git.distorted.org.uk Git - u/mdw/putty/blob - int64.c

   1 /*
   2  * Handling of the int64 and uint64 types. Done in 32-bit integers,
   3  * for (pre-C99) portability. Hopefully once C99 becomes widespread
   4  * we can kiss this lot goodbye...
   5  */
   6
   7 #include <assert.h>
   8
   9 typedef struct {
  10     unsigned long hi, lo;
  11 } uint64, int64;
  12
  13 uint64 uint64_div10(uint64 x, int *remainder)
  14 {
  15     uint64 y;
  16     int rem, r2;
  17     y.hi = x.hi / 10;
  18     y.lo = x.lo / 10;
  19     rem = x.lo % 10;
  20     /*
  21      * Now we have to add in the remainder left over from x.hi.
  22      */
  23     r2 = x.hi % 10;
  24     y.lo += r2 * 2 * (0x80000000 / 10);
  25     rem += r2 * 2 * (0x80000000 % 10);
  26     y.lo += rem / 10;
  27     rem %= 10;
  28
  29     if (remainder)
  30         *remainder = rem;
  31     return y;
  32 }
  33
  34 void uint64_decimal(uint64 x, char *buffer)
  35 {
  36     char buf[20];
  37     int start = 20;
  38     int d;
  39
  40     while (x.hi || x.lo) {
  41         x = uint64_div10(x, &d);
  42         assert(start > 0);
  43         buf[--start] = d + '0';
  44     }
  45
  46     memcpy(buffer, buf + start, sizeof(buf) - start);
  47     buffer[sizeof(buf) - start] = '\0';
  48 }
  49
  50 uint64 uint64_make(unsigned long hi, unsigned long lo)
  51 {
  52     uint64 y;
  53     y.hi = hi;
  54     y.lo = lo;
  55     return y;
  56 }
  57
  58 uint64 uint64_add(uint64 x, uint64 y)
  59 {
  60     x.lo += y.lo;
  61     x.hi += y.hi + (x.lo < y.lo ? 1 : 0);
  62     return x;
  63 }
  64
  65 uint64 uint64_add32(uint64 x, unsigned long y)
  66 {
  67     uint64 yy;
  68     yy.hi = 0;
  69     yy.lo = y;
  70     return uint64_add(x, yy);
  71 }