mempager.cpp

贡献一份commoncpp2,有兴趣的可以研究一下

// Copyright (C) 1999-2005 Open Source Telecom Corporation.
//  
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software 
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
// 
// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however    
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.    
//
// This exception applies only to the code released under the name GNU
// Common C++.  If you copy code from other releases into a copy of GNU
// Common C++, as the General Public License permits, the exception does
// not apply to the code that you add in this way.  To avoid misleading
// anyone as to the status of such modified files, you must delete
// this exception notice from them.
//
// If you write modifications of your own for GNU Common C++, it is your choice
// whether to permit this exception to apply to your modifications.
// If you do not wish that, delete this exception notice.
//

#include <cc++/config.h>
#include <cc++/export.h>
#include <cc++/slog.h>
#include <cc++/thread.h>
#include <cc++/misc.h>
#include "private.h"

#ifdef	CCXX_NAMESPACES
namespace ost {
using std::endl;
#endif

const static size_t palign = __BYTE_ALIGNMENT;

#if defined(HAVE_POSIX_MEMALIGN) && __BYTE_ALIGNMENT < 2
#undef	HAVE_POSIX_MEMALIGN
#endif

#ifdef	HAVE_POSIX_MEMALIGN
static volatile size_t malign = 0;
#endif

MemPager::MemPager(size_t pg)
{
	pagesize = ((pg + sizeof(void *) - 1) / sizeof(void *)) * sizeof(void *);
	pages = 1;

#ifdef	COMMON_MEMORY_AUDIT
	slog(Slog::levelDebug) << "MemPager: creating pool, id=" << this << endl;
	slog(Slog::levelDebug) << "MemPager: alloc, id="
		<< this << " page=" << page << endl;
#endif
#if defined(HAVE_POSIX_MEMALIGN)
	unsigned p2 = 2;
	if(!malign)
	{
		while(p2 < sizeof(void *))
			p2 *= 2;
		while(((p2 / sizeof(void *)) * sizeof(void *)) != p2)
			p2 *= 2;
		malign = p2;
	}
	posix_memalign((void **)&page, malign, pagesize);
#else
	page = (struct _page *)::new void *[pagesize / sizeof(void *)];
#endif
        page->next = NULL;
        page->used = sizeof(struct _page);
}

MemPager::~MemPager()
{
	struct _page *root = page;

	while(root)
	{
		page = page->next;
#ifdef	COMMON_MEMORY_AUDIT
		slog(Slog::levelDebug) << "MemPager: delete, id="
			<< this << " page=" << root << endl;
#endif
#ifdef	HAVE_POSIX_MEMALIGN
		::free(root);
#else
		delete[] root;
#endif
		root = page;
	}
#ifdef	COMMON_MEMORY_AUDIT
	slog(Slog::levelDebug) << "Mempager: destroy pool, id=" << this << endl;
#endif
}

void MemPager::purge(void)
{
	struct _page *root = page;

	while(root->next)
	{
		page = root->next;
#ifdef	COMMON_MEMORY_AUDIT
		slog(Slog::levelDebug) << "Mempager: delete, id="
			<< this << " page=" << root << endl;
#endif
#ifdef	HAVE_POSIX_MEMALIGN
		::free(root);
#else
		delete[] root;
#endif
		--pages;
		root = page;
	}
	page->used = sizeof(struct _page);
}
	

void *MemPager::alloc(size_t size)
{
	char *ptr;
	struct _page *npage;

#if __BYTE_ALIGNMENT > 1
	size_t align = size % palign;
	if (align) 
		size += palign - align;
#endif

	if(page->used + size > pagesize)
	{
#if defined(HAVE_POSIX_MEMALIGN)
		posix_memalign((void **)&npage, malign, pagesize);
#else
		npage = (struct _page *) ::new void *[pagesize / sizeof(void *)];
#endif

#ifdef	COMMON_MEMORY_AUDIT
		slog(Slog::levelDebug) << "MemPager: alloc, id="
			<< this << " page=" << npage << endl;
#endif
		npage->next = page;
		npage->used = sizeof(struct _page);
		page = npage;
		++pages;
	}
	ptr = (char *)page;
	ptr += page->used;
	page->used += size;
	return (void *)ptr; 
}

void *MemPager::first(size_t size)
{
	struct _page *npage = page;
	char *ptr;

#if	__BYTE_ALIGNMENT > 1
	size_t align = size % palign;
		
	if (align) 
		size += palign - align;
#endif

	while(npage)
	{
		if(npage->used + size <= pagesize)
			break;

		npage = npage->next;
	}
	if(!npage)
		return alloc(size);

	ptr = (char *)npage;
	ptr += npage->used;
	npage->used += size;
	return (void *)ptr;
}

char *MemPager::alloc(const char *str)
{
	size_t len = strlen(str) + 1;
	char *cp = (char *)alloc(len);
	return setString(cp, len, str);
}

char *MemPager::first(char *str)
{
	size_t len = strlen(str) + 1;
	char *cp = (char *)first(len);
	return setString(cp, len, str);
}

StackPager::StackPager(size_t pg) :
MemPager(pg)
{
	stack = NULL;
}

void StackPager::purge(void)
{
	MemPager::purge();
	stack = NULL;
}

void *StackPager::pull(void)
{
	frame_t *object = stack;

	if(!stack)
	{
		purge();
		return NULL;
	}

	stack = object->next;
	return object->data;	
}

void *StackPager::push(const void* object, size_t len)
{
	frame_t *frame = (frame_t *)alloc(len + sizeof(frame_t) - 1);

	if(!frame)
		return NULL;
	
	frame->next = stack;
	stack = frame;
	memcpy(frame->data, object, len);
	return (void *)frame->data;
}

void *StackPager::push(const char *string)
{
	return push(string, strlen(string) + 1);
}

SharedMemPager::SharedMemPager(size_t pg, const char *name) :
MemPager(pg), Mutex(name)
{}

void SharedMemPager::purge(void)
{
	enterMutex();
	MemPager::purge();
	leaveMutex();
}

void *SharedMemPager::first(size_t size)
{
	void *mem;

	enterMutex();
	mem = MemPager::first(size);
	leaveMutex();
	return mem;
}

void *SharedMemPager::alloc(size_t size)
{
	void *mem;

	enterMutex();
	mem = MemPager::alloc(size);
	leaveMutex();
	return mem;
}

#ifdef	CCXX_NAMESPACES
}
#endif

/** EMACS **
 * Local variables:
 * mode: c++
 * c-basic-offset: 8
 * End:
 */