ObjFW  Diff

#include "config.h"

#import "OFHMAC.h"
#import "OFSecureData.h"

#import "OFHashAlreadyCalculatedException.h"
#import "OFHashNotCalculatedException.h"
#import "OFInvalidArgumentException.h"

@implementation OFHMAC
@synthesize hashClass = _hashClass;
@synthesize allowsSwappableMemory = _allowsSwappableMemory;

+ (instancetype)HMACWithHashClass: (Class <OFCryptographicHash>)class

	@try {
		if (length > blockSize) {
			id <OFCryptographicHash> hash = [_hashClass
			    hashWithAllowsSwappableMemory:
			    _allowsSwappableMemory];
			[hash updateWithBuffer: key length: length];
			[hash calculate];

			length = hash.digestSize;
			if OF_UNLIKELY (length > blockSize)
				length = blockSize;

			memcpy(outerKeyPadItems, hash.digest, length);
			memcpy(innerKeyPadItems, hash.digest, length);

	if (_calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithObject: self];

	[_innerHash updateWithBuffer: buffer length: length];
}

- (void)calculate
{
	if (_calculated)
		@throw [OFHashAlreadyCalculatedException
		    exceptionWithObject: self];

	if (_outerHash == nil || _innerHash == nil)
		@throw [OFInvalidArgumentException exception];

	[_innerHash calculate];


	[_outerHash updateWithBuffer: _innerHash.digest
			      length: _innerHash.digestSize];
	[_outerHash calculate];
	_calculated = true;
}

- (const unsigned char *)digest
{
	if (!_calculated)
		@throw [OFHashNotCalculatedException exceptionWithObject: self];

	return _outerHash.digest;
}

- (size_t)digestSize
{
	return [_hashClass digestSize];