dataWithBytesNoCopy :length:
Creates and returns a data object that holds length bytes from the buffer bytes.
+ (id)dataWithBytesNoCopy:(void *)bytes length:(NSUInteger)length
Parameters
- bytes
- A buffer containing data for the new object. bytes must point to a memory block allocated with
malloc. - length
- The number of bytes to hold from bytes. This value must not exceed the length of bytes.
Return Value of [NSData dataWithBytesNoCopy]
A data object that holds length bytes from the buffer bytes. Returns
nil if the data object could not be created.Discussion of [NSData dataWithBytesNoCopy]
The returned object takes ownership of the bytes pointer and frees it on deallocation. Therefore, bytes must point to a memory block allocated with
malloc.
Example of [NSData dataWithBytesNoCopy]
+ (NSData*)AES128DecryptWithKey:(NSData*) data key:(NSData*)key {
NSUInteger dataLength = [data length];
NSLog(@"trying to decrypt >> %@ with key >> %@", data, key );
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void* buffer = malloc(bufferSize);
size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
[key bytes], kCCKeySizeAES128,
NULL /* initialization vector (optional) */,
[data bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesDecrypted);
NSLog(@"cryptstatus %d", cryptStatus);
if (cryptStatus == kCCSuccess)
{
return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
}
free(buffer); //free the buffer;
return nil;
}