Pool_std.c
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/*ident "@(#) @(#)Pool_std.c 1.1.1.2" */
/******************************************************************************
*
* C++ Standard Library
*
* Copyright (c) 1996 Lucent Technologies. All Rights Reserved.
*
* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF Lucent Technologies.
* The copyright notice above does not evidence any actual or
* intended publication of such source code.
*
******************************************************************************/
#include <Pool_std.h>
#include <memory.h>
#include <assert.h>
#ifdef NAMESPACES_LUCENT
namespace std {
#endif
static const int minblocksz = 1000;
//static const int maxblocksz = 10000;
// most stringent alignment, in chars
// must be a power of 2 for this code to work
static const int round = 8;
// offset in chars of the data part of a block
static const int blockoff = (sizeof(Block_header_std_LUCENT)+round-1) & (size_t)-round;
// rounds up n to the nearest multiple of round, except
// for 0, which gets rounded up to round
static size_t
roundup(size_t n)
{
return ((n + (n == 0) + round - 1) & (size_t)-round);
}
Block_pool_std_LUCENT::Block_pool_std_LUCENT (size_t n) : cnt(0), sz(n), head(0)
{
}
Block_pool_std_LUCENT::~Block_pool_std_LUCENT()
{
free();
}
void
Block_pool_std_LUCENT::free()
{
while (head) {
Block_header_std_LUCENT* b = head;
head = head->next;
delete (char*) b;
--cnt;
}
assert(cnt == 0);
cnt = 0;
}
char*
Block_pool_std_LUCENT::expand()
{
Block_header_std_LUCENT* b = (Block_header_std_LUCENT*) new char[size()+blockoff];
b->next = head;
head = b;
++cnt;
return ((char*) b) + blockoff;
}
// largest multiple of q that is <= p
static size_t
floor(size_t p, size_t q)
{
return p - p % (q + (q==0));
}
// smallest multiple of q that is >= p
static size_t
ceil(size_t p, size_t q)
{
return floor (p + q - 1, q);
}
Pool_std::Pool_std(size_t n): Block_pool_std_LUCENT(ceil(minblocksz, (elsize = roundup(n))))
{
count = Block_pool_std_LUCENT::size()/elsize;
head = 0;
}
void
Pool_std::grow()
{
register char* p = expand();
register int n = count;
while (--n >= 0) {
register Pool_std_element_header* ph = (Pool_std_element_header*) p;
ph->next = head;
head = ph;
p += elsize;
}
}
#ifdef NAMESPACES_LUCENT
}
#endif