src/util/bitvector.h

   1 /*********************                                                        */
   2 /*! \file bitvector.h
   3  ** \verbatim
   4  ** Original author: dejan
   5  ** Major contributors: mdeters, lianah
   6  ** Minor contributors (to current version): cconway
   7  ** This file is part of the CVC4 prototype.
   8  ** Copyright (c) 2009-2012  New York University and The University of Iowa
   9  ** See the file COPYING in the top-level source directory for licensing
  10  ** information.\endverbatim
  11  **
  12  ** \brief [[ Add one-line brief description here ]]
  13  **
  14  ** [[ Add lengthier description here ]]
  15  ** \todo document this file
  16  **/
  17
  18 #include "cvc4_public.h"
  19
  20 #ifndef __CVC4__BITVECTOR_H
  21 #define __CVC4__BITVECTOR_H
  22
  23 #include <iostream>
  24 #include "util/exception.h"
  25 #include "util/integer.h"
  26
  27 namespace CVC4 {
  28
  29 class CVC4_PUBLIC BitVector {
  30
  31 private:
  32
  33   /*
  34     Class invariants:
  35     * no overflows: 2^d_size < d_value
  36     * no negative numbers: d_value >= 0
  37    */
  38   unsigned d_size;
  39   Integer d_value;
  40
  41   Integer toSignedInt() const {
  42     // returns Integer corresponding to two's complement interpretation of bv
  43     unsigned size = d_size;
  44     Integer sign_bit = d_value.extractBitRange(1,size-1);
  45     Integer val = d_value.extractBitRange(size-1, 0);
  46     Integer res = Integer(-1) * sign_bit.multiplyByPow2(size - 1) + val;
  47     return res;
  48   }
  49
  50
  51 public:
  52
  53   BitVector(unsigned size, const Integer& val):
  54     d_size(size),
  55     d_value(val.modByPow2(size))
  56       {}
  57
  58   BitVector(unsigned size = 0)
  59     : d_size(size), d_value(0) {}
  60
  61   BitVector(unsigned size, unsigned int z)
  62     : d_size(size), d_value(z) {
  63     d_value = d_value.modByPow2(size);
  64   }
  65
  66   BitVector(unsigned size, unsigned long int z)
  67     : d_size(size), d_value(z) {
  68     d_value = d_value.modByPow2(size);
  69   }
  70
  71   BitVector(unsigned size, const BitVector& q)
  72     : d_size(size), d_value(q.d_value) {}
  73
  74   BitVector(const std::string& num, unsigned base = 2);
  75
  76   ~BitVector() {}
  77
  78   Integer toInteger() const {
  79     return d_value;
  80   }
  81
  82   BitVector& operator =(const BitVector& x) {
  83     if(this == &x)
  84       return *this;
  85     d_size = x.d_size;
  86     d_value = x.d_value;
  87     return *this;
  88   }
  89
  90   bool operator ==(const BitVector& y) const {
  91     if (d_size != y.d_size) return false;
  92     return d_value == y.d_value;
  93   }
  94
  95   bool operator !=(const BitVector& y) const {
  96     if (d_size != y.d_size) return true;
  97     return d_value != y.d_value;
  98   }
  99
 100   BitVector concat (const BitVector& other) const {
 101     return BitVector(d_size + other.d_size, (d_value.multiplyByPow2(other.d_size)) + other.d_value);
 102   }
 103
 104   BitVector extract(unsigned high, unsigned low) const {
 105     return BitVector(high - low + 1, d_value.extractBitRange(high - low + 1, low));
 106   }
 107
 108   /*
 109     Bitwise operations on BitVectors
 110    */
 111
 112   // xor
 113   BitVector operator ^(const BitVector& y) const {
 114     CheckArgument(d_size == y.d_size, y);
 115     return BitVector(d_size, d_value.bitwiseXor(y.d_value));
 116   }
 117
 118   // or
 119   BitVector operator |(const BitVector& y) const {
 120     CheckArgument(d_size == y.d_size, y);
 121     return BitVector(d_size, d_value.bitwiseOr(y.d_value));
 122   }
 123
 124   // and
 125   BitVector operator &(const BitVector& y) const {
 126     CheckArgument(d_size == y.d_size, y);
 127     return BitVector(d_size, d_value.bitwiseAnd(y.d_value));
 128   }
 129
 130   // not
 131   BitVector operator ~() const {
 132     return BitVector(d_size, d_value.bitwiseNot());
 133   }
 134
 135   /*
 136     Arithmetic operations on BitVectors
 137    */
 138
 139
 140   bool operator <(const BitVector& y) const {
 141     return d_value < y.d_value;
 142   }
 143
 144   bool operator >(const BitVector& y) const {
 145     return d_value > y.d_value ;
 146   }
 147
 148   bool operator <=(const BitVector& y) const {
 149     return d_value <= y.d_value;
 150   }
 151
 152   bool operator >=(const BitVector& y) const {
 153     return d_value >= y.d_value ;
 154   }
 155
 156
 157   BitVector operator +(const BitVector& y) const {
 158     CheckArgument(d_size == y.d_size, y);
 159     Integer sum = d_value +  y.d_value;
 160     return BitVector(d_size, sum);
 161   }
 162
 163   BitVector operator -(const BitVector& y) const {
 164     CheckArgument(d_size == y.d_size, y);
 165     // to maintain the invariant that we are only adding BitVectors of the
 166     // same size
 167     BitVector one(d_size, Integer(1));
 168     return *this + ~y + one;
 169   }
 170
 171   BitVector operator -() const {
 172     BitVector one(d_size, Integer(1));
 173     return ~(*this) + one;
 174   }
 175
 176   BitVector operator *(const BitVector& y) const {
 177     CheckArgument(d_size == y.d_size, y);
 178     Integer prod = d_value * y.d_value;
 179     return BitVector(d_size, prod);
 180   }
 181
 182   BitVector setBit(uint32_t i) const {
 183     CheckArgument(i < d_size, i);
 184     Integer res = d_value.setBit(i);
 185     return BitVector(d_size, res);
 186   }
 187
 188   bool isBitSet(uint32_t i) const {
 189     CheckArgument(i < d_size, i);
 190     return d_value.isBitSet(i);
 191   }
 192
 193   /**
 194    * Total division function that returns 0 when the denominator is 0.
 195    */
 196   BitVector unsignedDivTotal (const BitVector& y) const {
 197
 198     CheckArgument(d_size == y.d_size, y);
 199     if (y.d_value == 0) {
 200       return BitVector(d_size, 0u);
 201     }
 202     CheckArgument(d_value >= 0, this);
 203     CheckArgument(y.d_value > 0, y);
 204     return BitVector(d_size, d_value.floorDivideQuotient(y.d_value));
 205   }
 206
 207   /**
 208    * Total division function that returns 0 when the denominator is 0.
 209    */
 210   BitVector unsignedRemTotal(const BitVector& y) const {
 211     CheckArgument(d_size == y.d_size, y);
 212     if (y.d_value == 0) {
 213       return BitVector(d_size, 0u);
 214     }
 215     CheckArgument(d_value >= 0, this);
 216     CheckArgument(y.d_value > 0, y);
 217     return BitVector(d_size, d_value.floorDivideRemainder(y.d_value));
 218   }
 219
 220
 221   bool signedLessThan(const BitVector& y) const {
 222     CheckArgument(d_size == y.d_size, y);
 223     CheckArgument(d_value >= 0, this);
 224     CheckArgument(y.d_value >= 0, y);
 225     Integer a = (*this).toSignedInt();
 226     Integer b = y.toSignedInt();
 227
 228     return a < b;
 229   }
 230
 231   bool unsignedLessThan(const BitVector& y) const {
 232     CheckArgument(d_size == y.d_size, y);
 233     CheckArgument(d_value >= 0, this);
 234     CheckArgument(y.d_value >= 0, y);
 235     return d_value < y.d_value;
 236   }
 237
 238   bool signedLessThanEq(const BitVector& y) const {
 239     CheckArgument(d_size == y.d_size, y);
 240     CheckArgument(d_value >= 0, this);
 241     CheckArgument(y.d_value >= 0, y);
 242     Integer a = (*this).toSignedInt();
 243     Integer b = y.toSignedInt();
 244
 245     return a <= b;
 246   }
 247
 248   bool unsignedLessThanEq(const BitVector& y) const {
 249     CheckArgument(d_size == y.d_size, this);
 250     CheckArgument(d_value >= 0, this);
 251     CheckArgument(y.d_value >= 0, y);
 252     return d_value <= y.d_value;
 253   }
 254
 255
 256   /*
 257     Extend operations
 258    */
 259
 260   BitVector zeroExtend(unsigned amount) const {
 261     return BitVector(d_size + amount, d_value);
 262   }
 263
 264   BitVector signExtend(unsigned amount) const {
 265     Integer sign_bit = d_value.extractBitRange(1, d_size -1);
 266     if(sign_bit == Integer(0)) {
 267       return BitVector(d_size + amount, d_value);
 268     } else {
 269       Integer val = d_value.oneExtend(d_size, amount);
 270       return BitVector(d_size+ amount, val);
 271     }
 272   }
 273
 274   /*
 275     Shifts on BitVectors
 276    */
 277
 278   BitVector leftShift(const BitVector& y) const {
 279     if (y.d_value > Integer(d_size)) {
 280       return BitVector(d_size, Integer(0));
 281     }
 282     if (y.d_value == 0) {
 283       return *this;
 284     }
 285
 286     // making sure we don't lose information casting
 287     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 288     uint32_t amount = y.d_value.toUnsignedInt();
 289     Integer res = d_value.multiplyByPow2(amount);
 290     return BitVector(d_size, res);
 291   }
 292
 293   BitVector logicalRightShift(const BitVector& y) const {
 294     if(y.d_value > Integer(d_size)) {
 295       return BitVector(d_size, Integer(0));
 296     }
 297
 298     // making sure we don't lose information casting
 299     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 300     uint32_t amount = y.d_value.toUnsignedInt();
 301     Integer res = d_value.divByPow2(amount);
 302     return BitVector(d_size, res);
 303   }
 304
 305   BitVector arithRightShift(const BitVector& y) const {
 306     Integer sign_bit = d_value.extractBitRange(1, d_size - 1);
 307     if(y.d_value > Integer(d_size)) {
 308       if(sign_bit == Integer(0)) {
 309         return BitVector(d_size, Integer(0));
 310       } else {
 311         return BitVector(d_size, Integer(d_size).multiplyByPow2(d_size) -1 );
 312       }
 313     }
 314
 315     if (y.d_value == 0) {
 316       return *this;
 317     }
 318
 319     // making sure we don't lose information casting
 320     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 321
 322     uint32_t amount  = y.d_value.toUnsignedInt();
 323     Integer rest = d_value.divByPow2(amount);
 324
 325     if(sign_bit == Integer(0)) {
 326       return BitVector(d_size, rest);
 327     }
 328     Integer res = rest.oneExtend(d_size - amount, amount);
 329     return BitVector(d_size, res);
 330   }
 331
 332
 333   /*
 334     Convenience functions
 335    */
 336
 337   size_t hash() const {
 338     return d_value.hash() + d_size;
 339   }
 340
 341   std::string toString(unsigned int base = 2) const {
 342     std::string str = d_value.toString(base);
 343     if( base == 2 && d_size > str.size() ) {
 344       std::string zeroes;
 345       for( unsigned int i=0; i < d_size - str.size(); ++i ) {
 346         zeroes.append("0");
 347       }
 348       return zeroes + str;
 349     } else {
 350       return str;
 351     }
 352   }
 353
 354   unsigned getSize() const {
 355     return d_size;
 356   }
 357
 358   const Integer& getValue() const {
 359     return d_value;
 360   }
 361
 362   /**
 363    Returns k is the integer is equal to 2^{k-1} and zero
 364    otherwise
 365    @return k if the integer is equal to 2^{k-1} and zero otherwise
 366    */
 367   unsigned isPow2() {
 368     return d_value.isPow2();
 369   }
 370
 371 };/* class BitVector */
 372
 373
 374
 375 inline BitVector::BitVector(const std::string& num, unsigned base) {
 376   CheckArgument(base == 2 || base == 16, base);
 377
 378   if( base == 2 ) {
 379     d_size = num.size();
 380   } else {
 381     d_size = num.size() * 4;
 382   }
 383
 384   d_value = Integer(num, base);
 385 }/* BitVector::BitVector() */
 386
 387
 388 /**
 389  * Hash function for the BitVector constants.
 390  */
 391 struct CVC4_PUBLIC BitVectorHashFunction {
 392   inline size_t operator()(const BitVector& bv) const {
 393     return bv.hash();
 394   }
 395 };/* struct BitVectorHashFunction */
 396
 397 /**
 398  * The structure representing the extraction operation for bit-vectors. The
 399  * operation map bit-vectors to bit-vector of size <code>high - low + 1</code>
 400  * by taking the bits at indices <code>high ... low</code>
 401  */
 402 struct CVC4_PUBLIC BitVectorExtract {
 403   /** The high bit of the range for this extract */
 404   unsigned high;
 405   /** The low bit of the range for this extract */
 406   unsigned low;
 407
 408   BitVectorExtract(unsigned high, unsigned low)
 409   : high(high), low(low) {}
 410
 411   bool operator == (const BitVectorExtract& extract) const {
 412     return high == extract.high && low == extract.low;
 413   }
 414 };/* struct BitVectorExtract */
 415
 416 /**
 417  * Hash function for the BitVectorExtract objects.
 418  */
 419 struct CVC4_PUBLIC BitVectorExtractHashFunction {
 420   size_t operator()(const BitVectorExtract& extract) const {
 421     size_t hash = extract.low;
 422     hash ^= extract.high + 0x9e3779b9 + (hash << 6) + (hash >> 2);
 423     return hash;
 424   }
 425 };/* struct BitVectorExtractHashFunction */
 426
 427
 428 /**
 429  * The structure representing the extraction of one Boolean bit.
 430  */
 431 struct CVC4_PUBLIC BitVectorBitOf {
 432   /** The index of the bit */
 433   unsigned bitIndex;
 434   BitVectorBitOf(unsigned i)
 435     : bitIndex(i) {}
 436
 437   bool operator == (const BitVectorBitOf& other) const {
 438     return bitIndex == other.bitIndex;
 439   }
 440 };/* struct BitVectorBitOf */
 441
 442 /**
 443  * Hash function for the BitVectorBitOf objects.
 444  */
 445 struct CVC4_PUBLIC BitVectorBitOfHashFunction {
 446   size_t operator()(const BitVectorBitOf& b) const {
 447     return b.bitIndex;
 448   }
 449 };/* struct BitVectorBitOfHashFunction */
 450
 451
 452
 453 struct CVC4_PUBLIC BitVectorSize {
 454   unsigned size;
 455   BitVectorSize(unsigned size)
 456   : size(size) {}
 457   operator unsigned () const { return size; }
 458 };/* struct BitVectorSize */
 459
 460 struct CVC4_PUBLIC BitVectorRepeat {
 461   unsigned repeatAmount;
 462   BitVectorRepeat(unsigned repeatAmount)
 463   : repeatAmount(repeatAmount) {}
 464   operator unsigned () const { return repeatAmount; }
 465 };/* struct BitVectorRepeat */
 466
 467 struct CVC4_PUBLIC BitVectorZeroExtend {
 468   unsigned zeroExtendAmount;
 469   BitVectorZeroExtend(unsigned zeroExtendAmount)
 470   : zeroExtendAmount(zeroExtendAmount) {}
 471   operator unsigned () const { return zeroExtendAmount; }
 472 };/* struct BitVectorZeroExtend */
 473
 474 struct CVC4_PUBLIC BitVectorSignExtend {
 475   unsigned signExtendAmount;
 476   BitVectorSignExtend(unsigned signExtendAmount)
 477   : signExtendAmount(signExtendAmount) {}
 478   operator unsigned () const { return signExtendAmount; }
 479 };/* struct BitVectorSignExtend */
 480
 481 struct CVC4_PUBLIC BitVectorRotateLeft {
 482   unsigned rotateLeftAmount;
 483   BitVectorRotateLeft(unsigned rotateLeftAmount)
 484   : rotateLeftAmount(rotateLeftAmount) {}
 485   operator unsigned () const { return rotateLeftAmount; }
 486 };/* struct BitVectorRotateLeft */
 487
 488 struct CVC4_PUBLIC BitVectorRotateRight {
 489   unsigned rotateRightAmount;
 490   BitVectorRotateRight(unsigned rotateRightAmount)
 491   : rotateRightAmount(rotateRightAmount) {}
 492   operator unsigned () const { return rotateRightAmount; }
 493 };/* struct BitVectorRotateRight */
 494
 495 template <typename T>
 496 struct CVC4_PUBLIC UnsignedHashFunction {
 497   inline size_t operator()(const T& x) const {
 498     return (size_t)x;
 499   }
 500 };/* struct UnsignedHashFunction */
 501
 502 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) CVC4_PUBLIC;
 503 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) {
 504   return os << bv.toString();
 505 }
 506
 507 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) CVC4_PUBLIC;
 508 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) {
 509   return os << "[" << bv.high << ":" << bv.low << "]";
 510 }
 511
 512 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) CVC4_PUBLIC;
 513 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) {
 514   return os << "[" << bv.bitIndex << "]";
 515 }
 516
 517 }/* CVC4 namespace */
 518
 519 #endif /* __CVC4__BITVECTOR_H */