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    * Total division function that returns 0 when the denominator is 0.
 183    */
 184   BitVector unsignedDivTotal (const BitVector& y) const {
 185     CheckArgument(d_size == y.d_size, y);
 186     if (y.d_value == 0) {
 187       return BitVector(d_size, 0u);
 188     }
 189     CheckArgument(d_value >= 0, this);
 190     CheckArgument(y.d_value > 0, y);
 191     return BitVector(d_size, d_value.floorDivideQuotient(y.d_value));
 192   }
 193   /**
 194    * Total division function that returns 0 when the denominator is 0.
 195    */
 196   BitVector unsignedRemTotal(const BitVector& y) const {
 197     CheckArgument(d_size == y.d_size, y);
 198     if (y.d_value == 0) {
 199       return BitVector(d_size, 0u);
 200     }
 201     CheckArgument(d_value >= 0, this);
 202     CheckArgument(y.d_value > 0, y);
 203     return BitVector(d_size, d_value.floorDivideRemainder(y.d_value));
 204   }
 205
 206
 207   bool signedLessThan(const BitVector& y) const {
 208     CheckArgument(d_size == y.d_size, y);
 209     CheckArgument(d_value >= 0, this);
 210     CheckArgument(y.d_value >= 0, y);
 211     Integer a = (*this).toSignedInt();
 212     Integer b = y.toSignedInt();
 213
 214     return a < b;
 215   }
 216
 217   bool unsignedLessThan(const BitVector& y) const {
 218     CheckArgument(d_size == y.d_size, y);
 219     CheckArgument(d_value >= 0, this);
 220     CheckArgument(y.d_value >= 0, y);
 221     return d_value < y.d_value;
 222   }
 223
 224   bool signedLessThanEq(const BitVector& y) const {
 225     CheckArgument(d_size == y.d_size, y);
 226     CheckArgument(d_value >= 0, this);
 227     CheckArgument(y.d_value >= 0, y);
 228     Integer a = (*this).toSignedInt();
 229     Integer b = y.toSignedInt();
 230
 231     return a <= b;
 232   }
 233
 234   bool unsignedLessThanEq(const BitVector& y) const {
 235     CheckArgument(d_size == y.d_size, this);
 236     CheckArgument(d_value >= 0, this);
 237     CheckArgument(y.d_value >= 0, y);
 238     return d_value <= y.d_value;
 239   }
 240
 241
 242   /*
 243     Extend operations
 244    */
 245
 246   BitVector zeroExtend(unsigned amount) const {
 247     return BitVector(d_size + amount, d_value);
 248   }
 249
 250   BitVector signExtend(unsigned amount) const {
 251     Integer sign_bit = d_value.extractBitRange(1, d_size -1);
 252     if(sign_bit == Integer(0)) {
 253       return BitVector(d_size + amount, d_value);
 254     } else {
 255       Integer val = d_value.oneExtend(d_size, amount);
 256       return BitVector(d_size+ amount, val);
 257     }
 258   }
 259
 260   /*
 261     Shifts on BitVectors
 262    */
 263
 264   BitVector leftShift(const BitVector& y) const {
 265     if (y.d_value > Integer(d_size)) {
 266       return BitVector(d_size, Integer(0));
 267     }
 268     if (y.d_value == 0) {
 269       return *this;
 270     }
 271
 272     // making sure we don't lose information casting
 273     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 274     uint32_t amount = y.d_value.toUnsignedInt();
 275     Integer res = d_value.multiplyByPow2(amount);
 276     return BitVector(d_size, res);
 277   }
 278
 279   BitVector logicalRightShift(const BitVector& y) const {
 280     if(y.d_value > Integer(d_size)) {
 281       return BitVector(d_size, Integer(0));
 282     }
 283
 284     // making sure we don't lose information casting
 285     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 286     uint32_t amount = y.d_value.toUnsignedInt();
 287     Integer res = d_value.divByPow2(amount);
 288     return BitVector(d_size, res);
 289   }
 290
 291   BitVector arithRightShift(const BitVector& y) const {
 292     Integer sign_bit = d_value.extractBitRange(1, d_size - 1);
 293     if(y.d_value > Integer(d_size)) {
 294       if(sign_bit == Integer(0)) {
 295         return BitVector(d_size, Integer(0));
 296       } else {
 297         return BitVector(d_size, Integer(d_size).multiplyByPow2(d_size) -1 );
 298       }
 299     }
 300
 301     if (y.d_value == 0) {
 302       return *this;
 303     }
 304
 305     // making sure we don't lose information casting
 306     CheckArgument(y.d_value < Integer(1).multiplyByPow2(32), y);
 307
 308     uint32_t amount  = y.d_value.toUnsignedInt();
 309     Integer rest = d_value.divByPow2(amount);
 310
 311     if(sign_bit == Integer(0)) {
 312       return BitVector(d_size, rest);
 313     }
 314     Integer res = rest.oneExtend(d_size - amount, amount);
 315     return BitVector(d_size, res);
 316   }
 317
 318
 319   /*
 320     Convenience functions
 321    */
 322
 323   size_t hash() const {
 324     return d_value.hash() + d_size;
 325   }
 326
 327   std::string toString(unsigned int base = 2) const {
 328     std::string str = d_value.toString(base);
 329     if( base == 2 && d_size > str.size() ) {
 330       std::string zeroes;
 331       for( unsigned int i=0; i < d_size - str.size(); ++i ) {
 332         zeroes.append("0");
 333       }
 334       return zeroes + str;
 335     } else {
 336       return str;
 337     }
 338   }
 339
 340   unsigned getSize() const {
 341     return d_size;
 342   }
 343
 344   const Integer& getValue() const {
 345     return d_value;
 346   }
 347
 348   /**
 349    Returns k is the integer is equal to 2^{k-1} and zero
 350    otherwise
 351    @return k if the integer is equal to 2^{k-1} and zero otherwise
 352    */
 353   unsigned isPow2() {
 354     return d_value.isPow2();
 355   }
 356
 357 };/* class BitVector */
 358
 359
 360
 361 inline BitVector::BitVector(const std::string& num, unsigned base) {
 362   CheckArgument(base == 2 || base == 16, base);
 363
 364   if( base == 2 ) {
 365     d_size = num.size();
 366   } else {
 367     d_size = num.size() * 4;
 368   }
 369
 370   d_value = Integer(num, base);
 371 }/* BitVector::BitVector() */
 372
 373
 374 /**
 375  * Hash function for the BitVector constants.
 376  */
 377 struct CVC4_PUBLIC BitVectorHashFunction {
 378   inline size_t operator()(const BitVector& bv) const {
 379     return bv.hash();
 380   }
 381 };/* struct BitVectorHashFunction */
 382
 383 /**
 384  * The structure representing the extraction operation for bit-vectors. The
 385  * operation map bit-vectors to bit-vector of size <code>high - low + 1</code>
 386  * by taking the bits at indices <code>high ... low</code>
 387  */
 388 struct CVC4_PUBLIC BitVectorExtract {
 389   /** The high bit of the range for this extract */
 390   unsigned high;
 391   /** The low bit of the range for this extract */
 392   unsigned low;
 393
 394   BitVectorExtract(unsigned high, unsigned low)
 395   : high(high), low(low) {}
 396
 397   bool operator == (const BitVectorExtract& extract) const {
 398     return high == extract.high && low == extract.low;
 399   }
 400 };/* struct BitVectorExtract */
 401
 402 /**
 403  * Hash function for the BitVectorExtract objects.
 404  */
 405 struct CVC4_PUBLIC BitVectorExtractHashFunction {
 406   size_t operator()(const BitVectorExtract& extract) const {
 407     size_t hash = extract.low;
 408     hash ^= extract.high + 0x9e3779b9 + (hash << 6) + (hash >> 2);
 409     return hash;
 410   }
 411 };/* struct BitVectorExtractHashFunction */
 412
 413
 414 /**
 415  * The structure representing the extraction of one Boolean bit.
 416  */
 417 struct CVC4_PUBLIC BitVectorBitOf {
 418   /** The index of the bit */
 419   unsigned bitIndex;
 420   BitVectorBitOf(unsigned i)
 421     : bitIndex(i) {}
 422
 423   bool operator == (const BitVectorBitOf& other) const {
 424     return bitIndex == other.bitIndex;
 425   }
 426 };/* struct BitVectorBitOf */
 427
 428 /**
 429  * Hash function for the BitVectorBitOf objects.
 430  */
 431 struct CVC4_PUBLIC BitVectorBitOfHashFunction {
 432   size_t operator()(const BitVectorBitOf& b) const {
 433     return b.bitIndex;
 434   }
 435 };/* struct BitVectorBitOfHashFunction */
 436
 437
 438
 439 struct CVC4_PUBLIC BitVectorSize {
 440   unsigned size;
 441   BitVectorSize(unsigned size)
 442   : size(size) {}
 443   operator unsigned () const { return size; }
 444 };/* struct BitVectorSize */
 445
 446 struct CVC4_PUBLIC BitVectorRepeat {
 447   unsigned repeatAmount;
 448   BitVectorRepeat(unsigned repeatAmount)
 449   : repeatAmount(repeatAmount) {}
 450   operator unsigned () const { return repeatAmount; }
 451 };/* struct BitVectorRepeat */
 452
 453 struct CVC4_PUBLIC BitVectorZeroExtend {
 454   unsigned zeroExtendAmount;
 455   BitVectorZeroExtend(unsigned zeroExtendAmount)
 456   : zeroExtendAmount(zeroExtendAmount) {}
 457   operator unsigned () const { return zeroExtendAmount; }
 458 };/* struct BitVectorZeroExtend */
 459
 460 struct CVC4_PUBLIC BitVectorSignExtend {
 461   unsigned signExtendAmount;
 462   BitVectorSignExtend(unsigned signExtendAmount)
 463   : signExtendAmount(signExtendAmount) {}
 464   operator unsigned () const { return signExtendAmount; }
 465 };/* struct BitVectorSignExtend */
 466
 467 struct CVC4_PUBLIC BitVectorRotateLeft {
 468   unsigned rotateLeftAmount;
 469   BitVectorRotateLeft(unsigned rotateLeftAmount)
 470   : rotateLeftAmount(rotateLeftAmount) {}
 471   operator unsigned () const { return rotateLeftAmount; }
 472 };/* struct BitVectorRotateLeft */
 473
 474 struct CVC4_PUBLIC BitVectorRotateRight {
 475   unsigned rotateRightAmount;
 476   BitVectorRotateRight(unsigned rotateRightAmount)
 477   : rotateRightAmount(rotateRightAmount) {}
 478   operator unsigned () const { return rotateRightAmount; }
 479 };/* struct BitVectorRotateRight */
 480
 481 template <typename T>
 482 struct CVC4_PUBLIC UnsignedHashFunction {
 483   inline size_t operator()(const T& x) const {
 484     return (size_t)x;
 485   }
 486 };/* struct UnsignedHashFunction */
 487
 488 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) CVC4_PUBLIC;
 489 inline std::ostream& operator <<(std::ostream& os, const BitVector& bv) {
 490   return os << bv.toString();
 491 }
 492
 493 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) CVC4_PUBLIC;
 494 inline std::ostream& operator <<(std::ostream& os, const BitVectorExtract& bv) {
 495   return os << "[" << bv.high << ":" << bv.low << "]";
 496 }
 497
 498 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) CVC4_PUBLIC;
 499 inline std::ostream& operator <<(std::ostream& os, const BitVectorBitOf& bv) {
 500   return os << "[" << bv.bitIndex << "]";
 501 }
 502
 503 }/* CVC4 namespace */
 504
 505 #endif /* __CVC4__BITVECTOR_H */