initial version

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@560 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 154 insertions, 0 deletions

diff --git a/set_str.c b/set_str.c
new file mode 100644
index 000000000..97c6a95d1
--- /dev/null
+++ b/set_str.c
@@ -0,0 +1,154 @@
+/* mpfr_set_str -- set a floating-point number from a string
+
+Copyright (C) 2000 PolKA project, Inria Lorraine and Loria
+
+This file is part of the MPFR Library.
+
+The MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Library General Public License as published by
+the Free Software Foundation; either version 2 of the License, or (at your
+option) any later version.
+
+The MPFR Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the MPFR Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAS_STRING_H
+#include <string.h>
+#else
+#include <strings.h>
+#endif
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+#include "mpfr.h"
+
+int
+#if __STDC__
+mpfr_set_str(mpfr_ptr x, char *str, int base, mp_rnd_t rnd_mode)
+#else
+mpfr_set_str_raw(x, str, base, rnd_mode)
+     mpfr_ptr x;
+     char *str;
+     int base;
+     mp_rnd_t rnd_mode;
+#endif
+{
+  char negative = 0, *endptr;
+  unsigned long k = 0, l, q;
+  long expn = 0, e;
+  mpz_t mantissa;
+  mpfr_t y, z;
+
+  mpz_init(mantissa); mpz_set_ui(mantissa, 0);
+  l = strlen(str);
+  if (*str == '-') { negative = 1; str++; l--; }
+  else if (*str == '+') { str++; l--; }
+
+  while (*str == '0') { str++; l--; } /* skip initial zeros */
+
+  /* allowed characters are '0' to '0'+base-1 if base <= 10,
+     and '0' to '9' plus 'a' to 'a'+base-11 if 10 < base <= 36 */
+  while ((isdigit(*str) && *str < '0'+base)
+	 || (islower(*str) && *str < 'a'+base-10))
+    { 
+      mpz_mul_ui(mantissa, mantissa, base);
+      mpz_add_ui(mantissa, mantissa, (isdigit(*str)) ? (*str)-'0'
+		 : (*str)-'a'+10);
+      str++; l--;
+    }
+
+  /* k is the number of non-zero digits before the decimal point */
+
+  if (*str == '.') 
+    {
+      str++; l--;
+      while ((isdigit(*str) && *str < '0'+base)
+	     || (islower(*str) && *str < 'a'+base-10))
+	{ 
+	  mpz_mul_ui(mantissa, mantissa, base);
+	  mpz_add_ui(mantissa, mantissa, (isdigit(*str)) ? (*str)-'0'
+		     : (*str)-'a'+10);
+	  str++; l--;
+	  k++;
+	}
+    }
+    
+  if ((base <= 10 && (*str == 'e' || *str == 'E')) || *str == '@')
+    {
+      str++; l--;
+      e = strtol(str, &endptr, 10); /* signed exponent after 'e', 'E' or '@' */
+      expn = e - k; 
+      if (expn > e)
+	  fprintf(stderr, "Warning: exponent underflow in mpfr_set_str\n"); 
+    }
+  else if (l) {
+    fprintf(stderr, "Unexpected end of string in mpfr_set_str: %s\n", str);
+    return -1;
+  }
+  else {
+    expn = -k;
+    endptr = str;
+  }
+
+  /* the number is mantissa*base^expn */
+
+  q = (PREC(x)/BITS_PER_MP_LIMB)*BITS_PER_MP_LIMB;
+  mpfr_init(y);
+  mpfr_init(z);
+
+  do {
+    q += BITS_PER_MP_LIMB;
+    mpfr_set_prec(y, q);
+    mpfr_set_z(y, mantissa, GMP_RNDN); /* error <= 1/2*ulp(y) */
+
+    mpfr_set_prec(z, q);
+    if (expn>0) {
+      e = mpfr_ui_pow_ui(z, base, expn, GMP_RNDN);
+      mpfr_mul(y, y, z, GMP_RNDN);
+    }
+    else if (expn<0) {
+      e = mpfr_ui_pow_ui(z, base, -expn, GMP_RNDN);
+      mpfr_div(y, y, z, GMP_RNDN);
+    }
+    else e=1;
+    if (negative) mpfr_neg(y, y, GMP_RNDN);
+
+    /* now y is an approximation of mantissa*base^expn with error at most
+       2^e*ulp(y) */
+
+  } while (mpfr_can_round(y, q-e, GMP_RNDN, rnd_mode, PREC(x))==0
+	   && q<=2*PREC(x));
+
+  mpfr_set(x, y, rnd_mode);
+
+  mpz_clear(mantissa);
+  mpfr_clear(y);
+  mpfr_clear(z);
+  return ((*endptr=='\0') ? 0 : -1);
+}
+
+int
+#if __STDC__
+mpfr_init_set_str(mpfr_ptr x, char *str, int base, mp_rnd_t rnd_mode)
+#else
+mpfr_init_set_str_raw(x, str, base, rnd_mode)
+     mpfr_ptr x;
+     char *str;
+     int base;
+     mp_rnd_t rnd_mode;
+#endif
+{ 
+  mpfr_init(x); 
+  return mpfr_set_str(x, str, base, rnd_mode);
+}
+