iOS进制转换

+ (NSData *)stringToByte:(NSString *)str{//16进制字符串转换为NSData

    int j=0;

    Byte bytes[[str length]/2];

    for(int i=0;i<[str length];i++)

    {

        int int_ch;  ///两位16进制数转化后的10进制数

        unichar hex_char1 = [str 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 = [str 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_char2 >= 'A' && hex_char2 <='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;

        bytes[j] = int_ch;  ///将转化后的数放入Byte数组里

        j++;

    }

    NSData *newData = [[NSData alloc] initWithBytes:bytes length:[str length]/2 ];

    return newData;

}

+ (NSString *)stringFromHexString:(NSString *)hexString { //16进制转换成10进制

    char *myBuffer = (char *)malloc((int)[hexString length] / 2 + 1);

    bzero(myBuffer, [hexString length] / 2 + 1);

    for (int i = 0; i < [hexString length] - 1; i += 2) {

        unsigned int anInt;

        NSString * hexCharStr = [hexString substringWithRange:NSMakeRange(i, 2)];

        NSScanner * scanner = [[NSScanner alloc] initWithString:hexCharStr] ;

        [scanner scanHexInt:&anInt];

        myBuffer[i / 2] = (char)anInt;

    }

    NSString *unicodeString = [NSString stringWithCString:myBuffer encoding:4];

    NSLog(@"------字符串=======%@",unicodeString);

    return unicodeString;

    

    

}

+ (NSString *)hexStringFromString:(NSString *)string{//十进制转换成16进制

    NSData *myD = [string dataUsingEncoding:NSUTF8StringEncoding];

    Byte *bytes = (Byte *)[myD bytes];

    //下面是Byte 转换为16进制。

    NSString *hexStr=@"";

    for(int i=0;i<[myD length];i++)

        

    {

        NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数

        

        if([newHexStr length]==1)

            

            hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];

        

        else

            

            hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];

    }

    return hexStr;

}

+ (NSString *)hexStringFromData:(NSData *)data{//2进制转换为16进制

    Byte *bytes=(Byte*)[data bytes];

    NSString *hexStr=@"";

    for(int i=0;i<[data length];i++)

    {

        NSString *newHexStr=[NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数

        if([newHexStr length]==1)

            hexStr=[NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];

        else

            hexStr=[NSString stringWithFormat:@"%@%@",hexStr,newHexStr];

    }

    return hexStr;

}