mpf_const_ln_d.c

   1 /* LibTomFloat, multiple-precision floating-point library
   2  *
   3  * LibTomFloat is a library that provides multiple-precision
   4  * floating-point artihmetic as well as trigonometric functionality.
   5  *
   6  * This library requires the public domain LibTomMath to be installed.
   7  *
   8  * This library is free for all purposes without any express
   9  * gurantee it works
  10  *
  11  * Tom St Denis, tomstdenis@iahu.ca, http://float.libtomcrypt.org
  12  */
  13 #include <tomfloat.h>
  14
  15 int  mpf_const_ln_d(mp_float *a, long b)
  16 {
  17    int err;
  18
  19    /* test input */
  20    if (b < 0) {
  21       return MP_VAL;
  22    }
  23
  24    if (b == 0) {
  25       return mpf_const_d(a, 1);
  26    }
  27
  28    if (b == 1) {
  29       return mpf_const_d(a, 0);
  30    }
  31
  32    if ((err = mpf_const_d(a, b)) != MP_OKAY) {
  33       return err;
  34    }
  35    return mpf_ln(a, a);
  36 }
  37                 /* a = ln b    */
  38