CODEWITHSUNDEEP
iphoneobjective-ciosxcodeipad
CyberK
CyberK

Reputation: 1578

NSMutableArray to byte array to string

I have an iPad app which communicates with a webservice. There I can download an encrypted file. In a particular request I get a json with login credentials. Also in that json is a key which is used to encrypt the data.

The key looks like: [0,44,215,1,215,88,94,150]

With the json framework I can put this key into an NSMutableArray. After that I use a AES256 code to decrypt the file. But that code needs a NSString as a key. So my question is: how can I decode that NSMutableArray into an NSString? I guess I first need to put it into an byte arary, and then put it into an NSString?

Who can help me with this one?

Thanks in advance!

Upvotes: 0

Views: 3369

Answers (2)

occulus
occulus

Reputation: 17014

Firstly, convert your array of numbers (I assume they're given as NSNumbers) into a C array using code similar to the first snippet in the accepted answer here. In other words, something similar to this:

// Test array for now -- this data will come from JSON response
NSArray* nsArray = [NSArray arrayWithObjects:[NSNumber numberWithChar:1],
                                             [NSNumber numberWithChar:2],
                                             nil];
char cArray[2];

// Fill C-array with ints
int count = [nsArray count];

for (int i = 0; i < count; ++i) {
    cArray[i] = [[nsArray objectAtIndex:i] charValue];
}

Then create an NSString using the correct encoding:

NSString *encodedStr = [NSString stringWithCString:cArray encoding:NSUTF8StringEncoding];

Note: these are code sketches, they haven't been tested!

EDIT: changed from ints to chars.

Upvotes: 3

Jesse Black
Jesse Black

Reputation: 7976

If your array is the sequence of numbers, you can loop through it

//Assume you have created keyArray from your JSON
NSMutableString * keyString = [NSMutableString string];
for (id element in keyArray) {
    [string appendFormat:@"%@", id];
}

// if you need the comma's in the string
NSMutableString * keyString = [NSMutableString string];
for (id element in keyArray) {
    [string appendFormat:@"%@,", id];
}
int length = [string length];
NSRange range = NSMakeRange(0, length-1);
string = [string substringWithRange:range];

Upvotes: 0

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