mcmp.cpp

   1 // Bignum compare
   2 //
   3 //      returns
   4 //
   5 //      -1              a < b
   6 //
   7 //      0               a = b
   8 //
   9 //      1               a > b
  10
  11 #include "stdafx.h"
  12 #include "defs.h"
  13
  14 int
  15 mcmp(unsigned int *a, unsigned int *b)
  16 {
  17         int i;
  18
  19         if (MSIGN(a) == -1 && MSIGN(b) == 1)
  20                 return -1;
  21
  22         if (MSIGN(a) == 1 && MSIGN(b) == -1)
  23                 return 1;
  24
  25         // same sign
  26
  27         if (MLENGTH(a) < MLENGTH(b)) {
  28                 if (MSIGN(a) == 1)
  29                         return -1;
  30                 else
  31                         return 1;
  32         }
  33
  34         if (MLENGTH(a) > MLENGTH(b)) {
  35                 if (MSIGN(a) == 1)
  36                         return 1;
  37                 else
  38                         return -1;
  39         }
  40
  41         // same length
  42
  43         for (i = MLENGTH(a) - 1; i > 0; i--)
  44                 if (a[i] != b[i])
  45                         break;
  46
  47         if (a[i] < b[i]) {
  48                 if (MSIGN(a) == 1)
  49                         return -1;
  50                 else
  51                         return 1;
  52         }
  53
  54         if (a[i] > b[i]) {
  55                 if (MSIGN(a) == 1)
  56                         return 1;
  57                 else
  58                         return -1;
  59         }
  60
  61         return 0;
  62 }
  63
  64 int
  65 mcmpint(unsigned int *a, int n)
  66 {
  67         int t;
  68         unsigned int *b;
  69         b = mint(n);
  70         t = mcmp(a, b);
  71         mfree(b);
  72         return t;
  73 }