ios常见的数据转换

转自
http://www.eoeit.cn/?post=40

我们做移动支付常常需要各种数据编码，希望分享给大家有所帮助，代码在如下：

NSString 转换成NSData 对象

NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];

16进制字符串BCD转asiic码nsdata

- (NSData *) stringToHexData
{
    int len = (int)[self length] / 2; // Target length
    unsigned char *buf = malloc(len);
    unsigned char *whole_byte = buf;
    char byte_chars[3] = {'\0','\0','\0'};
   
    int i;
    for (i=0; i < [self length] / 2; i++) {
        byte_chars[0] = [self characterAtIndex:i*2];
        byte_chars[1] = [self characterAtIndex:i*2+1];
        *whole_byte = strtol(byte_chars, NULL, 16);
        whole_byte++;
    }
   
    NSData *data = [NSData dataWithBytes:buf length:len];
    free( buf );
    return data;
}s

NSData 转换成NSString对象

NSData * data; NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

nsdata转换成十六进制NSString对象




- (NSString *) dataToHexString {     NSUInteger len = [self length];     char * chars = (char *)[self bytes];     NSMutableString * hexString = [[NSMutableString alloc] init];          for(NSUInteger i = 0; i < len; i++ )         [hexString appendString:[NSString stringWithFormat:@"%0.2hhx", chars[i]]];          return hexString; }

NSData 转换成char*

NSData *data; char *test=[data bytes];

char* 转换成NSData对象

byte* tempData = malloc(sizeof(byte)*16);  NSData *content=[NSData dataWithBytes:tempData length:16];

byte转为十六进制bcd码

+(NSString*) convertByteToString:(Byte) data {
    NSString* s=@"";
    char c1 = (int)(data >> 4) + 0x30;
    if( c1 > 0x39){
        c1 = (int)(data >> 4) - 10 + 'A';
    }
    s = [NSString stringWithFormat:@"%@%c", s, c1];
   
    char c2 = (int)(data & 0x0f) + 0x30;
    if( c2 > 0x39){
        c2 = (int)(data & 0x0f) - 10 + 'A';
    }
    s = [NSString stringWithFormat:@"%@%c ", s, c2];
    return  s;

}

//10 进制转16进制

+ (NSString *)intToHex:(int)tmpid
{
    NSString *nLetterValue;
    NSString *str =@"";
   int ttmpig;
    for (int i = 0; i<9; i++) {
        ttmpig=tmpid%16;
        tmpid=tmpid/16;
        switch (ttmpig)
        {
            case 10:
                nLetterValue =@"A";break;
            case 11:
                nLetterValue =@"B";break;
            case 12:
                nLetterValue =@"C";break;
            case 13:
                nLetterValue =@"D";break;
            case 14:
                nLetterValue =@"E";break;
            case 15:
                nLetterValue =@"F";break;
            default:
                nLetterValue=[NSString stringWithFormat:@"%d",ttmpig];
               
        }
        str = [nLetterValue stringByAppendingString:str];
        if (tmpid == 0) {
            break; 
        } 
       
    } 
    return str; 
}

byte*转为十六进制bcd码

+(NSString*) convertByteToString:(Byte*) data length:(int)length {          unsigned char *buf = malloc(length);     Split(buf, data, length);     return [NSString stringWithFormat:@"%s", buf]; }

static void Split(unsigned char *dest, const unsigned char *src, unsigned short pair_len) {     unsigned short i = 0;     unsigned short j = 0;          if(src == NULL || dest == NULL)     {         return;     }          for(i = 0;i < pair_len;i++)     {         j = i*2;         dest[j] = (src[i]&0xF0)>>4;         if((dest[j] >= 0) && (dest[j] <= 9))         {             dest[j] += 0x30;         }         else         {             switch(dest[j])             {                 case 0x0A:                     dest[j] = 'A';                     break;                 case 0x0B:                     dest[j] = 'B';                     break;                 case 0x0C:                     dest[j] = 'C';                     break;                 case 0x0D:                     dest[j] = 'D';                     break;                 case 0x0E:                     dest[j] = 'E';                     break;                 case 0x0F:                     dest[j] = 'F';                     break;                 default:                     break;             }         }                  dest[j+1] = src[i]&0x0F;         if((dest[j+1] >= 0) && (dest[j+1] <= 9))         {             dest[j+1] += 0x30;         }         else         {             switch(dest[j+1])             {                 case 0x0A:                     dest[j+1] = 'A';                     break;                 case 0x0B:                     dest[j+1] = 'B';                     break;                 case 0x0C:                     dest[j+1] = 'C';                     break;                 case 0x0D:                     dest[j+1] = 'D';                     break;                 case 0x0E:                     dest[j+1] = 'E';                     break;                 case 0x0F:                     dest[j+1] = 'F';                     break;                 default:                     break;             }         }     } } static int str2hex(char *str, unsigned char *hex, int wStrLen) {     unsigned char bLowByte,bHighByte;     unsigned char bHiBase,bLowBase;     int i;          for(i = 0; i < wStrLen; i += 2)     {         bHighByte = toupper(str[i]);         if ((bHighByte >= 'A') && (bHighByte <= 'F'))             bHiBase = '7';         else if ((bHighByte >= '0') && (bHighByte <= '9'))             bHiBase = '0';         else             return -1;         bLowByte = toupper(str[i+1]);         if ((bLowByte >= 'A') && (bLowByte <= 'F'))             bLowBase = '7';         else if ((bLowByte >= '0') && (bLowByte <= '9'))             bLowBase = '0';         else             return -1;         hex[(i/2)] = ((bHighByte - bHiBase) * 16 + (bLowByte - bLowBase));     }     return 0; }