//  
//  CommonFunc.m  
//  PRJ_base64  
//  
//  Created by wangzhipeng on 12-11-29.  
//  Copyright (c) 2012年 com.comsoft. All rights reserved.  
//  
  
#import "CommonFunc.h"  
  
//引入IOS自帶密碼庫  
#import <CommonCrypto/CommonCryptor.h>  
  
//空字串  
#define     LocalStr_None           @""  
  
static const char
 
 encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";  
  
@implementation CommonFunc  
  
+ (NSString *)base64StringFromText:(NSString *)text  
{  
    if (text && ![text isEqualToString:LocalStr_None]) {  
        //取專案的bundleIdentifier作為KEY  改動了此處
        //NSString *key = [[NSBundle mainBundle] bundleIdentifier];  
 

        NSData *data = [text dataUsingEncoding:NSUTF8StringEncoding];  
        //IOS 自帶DES加密 Begin  改動了此處
        //data = [self DESEncrypt:data WithKey:key];  
        //IOS 自帶DES加密 End  
        return [self base64EncodedStringFrom:data];  
    }  
    else {  
        return LocalStr_None;  
    }  
}  
  
 
+ (NSString *)textFromBase64String:(NSString *)base64  
{  
    if (base64 && ![base64 isEqualToString:LocalStr_None]) {  
        //取專案的bundleIdentifier作為KEY   改動了此處
        //NSString *key = [[NSBundle mainBundle] bundleIdentifier];  
        NSData *data = [self dataWithBase64EncodedString:base64];  
        //IOS 自帶DES解密 Begin    改動了此處
        //data = [self DESDecrypt:data WithKey:key];    
        //IOS 自帶DES加密 End  
        return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];  
    }  
    else {  
        return LocalStr_None;  
    }  
}  
  
/****************************************************************************** 
 函式名稱 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key 
 函式描述 : 文字資料進行DES加密 
 輸入引數 : (NSData *)data     
          (NSString *)key 
 輸出引數 : N/A 
 返回引數 : (NSData *) 
 備註資訊 : 此函式不可用於過長文字 
 ******************************************************************************/  
+ (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key  
{  
    char keyPtr[kCCKeySizeAES256+1];  
    bzero(keyPtr, sizeof(keyPtr));  
      
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];  
      
    NSUInteger dataLength = [data length];  
      
    size_t bufferSize = dataLength + kCCBlockSizeAES128;  
    void *buffer = malloc(bufferSize);  
      
    size_t numBytesEncrypted = 0;  
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,  
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,  
                                          keyPtr, kCCBlockSizeDES,  
                                          NULL,  
                                          [data bytes], dataLength,  
                                          buffer, bufferSize,  
                                          &numBytesEncrypted);  
    if (cryptStatus == kCCSuccess) {  
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];  
    }  
      
    free(buffer);  
    return nil;  
}  
  
/****************************************************************************** 
 函式名稱 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key 
 函式描述 : 文字資料進行DES解密 
 輸入引數 : (NSData *)data 
          (NSString *)key 
 輸出引數 : N/A 
 返回引數 : (NSData *) 
 備註資訊 : 此函式不可用於過長文字 
 ******************************************************************************/  
+ (NSData *)DESDecrypt:(NSData *)data WithKey:(NSString *)key  
{  
    char keyPtr[kCCKeySizeAES256+1];  
    bzero(keyPtr, sizeof(keyPtr));  
      
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];  
      
    NSUInteger dataLength = [data length];  
      
    size_t bufferSize = dataLength + kCCBlockSizeAES128;  
    void *buffer = malloc(bufferSize);  
      
    size_t numBytesDecrypted = 0;  
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,  
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,  
                                          keyPtr, kCCBlockSizeDES,  
                                          NULL,  
                                          [data bytes], dataLength,  
                                          buffer, bufferSize,  
                                          &numBytesDecrypted);  
      
    if (cryptStatus == kCCSuccess) {  
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];  
    }  
      
    free(buffer);  
    return nil;  
}  
  
/****************************************************************************** 
 函式名稱 : + (NSData *)dataWithBase64EncodedString:(NSString *)string 
 函式描述 : base64格式字串轉換為文字資料 
 輸入引數 : (NSString *)string 
 輸出引數 : N/A 
 返回引數 : (NSData *) 
 備註資訊 : 
 ******************************************************************************/  
+ (NSData *)dataWithBase64EncodedString:(NSString *)string  
{  
    if (string == nil)  
        [NSException raise:NSInvalidArgumentException format:nil];  
    if ([string length] == 0)  
        return [NSData data];  
      
    static char *decodingTable = NULL;  
    if (decodingTable == NULL)  
    {  
        decodingTable = malloc(256);  
        if (decodingTable == NULL)  
            return nil;  
        memset(decodingTable, CHAR_MAX, 256);  
        NSUInteger i;  
        for (i = 0; i < 64; i++)  
            decodingTable[(short)encodingTable[i]] = i;  
    }  
      
    const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];  
    if (characters == NULL)     //  Not an ASCII string!  
        return nil;  
    char *bytes = malloc((([string length] + 3) / 4) * 3);  
    if (bytes == NULL)  
        return nil;  
    NSUInteger length = 0;  
      
    NSUInteger i = 0;  
    while (YES)  
    {  
        char buffer[4];  
        short bufferLength;  
        for (bufferLength = 0; bufferLength < 4; i++)  
        {  
            if (characters[i] == '\0')  
                break;  
            if (isspace(characters[i]) || characters[i] == '=')  
                continue;  
            buffer[bufferLength] = decodingTable[(short)characters[i]];  
            if (buffer[bufferLength++] == CHAR_MAX)      //  Illegal character!  
            {  
                free(bytes);  
                return nil;  
            }  
        }  
          
        if (bufferLength == 0)  
            break;  
        if (bufferLength == 1)      //  At least two characters are needed to produce one byte!  
        {  
            free(bytes);  
            return nil;  
        }  
          
        //  Decode the characters in the buffer to bytes.  
        bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);  
        if (bufferLength > 2)  
            bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);  
        if (bufferLength > 3)  
            bytes[length++] = (buffer[2] << 6) | buffer[3];  
    }  
      
    bytes = realloc(bytes, length);  
    return [NSData dataWithBytesNoCopy:bytes length:length];  
}  
  
/****************************************************************************** 
 函式名稱 : + (NSString *)base64EncodedStringFrom:(NSData *)data 
 函式描述 : 文字資料轉換為base64格式字串 
 輸入引數 : (NSData *)data 
 輸出引數 : N/A 
 返回引數 : (NSString *) 
 備註資訊 :  
 ******************************************************************************/  
+ (NSString *)base64EncodedStringFrom:(NSData *)data  
{  
    if ([data length] == 0)  
        return @"";  
      
    char *characters = malloc((([data length] + 2) / 3) * 4);  
    if (characters == NULL)  
        return nil;  
    NSUInteger length = 0;  
      
    NSUInteger i = 0;  
    while (i < [data length])  
    {  
        char buffer[3] = {0,0,0};  
        short bufferLength = 0;  
        while (bufferLength < 3 && i < [data length])  
            buffer[bufferLength++] = ((char *)[data bytes])[i++];  
          
        //  Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.  
        characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];  
        characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];  
        if (bufferLength > 1)  
            characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];  
        else characters[length++] = '=';  
        if (bufferLength > 2)  
            characters[length++] = encodingTable[buffer[2] & 0x3F];  
        else characters[length++] = '=';  
    }  
      
    return [[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES];  
}  
  
@end