The c string you receive is owned by a temporary object, and will become invalid when automatic deallocation takes place. Note, when creating a string constant in this fashion, you should use utf8 characters. Creating a base64 string from nsdata if you targeting on ios 7 there is an easy way using provided up vote 1 down. Nskeyedarchiver says that the nsdata is formated as a property list. Operations to represent pdf documents as data objects. How to convert nsdata to nsstring or vice versa in. Nsdatensstring nsstring nsstringnsdate nsdatensstring. Mar 12, 20 convert nsdata to nsstring in the previous post i wrote a few lines of code to convert an nsstring object to an nsdata object. In most cases, this is accomplished using an addition or concatenation operator. Since this is almost a direct translation from objectivec, is there any way to make this more swifty, say by using map or stride, without sacrificing speed stride is already used for the iteration.
I plan to have the user to upload a videopicture from their iphone and have that file be wrapped in a nsdata class. Recently i am keeping fighting with objective c, and i encounter some problems about string type. Nsdata can be represented as hexadecimal string, similar to what it outputs in its description method swift. Swift language convert string to and from data nsdata. Converting between c and objectivec strings nsstring. Objective c language nsdata and hexadecimal string example. If you want to convert string to nsdata using nsutf8stringencoding. Provide me any good code example of converting nsdata to nsstring. How would you determine the mime type for an nsdata object.
Learn how to useing the nsstring class objective c with iphone application. Sdladdcommand class reference section contents initwithhandler. Objectivec strings the string in objectivec programming language is represented using nsstring and its subclass nsmutablestring provides several ways for creating string objects. A c string is simply a series of characters a onedimensional character array that is nullterminated, whereas an nsstring object is a complete object with class methods, instance methods, etc. Am assuming you have your pdf in documents directory here. Learn more converting nsdata to nsstring in objective c. Appending strings to nsstring in objectivec udemy blog. For instance, if you store a file on a server and download the same onto a device, you can compare the server hosted md5 value to a received copy to verify the file was. Encoding and decoding a string using nsdata base64.
Foxit pdf sdk for mac objectivec api ships with simpletouse apis that can. If you want to get a permanent c string, you must create a buffer and copy the contents of the const char returned by the method. Hi all, i know this is suppose to be very straight forward and simple but i have been trying to convert nsdata to nsstring using obj c but the outputs are not what i really wanted. When you have some data which is encoded in utf8 data than you can use below code. I get the bellow code from this link nsstring stringnsstring. You get back a data object, which you can then write to disk however you want. In this post ill do the opposite, putting the conversion into the context how to print an nsdata object to the debugging console. It treats in this tutorial, we will learn how to convert images and pdf to base64 string in swift. All lengths, character indexes, and ranges are expressed in terms of 16bit platformendian values, with index values starting at 0 an nsstring object can be initialized from or written to a c buffer, an nsdata object, or the contents of an nsurl. The method takes as an argument an nsstring object containing the path to file. Your nsurlsession callback probably runs on a background thread. Create md5 hash from nsstring, nsdata or a file md5 messagedigest algorithm 5 is a crytographic hash function that is commonly used as a means to verify file integrity. Swift language convert string to and from data nsdata swift.
Objectivec objectivec notes for professionals notes for professionals free programming books disclaimer this is an uno cial free book created for educational purposes and is not a liated with o cial objectivec groups or companys. Objectivec language nsdata and hexadecimal string example. You initialize a pdfdocument object with pdf data or with a url to a pdf file. Data objects let simple allocated buffers that is, data with no embedded pointers take on the behavior of foundation objects. Pdf download objective c language for free previous next. An nsstring object initialized by converting the bytes in data into utf16 code units using encoding. String this is my string to convert to nsdata let utf8str stri. I need to convert its bytes to a string and send as json. Convert string to nsdata and nsdata to string swift.
Given the foundation of objectivec is built upon the c programming language, its good to know how to convert c based strings to nsstring objects, and viceversa for clarification. Try this to convert pdf to nsdata nsstring pdfpath documentsdirectory stringbyappendingpathcomponent. Nsdata can be represented as hexadecimal string, similar to what it outputs in its description method swift extension nsdata func hexstring string return unsafebufferpointer start. Once you have your content ready, call pdfdata on your renderer, begin a new. Nsdata and its mutable subclass nsmutable data provide data objects, or objectoriented wrappers for byte buffers. The most basic way in which nsstring object is represented is shown below. This is unreliable because it may result in null string values. How to convert nsdata to nsstring or vice versa in objective. Swift, the swift logo, swift playgrounds, xcode, instruments, cocoa touch. I was wondering if i can tell the mime type from the nsdata. In the previous post i wrote a few lines of code to convert an nsstring object to an nsdata object. In this post ill do the opposite, putting the conversion into the context how to print an nsdata object to the debugging console by default, when you print an nsdata object to the console using nslog, the output will be in hex, it will look something like the following. Besides assuming that your network requests arent erroring you should at least log if there are network errors, there are threading issues.
Returns an nsstring object initialized by using a given format string as a template into which the remaining argument values are substituted according to given locale information. Objective c strings the string in objective c programming language is represented using nsstring and its subclass nsmutablestring provides several ways for creating string objects. Nsdata converting nsdata to hex string essential ios. Printing pdf using airprint causes small output stack overflow. How to generate pdf using nsdata or using data bytes objective c. All trademarks and registered trademarks are the property of their respective owners 100. Copy the nshash classes into your project or add this line to your podfile. Does anyone have any idea how i can convert this nsdata to a string and back again. Returns nil if the initialization fails for some reason for example if data does not represent valid data for encoding. Objectivec language nsdata and hexadecimal string objective. Announcements assignment 1a download updated copy from web site assignment 1b available tonight on class website will send email to class when available both assignment 1a and 1b due next friday 118, by 5. The reason the string is being considered unreliable in previous stack posts is because they too were attempting to use nsdata objects where the ending bytes arent properly terminated with null.
Feb 28, 2011 create md5 hash from nsstring, nsdata or a file md5 messagedigest algorithm 5 is a crytographic hash function that is commonly used as a means to verify file integrity. Documents user documents and data files like user generated content. Objectivec language encoding and decoding a string. I do not see an usecase for map here but the performance can be improved considerably. Nshash adds hashing methods to nsstring and nsdata. An atomic write first writes the data to a temporary file and then, only if this write succeeds, moves the temporary file to its final location. Copies characters from a given range in the receiver into a given buffer. The nsstring pointer is not the same as a native char based c string. Ive gone through various encodings, utf8, ascii, etc. You can serialize the object to a byte array, then use that to create the nsdata object and get the byte array back out when you need it again you could also serialize the object to a string with for example, then create the nsdata from the string. The result will copy the content of the object, but internally it uses an unicode representation. String concatenation is one of the most commonlyused techniques in modern programming. The nsstring pointer is not the same as a native char based cstring. Find the example of iphone nsstring class in object c.
This method is meant to be called from within a variadic function, where the argument list will be available. Objectivec convert byte to nsdata objectivecbyte itgo. Objectivec language encoding and decoding a string using. Nsstring provides builtin support for unicode, which means that we can include utf8 characters directly in string literals. Hi all,in coding we have secure some information while we are sending it to server and vice versa,in this case we use encoding and decoding. Developer guide for foxit pdf sdk for mac objectivec. Pdf download objectivec language for free previous next. Matts answer should take care of it, but if it absolutely doesnt and youre somehow absolutely sure that your nsdata object has valid string data in it then you can access the data directly via the data bytes method, build a traditional c stri. The most famous one is utf8 which is an 8bit representation of unicode characters, suitable for transmission or storage by asciibased systems. There are only a few answers to this question and the most recent one is from 2010 4 years ago. Returns a string containing the bytes in a given c array, interpreted according to a given encoding. Stack overflow for teams is a private, secure spot for you and your coworkers to find and share information.
To convert string to and from data nsdata we need to encode this string with a specific encoding. Strings in objectivec are handled using the classes nsstring and nsmutablestring, and require a little more effort to work with on. How to render pdfs using uigraphicspdfrenderer free swift 5. Nsdata provides methods for atomically saving their contents to a file, which guarantee that the data is either saved in its entirety, or it fails completely. All lengths, character indexes, and ranges are expressed in terms of 16bit platformendian values, with index values starting at 0. If it is utf8 it will work fine as long as the code uses only ascii codes, but it will break as soon as the code uses nonascii characters. Objectivec how to add box around nsstring inside nstextview.
The returned object may be different from the original receiver. Pdf nsnumber nsnumber nsdata nsdata nsdata stringdouble. An nsstring object encodes a unicodecompliant text string, represented as a sequence of utf16 code units. Objective c bold and change string text size for drawing text onto pdf. Converting nsdata to nsstring in objective c stack overflow.
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