    return [NSAppleEventDescriptor descriptorWithDescriptorType:'RTF ' data:self];
}

@end