struct DATA
{
unsigned char USERNAME[32];
};
i want copy a NSString to struct DATA.USERNAME , how to do it ?
You can use the -[NSString UTF8String] method to get a C string of your NSString. Then, you can use strncpy(DATA.USERNAME, [mystring UTF8String], 32); to copy that string into the structure.
You first need to know what encoding is expected. NSString can generate bytes in a wide range of encodings. Then you pass a pointer to the USERNAME array to getCString:maxLength:encoding:. So, for example, if you want to copy the contents of the NSString myCocoaString as UTF-8 into USERNAME field of a DATA struct called myData, you'd do:
BOOL success = [myCocoaString getCString:myData.USERNAME maxLength:32 encoding:NSUTF8StringEncoding];
NSLog(#"Was %# to store string contents in USERNAME!", success ? #"able" : #"not able");
Related
So I'm saving the NSString encoding enum value in a database as a string. This is one of the values:
NSUTF16LittleEndianStringEncoding = 0x94000100,
And I'm saving it as a string with value 0x94000100. My goal is to read this value as an NSString, but then turn it into a value I can use to encode:
NSString* encodingValueAsString = [object objectForKey:kWSWordlistFilesEncodingKey];
// Convert 'encodingValueAsString' to variable 'encoding' that can act as enum
NSString* dataString = [[NSString alloc] initWithData:data
encoding:encoding];
How do I write that missing line?
There's no reason to convert the enum value to/from a string. Just save it and read it back as an int.
But the short answer to your original question is:
NSStringEncoding encoding = [encodingValueAsString intValue];
Wait - that won't work since you are saving the string as the hex value.
You need to use NSScanner:
NSScanner *scanner = [NSScanner scannerWithString:encodingValueAsString];
NSStringEncoding encoding;
[scanner scanHexInt:&encoding];
See why using int instead of a string would be easier?
Title pretty much says everything.
would like to print (NOT in decimal), but in unsigned char value (HEX).
example
unsigned char data[6] = {70,AF,80,1A, 01,7E};
NSLog(#"?",data); //need this output : 70 AF 80 1A 01 7E
Any idea? Thanks in advance.
There is no format specifier for an char array. One option would be to create an NSData object from the array and then log the NSData object.
NSData *dataData = [NSData dataWithBytes:data length:sizeof(data)];
NSLog(#"data = %#", dataData);
Nothing in the standard libraries will do it, so you could write a small hex dump function, or you could use something else that prints non-ambigious full data. Something like:
char buf[1 + 3*dataLength];
strvisx(buf, data, dataLength, VIS_WHITE|VIS_HTTPSTYLE);
NSLog(#"data=%s", buf);
For smallish chunks of data you could try to make a NSData and use the debugDescription method. That is currently a hex dump, but nothing promises it will always be one.
To print char* in NSLog try the following:
char data[6] = {'H','E','L','L','0','\n'};
NSString *string = [[NSString alloc] initWithUTF8String:data];
NSLog(#"%#", string);
You will need to null terminate your string.
From Apple Documentation:
- (instancetype)initWithUTF8String:(const char *)nullTerminatedCString;
Returns an NSString object initialized by copying the characters from a given C array of UTF8-encoded bytes.
Why does the following code produce the logging at the bottom ?
Here is the anomaly- my second NSLog should print the chrStr but produces nothing, empty, which is verified by this debug command:
(gdb) po chrStr
object returns empty description
However, the third NSString where I re-convert the NSString back to NSData object DOES display the the data, the same value as in the first NSLog, as it should. This would indicate to me that chrStr must have actual contents. But it seems not to be so from the NSLOG or the po command. Why ?
NSString *login;
NSString *pass;
// Purpose: NSString *loginString = [NSString stringWithFormat:#"\000%#\000%#", login, pass];
login = #"Loginname"; // text string1
pass = #"Password"; // text string2
// convert text strings to data objects
NSData *subData1 = [login dataUsingEncoding:NSUTF8StringEncoding];
NSData *subData2 = [pass dataUsingEncoding:NSUTF8StringEncoding];
// embed a NULL into new NSData object
NSMutableData *data = [NSMutableData data];
unsigned char zeroByte = 0;
[data appendBytes:&zeroByte length:1];
// append string1, NULL, string2 to data object
[data appendData:subData1];
[data appendBytes:&zeroByte length:1];
[data appendData:subData2];
NSLog(#"1.NSData: %#", data); // print data object
// create a character string from data object
NSString *chrStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"2.NSString: %#", chrStr); // print character string
// create data object from string object
NSData *chrData = [chrStr dataUsingEncoding:NSUTF8StringEncoding];
NSLog(#"3.NSDATA: %#", chrData); // print data object
Produces:
[1071:207] 1.NSData: 004c6f67 696e6e61 6d650050 61737377 6f7264
[1071:207] 2.NSString:
[1071:207] 3.NSDATA: 004c6f67 696e6e61 6d650050 61737377 6f7264
This is a real mystery to me. If chrStr is empty then 3-NSDATA could not display its info, but it does !
What am I trying to accomplish ? Well, check my very first comment line: // purpose:
That line when uncommented produces a warning, even though it actually works, so I was trying to do it another way that allowed me to have a clean compile. If you see a better way to accomplish that objective, I all eyes and ears. But please don't dwell on why that #"\000%#\000%#" string is necessary, start out accepting that it is. Thanks.
In C (and therefore objective-c), a null byte is used to represent the end of a string. When you create the string object, it takes all of the data you have given it without parsing, which is why you can convert it back to data successfully. However, when you display the string, the system reads the string up to the first null byte, which is the first byte. Therefore, the string contains data, but any system functions which read byte by byte instead of using the strings returned length will think it is empty. When you work with non-displayable characters, you should try to use data objects over string objects as often as possible.
I want the user to input a string and then assign the input to an NSString. Right now my code looks like this:
NSString *word;
scanf("%s", &word);
The scanf function reads into a C string (actually an array of char), like this:
char word[40];
int nChars = scanf("%39s", word); // read up to 39 chars (leave room for NUL)
You can convert a char array into NSString like this:
NSString* word2 = [NSString stringWithBytes:word
length:nChars
encoding:NSUTF8StringEncoding];
However scanf only works with console (command line) programs. If you're trying to get input on a Mac or iOS device then scanf is not what you want to use to get user input.
scanf does not work with any object types. If you have a C string and want to create an NSString from it, use -[NSString initWithBytes:length:encoding:].
scanf does not work with NSString as scanf doesn’t work on objects. It works only on primitive datatypes such as:
int
float
BOOL
char
What to do?
Technically a string is made up of a sequence of individual characters. So to accept string input, you can read in the sequence of characters and convert it to a string.
use:
[NSString stringWithCString:cstring encoding:1];
Here is a working example:
NSLog(#"What is the first name?");
char cstring[40];
scanf("%s", cstring);
firstName = [NSString stringWithCString:cstring encoding:1];
Here’s an explanation of the above code, comment by comment:
You declare a variable called cstring to hold 40 characters.
You then tell scanf to expect a list of characters by using the %s format specifier.
Finally, you create an NSString object from the list of characters that were read in.
Run your project; if you enter a word and hit Enter, the program should print out the same word you typed. Just make sure the word is less than 40 characters; if you enter more, you might cause the program to crash — you are welcome to test that out yourself! :]
Taken from: RW.
This is how I'd do it:
char word [40];
scanf("%s",word);
NSString * userInput = [[NSString alloc] initWithCString: word encoding: NSUTF8StringEncoding];
yes, but sscanf does, and may be a good solution for complex NSString parsing.
Maybe this will work for you because it accepts string with spaces as well.
NSLog(#"Enter The Name Of State");
char name[20];
gets(name);
NSLog(#"%s",name);
Simple Solution is
char word[40];
scanf("%39s", word);
NSString* word2 = [NSString stringWithUTF8String:word];
The NSFileHandle class is an object-oriented wrapper for a file descriptor. For files, you can read, write, and seek within the file.
NSFileHandle *inputFile = [NSFileHandle fileHandleWithStandardInput];
NSData *inputData = [inputFile availableData];
NSString *word = [[NSString alloc]initWithData:inputData encoding:NSUTF8StringEncoding];
I've got a problem with the following code:
NSString *strValue=#"你好";
char temp[200];
strcpy(temp, [strValue UTF8String]);
printf("%s", temp);
NSLog(#"%s", temp);
in the first line of the codes, two Chinese characters are double quoted. The problem is printf function can display the Chinese characters properly, but NSLog can't.
Thanks to all. I figured out a solution for this problem. Foundation uses UTF-16 by default, so in order to use NSLog to output the c string in the example, I have to use cStringUsingEncoding to get UTF-16 c string and use %S to replace %s.
NSString *strValue=#"你好";
char temp[200];
strcpy(temp, [strValue UTF8String]);
printf("%s", temp);
strcpy(temp, [strValue cStringUsingEncoding:NSUTF16LittleEndianStringEncoding]);
NSLog(#"%S", temp);
NSLog's %s format specifier is in the system encoding, which seems to always be MacRoman and not unicode, so it can only display characters in MacRoman encoding. Your best option with NSLog is just to use the native object format specifier %# and pass the NSString directly instead of converting it to a C String. If you only have a C string and you want to use NSLog to display a message instead of printf or asl, you will have to do something like Don suggests in order to convert the string to an NSString object first.
So, all of these should display the expected string:
NSString *str = #"你好";
const char *cstr = [str UTF8String];
NSLog(#"%#", str);
printf("%s\n", cstr);
NSLog(#"%#", [NSString stringWithUTF8String:cstr]);
If you do decide to use asl, note that while it accepts strings in UTF8 format and passes the correct encoding to the syslog daemon (so it will show up properly in the console), it encodes the string for visual encoding when displaying to the terminal or logging to a file handle, so non-ASCII values will be displayed as escaped character sequences.
My guess is that NSLog assumes a different encoding for 8-bit C-strings than UTF-8, and it may be one that doesn't support Chinese characters. Awkward as it is, you might try this:
NSLog(#"%#", [NSString stringWithCString: temp encoding: NSUTF8StringEncoding]);
I know you are probably looking for an answer that will help you understand what's going on.
But this is what you could do to solve your problem right now:
NSLog(#"%#", strValue);
# define NSLogUTF8(a,b) NSLog(a,[NSString stringWithCString:[[NSString stringWithFormat:#"%#",b] cStringUsingEncoding:NSUTF8StringEncoding] encoding:NSNonLossyASCIIStringEncoding])
#define NSLogUTF8Ex(a,b) NSLog(a,[MLTool utf8toNString:[NSString stringWithFormat:#"%#",b]])
+(NSString*)utf8toNString:(NSString*)str{
NSString* strT= [str stringByReplacingOccurrencesOfString:#"\\U" withString:#"\\u"];
//NSString *strT = [strTemp mutableCopy];
CFStringRef transform = CFSTR("Any-Hex/Java");
CFStringTransform((__bridge CFMutableStringRef)strT, NULL, transform, YES);
return strT;
}