// ===================================================================
// $Id: $
//
// allocgo2.cpp
//
// REPLACEMENT_STRING
//
// Copyright by Vlastimil Havran, 2006 - email to "vhavran AT seznam.cz"
// Initial coding by Vlastimil Havran, 2003

// standard headers
#include <cassert>
#include <iostream>

// GOLEM headers
#include "allocgo2.h"

namespace GtpVisibilityPreprocessor {

using namespace std;

// ************* size-equal item allocator with alligning in the cache ****

CAllocContinuous::CAllocContinuous(int sizeOfEntryV,
				   int numEntriesInBlockV,
				   int maxItemsForAllocation,
				   int allignEntrySizeV,
				   int allignBlockSizeV)
{
  if ((sizeOfEntryV < ((int)sizeof(void*))) || (numEntriesInBlockV < 2)) {
    cerr << "Error: The Spc size-equal allocator initialization wrong.\n";
    abort();
  }
  // input variables
  sizeOfEntry = sizeOfEntryV;
  granularity = numEntriesInBlockV;
  maxItemsAtOnce = maxItemsForAllocation;
  // Increase the allignment to be at least of entry size
  int ta =  allignEntrySizeV;
  while (sizeOfEntryV > allignEntrySizeV) {
    allignEntrySizeV += ta;
  } // while
  // Increase the allignment of the block to be at least the size of one entry
  ta = allignBlockSizeV;
  while (allignEntrySizeV > allignBlockSizeV) {
    allignBlockSizeV += ta;
  } // while

  // The allignment of entry
  allignEntrySize = allignEntrySizeV;

  // The allingment of block
  allignBlockSize = allignBlockSizeV;

  // Compute the memory needed for one block
  memoryForOneBlock = (sizeOfEntry * (granularity + 2*maxItemsAtOnce))/allignEntrySize;
  memoryForOneBlock = (memoryForOneBlock + 1) * allignEntrySize;
  // Now we want to make sure for the big allignment
  memoryForOneBlock /= allignBlockSize;
  memoryForOneBlock = (memoryForOneBlock+2) * allignBlockSize;
  
  // status variables
  initMemBlock = 0;
  mstor = &initMemBlock;
  // Release the memory and prepare the variables
  ReleaseMemory();

#if 0
  cout << "CAllocContinuous: item size " << sz << " alligned to size " << size
	 <<" granularity " << gran << "\n";
  cout << "     BigAlignment=" << bigAllignment << "\n";
#endif
}

void
CAllocContinuous::ReleaseMemory()
{
  // delete all allocated memory blocks
  void *bk = mstor;
  void *p;
  while (bk != &initMemBlock) {
    p = *(void**)bk;
    //cout << "Release " << "  p = " << (void*)bk << endl;
    delete [] (char*)bk;
    bk = p;
  } // while
  remainItems = 0;
  initMemBlock = 0;
  mstor = &initMemBlock;
  bytesAllocated = 0;
  lastEntryInBlockAllocated = 0;
  nextAllocp = 0;
  lastValidAddress = 0;
}

void*
CAllocContinuous::AllocNewBlock()
{
  int allocHere = 0;
  allocHere++;
  
  nextAllocp = new char[memoryForOneBlock]; // append to chain
  if (nextAllocp == NULL) {
    cerr << "Memory exhausted in CAllocContinuous\n";
    abort();
  }
  
#ifdef _DEBUG
  memset((void*)nextAllocp, 0xFF, memoryForOneBlock);
#endif  
  // Compute the last valid address to be used in the current block
  lastValidAddress = (void*)
    (nextAllocp + memoryForOneBlock - 1);
  
  //cout << "ALloc " << allocHere << "  p = " << (void*)nextAllocp << endl;
  
  // Link the block to the chain of block !
  *((void**)nextAllocp) = (void*)mstor; // link the previous chain
  mstor = (void**)nextAllocp; // link the currently allocated block

  // set chain of blocks .. allign the starting address
  nextAllocp = (char*)(allignBlockSize * (((unsigned long)nextAllocp +
                     sizeof(void*) + allignBlockSize - 1) / allignBlockSize));
#ifdef _DEBUG
  if ((unsigned long)mstor > (unsigned long)nextAllocp) {
    cerr << "Allignment of the block is wrong" << endl;
    abort();
  }
#endif
  // Compute Allignment
  unsigned long allignmentTotal = 2 * maxItemsAtOnce * sizeOfEntry;
      
  char *maxAddressInBlock = ((char*)mstor + memoryForOneBlock);
  // We have to put there the place for the last entry
  maxAddressInBlock -= allignmentTotal;

  // The maximum number of single items to be allocated, which then allows
  // also to allocate a last entry by a special routine
  remainItems = (unsigned long)( maxAddressInBlock - ((char*)nextAllocp) );
  remainItems /= sizeOfEntry;
  remainItems -= 2 * maxItemsAtOnce;

#ifdef _DEBUG
  if (remainItems<0) {
    cerr << "CAllocContinuous::Alloc Error\n";
    abort();
  }
#endif

  // Update the statistics, the total number of bytes allocated
  // by the instance of this allocator
  bytesAllocated += memoryForOneBlock;
  //cout << "The Alloc called\n" << flush;

  // We will be left with the last entry to allocate
  lastEntryInBlockAllocated = false;
  
  // Return the address to be allocated as the next one
  return (void*)nextAllocp;
}

// alloc the memory of size "sizeItem*entriesCnt" alligned in the memory
// started in the new block
void*
CAllocContinuous::NewEntryInNewBlock(int entriesCnt)
{
  // We require first to allocate a new block
  AllocNewBlock();
  return New(entriesCnt);
}

void*
CAllocContinuous::New(int entriesCnt)
{
  // void *m;  // <JK> is unreferenced
  assert(entriesCnt > 0);
  assert(entriesCnt <= maxItemsAtOnce);

  if (remainItems < entriesCnt) {
    return (void*)0; // not enough space left
  }

  unsigned long tmp = (unsigned long)nextAllocp;
  if ((tmp % allignEntrySize) == 0) {
    remainItems -= entriesCnt;
    nextAllocp = (char*)(tmp + entriesCnt * sizeOfEntry);
    return (void*)tmp;
  }
  // We have to allign the address to the allignEntrySize
  tmp /= allignEntrySize;
  tmp = (tmp+1) * allignEntrySize;
  remainItems -= (tmp - (unsigned long)nextAllocp) / entriesCnt;
  nextAllocp = (char*)(tmp + entriesCnt * sizeOfEntry);
  assert(nextAllocp < lastValidAddress);
  
  return (void*)tmp;
}

// alloc the memory of size "sizeItem*entriesCnt" alligned in the memory
// it can be in the current block, which is definitely the last one in
// the current block. This should be used only if function New() above
// returns 0.
void*
CAllocContinuous::NewLastEntry(int entriesCnt)
{
  if (!lastEntryInBlockAllocated) {
    // if the last entry in the current block was not yet allocated
    void *tmp = nextAllocp;
#ifdef _DEBUG
    // check if we do not go behind the block
    if ( (unsigned long)tmp + sizeOfEntry * entriesCnt >
	 (unsigned long)lastValidAddress) {
      cerr << "Problem with the allocator, using the memory" << endl;
      abort();
    }    
#endif // _DEBUG
    lastEntryInBlockAllocated = true; // do not allocate again
    return nextAllocp;
  } // if the last entry

  return (void*)0; // the entry was already allocated
}

void
CAllocContinuous::Report()
{
  cout << "Unused entries in the current block = " << remainItems << "\n";
  cout << "Total consumed memory = " << bytesAllocated << "\n";
}


}