mpfr_set_str now accepts a binary exponent for base 16

(as defined by the ISO C99 standard).


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2252 280ebfd0-de03-0410-8827-d642c229c3f4

3 files changed, 36 insertions, 8 deletions

diff --git a/mpfr.texi b/mpfr.texi
index ba73c9cbd..995cac501 100644
--- a/mpfr.texi
+++ b/mpfr.texi
@@ -1349,10 +1349,12 @@ Return the number of bytes written, or if an error occurred, return 0.
 Input a string in base @var{base} from stdio stream @var{stream},
 rounded in direction @var{rnd}, and put the
 read float in @var{rop}.  The string is of the form @samp{M@@N} or, if the
-base is 10 or less, alternatively @samp{MeN} or @samp{MEN}.
-@samp{M} is the mantissa and
-@samp{N} is the exponent.  The mantissa is always in the specified base.  The
-exponent is read in decimal.
+base is 10 or less, alternatively @samp{MeN} or @samp{MEN}, or, if the base
+is 16, alternatively @samp{MpB} or @samp{MPB}.
+@samp{M} is the mantissa in the specified base, @samp{N} is the exponent
+written in decimal for the specified base, and in base 16, @samp{B} is the
+binary exponent written in decimal (it indicates the power of 2 by which
+the mantissa is to be scaled).
 The argument @var{base} may be in the range 2 to 36.
 
 Unlike the corresponding @code{mpz} function, the base will not be determined
diff --git a/set_str.c b/set_str.c
index c177d4017..5ae402693 100644
--- a/set_str.c
+++ b/set_str.c
@@ -79,6 +79,7 @@ mpfr_set_str (mpfr_t x, const char *str, int base, mp_rnd_t rnd)
   mp_exp_t pr;                 /* needed precision requise for str */
   mp_exp_t exp_s = 0;          /* exponent in base 'base', normalized for a
                                   mantissa 0.xxx...xxx */
+  mp_exp_t binexp = 0;         /* binary exponent (for base 16) */
   mp_exp_t prec_x;             /* working precision for x */
   char *str1;                  /* copy of str, should not be modified */
   size_t size_str1;            /* number of characters in str1 */
@@ -146,6 +147,17 @@ mpfr_set_str (mpfr_t x, const char *str, int base, mp_rnd_t rnd)
             }
 	  break;
 	}
+      else if (base == 16 && (*str == 'p' || *str == 'P'))
+        {
+          char *endptr[1];
+          binexp = (mp_exp_t) strtol (str + 1, endptr, 10);
+          if (**endptr != '\0')
+            {
+              res = -1; /* invalid input: garbage after exponent */
+              goto end;
+            }
+	  break;
+        }
       else if (*str == '.')
 	{	
 	  point = 1;
@@ -177,7 +189,7 @@ mpfr_set_str (mpfr_t x, const char *str, int base, mp_rnd_t rnd)
       goto sign_and_flags;
     }
 
-  /* now we have str = 0.mant_s[0]...mant_s[prec_s-1]*base^exp_s */
+  /* now we have str = 0.mant_s[0]...mant_s[prec_s-1]*base^exp_s*2^binexp */
 
   /* determine the minimal precision for the computation */
   prec_x = MPFR_PREC(x) + (mp_exp_t) __gmpfr_ceil_log2 ((double) MPFR_PREC(x));
@@ -239,8 +251,8 @@ mpfr_set_str (mpfr_t x, const char *str, int base, mp_rnd_t rnd)
 
 	  count_leading_zeros (pow2, (mp_limb_t) base);
 	  pow2 = BITS_PER_MP_LIMB - pow2 - 1; /* base = 2^pow2 */
-	  
-	  exp_y = exp_y + pow2 * (exp_s - (mp_exp_t) pr);
+
+	  exp_y += pow2 * (exp_s - (mp_exp_t) pr) + binexp;
 
 	  result = y - n;
 	}
diff --git a/tests/tset_str.c b/tests/tset_str.c
index e8a31f18e..1eb550908 100644
--- a/tests/tset_str.c
+++ b/tests/tset_str.c
@@ -89,7 +89,7 @@ main (int argc, char *argv[])
   mpfr_set_str (y, "4.936a52bc17254@-133", 16, GMP_RNDN);
   if (mpfr_cmp (x, y))
     {
-      fprintf (stderr, "Error in mpfr_set_str (1):\n");
+      fprintf (stderr, "Error in mpfr_set_str (1a):\n");
       mpfr_print_binary (x);
       putchar ('\n');
       mpfr_print_binary (y);
@@ -99,6 +99,20 @@ main (int argc, char *argv[])
       exit (1);
     }
 
+  mpfr_set_str_raw (x, "0.111111101101110010111010100110000111011001010100001101E-529");
+  mpfr_set_str (y, "0.fedcba98765434P-529", 16, GMP_RNDN);
+  if (mpfr_cmp (x, y))
+    {
+      fprintf (stderr, "Error in mpfr_set_str (1b):\n");
+      mpfr_print_binary (x);
+      putchar ('\n');
+      mpfr_print_binary (y);
+      putchar ('\n');
+      mpfr_clear (x);
+      mpfr_clear (y);
+      exit (1);
+    }
+
   (*__gmp_free_func) (str, nc * sizeof(char));
 
   mpfr_set_prec (x, 53);