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/**
* \file bignum_helpers.h
*
* \brief This file contains the prototypes of helper functions for
* bignum-related testing.
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#ifndef TEST_BIGNUM_HELPERS_H
#define TEST_BIGNUM_HELPERS_H
#include <mbedtls/build_info.h>
#if defined(MBEDTLS_BIGNUM_C)
#include <mbedtls/bignum.h>
#include <bignum_mod.h>
/** Allocate and populate a core MPI from a test case argument.
*
* This function allocates exactly as many limbs as necessary to fit
* the length of the input. In other words, it preserves leading zeros.
*
* The limb array is allocated with mbedtls_calloc() and must later be
* freed with mbedtls_free().
*
* \param[in,out] pX The address where a pointer to the allocated limb
* array will be stored.
* \c *pX must be null on entry.
* On exit, \c *pX is null on error or if the number
* of limbs is 0.
* \param[out] plimbs The address where the number of limbs will be stored.
* \param[in] input The test argument to read.
* It is interpreted as a hexadecimal representation
* of a non-negative integer.
*
* \return \c 0 on success, an \c MBEDTLS_ERR_MPI_xxx error code otherwise.
*/
int mbedtls_test_read_mpi_core(mbedtls_mpi_uint **pX, size_t *plimbs,
const char *input);
/** Read a modulus from a hexadecimal string.
*
* This function allocates exactly as many limbs as necessary to fit
* the length of the input. In other words, it preserves leading zeros.
*
* The limb array is allocated with mbedtls_calloc() and must later be
* freed with mbedtls_free(). You can do that by calling
* mbedtls_test_mpi_mod_modulus_free_with_limbs().
*
* \param[in,out] N A modulus structure. It must be initialized, but
* not set up.
* \param[in] s The null-terminated hexadecimal string to read from.
* \param int_rep The desired representation of residues.
*
* \return \c 0 on success, an \c MBEDTLS_ERR_MPI_xxx error code otherwise.
*/
int mbedtls_test_read_mpi_modulus(mbedtls_mpi_mod_modulus *N,
const char *s,
mbedtls_mpi_mod_rep_selector int_rep);
/** Free a modulus and its limbs.
*
* \param[in] N A modulus structure such that there is no other
* reference to `N->p`.
*/
void mbedtls_test_mpi_mod_modulus_free_with_limbs(mbedtls_mpi_mod_modulus *N);
/** Read an MPI from a hexadecimal string.
*
* Like mbedtls_mpi_read_string(), but with tighter guarantees around
* edge cases.
*
* - This function guarantees that if \p s begins with '-' then the sign
* bit of the result will be negative, even if the value is 0.
* When this function encounters such a "negative 0", it calls
* mbedtls_test_increment_case_uses_negative_0().
* - The size of the result is exactly the minimum number of limbs needed to fit
* the digits in the input. In particular, this function constructs a bignum
* with 0 limbs for an empty string, and a bignum with leading 0 limbs if the
* string has sufficiently many leading 0 digits. This is important so that
* the "0 (null)" and "0 (1 limb)" and "leading zeros" test cases do what they
* claim.
*
* \param[out] X The MPI object to populate. It must be initialized.
* \param[in] s The null-terminated hexadecimal string to read from.
*
* \return \c 0 on success, an \c MBEDTLS_ERR_MPI_xxx error code otherwise.
*/
int mbedtls_test_read_mpi(mbedtls_mpi *X, const char *s);
#endif /* MBEDTLS_BIGNUM_C */
#endif /* TEST_BIGNUM_HELPERS_H */