New bigint implementation in the vm.

runtime/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);
-
-  // Compute chunk length of the bigint instance created for the
-  // specified hex string.  The specified hex string must be a
-  // nul-terminated string of hex-digits.  It must only contain
-  // hex-digits. Leading "0x" is not allowed.
-  static intptr_t ComputeChunkLength(const char* hex_string);
-
-  // Create a bigint instance from the specified hex string. The given string
-  // must be a nul-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);
-
-  // Helper method to initialize a bigint instance object with the bigint value
-  // in the specified string. The given string must be a nul-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 nul-terminated string of decimal digits. It
-  // 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,
-                                  uword (*allocator)(intptr_t size));
-
-  static const char* ToHexCString(const Bigint& bigint,
-                                  uword (*allocator)(intptr_t size));
-
-  static const char* ToDecimalCString(const Bigint& bigint,
-                                      uword (*allocator)(intptr_t size));
-
-  static bool FitsIntoSmi(const Bigint& bigint);
-  static RawSmi* ToSmi(const Bigint& bigint);
-
-  static bool FitsIntoInt64(const Bigint& bigint);
-  static int64_t ToInt64(const Bigint& bigint);
-
-  static bool FitsIntoUint64(const Bigint& bigint);
-  static bool AbsFitsIntoUint64(const Bigint& bigint);
-  static uint64_t ToUint64(const Bigint& bigint);
-  static uint32_t TruncateToUint32(const Bigint& bigint);
-  static uint64_t AbsToUint64(const Bigint& bigint);
-
-  static RawDouble* ToDouble(const Bigint& bigint);
-
-  static RawBigint* Add(const Bigint& a, const Bigint& b) {
-    bool negate_b = false;
-    return AddSubtract(a, b, negate_b);
-  }
-  static RawBigint* Subtract(const Bigint& a, const Bigint& b) {
-    bool negate_b = true;
-    return AddSubtract(a, b, negate_b);
-  }
-  static RawBigint* Multiply(const Bigint& a, const Bigint& b);
-  // TODO(floitsch): what to do for divisions by zero.
-  static RawBigint* Divide(const Bigint& a, const Bigint& b);
-  static RawBigint* Modulo(const Bigint& a, const Bigint& b);
-  static RawBigint* Remainder(const Bigint& a, const Bigint& b);
-
-  static RawBigint* ShiftLeft(const Bigint& bigint, intptr_t amount);
-  static RawBigint* ShiftRight(const Bigint& bigint, intptr_t amount);
-  static RawBigint* BitAnd(const Bigint& a, const Bigint& b);
-  static RawBigint* BitOr(const Bigint& a, const Bigint& b);
-  static RawBigint* BitXor(const Bigint& a, const Bigint& b);
-  static RawBigint* BitNot(const Bigint& bigint);
-  static int64_t BitLength(const Bigint& bigint);
-
-  static int Compare(const Bigint& a, const Bigint& b);
-
-  static bool IsClamped(const Bigint& bigint) {
-    intptr_t length = bigint.Length();
-    return (length == 0) || (bigint.GetChunkAt(length - 1) != 0);
-  }
-
- 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();
-    return result.raw();
-  }
-
-  // Performs an addition or subtraction depending on the negate_b argument.
-  static RawBigint* AddSubtract(const Bigint& a,
-                                const Bigint& b,
-                                bool negate_b);
-
-  static int UnsignedCompare(const Bigint& a, const Bigint& b);
-  static int UnsignedCompareNonClamped(const Bigint& a, const Bigint& b);
-  static RawBigint* UnsignedAdd(const Bigint& a, const Bigint& b);
-  static RawBigint* UnsignedSubtract(const Bigint& a, const Bigint& b);
-
-  static RawBigint* MultiplyWithDigit(const Bigint& bigint, Chunk digit);
-  static RawBigint* DigitsShiftLeft(const Bigint& bigint, intptr_t amount) {
-    return ShiftLeft(bigint, amount * kDigitBitSize);
-  }
-  static void DivideRemainder(const Bigint& a, const Bigint& b,
-                              Bigint* quotient, Bigint* remainder);
-  static Chunk InplaceUnsignedDivideRemainderDigit(
-      const Bigint& dividend_quotient, Chunk divisor_digit);
-
-  // Removes leading zero-chunks by adjusting the bigint's length.
-  static void Clamp(const Bigint& bigint);
-
-  static RawBigint* Copy(const Bigint& bigint);
-
-  static intptr_t CountBits(Chunk digit);
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(BigintOperations);
-};
-
-}  // namespace dart
-
-#endif  // VM_BIGINT_OPERATIONS_H_