Term.cpp

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/* Frobby: Software for monomial ideal computations.
   Copyright (C) 2007 Bjarke Hammersholt Roune (www.broune.com)
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see http://www.gnu.org/licenses/.
*/
#include "stdinc.h"
#include "Term.h"
 
#include "TermPredicate.h"
#include <sstream>
#include <vector>
 
const unsigned int PoolCount = 50;
const unsigned int ObjectPoolSize = 1000;
 
Term::Term(const string& str):
  _exponents(0), _varCount(0) {
  istringstream in(str);
 
  vector<Exponent> exponents;
  mpz_class ex;
  while (in >> ex) {
    ASSERT(ex.fits_uint_p());
    exponents.push_back(ex.get_ui());
  }
 
  if (!exponents.empty())
    initialize(&(exponents[0]), exponents.size());
}
 
namespace {
  struct ObjectPool {
    ObjectPool(): objectsStored(0), objects(0) {}
 
    void ensureInit() {
      if (objects == 0)
        objects = new Exponent*[ObjectPoolSize];
    }
 
    bool empty() const {
      return objectsStored == 0;
    }
 
    bool canStoreMore() const {
      return objectsStored < ObjectPoolSize;
    }
 
    Exponent* removeObject() {
      ASSERT(!empty());
      --objectsStored;
      return objects[objectsStored];
    }
 
    void addObject(Exponent* object) {
      ASSERT(canStoreMore());
      ASSERT(objects != 0);
 
      objects[objectsStored] = object;
      ++objectsStored;
    }
 
    ~ObjectPool() {
      if (objects == 0)
        return;
      for (size_t i = 0; i < objectsStored; ++i)
        delete[] objects[i];
      delete[] objects;
    }
 
    unsigned int objectsStored;
    Exponent** objects;
  } pools[PoolCount];
}
 
Exponent* Term::allocate(size_t size) {
  ASSERT(size > 0);
 
  if (size < PoolCount) {
    pools[size].ensureInit();
    if (!pools[size].empty())
      return pools[size].removeObject();
  }
 
  return new Exponent[size];
}
 
void Term::deallocate(Exponent* p, size_t size) {
  if (p == 0)
    return;
 
  ASSERT(size > 0);
 
  if (size < PoolCount && pools[size].canStoreMore())
    pools[size].addObject(p);
  else
    delete[] p;
}
 
void Term::print(FILE* file, const Exponent* e, size_t varCount) {
  ostringstream out;
  print(out, e, varCount);
  fputs(out.str().c_str(), file);
}
 
void Term::print(ostream& out, const Exponent* e, size_t varCount) {
  ASSERT(e != 0 || varCount == 0);
 
  out << '(';
  for (size_t var = 0; var < varCount; ++var) {
    if (var != 0)
      out << ", ";
    out << e[var];
  }
  out << ')';
}
 
bool Term::operator==(const Exponent* term) const {
  return equals(begin(), term, getVarCount());
}