Fix for issue 2233

vm/bigint_operations.h

 // Copyright 2012 Google Inc. All Rights Reserved.
 
 #ifndef VM_BIGINT_OPERATIONS_H_
 #define VM_BIGINT_OPERATIONS_H_
 
 #include "platform/utils.h"
 
 #include "vm/object.h"
 
 namespace dart {
 
 class BigintOperations : public AllStatic {
  public:
   static RawBigint* NewFromSmi(const Smi& smi, Heap::Space space = Heap::kNew);
   static RawBigint* NewFromInt64(int64_t value, Heap::Space space = Heap::kNew);
   static RawBigint* NewFromUint64(uint64_t value,
                                   Heap::Space space = Heap::kNew);
   // The given string must be a valid integer representation. It may be
   // prefixed by a minus and/or "0x".
   // Returns Bigint::null() if the string cannot be parsed.
   static RawBigint* NewFromCString(const char* str,
                                    Heap::Space space = Heap::kNew);
   static RawBigint* NewFromDouble(double d, Heap::Space space = Heap::kNew);
 
-  // The given string must be a nul-terminated string of hex-digits. It must
-  // only contain hex-digits. No sign or leading "0x" is allowed.
-  static RawBigint* FromHexCString(const char* str,
+  // Compute length of bigint instance created for the specified hex string.

[cshapiro, 2012/03/24 01:48:07]

What is the unit for this length?

[siva, 2012/03/24 02:25:03]

Changed comment.

On 2012/03/24 01:48:07, cshapiro wrote:

+  // The specified hex string must be a null-terminated string of hex-digits.
+  // It must only contain hex-digits. Leading "0x" is not allowed.
+  static intptr_t ComputeLength(const char* hex_string);
+
+  // Create a bigint instance from the specified hex string. The given string
+  // must be a null-terminated string of hex-digits. It must only contain
+  // hex-digits. Leading "0x" is not allowed.
+  static RawBigint* FromHexCString(const char* hex_string,
                                    Heap::Space space = Heap::kNew);
 
-  // The given string must be a nul-terminated string of decimal digits. It
+  // Helper method to initialize a bigint instance object with the bigint value
+  // in the specified string. The given string must be a null-terminated string
+  // of hex-digits. It must only contain hex-digits, leading "0x" is not
+  // allowed.
+  static void FromHexCString(const char* hex_string, const Bigint& value);
+
+  // The given string must be a null-terminated string of decimal digits. It

[cshapiro, 2012/03/24 01:48:07]

just an fyi, nul (one 'l') is the name of the ascii character, but null (two
'l') is okay as well.  the original used one 'l'.

[siva, 2012/03/24 02:25:03]

Reverted to nul-terminated.

On 2012/03/24 01:48:07, cshapiro wrote:

   // must only contain decimal digits (0-9). No sign is allowed. Leading
   // zeroes are ignored.
   static RawBigint* FromDecimalCString(const char* str,
                                    Heap::Space space = Heap::kNew);
 
   // Converts the bigint to a HEX string. The returned string is prepended by
   // a "0x" (after the optional minus-sign).
   static const char* ToHexCString(intptr_t length,
                                   bool is_negative,
                                   void* data,
@@ skipping 47 matching lines @@
 
  private:
   typedef Bigint::Chunk Chunk;
   typedef Bigint::DoubleChunk DoubleChunk;
 
   static const int kDigitBitSize = 28;
   static const Chunk kDigitMask = (static_cast<Chunk>(1) << kDigitBitSize) - 1;
   static const Chunk kDigitMaxValue = kDigitMask;
   static const int kChunkSize = sizeof(Chunk);
   static const int kChunkBitSize = kChunkSize * kBitsPerByte;
+  static const int kHexCharsPerDigit = kDigitBitSize / 4;
 
   static RawBigint* Zero() { return Bigint::Allocate(0); }
   static RawBigint* One() {
     Bigint& result = Bigint::Handle(Bigint::Allocate(1));
     result.SetChunkAt(0, 1);
     return result.raw();
   }
   static RawBigint* MinusOne() {
     Bigint& result = Bigint::Handle(One());
     result.ToggleSign();
@@ skipping 23 matching lines @@
   static RawBigint* Copy(const Bigint& bigint);
 
   static int CountBits(Chunk digit);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(BigintOperations);
 };
 
 }  // namespace dart
 
 #endif  // VM_BIGINT_OPERATIONS_H_