Branch data     Line data    Source code

       1                 :            : // SPDX-License-Identifier: GPL-2.0-or-later
       2                 :            : /* mpihelp-sub.c  -  MPI helper functions
       3                 :            :  *      Copyright (C) 1994, 1996 Free Software Foundation, Inc.
       4                 :            :  *      Copyright (C) 1998, 1999, 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                 :            : #include "mpi-internal.h"
      18                 :            : 
      19                 :            : /****************
      20                 :            :  * Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
      21                 :            :  * There are no restrictions on the relative sizes of
      22                 :            :  * the two arguments.
      23                 :            :  * Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
      24                 :            :  */
      25                 :        949 : int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
      26                 :            : {
      27                 :        949 :         mpi_size_t i;
      28                 :        949 :         mpi_limb_t op1_word, op2_word;
      29                 :            : 
      30         [ +  - ]:        949 :         for (i = size - 1; i >= 0; i--) {
      31                 :        949 :                 op1_word = op1_ptr[i];
      32                 :        949 :                 op2_word = op2_ptr[i];
      33         [ +  - ]:        949 :                 if (op1_word != op2_word)
      34                 :        949 :                         goto diff;
      35                 :            :         }
      36                 :            :         return 0;
      37                 :            : 
      38                 :            : diff:
      39                 :            :         /* This can *not* be simplified to
      40                 :            :          *   op2_word - op2_word
      41                 :            :          * since that expression might give signed overflow.  */
      42         [ +  + ]:        949 :         return (op1_word > op2_word) ? 1 : -1;
      43                 :            : }