/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#import "OFObject.h"
OF_ASSUME_NONNULL_BEGIN
/**
* @protocol OFCryptographicHash \
* OFCryptographicHash.h ObjFW/OFCryptographicHash.h
*
* @brief A protocol for classes providing cryptographic hash functions.
*
* A cryptographic hash implementing this protocol can be copied. The entire
* state is copied, allowing to calculate a new hash from there. This is
* especially useful for generating many hashes with a common prefix.
*/
@protocol OFCryptographicHash <OFObject, OFCopying>
#ifdef OF_HAVE_CLASS_PROPERTIES
@property (class, readonly, nonatomic) size_t digestSize;
@property (class, readonly, nonatomic) size_t blockSize;
#endif
/**
* @brief The digest size of the cryptographic hash, in bytes.
*/
@property (readonly, nonatomic) size_t digestSize;
/**
* @brief The block size of the cryptographic hash, in bytes.
*/
@property (readonly, nonatomic) size_t blockSize;
/**
* @brief Whether data may be stored in swappable memory.
*/
@property (readonly, nonatomic) bool allowsSwappableMemory;
/**
* @brief A boolean whether the hash has already been calculated.
*/
@property (readonly, nonatomic, getter=isCalculated) bool calculated;
/**
* @brief A buffer containing the cryptographic hash.
*
* The size of the buffer depends on the hash used. The buffer is part of the
* receiver's memory pool.
*
* @throw OFHashNotCalculatedException The hash hasn't been calculated yet
*/
@property (readonly, nonatomic) const unsigned char *digest
OF_RETURNS_INNER_POINTER;
/**
* @brief Creates a new cryptographic hash.
*
* @return A new autoreleased cryptographic hash
*/
+ (instancetype)hashWithAllowsSwappableMemory: (bool)allowsSwappableMemory;
/**
* @brief Returns the digest size of the cryptographic hash, in bytes.
*
* @return The digest size of the cryptographic hash, in bytes
*/
+ (size_t)digestSize;
/**
* @brief Returns the block size of the cryptographic hash, in bytes.
*
* @return The block size of the cryptographic hash, in bytes
*/
+ (size_t)blockSize;
/**
* @brief Initializes an already allocated cryptographic hash.
*
* @return An initialized cryptographic hash
*/
- (instancetype)initWithAllowsSwappableMemory: (bool)allowsSwappableMemory;
- (instancetype)init OF_UNAVAILABLE;
/**
* @brief Adds a buffer to the cryptographic hash to be calculated.
*
* @param buffer The buffer which should be included into the calculation
* @param length The length of the buffer
* @throw OFHashAlreadyCalculatedException The hash has already been calculated
*/
- (void)updateWithBuffer: (const void *)buffer length: (size_t)length;
/**
* @brief Performs the final calculation of the cryptographic hash.
*
* @throw OFHashAlreadyCalculatedException The hash has already been calculated
*/
- (void)calculate;
/**
* @brief Resets all state so that a new hash can be calculated.
*
* @warning This invalidates any pointer previously returned by @ref digest. If
* you are still interested in the previous digest, you need to memcpy
* it yourself before calling @ref reset!
*/
- (void)reset;
@end
OF_ASSUME_NONNULL_END