Разбор кода

#include<vcl.h>
#pragma hdrstop
#pragma argsused
#include <dos.h>
#include <stdio.h>
#include <windows.h>
#include <conio.h>
#include <winnt.h>
staticintmaxindex;
staticintxfilter(EXCEPTION_POINTERS *xp)
{  intrc;
        EXCEPTION_RECORD *xr = xp->ExceptionRecord;
        CONTEXT *xc = xp->ContextRecord;
printf("Code %ul  ", (unsigned long)xr->ExceptionCode);
switch (xr->ExceptionCode) {
case EXCEPTION_BREAKPOINT:
                // just step over it (1 byte on x86)
                ++xc->Eip;
rc = EXCEPTION_CONTINUE_EXECUTION;
break;
case EXCEPTION_ACCESS_VIOLATION:
rc = EXCEPTION_EXECUTE_HANDLER;
break;
default:
                // give up
rc = EXCEPTION_CONTINUE_SEARCH;
break;
                    };
returnrc;
    }
char *getbuffer()
{SYSTEM_INFO info;
unsigned long a;
GetSystemInfo(&info);
char *rv;
rv=(char *)VirtualAlloc(NULL, maxindex=info.dwPageSize*6,     MEM_RESERVE,PAGE_READWRITE);                                         VirtualProtect (rv,1,PAGE_READONLY,&a);
returnrv;
}
 
voidputbuffer(char *p,int index, char value)
{ int code;
 
try
          {
p[index]=value;
       }
 
__except(code = xfilter(GetExceptionInformation()))
      {
printf("Index %d\n", index);
if (code!=EXCEPTION_EXECUTE_HANDLER)
    {printf("Neisvestmoeiscluchenie\n");
                 //exit(1);
    }
if (index>=maxindex)
{   printf("Vserabotaet, vsestranicizashisheniotzapisi\n");              //exit(2);
sleep ('100');
    }
VirtualAlloc(p+index, 1, MEM_COMMIT, PAGE_READWRITE);
putbuffer(p,index,value);
      }
}
 
voidfreebuffer(char *p)
{
VirtualFree(p,0,MEM_RELEASE);
 }
 
 
void main()
{  char *p=getbuffer();
for (inti=0;i<4000000;i++)   putbuffer(p, i, i&0xFF);
freebuffer(p);
 
printf("Pass #2\n");
  p=getbuffer();
    // now backwards for variety
for (int j=4000000-1;j>=0;j--)   putbuffer(p, j, j&0xFF);
freebuffer(p);
sleep ('100');
  }

static int maxindex;
static int xfilter(EXCEPTION_POINTERS *xp)