int rawdv_close(dv_t *dv)
{
close(dv->fd);
mmap_free(dv->mmap_region);
rawdv_free( dv);
return 1;
}
void *
mmap_realloc (void **var, size_t nbytes)
{
MEMORY_BASIC_INFORMATION memInfo, m2;
void *old_ptr;
if (*var == NULL)
return mmap_alloc (var, nbytes);
/* This case happens in init_buffer(). */
if (nbytes == 0)
{
mmap_free (var);
return mmap_alloc (var, nbytes);
}
memset (&memInfo, 0, sizeof (memInfo));
if (VirtualQuery (*var, &memInfo, sizeof (memInfo)) == 0)
DebPrint (("mmap_realloc: VirtualQuery error = %ld\n", GetLastError ()));
/* We need to enlarge the block. */
if (memInfo.RegionSize < nbytes)
{
memset (&m2, 0, sizeof (m2));
if (VirtualQuery ((char *)*var + memInfo.RegionSize, &m2, sizeof(m2)) == 0)
DebPrint (("mmap_realloc: VirtualQuery error = %ld\n",
GetLastError ()));
/* If there is enough room in the current reserved area, then
commit more pages as needed. */
if (m2.State == MEM_RESERVE
&& m2.AllocationBase == memInfo.AllocationBase
&& nbytes <= memInfo.RegionSize + m2.RegionSize)
{
void *p;
p = VirtualAlloc (*var, nbytes, MEM_COMMIT, PAGE_READWRITE);
if (!p /* && GetLastError() != ERROR_NOT_ENOUGH_MEMORY */)
{
DebPrint (("realloc enlarge: VirtualAlloc (%p + %I64x, %I64x) error %ld\n",
*var, (uint64_t)memInfo.RegionSize,
(uint64_t)(nbytes - memInfo.RegionSize),
GetLastError ()));
DebPrint (("next region: %p %p %I64x %x\n", m2.BaseAddress,
m2.AllocationBase, (uint64_t)m2.RegionSize,
m2.AllocationProtect));
}
else
return *var;
}
/* Else we must actually enlarge the block by allocating a new
one and copying previous contents from the old to the new one. */
old_ptr = *var;
if (mmap_alloc (var, nbytes))
{
CopyMemory (*var, old_ptr, memInfo.RegionSize);
mmap_free (&old_ptr);
return *var;
}
else
{
/* We failed to reallocate the buffer. */
*var = old_ptr;
return NULL;
}
}
/* If we are shrinking by more than one page... */
if (memInfo.RegionSize > nbytes + getpagesize())
{
/* If we are shrinking a lot... */
if ((memInfo.RegionSize / 2) > nbytes)
{
/* Let's give some memory back to the system and release
some pages. */
old_ptr = *var;
if (mmap_alloc (var, nbytes))
{
CopyMemory (*var, old_ptr, nbytes);
mmap_free (&old_ptr);
return *var;
}
else
{
/* In case we fail to shrink, try to go on with the old block.
But that means there is a lot of memory pressure.
We could also decommit pages. */
*var = old_ptr;
return *var;
}
}
/* We still can decommit pages. */
if (VirtualFree ((char *)*var + nbytes + get_page_size(),
memInfo.RegionSize - nbytes - get_page_size(),
MEM_DECOMMIT) == 0)
DebPrint (("mmap_realloc: VirtualFree error %ld\n", GetLastError ()));
return *var;
}
/* Not enlarging, not shrinking by more than one page. */
return *var;
}
~page()
{
mmap_free( _data, PageSize );
}