Byte2Hex和Hex2Byte转换

Question

我正在寻找Hex2yte和Byte2Hex转换。这些在Java语言中是可用的，在C#中也可以很容易地完成，但是我不知道如何在objective-c中做到这一点。

任何人有一个想法或以前做过这一点，请帮助我。

Answer 1

我是这样想出来的

编辑：

/**
 * Byte array to HexBinary string conversion
 * @param pVal Byte buffer to be encoded
 * @return HexBinary encoded value
 */
+ (NSString *) Byte2Hex:(NSArray *) pVal{
    NSMutableString *str = [NSMutableString string];
    for(int i=0; i < [pVal count]; i++){    
        int v1 = ([[pVal objectAtIndex:i] intValue] & 0xf0) >> 4;
        int v2 = ([[pVal objectAtIndex:i] intValue] & 0x0f);

        [str appendFormat:@"%c",[self HexCharFromDigit:v1]];
        [str appendFormat:@"%c",[self HexCharFromDigit:v2]];
    }
    return str;
}

/**
 * HexBinary to Byte array conversion
 * @param pVal Byte buffer to be encoded
 * @return HexBinary encoded value
 */
+ (NSArray *)Hex2Byte:(NSString *)pVal{
    NSMutableArray *arr = [NSMutableArray array];
    for (int i = 0; i < [pVal length]; i += 2){
        int hinibble = [self HexDigitFromChar:[pVal characterAtIndex:i]];
        int lonibble =  [self HexDigitFromChar:[pVal characterAtIndex:(i+1)]];
        Byte val = (Byte)((Byte)(hinibble << 4) | (Byte)lonibble);
        [arr addObject:[NSNumber numberWithInt:val]];
    }
    return arr;
}/**
 * Hex digit retrieval 
 * @param v Hexadecimal value
 * @return Hexadecimal digit
 */
+ (char) HexCharFromDigit:(int) v{

    switch (v)
    {
        case 0:
            return '0';
        case 1:
            return '1';
        case 2:
            return '2';
        case 3:
            return '3';
        case 4:
            return '4';
        case 5:
            return '5';
        case 6:
            return '6';
        case 7:
            return '7';
        case 8:
            return '8';
        case 9:
            return '9';
        case 10:
            return 'A';
        case 11:
            return 'B';
        case 12:
            return 'C';
        case 13:
            return 'D';
        case 14:
            return 'E';
        case 15:
            return 'F';
    }

    return '.';
}

/**
 * Hex digit retrieval
 * @param v Hexadecimal value
 * @return Hexadecimal digit
 */
+ (int) HexDigitFromChar:(char) v{
    switch (v)
    {
        case '0':
            return 0;
        case '1':
            return 1;
        case '2':
            return 2;
        case '3':
            return 3;
        case '4':
            return 4;
        case '5':
            return 5;
        case '6':
            return 6;
        case '7':
            return 7;
        case '8':
            return 8;
        case '9':
            return 9;
        case 'A':
        case 'a':
            return 10;
        case 'B':
        case 'b':
            return 11;
        case 'C':
            return 12;
        case 'D':
        case 'd':
            return 13;
        case 'E':
        case 'e':
            return 14;
        case 'F':
        case 'f':
            return 15;
    }

    return '.';
}