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   BitVector unsignedDiv (const BitVector& y) const {
 194     CheckArgument(d_size == y.d_size, y);
 195     // TODO: decide whether we really want these semantics
 196     if (y.d_value == 0) {
 197       return BitVector(d_size, Integer(0));
 198     }
 199     CheckArgument(d_value >= 0, this);
 200     CheckArgument(y.d_value > 0, y);
 201     return BitVector(d_size, d_value.floorDivideQuotient(y.d_value));
 202   }
 203
 204   BitVector unsignedRem(const BitVector& y) const {
 205     CheckArgument(d_size == y.d_size, y);
 206     // TODO: decide whether we really want these semantics
 207     if (y.d_value == 0) {
 208       return BitVector(d_size, d_value);
 209     }
 210     CheckArgument(d_value >= 0, this);
 211     CheckArgument(y.d_value > 0, y);
 212     return BitVector(d_size, d_value.floorDivideRemainder(y.d_value));
 213   }
 214
 215
 216   bool signedLessThan(const BitVector& y) const {
 217     CheckArgument(d_size == y.d_size, y);
 218     CheckArgument(d_value >= 0, this);
 219     CheckArgument(y.d_value >= 0, y);
 220     Integer a = (*this).toSignedInt();
 221     Integer b = y.toSignedInt();
 222
 223     return a < b;
 224   }
 225
 226   bool unsignedLessThan(const BitVector& y) const {
 227     CheckArgument(d_size == y.d_size, y);
 228     CheckArgument(d_value >= 0, this);
 229     CheckArgument(y.d_value >= 0, y);
 230     return d_value < y.d_value;
 231   }
 232
 233   bool signedLessThanEq(const BitVector& y) const {
 234     CheckArgument(d_size == y.d_size, y);
 235     CheckArgument(d_value >= 0, this);
 236     CheckArgument(y.d_value >= 0, y);
 237     Integer a = (*this).toSignedInt();
 238     Integer b = y.toSignedInt();
 239
 240     return a <= b;
 241   }
 242
 243   bool unsignedLessThanEq(const BitVector& y) const {
 244     CheckArgument(d_size == y.d_size, this);
 245     CheckArgument(d_value >= 0, this);
 246     CheckArgument(y.d_value >= 0, y);
 247     return d_value <= y.d_value;
 248   }
 249
 250
 251   /*
 252     Extend operations
 253    */
 254
 255   BitVector zeroExtend(unsigned amount) const {
 256     return BitVector(d_size + amount, d_value);
 257   }
 258
 259   BitVector signExtend(unsigned amount) const {
 260     Integer sign_bit = d_value.extractBitRange(1, d_size -1);
 261     if(sign_bit == Integer(0)) {
 262       return BitVector(d_size + amount, d_value);
 263     } else {
 264       Integer val = d_value.oneExtend(d_size, amount);
 265       return BitVector(d_size+ amount, val);
 266     }
 267   }
 268
 269   /*
 270     Shifts on BitVectors
 271    */
 272
 273   BitVector leftShift(const BitVector& y) const {
 274     if (y.d_value > Integer(d_size)) {
 275       return BitVector(d_size, Integer(0));
 276     }
 277     if (y.d_value == 0) {
 278       return *this;
 279     }
 280
 281     // making sure we don't lose information casting
 282     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 283     uint32_t amount = y.d_value.toUnsignedInt();
 284     Integer res = d_value.multiplyByPow2(amount);
 285     return BitVector(d_size, res);
 286   }
 287
 288   BitVector logicalRightShift(const BitVector& y) const {
 289     if(y.d_value > Integer(d_size)) {
 290       return BitVector(d_size, Integer(0));
 291     }
 292
 293     // making sure we don't lose information casting
 294     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 295     uint32_t amount = y.d_value.toUnsignedInt();
 296     Integer res = d_value.divByPow2(amount);
 297     return BitVector(d_size, res);
 298   }
 299
 300   BitVector arithRightShift(const BitVector& y) const {
 301     Integer sign_bit = d_value.extractBitRange(1, d_size - 1);
 302     if(y.d_value > Integer(d_size)) {
 303       if(sign_bit == Integer(0)) {
 304         return BitVector(d_size, Integer(0));
 305       } else {
 306         return BitVector(d_size, Integer(d_size).multiplyByPow2(d_size) -1 );
 307       }
 308     }
 309
 310     if (y.d_value == 0) {
 311       return *this;
 312     }
 313
 314     // making sure we don't lose information casting
 315     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 316
 317     uint32_t amount  = y.d_value.toUnsignedInt();
 318     Integer rest = d_value.divByPow2(amount);
 319
 320     if(sign_bit == Integer(0)) {
 321       return BitVector(d_size, rest);
 322     }
 323     Integer res = rest.oneExtend(d_size - amount, amount);
 324     return BitVector(d_size, res);
 325   }
 326
 327
 328   /*
 329     Convenience functions
 330    */
 331
 332   size_t hash() const {
 333     return d_value.hash() + d_size;
 334   }
 335
 336   std::string toString(unsigned int base = 2) const {
 337     std::string str = d_value.toString(base);
 338     if( base == 2 && d_size > str.size() ) {
 339       std::string zeroes;
 340       for( unsigned int i=0; i < d_size - str.size(); ++i ) {
 341         zeroes.append("0");
 342       }
 343       return zeroes + str;
 344     } else {
 345       return str;
 346     }
 347   }
 348
 349   unsigned getSize() const {
 350     return d_size;
 351   }
 352
 353   const Integer& getValue() const {
 354     return d_value;
 355   }
 356
 357   /**
 358    Returns k is the integer is equal to 2^{k-1} and zero
 359    otherwise
 360    @return k if the integer is equal to 2^{k-1} and zero otherwise
 361    */
 362   unsigned isPow2() {
 363     return d_value.isPow2();
 364   }
 365
 366 };/* class BitVector */
 367
 368
 369
 370 inline BitVector::BitVector(const std::string& num, unsigned base) {
 371   CheckArgument(base == 2 || base == 16, base);
 372
 373   if( base == 2 ) {
 374     d_size = num.size();
 375   } else {
 376     d_size = num.size() * 4;
 377   }
 378
 379   d_value = Integer(num, base);
 380 }/* BitVector::BitVector() */
 381
 382
 383 /**
 384  * Hash function for the BitVector constants.
 385  */
 386 struct CVC4_PUBLIC BitVectorHashFunction {
 387   inline size_t operator()(const BitVector& bv) const {
 388     return bv.hash();
 389   }
 390 };/* struct BitVectorHashFunction */
 391
 392 /**
 393  * The structure representing the extraction operation for bit-vectors. The
 394  * operation map bit-vectors to bit-vector of size <code>high - low + 1</code>
 395  * by taking the bits at indices <code>high ... low</code>
 396  */
 397 struct CVC4_PUBLIC BitVectorExtract {
 398   /** The high bit of the range for this extract */
 399   unsigned high;
 400   /** The low bit of the range for this extract */
 401   unsigned low;
 402
 403   BitVectorExtract(unsigned high, unsigned low)
 404   : high(high), low(low) {}
 405
 406   bool operator == (const BitVectorExtract& extract) const {
 407     return high == extract.high && low == extract.low;
 408   }
 409 };/* struct BitVectorExtract */
 410
 411 /**
 412  * Hash function for the BitVectorExtract objects.
 413  */
 414 struct CVC4_PUBLIC BitVectorExtractHashFunction {
 415   size_t operator()(const BitVectorExtract& extract) const {
 416     size_t hash = extract.low;
 417     hash ^= extract.high + 0x9e3779b9 + (hash << 6) + (hash >> 2);
 418     return hash;
 419   }
 420 };/* struct BitVectorExtractHashFunction */
 421
 422
 423 /**
 424  * The structure representing the extraction of one Boolean bit.
 425  */
 426 struct CVC4_PUBLIC BitVectorBitOf {
 427   /** The index of the bit */
 428   unsigned bitIndex;
 429   BitVectorBitOf(unsigned i)
 430     : bitIndex(i) {}
 431
 432   bool operator == (const BitVectorBitOf& other) const {
 433     return bitIndex == other.bitIndex;
 434   }
 435 };/* struct BitVectorBitOf */
 436
 437 /**
 438  * Hash function for the BitVectorBitOf objects.
 439  */
 440 struct CVC4_PUBLIC BitVectorBitOfHashFunction {
 441   size_t operator()(const BitVectorBitOf& b) const {
 442     return b.bitIndex;
 443   }
 444 };/* struct BitVectorBitOfHashFunction */
 445
 446
 447
 448 struct CVC4_PUBLIC BitVectorSize {
 449   unsigned size;
 450   BitVectorSize(unsigned size)
 451   : size(size) {}
 452   operator unsigned () const { return size; }
 453 };/* struct BitVectorSize */
 454
 455 struct CVC4_PUBLIC BitVectorRepeat {
 456   unsigned repeatAmount;
 457   BitVectorRepeat(unsigned repeatAmount)
 458   : repeatAmount(repeatAmount) {}
 459   operator unsigned () const { return repeatAmount; }
 460 };/* struct BitVectorRepeat */
 461
 462 struct CVC4_PUBLIC BitVectorZeroExtend {
 463   unsigned zeroExtendAmount;
 464   BitVectorZeroExtend(unsigned zeroExtendAmount)
 465   : zeroExtendAmount(zeroExtendAmount) {}
 466   operator unsigned () const { return zeroExtendAmount; }
 467 };/* struct BitVectorZeroExtend */
 468
 469 struct CVC4_PUBLIC BitVectorSignExtend {
 470   unsigned signExtendAmount;
 471   BitVectorSignExtend(unsigned signExtendAmount)
 472   : signExtendAmount(signExtendAmount) {}
 473   operator unsigned () const { return signExtendAmount; }
 474 };/* struct BitVectorSignExtend */
 475
 476 struct CVC4_PUBLIC BitVectorRotateLeft {
 477   unsigned rotateLeftAmount;
 478   BitVectorRotateLeft(unsigned rotateLeftAmount)
 479   : rotateLeftAmount(rotateLeftAmount) {}
 480   operator unsigned () const { return rotateLeftAmount; }
 481 };/* struct BitVectorRotateLeft */
 482
 483 struct CVC4_PUBLIC BitVectorRotateRight {
 484   unsigned rotateRightAmount;
 485   BitVectorRotateRight(unsigned rotateRightAmount)
 486   : rotateRightAmount(rotateRightAmount) {}
 487   operator unsigned () const { return rotateRightAmount; }
 488 };/* struct BitVectorRotateRight */
 489
 490 template <typename T>
 491 struct CVC4_PUBLIC UnsignedHashFunction {
 492   inline size_t operator()(const T& x) const {
 493     return (size_t)x;
 494   }
 495 };/* struct UnsignedHashFunction */
 496
 497 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) CVC4_PUBLIC;
 498 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) {
 499   return os << bv.toString();
 500 }
 501
 502 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) CVC4_PUBLIC;
 503 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) {
 504   return os << "[" << bv.high << ":" << bv.low << "]";
 505 }
 506
 507 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) CVC4_PUBLIC;
 508 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) {
 509   return os << "[" << bv.bitIndex << "]";
 510 }
 511
 512 }/* CVC4 namespace */
 513
 514 #endif /* __CVC4__BITVECTOR_H */