bigblock.C

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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "stdtypes.h"
#include "blockpool.h"

/*===============================<o>=====================================

Copyright 1996, 1997, 2004 Ian Kaplan, Bear Products International,
www.bearcave.com.

All Rights Reserved

You may use this software in software components for which you do
not collect money (e.g., non-commercial software).  All commercial
use is reserved.

===============================<o>=====================================*/


#ifdef _WIN32

#include <windows.h>  // for VirtualAlloc and GetSysInfo

#else

#define _UNIX_
extern "C" int getpagesize(void);

#endif



void big_block_alloc::alloc_error(void)
{
  printf("big_block_alloc: memory allocation error\n");
  exit( 1 );
} /* big_block_alloc::alloc_error */



void *big_block_alloc::MemoryAlloc( unsigned int num_bytes )
{
  void *mem;

  assert( num_bytes >= alloc_gran );  
  assert( num_bytes % page_size == 0 );  // should be an integral number of pages

#ifdef _UNIX_
  mem = (void *)malloc( num_bytes );
  if (mem != NULL) { // zero out the memory
    memset(mem, 0, num_bytes);
  }

#else

  // Call the Win32 virtual memory allocater.  Virtual blocks are always
  // zeroed out (see Microsoft documentation on VirtualAlloc).
  mem = VirtualAlloc(NULL, num_bytes, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE );
#endif

  if (mem == NULL)
    alloc_error();

  return mem;
} // big_block_alloc::MemoryAlloc



void big_block_alloc::MemoryFree( void *address )
{

#ifdef _UNIX_

  free( address );

#else

  if (! VirtualFree(address, 0, MEM_RELEASE))
    alloc_error();

#endif

} // big_block_alloc::MemoryFree



void big_block_alloc::GetSysInfo(void)
{

#ifdef _UNIX_
  const int page_multiple = 4;

  page_size = getpagesize();
  // on HP-UX 9.0 use page_size = (unsigned int)sysconf( _SC_PAGE_SIZE );
  alloc_gran = page_size * page_multiple;

#else
  
  SYSTEM_INFO sys_info;  // system info structure, defined in windows.h

  GetSystemInfo( &sys_info );
  page_size = sys_info.dwPageSize;
  alloc_gran = sys_info.dwAllocationGranularity;

#endif
  assert( page_size != 0 );
  assert( alloc_gran != 0 );
} // big_block_alloc::GetSysInfo

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