/**
 * \file ecp_alt.h
 *
 * \brief Utility macros for internal use in the library
 */
/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#ifndef ECP_ALT_H
#define ECP_ALT_H

#if defined(MBEDTLS_ECP_ALT)

typedef struct mbedtls_ecp_group
{
    mbedtls_ecp_group_id id; /*!< An internal group identifier. */
    mbedtls_mpi P;           /*!< The prime modulus of the base field. */
    mbedtls_mpi A;           /*!< For Short Weierstrass: \p A in the equation. For
                                  Montgomery curves: <code>(A + 2) / 4</code>. */
    mbedtls_mpi B;           /*!< For Short Weierstrass: \p B in the equation.
                                  For Montgomery curves: unused. */
    mbedtls_ecp_point G;     /*!< The generator of the subgroup used. */
    mbedtls_mpi N;           /*!< The order of \p G. */
    size_t pbits;            /*!< The number of bits in \p P.*/
    size_t nbits;            /*!< For Short Weierstrass: The number of bits in \p P.
                                  For Montgomery curves: the number of bits in the
                                  private keys. */
    /* End of public fields */

    unsigned int MBEDTLS_PRIVATE(h);                             /*!< \internal 1 if the constants are static. */
    int (*MBEDTLS_PRIVATE(modp))(mbedtls_mpi *);                 /*!< The function for fast pseudo-reduction mod \p P (see above).*/
    int (*MBEDTLS_PRIVATE(t_pre))(mbedtls_ecp_point *, void *);  /*!< Unused. */
    int (*MBEDTLS_PRIVATE(t_post))(mbedtls_ecp_point *, void *); /*!< Unused. */
    void * MBEDTLS_PRIVATE(t_data);                              /*!< Unused. */
    mbedtls_ecp_point * MBEDTLS_PRIVATE(T);                      /*!< Pre-computed points for ecp_mul_comb(). */
    size_t MBEDTLS_PRIVATE(T_size);                              /*!< The number of dynamic allocated pre-computed points. */
} mbedtls_ecp_group;

/**
 * \name SECTION: Module settings
 *
 * The configuration options you can set for this module are in this section.
 * Either change them in mbedtls_config.h, or define them using the compiler command line.
 * \{
 */

#if !defined(MBEDTLS_ECP_WINDOW_SIZE)
/*
 * Maximum "window" size used for point multiplication.
 * Default: a point where higher memory usage yields disminishing performance
 *          returns.
 * Minimum value: 2. Maximum value: 7.
 *
 * Result is an array of at most ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) )
 * points used for point multiplication. This value is directly tied to EC
 * peak memory usage, so decreasing it by one should roughly cut memory usage
 * by two (if large curves are in use).
 *
 * Reduction in size may reduce speed, but larger curves are impacted first.
 * Sample performances (in ECDHE handshakes/s, with FIXED_POINT_OPTIM = 1):
 *      w-size:     6       5       4       3       2
 *      521       145     141     135     120      97
 *      384       214     209     198     177     146
 *      256       320     320     303     262     226
 *      224       475     475     453     398     342
 *      192       640     640     633     587     476
 */
#define MBEDTLS_ECP_WINDOW_SIZE 4 /**< The maximum window size used. */
#endif                            /* MBEDTLS_ECP_WINDOW_SIZE */

#if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM)
/*
 * Trade code size for speed on fixed-point multiplication.
 *
 * This speeds up repeated multiplication of the generator (that is, the
 * multiplication in ECDSA signatures, and half of the multiplications in
 * ECDSA verification and ECDHE) by a factor roughly 3 to 4.
 *
 * For each n-bit Short Weierstrass curve that is enabled, this adds 4n bytes
 * of code size if n < 384 and 8n otherwise.
 *
 * Change this value to 0 to reduce code size.
 */
#define MBEDTLS_ECP_FIXED_POINT_OPTIM 1 /**< Enable fixed-point speed-up. */
#endif                                  /* MBEDTLS_ECP_FIXED_POINT_OPTIM */

/* \} name SECTION: Module settings */

#endif /* MBEDTLS_ECP_ALT */

#endif /* ecp_alt.h */