src/utils/sha256.hpp

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/**
 * @file
 *   This file includes definitions for performing SHA-256 computations.
 */

#ifndef SHA256_HPP_
#define SHA256_HPP_

#include <openthread/crypto.h>
#include <openthread/platform/crypto.h>
#include "common/code_utils.hpp"

#include <mbedtls/sha256.h>

namespace otbr {
/**
 * @addtogroup core-security
 *
 * @{
 *
 */

/**
 * This class implements SHA-256 computation.
 *
 */
class Sha256
{
public:
    /**
     * This type represents a SHA-256 hash.
     *
     */
    class Hash : public otCryptoSha256Hash
    {
    public:
        static const uint8_t kSize = OT_CRYPTO_SHA256_HASH_SIZE; ///< SHA-256 hash size (bytes)

        /**
         * This method returns a pointer to a byte array containing the hash value.
         *
         * @returns A pointer to a byte array containing the hash.
         *
         */
        const uint8_t *GetBytes(void) const { return m8; }
    };

    /**
     * Constructor for `Sha256` object.
     *
     */
    Sha256(void);

    /**
     * Destructor for `Sha256` object.
     *
     */
    ~Sha256(void);

    /**
     * This method starts the SHA-256 computation.
     *
     */
    void Start(void);

    /**
     * This method inputs bytes into the SHA-256 computation.
     *
     * @param[in]  aBuf        A pointer to the input buffer.
     * @param[in]  aBufLength  The length of @p aBuf in bytes.
     *
     */
    void Update(const void *aBuf, uint16_t aBufLength);

    /**
     * This method finalizes the hash computation.
     *
     * @param[out]  aHash  A reference to a `Hash` to output the calculated hash.
     *
     */
    void Finish(Hash &aHash);

private:
    otCryptoContext       mContext;
    const static uint16_t kSha256ContextSize = sizeof(mbedtls_sha256_context);
    OT_DEFINE_ALIGNED_VAR(mContextStorage, kSha256ContextSize, uint64_t);
};
} // namespace otbr

#endif // SHA256_HPP_