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# csutil/bitarray.h

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    00001 /*
    00002     Copyright (C) 2000 by Andrew Kirmse
    00003
    00004     This library is free software; you can redistribute it and/or
    00005     modify it under the terms of the GNU Library General Public
    00006     License as published by the Free Software Foundation; either
    00007     version 2 of the License, or (at your option) any later version.
    00008
    00009     This library is distributed in the hope that it will be useful,
    00010     but WITHOUT ANY WARRANTY; without even the implied warranty of
    00011     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00012     Library General Public License for more details.
    00013
    00014     You should have received a copy of the GNU Library General Public
    00015     License along with this library; if not, write to the Free
    00016     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    00017 */
    00018
    00019 // A one-dimensional array of bits, similar to STL bitset.
    00020 //
    00021 // Copyright 2000 Andrew Kirmse.  All rights reserved.
    00022 //
    00023 // Permission is granted to use this code for any purpose, as long as this
    00024 // copyright message remains intact.
    00025
    00026 #ifndef __CS_BITARRAY_H__
    00027 #define __CS_BITARRAY_H__
    00028
    00033 #include "csextern.h"
    00034 #include "allocator.h"
    00035 #include "comparator.h"
    00036 #include "hash.h"
    00037
    00038 #if defined(CS_COMPILER_MSVC) && (CS_PROCESSOR_SIZE == 64)
    00039 /* long is 32 bit even on 64-bit MSVC, so use uint64 to utilize a storage in
    00040  * 64 bit units.
    00041  */
    00042 typedef uint64 csBitArrayStorageType;
    00043 #else
    00045 typedef unsigned long csBitArrayStorageType;
    00046 #endif
    00047 const size_t csBitArrayDefaultInlineBits =
    00048   sizeof (csBitArrayStorageType) * 8;
    00049
    00050
    00052 template<typename BitArray>
    00053 class csComparatorBitArray
    00054 {
    00055 public:
    00056   static int Compare (BitArray const& key1, BitArray const& key2)
    00057   {
    00058     csBitArrayStorageType const* p0 = key1.GetStore();
    00059     csBitArrayStorageType const* p1 = key2.GetStore();
    00060     size_t compareNum = MIN (key1.mLength, key2.mLength);
    00061     size_t i = 0;
    00062     for (; i < compareNum; i++)
    00063       if (p0[i] != p1[i])
    00064         return (int)p0[i] - (int)p1[i];
    00065     if (key1.mLength > key2.mLength)
    00066     {
    00067       for (; i < key1.mLength; i++)
    00068         if (p0[i] != 0)
    00069           return (int)p0[i];
    00070     }
    00071     else
    00072     {
    00073       for (; i < key2.mLength; i++)
    00074         if (p1[i] != 0)
    00075           return -((int)p1[i]);
    00076     }
    00077     return 0;
    00078   }
    00079 };
    00080
    00081
    00083 template<typename BitArray>
    00084 class csHashComputerBitArray
    00085 {
    00086 public:
    00087   static uint ComputeHash (BitArray const& key)
    00088   {
    00089     const size_t uintCount = sizeof (csBitArrayStorageType) / sizeof (uint);
    00090     uint ui[uintCount];
    00091     uint hash = 0;
    00092     csBitArrayStorageType const* p = key.GetStore();
    00093     // \todo Not very good. Find a better hash function; however, it should
    00094     // return the same hash for two bit arrays that are the same except for
    00095     // the amount of trailing zeros. (e.g. f(10010110) == f(100101100000...))
    00096     for (size_t i = 0; i < key.mLength; i++)
    00097     {
    00098       memcpy (ui, &p[i], sizeof (ui));
    00099       for (size_t j = 0; j < uintCount; j++)
    00100         hash += ui[j];
    00101     }
    00102     return hash;
    00103   }
    00104 };
    00105
    00125 template<int InlinedBits = csBitArrayDefaultInlineBits,
    00126   typename Allocator = CS::Memory::AllocatorMalloc>
    00127 class csBitArrayTweakable
    00128 {
    00129 public:
    00130   typedef csBitArrayTweakable<InlinedBits, Allocator> ThisType;
    00131   typedef Allocator AllocatorType;
    00132
    00133 private:
    00134   template<typename BitArray> friend class csComparatorBitArray;
    00135   template<typename BitArray> friend class csHashComputerBitArray;
    00136
    00137   enum
    00138   {
    00139     cellSize    = csBitArrayDefaultInlineBits,
    00140     cellCount   = (InlinedBits + (cellSize-1)) / cellSize
    00141   };
    00142
    00143   struct Storage : public Allocator
    00144   {
    00145     union
    00146     {
    00147       csBitArrayStorageType* heapStore;
    00148       csBitArrayStorageType inlineStore[cellCount];
    00149     };
    00150     Storage()
    00151     {
    00152       memset (&inlineStore, 0,
    00153         MAX(sizeof (heapStore), sizeof (inlineStore)));
    00154     }
    00155   };
    00156   Storage storage;
    00158   size_t mLength;
    00159   size_t mNumBits;
    00160
    00162   static size_t GetIndex (size_t bit_num)
    00163   {
    00164     return bit_num / cellSize;
    00165   }
    00166
    00168   static size_t GetOffset (size_t bit_num)
    00169   {
    00170     return bit_num % cellSize;
    00171   }
    00172
    00174   bool UseInlineStore () const
    00175   {
    00176     return mLength <= cellCount;
    00177   }
    00178
    00183   csBitArrayStorageType const* GetStore() const
    00184   {
    00185     return UseInlineStore () ? storage.inlineStore : storage.heapStore;
    00186   }
    00187
    00192   csBitArrayStorageType* GetStore()
    00193   {
    00194     return UseInlineStore () ? storage.inlineStore : storage.heapStore;
    00195   }
    00196
    00198   void Trim()
    00199   {
    00200     size_t extra_bits = mNumBits % cellSize;
    00201     if (mLength > 0 && extra_bits != 0)
    00202       GetStore()[mLength - 1] &= ~((~(csBitArrayStorageType)0) << extra_bits);
    00203   }
    00204
    00205 public:
    00209   class BitProxy
    00210   {
    00211   private:
    00212     csBitArrayTweakable& mArray;
    00213     size_t mPos;
    00214   public:
    00216     BitProxy (csBitArrayTweakable& array, size_t pos): mArray(array), mPos(pos)
    00217     {}
    00218
    00220     BitProxy &operator= (bool value)
    00221     {
    00222       mArray.Set (mPos, value);
    00223       return *this;
    00224     }
    00225
    00227     BitProxy &operator= (const BitProxy &that)
    00228     {
    00229       mArray.Set (mPos, that.mArray.IsBitSet (that.mPos));
    00230       return *this;
    00231     }
    00232
    00234     operator bool() const
    00235     {
    00236       return mArray.IsBitSet (mPos);
    00237     }
    00238
    00243     bool Flip()
    00244     {
    00245       mArray.FlipBit (mPos);
    00246       return mArray.IsBitSet (mPos);
    00247     }
    00248   };
    00249   friend class BitProxy;
    00250
    00254   csBitArrayTweakable () : mLength(0), mNumBits(0)
    00255   {
    00256     SetSize (0);
    00257   }
    00258
    00262   explicit csBitArrayTweakable (size_t size) : mLength(0), mNumBits(0)
    00263   {
    00264     SetSize (size);
    00265   }
    00266
    00270   csBitArrayTweakable (const csBitArrayTweakable& that) : mLength(0), mNumBits(0)
    00271   {
    00272     *this = that; // Invokes this->operator=().
    00273   }
    00274
    00276   ~csBitArrayTweakable()
    00277   {
    00278     if (!UseInlineStore ())
    00279       storage.Free (storage.heapStore);
    00280   }
    00281
    00283   size_t GetSize() const
    00284   {
    00285     return mNumBits;
    00286   }
    00287
    00292   /*CS_DEPRECATED_METHOD_MSG("Use GetSize() instead.")*/
    00293   size_t Length () const
    00294   {
    00295     return GetSize();
    00296   }
    00297
    00302   /*CS_DEPRECATED_METHOD_MSG("Use SetSize() instead.")*/
    00303   void SetLength (size_t newSize)
    00304   {
    00305     SetSize (newSize);
    00306   }
    00307
    00313   void SetSize (size_t newSize)
    00314   {
    00315     size_t newLength;
    00316     if (newSize == 0)
    00317       newLength = 0;
    00318     else
    00319       newLength = 1 + GetIndex (newSize - 1);
    00320
    00321     if (newLength != mLength)
    00322     {
    00323       // Avoid allocation if length is 1 (common case)
    00324       csBitArrayStorageType* newStore;
    00325       if (newLength <= cellCount)
    00326         newStore = storage.inlineStore;
    00327       else
    00328         newStore = (csBitArrayStorageType*)storage.Alloc (
    00329           newLength * sizeof (csBitArrayStorageType));
    00330
    00331       if (newLength > 0)
    00332       {
    00333         if (mLength > 0)
    00334         {
    00335           csBitArrayStorageType* oldStore = GetStore();
    00336           if (newStore != oldStore)
    00337           {
    00338             memcpy (newStore, oldStore,
    00339               (MIN (mLength, newLength)) * sizeof (csBitArrayStorageType));
    00340             if (newLength > mLength)
    00341               memset(newStore + mLength, 0,
    00342                      (newLength - mLength) * sizeof (csBitArrayStorageType));
    00343             if (!UseInlineStore ())
    00344               storage.Free (oldStore);
    00345           }
    00346         }
    00347         else
    00348           memset (newStore, 0, newLength * sizeof (csBitArrayStorageType));
    00349       }
    00350       mLength = newLength;
    00351       if (!UseInlineStore()) storage.heapStore = newStore;
    00352     }
    00353
    00354     mNumBits = newSize;
    00355     Trim();
    00356   }
    00357
    00358   //
    00359   // Operators
    00360   //
    00361
    00363   csBitArrayTweakable& operator=(const csBitArrayTweakable& that)
    00364   {
    00365     if (this != &that)
    00366     {
    00367       SetSize (that.mNumBits);
    00368       memcpy (GetStore(), that.GetStore(),
    00369         mLength * sizeof (csBitArrayStorageType));
    00370     }
    00371     return *this;
    00372   }
    00373
    00375   BitProxy operator[] (size_t pos)
    00376   {
    00377     CS_ASSERT (pos < mNumBits);
    00378     return BitProxy(*this, pos);
    00379   }
    00380
    00382   bool operator[] (size_t pos) const
    00383   {
    00384     return IsBitSet(pos);
    00385   }
    00386
    00388   bool operator==(const csBitArrayTweakable& that) const
    00389   {
    00390     if (mNumBits != that.mNumBits)
    00391       return false;
    00392
    00393     csBitArrayStorageType const* p0 = GetStore();
    00394     csBitArrayStorageType const* p1 = that.GetStore();
    00395     for (unsigned i = 0; i < mLength; i++)
    00396       if (p0[i] != p1[i])
    00397         return false;
    00398     return true;
    00399   }
    00400
    00402   bool operator != (const csBitArrayTweakable& that) const
    00403   {
    00404     return !(*this == that);
    00405   }
    00406
    00408   csBitArrayTweakable& operator &= (const csBitArrayTweakable &that)
    00409   {
    00410     CS_ASSERT (mNumBits == that.mNumBits);
    00411     csBitArrayStorageType* p0 = GetStore();
    00412     csBitArrayStorageType const* p1 = that.GetStore();
    00413     for (size_t i = 0; i < mLength; i++)
    00414       p0[i] &= p1[i];
    00415     return *this;
    00416   }
    00417
    00419   csBitArrayTweakable operator |= (const csBitArrayTweakable& that)
    00420   {
    00421     CS_ASSERT (mNumBits == that.mNumBits);
    00422     csBitArrayStorageType* p0 = GetStore();
    00423     csBitArrayStorageType const* p1 = that.GetStore();
    00424     for (size_t i = 0; i < mLength; i++)
    00425       p0[i] |= p1[i];
    00426     return *this;
    00427   }
    00428
    00430   csBitArrayTweakable operator ^= (const csBitArrayTweakable& that)
    00431   {
    00432     CS_ASSERT (mNumBits == that.mNumBits);
    00433     csBitArrayStorageType* p0 = GetStore();
    00434     csBitArrayStorageType const* p1 = that.GetStore();
    00435     for (size_t i = 0; i < mLength; i++)
    00436       p0[i] ^= p1[i];
    00437     return *this;
    00438   }
    00439
    00441   csBitArrayTweakable operator~() const
    00442   {
    00443     return csBitArrayTweakable(*this).FlipAllBits();
    00444   }
    00445
    00447   friend csBitArrayTweakable operator& (const csBitArrayTweakable& a1,
    00448     const csBitArrayTweakable& a2)
    00449   {
    00450     return csBitArrayTweakable (a1) &= a2;
    00451   }
    00452
    00454   friend csBitArrayTweakable operator | (const csBitArrayTweakable& a1,
    00455     const csBitArrayTweakable& a2)
    00456   {
    00457     return csBitArrayTweakable (a1) |= a2;
    00458   }
    00459
    00461   friend csBitArrayTweakable operator ^ (const csBitArrayTweakable& a1,
    00462     const csBitArrayTweakable& a2)
    00463   {
    00464     return csBitArrayTweakable (a1) ^= a2;
    00465   }
    00466
    00467   //
    00468   // Plain English interface
    00469   //
    00470
    00472   void Clear()
    00473   {
    00474     memset (GetStore(), 0, mLength * sizeof(csBitArrayStorageType));
    00475   }
    00476
    00478   void SetBit (size_t pos)
    00479   {
    00480     CS_ASSERT (pos < mNumBits);
    00481     GetStore()[GetIndex(pos)] |= ((csBitArrayStorageType)1) << GetOffset(pos);
    00482   }
    00483
    00485   void ClearBit (size_t pos)
    00486   {
    00487     CS_ASSERT (pos < mNumBits);
    00488     GetStore()[GetIndex(pos)] &= ~(((csBitArrayStorageType)1) << GetOffset(pos));
    00489   }
    00490
    00492   void FlipBit (size_t pos)
    00493   {
    00494     CS_ASSERT (pos < mNumBits);
    00495     GetStore()[GetIndex(pos)] ^= ((csBitArrayStorageType)1) << GetOffset(pos);
    00496   }
    00497
    00499   void Set (size_t pos, bool val = true)
    00500   {
    00501     if (val)
    00502       SetBit(pos);
    00503     else
    00504       ClearBit(pos);
    00505   }
    00506
    00508   bool IsBitSet (size_t pos) const
    00509   {
    00510     CS_ASSERT (pos < mNumBits);
    00511     return (GetStore()[GetIndex(pos)]
    00512       & (((csBitArrayStorageType)1) << GetOffset(pos))) != 0;
    00513   }
    00514
    00516   bool AreSomeBitsSet (size_t pos, size_t count) const
    00517   {
    00518     CS_ASSERT (pos + count <= mNumBits);
    00519     csBitArrayStorageType const* p = GetStore();
    00520     while (count > 0)
    00521     {
    00522       size_t index = GetIndex (pos);
    00523       size_t offset = GetOffset (pos);
    00524       size_t checkCount = MIN(count, cellSize - offset);
    00525       csBitArrayStorageType mask = ((checkCount == cellSize)
    00526         ? ~(csBitArrayStorageType)0
    00527         : ((((csBitArrayStorageType)1) << checkCount) - 1)) << offset;
    00528       if (p[index] & mask)
    00529         return true;
    00530       pos += checkCount;
    00531       count -= checkCount;
    00532     }
    00533     return false;
    00534   }
    00535
    00537   bool AllBitsFalse() const
    00538   {
    00539     csBitArrayStorageType const* p = GetStore();
    00540     for (size_t i = 0; i < mLength; i++)
    00541       if (p[i] != 0)
    00542         return false;
    00543     return true;
    00544   }
    00545
    00547   csBitArrayTweakable& FlipAllBits()
    00548   {
    00549     csBitArrayStorageType* p = GetStore();
    00550     for (size_t i = 0; i < mLength; i++)
    00551       p[i] = ~p[i];
    00552     Trim();
    00553     return *this;
    00554   }
    00555
    00560   void Delete(size_t pos, size_t count)
    00561   {
    00562     if (count > 0)
    00563     {
    00564       size_t dst = pos;
    00565       size_t src = pos + count;
    00566       CS_ASSERT(src <= mNumBits);
    00567       size_t ntail = mNumBits - src;
    00568       while (ntail-- > 0)
    00569         Set(dst++, IsBitSet(src++));
    00570       SetSize(mNumBits - count);
    00571     }
    00572   }
    00573
    00578   csBitArrayTweakable Slice(size_t pos, size_t count) const
    00579   {
    00580     CS_ASSERT(pos + count <= mNumBits);
    00581     csBitArrayTweakable a (count);
    00582     for (size_t i = pos, o = 0; i < pos + count; i++)
    00583       if (IsBitSet(i))
    00584         a.SetBit(o++);
    00585     return a;
    00586   }
    00587
    00589   csBitArrayStorageType* GetArrayBits()
    00590   {
    00591     return GetStore();
    00592   }
    00593 };
    00594
    00599 class csBitArray : public csBitArrayTweakable<>
    00600 {
    00601 public:
    00603   csBitArray () { }
    00605   explicit csBitArray (size_t size) : csBitArrayTweakable<> (size) { }
    00607   csBitArray (const csBitArray& that) : csBitArrayTweakable<> (that) { }
    00608 };
    00609
    00610
    00615 template<>
    00616 class csComparator<csBitArray, csBitArray> :
    00617   public csComparatorBitArray<csBitArray> { };
    00618
    00619
    00624 template<>
    00625 class csHashComputer<csBitArray> :
    00626   public csHashComputerBitArray<csBitArray> { };
    00627
    00628
    00629 #endif // __CS_BITARRAY_H__