mscan.cpp

   1 // bignum scanner
   2
   3 #include "stdafx.h"
   4 #include "defs.h"
   5
   6 static unsigned int *addf(unsigned int *, int);
   7 static unsigned int *mulf(unsigned int *, int);
   8
   9 unsigned int *
  10 mscan(char *s)
  11 {
  12         int sign;
  13         unsigned int *a, *b, *c;
  14
  15         sign = 1;
  16
  17         if (*s == '-') {
  18                 sign = -1;
  19                 s++;
  20         }
  21
  22         a = mint(0);
  23
  24         while (*s) {
  25                 b = mulf(a, 10);
  26                 c = addf(b, *s - '0');
  27                 mfree(a);
  28                 mfree(b);
  29                 a = c;
  30                 s++;
  31         }
  32
  33         if (!MZERO(a))
  34                 MSIGN(a) *= sign;
  35
  36         return a;
  37 }
  38
  39 static unsigned int *
  40 addf(unsigned int *a, int n)
  41 {
  42         unsigned int *b, *c;
  43         b = mint(n);
  44         c = madd(a, b);
  45         mfree(b);
  46         return c;
  47 }
  48
  49 static unsigned int *
  50 mulf(unsigned int *a, int n)
  51 {
  52         unsigned int *b, *c;
  53         b = mint(n);
  54         c = mmul(a, b);
  55         mfree(b);
  56         return c;
  57 }