iOS蓝牙传输数据常用到的进制转换的方法

1、Byte转NSData

Byte value[3]={0};
value[0]=0x1B;
value[1]=0x99;
value[2]=0x01;
NSData * data = [NSData dataWithBytes:&value length:sizeof(value)];

优点：这种方法比较简单，没有进行转换，直接一个字节一个字节的拼装好发送出去。
缺点：当发送数据比较长时会很麻烦，而且不易更改。

2、NSString转NSData

- (NSData *)hexToBytes:(NSString *)str{

NSMutableData* data = [NSMutableData data];
int idx;
for (idx = 0; idx+2 <= str.length; idx+=2) { 
NSRange range = NSMakeRange(idx, 2);
 NSString* hexStr = [str substringWithRange:range]; NSScanner* scanner = [NSScanner scannerWithString:hexStr]; 
unsigned int intValue; 
[scanner scanHexInt:&intValue];
 [data appendBytes:&intValue length:1];
}
return data;
}

3、将十进制转化为十六进制

- (NSString *)ToHex:(int)tepid{

NSString *nLetterValue;
NSString *str =@"";
int tamping;
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:@"%u",ttmpig]; } 
str = [nLetterValue stringByAppendingString:str];
 if (tmpid == 0) { 
break;
 }
}
//不够一个字节凑0
if(str.length == 1){
 return [NSString stringWithFormat:@"0%@",str];
}else{ 
return str;
}
}

4、10进制转2进制

- (NSString *)toBinarySystemWithDecimalSystem:(int)num length:(int)length{
int remainder = 0; //余数
int divisor = 0; //除数
NSString * prepare = @"";
while (true){ 
remainder = num%2; 
divisor = num/2; 
num = divisor; 
prepare = [prepare stringByAppendingFormat:@"%d",remainder]; 
if (divisor == 0) {
 break; 
}
}
//倒序输出
NSString * result = @"";
for (int i = length -1; i >= 0; i --){
 if (i <= prepare.length - 1) { 
result = [result stringByAppendingFormat:@"%@", [prepare substringWithRange:NSMakeRange(i , 1)]];
 }else{
 result = [result stringByAppendingString:@"0"];
 }
}
return result;
}

5、2进制转10进制

- (NSString *)toDecimalWithBinary:(NSString *)binary{
int ll = 0 ;
int temp = 0 ;
for (int i = 0; i < binary.length; i ++){ 
temp = [[binary substringWithRange:NSMakeRange(i, 1)] intValue]; 
temp = temp * powf(2, binary.length - i - 1); 
ll += temp;
}
NSString * result = [NSString stringWithFormat:@"%d",ll];
return result;
}

6、16进制和2进制互转

- (NSString *)getBinaryByhex:(NSString *)hex binary:(NSString *)binary{
NSMutableDictionary *hexDic = [[NSMutableDictionary alloc] init];
hexDic = [[NSMutableDictionary alloc] initWithCapacity:16];
[hexDic setObject:@"0000" forKey:@"0"];
[hexDic setObject:@"0001" forKey:@"1"];
[hexDic setObject:@"0010" forKey:@"2"];
[hexDic setObject:@"0011" forKey:@"3"];
[hexDic setObject:@"0100" forKey:@"4"];
[hexDic setObject:@"0101" forKey:@"5"];
[hexDic setObject:@"0110" forKey:@"6"];
[hexDic setObject:@"0111" forKey:@"7"];
[hexDic setObject:@"1000" forKey:@"8"];
[hexDic setObject:@"1001" forKey:@"9"];
[hexDic setObject:@"1010" forKey:@"a"];
[hexDic setObject:@"1011" forKey:@"b"];
[hexDic setObject:@"1100" forKey:@"c"];
[hexDic setObject:@"1101" forKey:@"d"];
[hexDic setObject:@"1110" forKey:@"e"];
[hexDic setObject:@"1111" forKey:@"f"];
NSMutableString *binaryString=[[NSMutableString alloc] init];
if (hex.length) { 
for (int i=0; i<[hex length]; i++) {
 NSRange rage; 
rage.length = 1;
 rage.location = i; 
NSString *key = [hex substringWithRange:rage]; [binaryString appendString:hexDic[key]]; 
}
}else{
 for (int i=0; i<binary.length; i+=4) {
 NSString *subStr = [binary substringWithRange:NSMakeRange(i, 4)]; 
int index = 0; 
for (NSString *str in hexDic.allValues) { 
index ++;
 if ([subStr isEqualToString:str]) { 
[binaryString appendString:hexDic.allKeys[index-1]]; break;
 } 
} 
}
}
return binaryString;
}

7、int转NSData

- (NSData *) setId:(int)Id {
//用4个字节接收
Byte bytes[4];
bytes[0] = (Byte)(Id>>24);
bytes[1] = (Byte)(Id>>16);
bytes[2] = (Byte)(Id>>8);
bytes[3] = (Byte)(Id);
NSData *data = [NSData dataWithBytes:bytes length:4];
}

8、NSData转int

接受到的数据0x00000a0122

//4字节表示的int
NSData *intData = [data subdataWithRange:NSMakeRange(2, 4)];
int value = CFSwapInt32BigToHost(*(int*)([intData bytes]));//655650

//2字节表示的int
NSData *intData = [data subdataWithRange:NSMakeRange(4, 2)];int value = CFSwapInt16BigToHost(*(int*)([intData bytes]));//290

//1字节表示的intchar *bs = (unsigned char *)[[data subdataWithRange:NSMakeRange(5, 1) ] bytes];int value = *bs;//34

9、NSString转化为UNICODE String

(NSString*)fname ＝ @“Test”;

char fnameStr[10];

memcpy(fnameStr, [fname cStringUsingEncoding:NSUnicodeStringEncoding], 2*([fname length]));

10、NSString转化为char

(NSString*)fname ＝ @“Test”;

char fnameStr[10];

fnameStr =[fname UTF8String];

11、char -> NSData

方法一：

   char * postData = "TEST";
   NSData *data = [NSData dataWithBytes:postData length:strlen(postData)];

 方法二：

    转换为NSString： - (id)initWithUTF8String:(const char *)bytes
    然后用NSString的 - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding

12、NSData ->char

 NSData returnData ；

  char* bu=[returnData bytes];

13、NSData->NSString

NSString* aStr;
aStr = [[NSString alloc] initWithData:aData encoding:NSASCIIStringEncoding];

14、NSString->NSData

NSData* aData;
aData = [aStr dataUsingEncoding: NSASCIIStringEncoding];

15、NSData 与 Byte

NSString *testString = @"1234567890";

NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];

Byte *testByte = (Byte *)[testData bytes];

for(int i=0;i<[testData length];i++)

printf("testByte = %d\n",testByte[i]);

16、Byte数组－> NSData

Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};

NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

17、Byte数组－>16进制数

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

NSString *hexStr=@"";

for(int i=0;i<[encryData 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];

}

NSLog(@"bytes 的16进制数为:%@",hexStr);

18、将16进制数据转化成Byte 数组

NSString *hexString = @"3e435fab9c34891f"; //16进制字符串

int j=0;

Byte bytes[128];  ///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=%d",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:128];

NSLog(@"newData=%@",newData);

19、将一个8个字节的字符串转化成NSData

- (NSData *)change:(NSString *)string Length:(int)length{

    Byte byte[8];
    memset(byte, 0, 8 * sizeof(Byte));
    NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
    Byte *stringByte = (Byte *)[data bytes];
    memcpy(byte + 0*sizeof(Byte), stringByte , length*sizeof(Byte));
    
    return [NSData dataWithBytes:byte length:8];
}