NSData+EncodeAdditions.m

//
//  NSData+EncodeAdditions.m
//  XFFruit
//
//  Created by Xummer on 15/4/13.
//  Copyright (c) 2015年 Xummer. All rights reserved.
//

#import "NSData+EncodeAdditions.h"
#import <CommonCrypto/CommonCryptor.h>
#import <CommonCrypto/CommonDigest.h>

#if ! __has_feature(objc_arc)
#warning This file must be compiled with ARC. Use -fobjc-arc flag (or convert project to ARC).
#endif

//
// Mapping from 6 bit pattern to ASCII character.
//
static unsigned char base64EncodeLookup[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

//
// Definition for "masked-out" areas of the base64DecodeLookup mapping
//
#define xx 65

//
// Mapping from ASCII character to 6 bit pattern.
//
static unsigned char base64DecodeLookup[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, 62, xx, xx, xx, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, xx, xx, xx, xx, xx, xx,
    xx,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, xx, xx, xx, xx, xx,
    xx, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 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,
};

//
// Fundamental sizes of the binary and base64 encode/decode units in bytes
//
#define BINARY_UNIT_SIZE 3
#define BASE64_UNIT_SIZE 4

//
// NewBase64Decode
//
// Decodes the base64 ASCII string in the inputBuffer to a newly malloced
// output buffer.
//
//  inputBuffer - the source ASCII string for the decode
//	length - the length of the string or -1 (to specify strlen should be used)
//	outputLength - if not-NULL, on output will contain the decoded length
//
// returns the decoded buffer. Must be free'd by caller. Length is given by
//	outputLength.
//
void *NewBase64Decode(
                      const char *inputBuffer,
                      size_t length,
                      size_t *outputLength)
{
    if (length == -1)
    {
        length = strlen(inputBuffer);
    }
    
    size_t outputBufferSize =
    ((length+BASE64_UNIT_SIZE-1) / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE;
    unsigned char *outputBuffer = (unsigned char *)malloc(outputBufferSize);
    
    size_t i = 0;
    size_t j = 0;
    while (i < length)
    {
        //
        // Accumulate 4 valid characters (ignore everything else)
        //
        unsigned char accumulated[BASE64_UNIT_SIZE];
        size_t accumulateIndex = 0;
        while (i < length)
        {
            unsigned char decode = base64DecodeLookup[inputBuffer[i++]];
            if (decode != xx)
            {
                accumulated[accumulateIndex] = decode;
                accumulateIndex++;
                
                if (accumulateIndex == BASE64_UNIT_SIZE)
                {
                    break;
                }
            }
        }
        
        //
        // Store the 6 bits from each of the 4 characters as 3 bytes
        //
        // (Uses improved bounds checking suggested by Alexandre Colucci)
        //
        if(accumulateIndex >= 2)
            outputBuffer[j] = (accumulated[0] << 2) | (accumulated[1] >> 4);
        if(accumulateIndex >= 3)
            outputBuffer[j + 1] = (accumulated[1] << 4) | (accumulated[2] >> 2);
        if(accumulateIndex >= 4)
            outputBuffer[j + 2] = (accumulated[2] << 6) | accumulated[3];
        j += accumulateIndex - 1;
    }
    
    if (outputLength)
    {
        *outputLength = j;
    }
    return outputBuffer;
}

//
// NewBase64Encode
//
// Encodes the arbitrary data in the inputBuffer as base64 into a newly malloced
// output buffer.
//
//  inputBuffer - the source data for the encode
//	length - the length of the input in bytes
//  separateLines - if zero, no CR/LF characters will be added. Otherwise
//		a CR/LF pair will be added every 64 encoded chars.
//	outputLength - if not-NULL, on output will contain the encoded length
//		(not including terminating 0 char)
//
// returns the encoded buffer. Must be free'd by caller. Length is given by
//	outputLength.
//
char *NewBase64Encode(
                      const void *buffer,
                      size_t length,
                      bool separateLines,
                      size_t *outputLength)
{
    const unsigned char *inputBuffer = (const unsigned char *)buffer;
    
#define MAX_NUM_PADDING_CHARS 2
#define OUTPUT_LINE_LENGTH 64
#define INPUT_LINE_LENGTH ((OUTPUT_LINE_LENGTH / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE)
#define CR_LF_SIZE 2
    
    //
    // Byte accurate calculation of final buffer size
    //
    size_t outputBufferSize =
    ((length / BINARY_UNIT_SIZE)
     + ((length % BINARY_UNIT_SIZE) ? 1 : 0))
    * BASE64_UNIT_SIZE;
    if (separateLines)
    {
        outputBufferSize +=
        (outputBufferSize / OUTPUT_LINE_LENGTH) * CR_LF_SIZE;
    }
    
    //
    // Include space for a terminating zero
    //
    outputBufferSize += 1;
    
    //
    // Allocate the output buffer
    //
    char *outputBuffer = (char *)malloc(outputBufferSize);
    if (!outputBuffer)
    {
        return NULL;
    }
    
    size_t i = 0;
    size_t j = 0;
    const size_t lineLength = separateLines ? INPUT_LINE_LENGTH : length;
    size_t lineEnd = lineLength;
    
    while (true)
    {
        if (lineEnd > length)
        {
            lineEnd = length;
        }
        
        for (; i + BINARY_UNIT_SIZE - 1 < lineEnd; i += BINARY_UNIT_SIZE)
        {
            //
            // Inner loop: turn 48 bytes into 64 base64 characters
            //
            outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
            outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
                                                   | ((inputBuffer[i + 1] & 0xF0) >> 4)];
            outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i + 1] & 0x0F) << 2)
                                                   | ((inputBuffer[i + 2] & 0xC0) >> 6)];
            outputBuffer[j++] = base64EncodeLookup[inputBuffer[i + 2] & 0x3F];
        }
        
        if (lineEnd == length)
        {
            break;
        }
        
        //
        // Add the newline
        //
        outputBuffer[j++] = '\r';
        outputBuffer[j++] = '\n';
        lineEnd += lineLength;
    }
    
    if (i + 1 < length)
    {
        //
        // Handle the single '=' case
        //
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
        outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
                                               | ((inputBuffer[i + 1] & 0xF0) >> 4)];
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i + 1] & 0x0F) << 2];
        outputBuffer[j++] =	'=';
    }
    else if (i < length)
    {
        //
        // Handle the double '=' case
        //
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0x03) << 4];
        outputBuffer[j++] = '=';
        outputBuffer[j++] = '=';
    }
    outputBuffer[j] = 0;
    
    //
    // Set the output length and return the buffer
    //
    if (outputLength)
    {
        *outputLength = j;
    }
    return outputBuffer;
}

@implementation NSData (EncodeAdditions)

- (NSData *)md5Digest
{
    unsigned char result[CC_MD5_DIGEST_LENGTH];
    
    CC_MD5([self bytes], (CC_LONG)[self length], result);
    return [NSData dataWithBytes:result length:CC_MD5_DIGEST_LENGTH];
}

- (NSData *)sha1Digest
{
    unsigned char result[CC_SHA1_DIGEST_LENGTH];
    
    CC_SHA1([self bytes], (CC_LONG)[self length], result);
    return [NSData dataWithBytes:result length:CC_SHA1_DIGEST_LENGTH];
}

- (NSString *)hexStringValue
{
    NSMutableString *stringBuffer = [NSMutableString stringWithCapacity:([self length] * 2)];
    
    const unsigned char *dataBuffer = [self bytes];
    int i;
    
    for (i = 0; i < [self length]; ++i)
    {
        [stringBuffer appendFormat:@"%02x", (unsigned int)dataBuffer[i]];
    }
    
    return [stringBuffer copy];
}

- (NSData *)AES256EncryptWithKey:(NSString *)key   //加密
{
    char keyPtr[kCCKeySizeAES256+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeAES128,
                                          NULL,
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
    free(buffer);
    return nil;
}


- (NSData *)AES256DecryptWithKey:(NSString *)key   //解密
{
    char keyPtr[kCCKeySizeAES256+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeAES128,
                                          NULL,
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesDecrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
    free(buffer);
    return nil;
}

+ (NSData *)dataFromBase64String:(NSString *)aString
{
    if (IBT_IOS7_OR_LATER) {
        return [[NSData alloc] initWithBase64EncodedString:aString options:NSDataBase64DecodingIgnoreUnknownCharacters];
    }
    else {
        NSData *data = [aString dataUsingEncoding:NSASCIIStringEncoding];
        size_t outputLength;
        void *outputBuffer = NewBase64Decode([data bytes], [data length], &outputLength);
        NSData *result = [NSData dataWithBytes:outputBuffer length:outputLength];
        free(outputBuffer);
        return result;
    }
}

- (NSString *)base64EncodedString
{
    if (IBT_IOS7_OR_LATER) {
        return [self base64EncodedStringWithOptions:0];
    }
    else {
        size_t outputLength;
        char *outputBuffer =
        NewBase64Encode([self bytes], [self length], true, &outputLength);
        
        NSString *result = [[NSString alloc] initWithBytes:outputBuffer length:outputLength encoding:NSASCIIStringEncoding];
        free(outputBuffer);
        return result;
    }
}

@end


@import MobileCoreServices;
@implementation NSData (FileExt)

static CFStringRef UTTypeForImageData(NSData *data) {
    const unsigned char * bytes = [data bytes];
    
    if (data.length >= 8) {
        if (bytes[0] == 0x89 &&
            bytes[1] == 0x50 &&
            bytes[2] == 0x4E &&
            bytes[3] == 0x47 &&
            bytes[4] == 0x0D &&
            bytes[5] == 0x0A &&
            bytes[6] == 0x1A &&
            bytes[7] == 0x0A )
        {
            return kUTTypePNG;
        }
    }
    
    if (data.length >= 4) {
        if (bytes[0] == 0xFF &&
            bytes[1] == 0xD8 &&
            bytes[2] == 0xFF &&
            bytes[2] == 0xE0 )
        {
            return kUTTypeJPEG;
        }
    }
    
    if (data.length >= 3) {
        if (bytes[0] == 0x47 &&
            bytes[1] == 0x49 &&
            bytes[2] == 0x46 )
        {
            return kUTTypeGIF;
        }
        else if (bytes[0] == 0x49 &&
                 bytes[1] == 0x49 &&
                 bytes[2] == 0x2A )
        {
            return kUTTypeBMP;
        }
    }
    
    if (data.length >= 2) {
        if (bytes[0] == 0x42 &&
            bytes[1] == 0x4D )
        {
            return kUTTypeBMP;
        }
    }
    
    return nil;
}

- (BOOL)isImageType {
    CFStringRef imgType = UTTypeForImageData(self);
    return imgType ? YES : NO;
}

@end