//
//  DesUtil.m
//  jiaPei
//
//  Created by apple on 2016/12/27.
//  Copyright © 2016年 JCZ. All rights reserved.
//

#import "DesUtil.h"
#import <CommonCrypto/CommonCryptor.h>


//空字符串
#define     LocalStr_None           @""

static const char encodingTable[] = "fujianxzz";



@implementation DesUtil


+ (NSString *)base64StringFromText:(NSString *)text
{
    if (text && ![text isEqualToString:LocalStr_None]) {
        //取项目的bundleIdentifier作为KEY
        NSString *key = [[NSBundle mainBundle] bundleIdentifier];
        NSData *data = [text dataUsingEncoding:NSUTF8StringEncoding];
        //IOS 自带DES加密 Begin
        data = [self DESEncrypt:data WithKey:key];
        //IOS 自带DES加密 End
        return [self base64EncodedStringFrom:data];
    }
    else {
        return LocalStr_None;
    }
}

+ (NSString *)textFromBase64String:(NSString *)base64
{
    if (base64 && ![base64 isEqualToString:LocalStr_None]) {
        //取项目的bundleIdentifier作为KEY
        NSString *key = [[NSBundle mainBundle] bundleIdentifier];
        NSData *data = [self dataWithBase64EncodedString:base64];
        //IOS 自带DES解密 Begin
        data = [self DESDecrypt:data WithKey:key];
        //IOS 自带DES加密 End
        return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    }
    else {
        return LocalStr_None;
    }
}

/************************************************************
 函数名称 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key
 函数描述 : 文本数据进行DES加密
 输入参数 : (NSData *)data
 (NSString *)key
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 : 此函数不可用于过长文本
 **********************************************************/
+ (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;
}

/************************************************************
 函数名称 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key
 函数描述 : 文本数据进行DES解密
 输入参数 : (NSData *)data
 (NSString *)key
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 : 此函数不可用于过长文本
 **********************************************************/
+ (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;
}

/************************************************************
 函数名称 : + (NSData *)dataWithBase64EncodedString:(NSString *)string
 函数描述 : base64格式字符串转换为文本数据
 输入参数 : (NSString *)string
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 :
 **********************************************************/
+ (NSData *)dataWithBase64EncodedString:(NSString *)string
{
    if (string == nil)
        [NSException raise:NSInvalidArgumentException format:@""];
    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];
}

/************************************************************
 函数名称 : + (NSString *)base64EncodedStringFrom:(NSData *)data
 函数描述 : 文本数据转换为base64格式字符串
 输入参数 : (NSData *)data
 输出参数 : N/A
 返回参数 : (NSString *)
 备注信息 :
 **********************************************************/
+ (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];
}











//加密
+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key;
{
    NSString *ciphertext = nil;
    const char *textBytes = [plainText UTF8String];
    NSUInteger dataLength = [plainText length];
    unsigned char buffer[1024];
    memset(buffer, 0, sizeof(char));
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding,
                                          [key UTF8String], kCCKeySizeDES,
                                          NULL,
                                          textBytes, dataLength,
                                          buffer, 1024,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        ciphertext = [self dataTohexString:data];
    }
    
    return ciphertext;
}

//解密
+(NSString *) decryptUseDES:(NSString *)plainText key:(NSString *)key
{
    NSString *cleartext = nil;
    NSData *textData = [self hexStringToData:plainText];
    NSUInteger dataLength = [textData length];
    unsigned char buffer[1024];
    memset(buffer, 0, sizeof(char));
    size_t numBytesEncrypted = 0;
    
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,kCCOptionPKCS7Padding,
                                          [key UTF8String], kCCKeySizeDES,
                                          NULL,
                                          [textData bytes]  , dataLength,
                                          buffer, 1024,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        //NSLog(@"DES解密成功");
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        cleartext = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    }else{
        //NSLog(@"DES解密失败");
    }
    return cleartext;
}

+ (NSString *)dataTohexString:(NSData*)data
{
    Byte *bytes = (Byte *)[data bytes];
    NSString *hexStr=@"";
    for(int i=0;i<[data length];i++)
    {
        
        int intTmp = bytes[i];
        // 把负数转换为正数
        if (intTmp < 0) {
            intTmp = intTmp + 256;
        }
        
        
        NSString *newHexStr = [NSString stringWithFormat:@"%x",intTmp&0xff];//16进制数
        
        // 小于0F的数需要在前面补0
        if (intTmp < 16) {
            hexStr = [NSString  stringWithFormat:@"%@0%@",hexStr,newHexStr];
        }else{
            hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
        }
        
        
        
//        NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];//16进制数
        
//        int intTmp = [newHexStr intValue];
//        
//        if (intTmp < 0) {
//            intTmp = intTmp + 256;
//        }
//        NSLog(@"---->%@---->%d",newHexStr,intTmp);
//        
//        newHexStr = [NSString stringWithFormat:@"%d",intTmp];
//        
//        if([newHexStr length]==1)
//            hexStr = [NSString  stringWithFormat:@"%@0%@",hexStr,newHexStr];
//        else
//            hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
    }
    return hexStr;
}


+ (NSData*)hexStringToData:(NSString*)hexString
{
    //NSString *hexString = @"3e435fab9c34891f"; //16进制字符串
    int j=0;
    Byte bytes[hexString.length];  ///3ds key的Byte 数组， 128位
    for(int i=0;i<[hexString length];i++)
    {
        int int_ch;  /// 两位16进制数转化后的10进制数
        
        unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
        int int_ch1;
        if(hex_char1 >= '0' && hex_char1 <='9')
            int_ch1 = (hex_char1-48)*16;   //// 0 的Ascll - 48
        else if(hex_char1 >= 'A' && hex_char1 <='F')
            int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65
        else
            int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97
        i++;
        
        unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
        int int_ch2;
        if(hex_char2 >= '0' && hex_char2 <='9')
            int_ch2 = (hex_char2-48); //// 0 的Ascll - 48
        else if(hex_char1 >= 'A' && hex_char1 <='F')
            int_ch2 = hex_char2-55; //// A 的Ascll - 65
        else
            int_ch2 = hex_char2-87; //// a 的Ascll - 97
        
        int_ch = int_ch1+int_ch2;
        //NSLog(@"int_ch=%x",int_ch);
        bytes[j] = int_ch;  ///将转化后的数放入Byte数组里
        j++;
    }
    //    NSData *newData = [[NSData alloc] initWithBytes:bytes length:j];
    NSData *newData = [[NSData alloc] initWithBytes:bytes length:j];
    //NSLog(@"newData=%@",newData);
    return newData;
}



@end