[Python-checkins] r56775 - python/branches/decimal-branch/Lib/decimal.py

[facundo.batista]

Author: facundo.batista
Date: Mon Aug  6 20:19:06 2007
New Revision: 56775

Modified:
   python/branches/decimal-branch/Lib/decimal.py
Log:

Coded next_plus() function, all tests pass ok. Also
cleaned slightly next_minus().


Modified: python/branches/decimal-branch/Lib/decimal.py
==============================================================================
--- python/branches/decimal-branch/Lib/decimal.py	(original)
+++ python/branches/decimal-branch/Lib/decimal.py	Mon Aug  6 20:19:06 2007
@@ -2698,21 +2698,68 @@
             d = Decimal((newself._sign, newself._int+(0,)*expdif, newself._exp-expdif))
         dif = Decimal((0, (0,)*(len(d._int)-1)+(1,), d._exp))
         d = d - dif
-        if d._isinfinity():
-            return d
 
         digdif = context.prec - len(d._int)
         if digdif > 0 and d._exp-digdif > context.Emin:
             d = Decimal((d._sign, d._int + (9,)*digdif, d._exp-digdif))
         if d.adjusted() > context.Emax:
-            if d._sign:
-                return negInf
-            else:
-                return Inf
+            return negInf
         return d
 
     def next_plus(self, context=None):
         """Returns the smallest representable number larger than itself."""
+        if context is None:
+            context = getcontext()
+
+        ans = self._check_nans(self, context)
+        if ans:
+            return ans
+
+        if self._isinfinity() == 1:
+            return self
+        if self._isinfinity() == -1:
+            return Decimal((1, (9,)*context.prec, context.Emax-context.prec+1))
+
+        minime = context.Emin-context.prec+1
+        if self._exp < minime:
+            newself = Decimal((self._sign, self._int, minime))
+            if newself._sign == 0:
+                return newself
+        else:
+            newself = Decimal(self)
+
+        if not newself:
+            return Decimal((0, (1,), minime))
+        expdif = context.prec - len(newself._int)
+
+        if expdif < 0:
+            resto = newself._int[context.prec:]
+            if resto != (0,)*(-expdif):
+                # the rest is not all zeroes
+                d = newself._round_ceiling(context.prec, expdif, context)
+                return d
+            # negative expdif, but all zeroes
+            d = Decimal((newself._sign, newself._int[:expdif], newself._exp-expdif))
+        else:
+            # positive expdif
+            if newself._exp-expdif < minime:
+                expdif = newself._exp - minime
+            d = Decimal((newself._sign, newself._int+(0,)*expdif, newself._exp-expdif))
+
+        dif = Decimal((0, (0,)*(len(d._int)-1)+(1,), d._exp))
+        d = d + dif
+        if not d:
+            # restablish previos sign
+            d._sign = newself._sign
+            return d
+
+        digdif = context.prec - len(d._int)
+        if digdif > 0 and d._exp-digdif > context.Emin:
+            d = Decimal((d._sign, d._int + (9,)*digdif, d._exp-digdif))
+        if d.adjusted() > context.Emax:
+            return Inf
+        return d
+
 
     def next_toward(self, other, context=None):
         """Returns the number closest to itself, in direction towards other.