include/linux/mpi.h

   1 /* mpi.h  -  Multi Precision Integers
   2  *      Copyright (C) 1994, 1996, 1998, 1999,
   3  *                    2000, 2001 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GNUPG.
   6  *
   7  * GNUPG is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * GNUPG is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  20  *
  21  * Note: This code is heavily based on the GNU MP Library.
  22  *       Actually it's the same code with only minor changes in the
  23  *       way the data is stored; this is to support the abstraction
  24  *       of an optional secure memory allocation which may be used
  25  *       to avoid revealing of sensitive data due to paging etc.
  26  *       The GNU MP Library itself is published under the LGPL;
  27  *       however I decided to publish this code under the plain GPL.
  28  */
  29
  30 #ifndef G10_MPI_H
  31 #define G10_MPI_H
  32
  33 #include <linux/types.h>
  34 #include <linux/scatterlist.h>
  35
  36 #define BYTES_PER_MPI_LIMB      (BITS_PER_LONG / 8)
  37 #define BITS_PER_MPI_LIMB       BITS_PER_LONG
  38
  39 typedef unsigned long int mpi_limb_t;
  40 typedef signed long int mpi_limb_signed_t;
  41
  42 struct gcry_mpi {
  43         int alloced;            /* array size (# of allocated limbs) */
  44         int nlimbs;             /* number of valid limbs */
  45         int nbits;              /* the real number of valid bits (info only) */
  46         int sign;               /* indicates a negative number */
  47         unsigned flags;         /* bit 0: array must be allocated in secure memory space */
  48         /* bit 1: not used */
  49         /* bit 2: the limb is a pointer to some m_alloced data */
  50         mpi_limb_t *d;          /* array with the limbs */
  51 };
  52
  53 typedef struct gcry_mpi *MPI;
  54
  55 #define mpi_get_nlimbs(a)     ((a)->nlimbs)
  56
  57 /*-- mpiutil.c --*/
  58 MPI mpi_alloc(unsigned nlimbs);
  59 void mpi_free(MPI a);
  60 int mpi_resize(MPI a, unsigned nlimbs);
  61
  62 /*-- mpicoder.c --*/
  63 MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
  64 MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
  65 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
  66 void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
  67 int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
  68                     int *sign);
  69 int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
  70                      int *sign);
  71
  72 /*-- mpi-pow.c --*/
  73 int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
  74
  75 /*-- mpi-cmp.c --*/
  76 int mpi_cmp_ui(MPI u, ulong v);
  77 int mpi_cmp(MPI u, MPI v);
  78
  79 /*-- mpi-bit.c --*/
  80 void mpi_normalize(MPI a);
  81 unsigned mpi_get_nbits(MPI a);
  82
  83 /* inline functions */
  84
  85 /**
  86  * mpi_get_size() - returns max size required to store the number
  87  *
  88  * @a:  A multi precision integer for which we want to allocate a bufer
  89  *
  90  * Return: size required to store the number
  91  */
  92 static inline unsigned int mpi_get_size(MPI a)
  93 {
  94         return a->nlimbs * BYTES_PER_MPI_LIMB;
  95 }
  96 #endif /*G10_MPI_H */