LXR linux/include/linux/mpi.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/* mpi.h  -  Multi Precision Integers
   3 *      Copyright (C) 1994, 1996, 1998, 1999,
   4 *                    2000, 2001 Free Software Foundation, Inc.
   5 *
   6 * This file is part of GNUPG.
   7 *
   8 * Note: This code is heavily based on the GNU MP Library.
   9 *       Actually it's the same code with only minor changes in the
  10 *       way the data is stored; this is to support the abstraction
  11 *       of an optional secure memory allocation which may be used
  12 *       to avoid revealing of sensitive data due to paging etc.
  13 *       The GNU MP Library itself is published under the LGPL;
  14 *       however I decided to publish this code under the plain GPL.
  15 */
  16
  17#ifndef G10_MPI_H
  18#define G10_MPI_H
  19
  20#include <linux/types.h>
  21#include <linux/scatterlist.h>
  22
  23#define BYTES_PER_MPI_LIMB      (BITS_PER_LONG / 8)
  24#define BITS_PER_MPI_LIMB       BITS_PER_LONG
  25
  26typedef unsigned long int mpi_limb_t;
  27typedef signed long int mpi_limb_signed_t;
  28
  29struct gcry_mpi {
  30        int alloced;            /* array size (# of allocated limbs) */
  31        int nlimbs;             /* number of valid limbs */
  32        int nbits;              /* the real number of valid bits (info only) */
  33        int sign;               /* indicates a negative number */
  34        unsigned flags;         /* bit 0: array must be allocated in secure memory space */
  35        /* bit 1: not used */
  36        /* bit 2: the limb is a pointer to some m_alloced data */
  37        mpi_limb_t *d;          /* array with the limbs */
  38};
  39
  40typedef struct gcry_mpi *MPI;
  41
  42#define mpi_get_nlimbs(a)     ((a)->nlimbs)
  43
  44/*-- mpiutil.c --*/
  45MPI mpi_alloc(unsigned nlimbs);
  46void mpi_free(MPI a);
  47int mpi_resize(MPI a, unsigned nlimbs);
  48
  49/*-- mpicoder.c --*/
  50MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
  51MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
  52MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
  53void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
  54int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
  55                    int *sign);
  56int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
  57                     int *sign);
  58
  59/*-- mpi-pow.c --*/
  60int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
  61
  62/*-- mpi-cmp.c --*/
  63int mpi_cmp_ui(MPI u, ulong v);
  64int mpi_cmp(MPI u, MPI v);
  65
  66/*-- mpi-bit.c --*/
  67void mpi_normalize(MPI a);
  68unsigned mpi_get_nbits(MPI a);
  69
  70/* inline functions */
  71
  72/**
  73 * mpi_get_size() - returns max size required to store the number
  74 *
  75 * @a:  A multi precision integer for which we want to allocate a bufer
  76 *
  77 * Return: size required to store the number
  78 */
  79static inline unsigned int mpi_get_size(MPI a)
  80{
  81        return a->nlimbs * BYTES_PER_MPI_LIMB;
  82}
  83#endif /*G10_MPI_H */
  84