LCOV - code coverage report
Current view: top level - source4/heimdal/lib/hcrypto/libtommath - bn_mp_lshd.c (source / functions) Hit Total Coverage
Test: coverage report for abartlet/fix-coverage dd10fb34 Lines: 14 15 93.3 %
Date: 2021-09-23 10:06:22 Functions: 1 1 100.0 %

          Line data    Source code
       1             : #include <tommath.h>
       2             : #ifdef BN_MP_LSHD_C
       3             : /* LibTomMath, multiple-precision integer library -- Tom St Denis
       4             :  *
       5             :  * LibTomMath is a library that provides multiple-precision
       6             :  * integer arithmetic as well as number theoretic functionality.
       7             :  *
       8             :  * The library was designed directly after the MPI library by
       9             :  * Michael Fromberger but has been written from scratch with
      10             :  * additional optimizations in place.
      11             :  *
      12             :  * The library is free for all purposes without any express
      13             :  * guarantee it works.
      14             :  *
      15             :  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
      16             :  */
      17             : 
      18             : /* shift left a certain amount of digits */
      19       78946 : int mp_lshd (mp_int * a, int b)
      20             : {
      21             :   int     x, res;
      22             : 
      23             :   /* if its less than zero return */
      24       78946 :   if (b <= 0) {
      25        1560 :     return MP_OKAY;
      26             :   }
      27             : 
      28             :   /* grow to fit the new digits */
      29       77312 :   if (a->alloc < a->used + b) {
      30        5504 :      if ((res = mp_grow (a, a->used + b)) != MP_OKAY) {
      31           0 :        return res;
      32             :      }
      33             :   }
      34             : 
      35             :   {
      36             :     register mp_digit *top, *bottom;
      37             : 
      38             :     /* increment the used by the shift amount then copy upwards */
      39       77312 :     a->used += b;
      40             : 
      41             :     /* top */
      42       77312 :     top = a->dp + a->used - 1;
      43             : 
      44             :     /* base */
      45       77312 :     bottom = a->dp + a->used - 1 - b;
      46             : 
      47             :     /* much like mp_rshd this is implemented using a sliding window
      48             :      * except the window goes the otherway around.  Copying from
      49             :      * the bottom to the top.  see bn_mp_rshd.c for more info.
      50             :      */
      51     5756446 :     for (x = a->used - 1; x >= b; x--) {
      52     5679134 :       *top-- = *bottom--;
      53             :     }
      54             : 
      55             :     /* zero the lower digits */
      56       73714 :     top = a->dp;
      57     3108177 :     for (x = 0; x < b; x++) {
      58     3034463 :       *top++ = 0;
      59             :     }
      60             :   }
      61       73714 :   return MP_OKAY;
      62             : }
      63             : #endif
      64             : 
      65             : /* $Source: /cvs/libtom/libtommath/bn_mp_lshd.c,v $ */
      66             : /* $Revision: 1.4 $ */
      67             : /* $Date: 2006/12/28 01:25:13 $ */

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