text: /////////////////////////////////////////////////////////////////////////////
  // Copyright (c) 2009-2014 Alan Wright. All rights reserved.
  // Distributable under the terms of either the Apache License (Version 2.0)
  // or the GNU Lesser General Public License.
  /////////////////////////////////////////////////////////////////////////////
  
  #ifndef MISCUTILS_H
  #define MISCUTILS_H
  
  #include "Lucene.h"
  
  namespace Lucene {
  
  class LPPAPI MiscUtils {
  protected:
      static const uint32_t SINGLE_EXPONENT_MASK;
      static const uint32_t SINGLE_MANTISSA_MASK;
      static const uint32_t SINGLE_NAN_BITS;
  
      static const uint64_t DOUBLE_SIGN_MASK;
      static const uint64_t DOUBLE_EXPONENT_MASK;
      static const uint64_t DOUBLE_MANTISSA_MASK;
      static const uint64_t DOUBLE_NAN_BITS;
  
  public:
      /// Return given time in milliseconds.
      static uint64_t getTimeMillis(boost::posix_time::ptime time);
  
      /// Returns the current time in milliseconds.
      static uint64_t currentTimeMillis();
  
      /// This over-allocates proportional to the list size, making room for additional growth.
      /// The over-allocation is mild, but is enough to give linear-time amortized behavior over a long
      /// sequence of appends().
      /// The growth pattern is:  0, 4, 8, 16, 25, 35, 46, 58, 72, 88, ...
      static int32_t getNextSize(int32_t targetSize);
  
      /// Only reallocate if we are "substantially" smaller.  This saves us from "running hot" (constantly
      /// making a bit bigger then a bit smaller, over and over)
      static int32_t getShrinkSize(int32_t currentSize, int32_t targetSize);
  
      /// Compares two byte[] arrays, element by element, and returns the number of elements common to
      /// both arrays.
      /// @param bytes1 The first byte[] to compare
      /// @param bytes2 The second byte[] to compare
      /// @return The number of common elements.
      static int32_t bytesDifference(uint8_t* bytes1, int32_t len1, uint8_t* bytes2, int32_t len2);
  
      template <typename TYPE>
      static int32_t hashLucene(TYPE type) {
          return type->hashCode();
      }
  
      template <typename TYPE>
      static int32_t hashNumeric(TYPE type) {
          return type;
      }
  
      template <typename ITER, typename PRED>
      static int32_t hashCode(ITER first, ITER last, PRED pred) {
          int32_t code = 0;
          for (ITER hash = first; hash != last; ++hash) {
              code = code * 31 + pred(*hash);
          }
          return code;
      }
  
      /// Returns hash of chars in range start (inclusive) to end (inclusive)
      static int32_t hashCode(const wchar_t* array, int32_t start, int32_t end);
  
      /// Returns hash of bytes in range start (inclusive) to end (inclusive)
      static int32_t hashCode(const uint8_t* array, int32_t start, int32_t end);
  
      /// Returns hash code of given boolean
      static int32_t hashCode(bool value);
  
      /// Copy elements from on buffer to another
      template <typename SOURCE, typename DEST>
      static void arrayCopy(SOURCE source, int32_t sourceOffset, DEST dest, int32_t destOffset, int32_t length) {
          std::copy(source + sourceOffset, source + sourceOffset + length, dest + destOffset);
      }
  
      /// Fill buffer with given element
      template <typename DEST, typename FILL>
      static void arrayFill(DEST dest, int32_t destFrom, int32_t destTo, FILL value) {
          std::fill(dest + destFrom, dest + destTo, value);
      }
  
      /// Returns a representation of the specified floating-point value according to the IEEE 754 floating-point
      /// "single format" bit layout.
      static int32_t doubleToIntBits(double value);
  
      /// Returns a representation of the specified floating-point value according to the IEEE 754 floating-point
      /// "single format" bit layout, preserving Not-a-Number (NaN) values.
      static int32_t doubleToRawIntBits(double value);
  
      /// Returns the float value corresponding to a given bit representation. The argument is considered to be a
      /// representation of a floating-point value according to the IEEE 754 floating-point "single format" bit layout.
      static double intBitsToDouble(int32_t bits);
  
      /// Returns a representation of the specified floating-point value according to the IEEE 754 floating-point
      /// "double format" bit layout.
      static int64_t doubleToLongBits(double value);
  
      /// Returns a representation of the specified floating-point value according to the IEEE 754 floating-point
      /// "double format" bit layout, preserving Not-a-Number (NaN) values.
      static int64_t doubleToRawLongBits(double value);
  
      /// Returns the double value corresponding to a given bit representation. The argument is considered to be a
      /// representation of a floating-point value according to the IEEE 754 floating-point "double format" bit layout.
      static double longBitsToDouble(int64_t bits);
  
      /// Returns true if the specified number is infinitely large in magnitude, false otherwise.
      static bool isInfinite(double value);
  
      /// Returns true if this Double value is a Not-a-Number (NaN), false otherwise.
      static bool isNaN(double value);
  
      /// Return whether given Lucene object is of a specified type
      template <typename TYPE>
      static bool typeOf(const LuceneObjectPtr& object) {
          return boost::dynamic_pointer_cast<TYPE>(object).get() != NULL;
      }
  
      /// Return whether given Lucene objects are of equal type.
      static bool equalTypes(const LuceneObjectPtr& first, const LuceneObjectPtr& second);
  
      /// Perform unsigned right-shift (left bits are zero filled)
      static int64_t unsignedShift(int64_t num, int64_t shift);
  
      /// Perform unsigned right-shift (left bits are zero filled)
      static int32_t unsignedShift(int32_t num, int32_t shift);
  };
  
  }
  
  #endif
  