I have an NSData object that contains just <64> which is supposed to represent the int 100
How can I convert this NSData to an int?
I can convert it to it's Chr equivalent d using
NSString *string = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];
but I need the Dec equivalent of 100
Thanks
<64> means that the NSData object contains a single byte with the value 0x64 = 100,
so the following should work;
const uint8_t *bytes = [data bytes]; // pointer to the bytes in data
int value = bytes[0]; // first byte
int *b = (int *)data.bytes;
printf("%d",*b); //prints 100
Below logic converts NSData to integer perefctly. Length of bytes does not matter. It just works.
NSData *data;
NSString *stringData = [data description];
stringData = [stringData substringWithRange:NSMakeRange(1, [stringData length]-2)];
unsigned dataAsInt = 0;
NSScanner *scanner = [NSScanner scannerWithString: stringData];
[scanner scanHexInt:& dataAsInt];
Related
I need to send data over melodyManager & free from NonHexCharacters,
I already gone throught link How to convert an NSData into an NSString Hex string?
NSData from hex String?
In Both links i am not able to get NonHexFree charater data.
My input string is this,
0x0009 0xB0 0xFD 0xC2 0xA1 0x06 0x01%#040404 0x01 0xss1 0xhh 0xyy1
I need to convert this string into NSData which is free from nonhex characters i mean data should get only of hex string like from 0-9 symbols & A, B, C, D, E, F (alternatively a, b, c, d, e, f) and also remove space with 0x prefixes & output string should be 0009B0FDC2A10601040404111
then it should get converted to `NSData'
For cleaning nonHex characters check this,
NSString *input = #"0x0009 0xB0 0xFD 0xC2 0xA1 0x06 0x01%#040404 0x01 0xss1 0xhh 0xyy1";
I am considering that you don't required '0x' into your case.
NSString * output = [input stringByReplacingOccurrencesOfString:#"0x" withString:#""
options:NSCaseInsensitiveSearch range:NSMakeRange(0, input.length)];
NSString * hexChars = #"0123456789abcdefABCDEF";
NSCharacterSet *hexc = [NSCharacterSet characterSetWithCharactersInString:hexChars];
NSCharacterSet *invalidHexc = [hexc invertedSet];
NSString * allHex = [[output componentsSeparatedByCharactersInSet:invalidHexc] componentsJoinedByString:#""];
Then resultant hexstring pass to scan hexString & append into NSMUtableData then convert it into NSData,
//Check condition if required `allHex.lenght != nil`
NSMutableData *result = [[NSMutableData alloc] init];
int i = 0;
for (i = 0; i+2 <= allHex.length; i+=2) {
NSRange range = NSMakeRange(i, 2);
NSString* hexStr = [allHex substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
unsigned char uc = (unsigned char) intValue;
[result appendBytes:&uc length:1];
}
NSData * data = [NSData dataWithData:result];
I want to convert the 8 bytes I have in an NSData instance to a uint32_t array that has 2 items. I did the following, but it's not correct.
NSLog(#"Challenge data %#",dataChallenge);
uint32_t *data = (uint32_t *)dataChallenge.bytes;
NSLog(#"data0: %08x, data1: %08x", data[0], data[1]);
And this is the result:
Challenge data <3ce3e664 dafda14b>
data0: 64e6e33c, data1: 4ba1fdda
The order of data is not correct.
The values should be:
Challenge data <3ce3e664 dafda14b>
data0: 3ce3e664, data1: dafda14b
uint32_t *data = (uint32_t *)dataChallenge.bytes;
Example:
NSData *dataChallenge = [#"12345678" dataUsingEncoding:NSUTF8StringEncoding];
NSLog(#"dataChallenge: %#", dataChallenge);
uint32_t *data = (uint32_t *)dataChallenge.bytes;
NSLog(#"data0: %08x, data1: %08x", data[0], data[1]);
NSLog output:
dataChallenge: <31323334 35363738>
data0: 34333231, data1: 38373635
Note: The bytes are reversed because this is a lithe-endian machine
With memcpy:
NSData *dataChallenge = [#"12345678" dataUsingEncoding:NSUTF8StringEncoding];
NSLog(#"dataChallenge: %#", dataChallenge);
uint32_t data[2];
memcpy(data, (uint32_t *)dataChallenge.bytes, dataChallenge.length);
NSLog(#"data0: %08x, data1: %08x", data[0], data[1]);
NSLog output:
dataChallenge: <31323334 35363738>
data0: 34333231, data1: 38373635
Swapping the byte order:
NSLog(#"data0: %08x, data1: %08x", CFSwapInt32BigToHost(data[0]), CFSwapInt32BigToHost(data[1]));
NSLog output:
data0: 31323334, data1: 35363738
Note: See CFByteOrder.h for more combinations of byte swapping.
Below logic converts NSData to integer perfectly. Length of bytes does not matter. It just works.
NSData *data;
NSString *stringData = [data description];
stringData = [stringData substringWithRange:NSMakeRange(1, [stringData length]-2)];
unsigned dataAsInt = 0;
NSScanner *scanner = [NSScanner scannerWithString: stringData];
[scanner scanHexInt:& dataAsInt];
I need to represent a NSInteger and NSString into array of bytes. below are the sample of what I am looking for.
For how, this harcodings are working fine. I want to do this through code. Any clue.
First, NSInteger into bytes of Hex:
NSInteger test = 1;
unsigned char byte[] = { 0x00, 0x01 };
NSInteger test = 16;
unsigned char byte[] = { 0x00, 0x10 };
NSData *data = [NSData dataWithBytes:byte length:sizeof(byte)];
Second, NSString into bytes of Hex:
NSString *test = #"31C5B562-BD07-4616-BCBD-130BA6822790";
unsigned char byte[] = {0x31, 0xC5, 0xB5, 0x62, 0xBD, 0x07, 0x46, 0x16, 0xBC, 0xBD, 0x13, 0x0B, 0xA6, 0x82, 0x27, 0x90};
NSData *data = [NSData dataWithBytes:byte length:sizeof(byte)];
I tried with below code and it works well for my UUID but for NSInteger to to be working I need to send "0010" instead of 16 and "0001" instead of 1. So any clue on how to do this conversion.
- (NSData *)hexData {
NSMutableData *hexData = [NSMutableData data];
int idx = 0;
for (idx = 0; idx+2 <= self.length; idx+=2) {
NSRange range = NSMakeRange(idx, 2);
NSString* hexStr = [self substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
[hexData appendBytes:&intValue length:1];
}
return hexData;
}
EDIT:
int8_t test = -59;
int8_t bytes = CFSwapInt16HostToBig(test);
NSData *data1 = [NSData dataWithBytes:&bytes length:sizeof(bytes)];
Reaching as 0xFF instead of 0xC4
Since your string is a UUID string you can do something like this:
NSString *test = #"";
uuid_t uuid;
uuid_parse([test UTF8String], uuid)
NSData *data = [NSData dataWithBytes:uuid length:16];
For the number you can do:
NSInteger test = 1;
NSData *data = [NSData dataWithBytes:&test length:sizeof(test)];
Keep in mind that NSInteger is probably more than two bytes and you may also need to worry about byte order.
Update: Since it seems you need the integer value to be two bytes, you should do:
uint16_t test = 1;
NSData *data = [NSData dataWithBytes:&test length:sizeof(test)];
This will ensure 2 bytes. You also need to worry about byte ordering so you really need:
uint16_t test = 1;
uint16_t bytes = CFSwapInt16HostToBig(test);
NSData *data = [NSData dataWithBytes:&bytes length:sizeof(bytes)];
Change CFSwapInt16HostToBig to CFSwapInt16HostToLitte if appropriate.
I have a requirement to integrate with a web service that serves as a login. The hash needs to be generated on the client. I am able to produce the correct hash as NSMutableData, but then I need to convert it to a string, without the spaces or brackets produced when the NSMutableData object is rendered as a string in the output console. I have read several posts, all seeming to say the same thing:
NSString *newstring = [[NSString alloc] initWithDSata:dataToConvert encoding:NSUTF8StringEncoding];
Unfortunately, this doesnt work for me. Using NSUTF8StringEncoding returns null. NSASCIIStringEncoding is even worse.
Here is my code:
NSString *password = [NSString stringWithFormat:#"%#%#", kPrefix, [self.txtPassword text]];
NSLog(#"PLAIN: %#", password);
NSData *data = [password dataUsingEncoding:NSASCIIStringEncoding];
NSMutableData *sha256Out = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
CC_SHA256(data.bytes, data.length, sha256Out.mutableBytes);
NSString *preppedPassword = [[NSString alloc] initWithData:sha256Out encoding:NSASCIIStringEncoding];
NSLog(#"HASH: %#\n", preppedPassword);
How can I convert the NSMutableData to string?
My problem is that I need to from this
<7e8df5b3 17c99263 e4fe6220 bb75b798 4a41de45 44464ba8 06266397 f165742e>
to this
7e8df5b317c99263e4fe6220bb75b7984a41de4544464ba806266397f165742e
See How to convert an NSData into an NSString Hex string?
I use a slightly modified version myself:
#implementation NSData (Hex)
- (NSString *)hexRepresentationWithSpaces:(BOOL)spaces uppercase:(BOOL)uppercase {
const unsigned char *bytes = (const unsigned char *)[self bytes];
NSUInteger nbBytes = [self length];
// If spaces is true, insert a space every this many input bytes (twice this many output characters).
static const NSUInteger spaceEveryThisManyBytes = 4UL;
// If spaces is true, insert a line-break instead of a space every this many spaces.
static const NSUInteger lineBreakEveryThisManySpaces = 4UL;
const NSUInteger lineBreakEveryThisManyBytes = spaceEveryThisManyBytes * lineBreakEveryThisManySpaces;
NSUInteger strLen = 2 * nbBytes + (spaces ? nbBytes / spaceEveryThisManyBytes : 0);
NSMutableString *hex = [[NSMutableString alloc] initWithCapacity:strLen];
for (NSUInteger i = 0; i < nbBytes; ) {
if (uppercase) {
[hex appendFormat:#"%02X", bytes[i]];
} else {
[hex appendFormat:#"%02x", bytes[i]];
}
// We need to increment here so that the every-n-bytes computations are right.
++i;
if (spaces) {
if (i % lineBreakEveryThisManyBytes == 0) {
[hex appendString:#"\n"];
} else if (i % spaceEveryThisManyBytes == 0) {
[hex appendString:#" "];
}
}
}
return hex;
}
#end
According to my requirement:
The input string has to be converted into Byte Values.
Each character of string , which are 16 bit values , has to be converted to low 8 bits.
The Sha1 is then computed over the byte Array.
The resulting SHA-1 is converted into a 40 character string.
I know how to convert a string into SHA1 , but the rest of part is a bit gloomy to me.
I have been able to do the last two steps.
unsigned char digest[CC_SHA1_DIGEST_LENGTH];
NSData *dataString = [yourString dataUsingEncoding: NSUTF8StringEncoding];
if (CC_SHA1([dataString bytes], [dataString length], digest)) {
//Sha1 is calculated & stored in digest.
}
Any help will be appreciated.
I have created this function , which works fine according to your requirement . You just have to input a string.
#import <CommonCrypto/CommonDigest.h>
- (NSString *)calculateSHA:(NSString *)yourString
{
const char *ptr = [yourString UTF8String];
int i =0;
int len = strlen(ptr);
Byte byteArray[len];
while (i!=len)
{
unsigned eachChar = *(ptr + i);
unsigned low8Bits = eachChar & 0xFF;
byteArray[i] = low8Bits;
i++;
}
unsigned char digest[CC_SHA1_DIGEST_LENGTH];
CC_SHA1(byteArray, len, digest);
NSMutableString *hex = [NSMutableString string];
for (int i=0; i<20; i++)
[hex appendFormat:#"%02x", digest[i]];
NSString *immutableHex = [NSString stringWithString:hex];
return immutableHex;
}
Then you just have to call the above method.
[self calculateSHA:yourString];
NSData *dataString = [yourString dataUsingEncoding: NSUTF8StringEncoding];
converts the string to UTF-8 bytes, e.g. "é" = Unicode 00E9 is converted to the two bytes C3 A9, and "€" = Unicode 20AC is converted to three bytes E2 82 AC.
If your requirement is to "truncate" the Unicode characters to the lower 8 bits, you have to do this "manually", I do not know a built-in encoding that could be used for that:
NSMutableData *dataString = [NSMutableData dataWithLength:[yourString length]];
uint8_t *dataBytes = [dataString mutableBytes];
for (NSUInteger i = 0; i < [yourString length]; i++) {
// assigning the character to a uint_8 truncates to the lower 8 bit:
dataBytes[i] = [yourString characterAtIndex:i];
}
Based on your code snippet, you want to do something like:
unsigned char digest[CC_SHA1_DIGEST_LENGTH];
NSData *dataString = [yourString dataUsingEncoding: NSUTF8StringEncoding];
NSMutableString *outString;
if (CC_SHA1([dataString bytes], [dataString length], digest)) {
for (int i=0;i<CC_SHA1_DIGEST_LENGTH;i++) {
[outString appendFormat:#"%02x", digest[i]];
}
}
Where outString will be your 40-char string.
Here's an NSString category for creating a SHA1 hash of an NSString.
Creating SHA1 Hash from NSString