Handle Bigint.toCString when remainder equals 0.

runtime/vm/bigint_operations.cc

 // Copyright 2012 Google Inc. All Rights Reserved.
 
 #include "vm/bigint_operations.h"
 
 #include "platform/utils.h"
 
 #include "vm/double_internals.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/zone.h"
@@ skipping 372 matching lines @@
   ASSERT(static_cast<Chunk>(kDivisorValue) < kDigitMaxValue);
   ASSERT(Smi::IsValid(kDivisorValue));
   const Bigint& divisor = Bigint::Handle(NewFromInt64(kDivisorValue));
 
   // Rest contains the remaining bigint that needs to be printed.
   Bigint& rest = Bigint::Handle(bigint.raw());
   Bigint& quotient = Bigint::Handle();
   Bigint& remainder = Bigint::Handle();
   while (!rest.IsZero()) {
     DivideRemainder(rest, divisor, &quotient, &remainder);
-    ASSERT(remainder.Length() == 1);
-    intptr_t part = static_cast<intptr_t>(remainder.GetChunkAt(0));
+    ASSERT(remainder.Length() <= 1);
+    intptr_t part = 0;

[kasperl, 2012/03/07 12:47:01]

intptr_t part = (remainder.Length() == 1)
   ? static_cast<intptr_t>(remainder.GetChunkAt(0))
   : 0;

[floitsch, 2012/03/07 12:51:26]

Done.

+    if (remainder.Length() == 1) {
+      part = static_cast<intptr_t>(remainder.GetChunkAt(0));
+    }
     for (int i = 0; i < kPowerOfTen; i++) {
       result[result_pos++] = '0' + (part % 10);
       part /= 10;
     }
     ASSERT(part == 0);
     rest = quotient.raw();
   }
   // Move the resulting position back until we don't have any zeroes anymore.
   // This is done so that we can remove all leading zeroes.
   while (result_pos > 1 && result[result_pos - 1] == '0') {
@@ skipping 1097 matching lines @@
 int BigintOperations::CountBits(Chunk digit) {
   int result = 0;
   while (digit != 0) {
     digit >>= 1;
     result++;
   }
   return result;
 }
 
 }  // namespace dart