Top 10 Reasons Why CSS is Better than HTML Tables

It has long been debated that the use of style sheet languages such as CSS is said to be much more efficient than the use of ordinary HTML tables. Ever since the growth of the world wide web, professionals of the industry have sought ways on how to improve the presentation of their websites both efficiently and effectively. Style sheet languages such as CSS have perfected this need and became the universal language for designers and developers alike. The question is, what are the reasons why CSS is much more useful than the use of HTML tables?
Several advantages has been cited on the use of CSS in web design. Some of those advantages are as follows:

• Faster loading of pages
• Efficient and easy
• Consistency
• SEO friendly
• Accessibility
• Maintainability
• Usability
• Sophisticated layouts and designs
• Bandwidth efficient

Faster Loading of Pages One common problem of using tables for web layout is the slow loading process. This is usually caused by using too much markup tags in one HTML file such as “td align“, “td width“, “bgcolor“, “width“, “height“, “br“, “font face“, “font color“, “cellpadding“, “cellspacing“, “border“, etc along with the content of the HTML. CSS makes up for this by separating the content of the web page which is text and images into the HTML file and the visual presentation such as the web design, positioning, and text sizes into a CSS file. In a CSS-based layout, Table tags or markups are replaced by using its own language such as the popular “div“. This replacements includes:

• Instead of the usual table tags such as td align or td width, CSS have replaced this by using “divs“.
• Removed all layout editing markups such as height, width, cellpadding, cellspacing, border, bgcolor, font tags from the HTML. All layouts are found in the CSS file.
• header tags such as h1 or h2 are used for font tags headings.
• Breakline tags (br) is not used.

Because CSS have cut the use of too much markups, websites can load a lot faster than using tables which is good when attracting visitors to a website. Visit an online Web design Philippines site to learn more about CSS and its use in web design.
Efficient and Easy As mentioned above, by using CSS, the layout of the HTML is separated from the content thus allowing a quicker, efficient, and easier redesign. Tables would require more time as the HTML content and layout tags are in the same file. By simply editing the CSS file, designers could easily rearrange the size or the color of an element found in a website.
Consistency In relation with the above statements, web designers can easily redesign the whole website by just editing the CSS file. Unlike the use of table in which a designer would have to open every HTML file just to edit a simple element found in every page such as a header, CSS can offer an easy way to edit it all in one CSS file. All it takes is opening the CSS file, edit the elements found in the header (such as width, height, etc), and re-upload it.
SEO Friendly There are several reasons to this. This reasons are:

• Because CSS is much faster to load than tables, search engine spiders could easily crawl through the website.
• Because CSS doesn’t require too much markup which makes it easier for search engine spiders to crawl the website.
• The use of header tags such as h1, h2, or h3 makes it easier for the search engine spiders to determine the information in a website.
• The use of Javascripts for visual effects are replaced by CSS’ own effect engine which makes it more SEO friendly.

Accessibility

Because of the Internet’s rapid growth, disability discrimination legislation, and the increasing use of mobile phones and PDAs, it is necessary for Web content to be made accessible to users operating a wide variety of devices. Tableless Web design considerably improves Web accessibility in this respect. Screen readers and braille devices have fewer problems with tableless designs because they follow a logical structure.

As a result of the separation of design (CSS) and structure (HTML), it is also possible to provide different layouts for different devices, e.g. handhelds, mobile phones, etc. It is also possible to specify a different style sheet for print, e.g. to hide or modify the appearance of advertisements or navigation elements that are irrelevant and a nuisance in the printable version of the page. For more web design and development solutions, then visit an online Web design Philippines site.

Maintainability Under table-based layout, the layout is part of the HTML itself. As such, without the aid of template-based visual editors such as HTML editors, changing the positional layout of elements on a whole site may require a great deal of effort, depending on the amount of repetitive changes required. Even employing sed or similar global find-and-replace utilities cannot alleviate the problem entirely.

By use of CSS, virtually all of the layout information resides in one place. Because the layout information is centralized, these changes can be made quickly and globally by default. The HTML files themselves do not, usually, need to be adjusted when making layout changes. If they do, it is usually to add class-tags to specific markup elements or to change the grouping of various sections with respect to one another.
Usability By combining CSS with the functionality of a Content Management System, a considerable amount of flexibility can be programmed into content submission forms. This allows a contributor, who may not be familiar or able to understand or edit CSS or HTML code to select the layout of an article or other page they are submitting on-the-fly, in the same form.

Sophisticated Layouts and Designs Unlike the use of tables, CSS offers freedom in designing. Because of the rigid, inflexible, and grid based form of tables, designers cannot utilize their potential in designing. CSS offers absolute positioning of elements paired with the z-index property allows CSS-based designs to position elements on top of one another (like layers in Photoshop), allowing for more unique, complex, and beautiful layouts. Bandwidth Efficient A stylesheet will usually be stored in the browser cache, and can therefore be used on multiple pages without being reloaded, increasing download speeds and reducing data transfer over a network. Visit a Web design Philippines site to get the solution you needed with your website.Visit http://www.myoptimind.com for more info.

About the Author

Margarette Mcbride is a copywriter of Optimind Web Design and SEO, a web design and seo company in the Philippines. Optimind specializes in building and promoting websites that are designed for conversion..

Technorati Tags: css, design, html, html table border width thin, table border width, table border width css, table border width html, table border width style, tables, webdesign

Tags: css, design, html, html table border width thin, table border width, table border width css, table border width html, table border width style, tables, webdesign

Information On Sea Freight Shipping When Moving Abroad

Moving to another country can be a hassle for everyone. There are so many different things to think about. One of the most important things to think about is how you are going to move all of your possessions to your new location.

The answer: by overseas freight.

There are many different options for you to choose from when deciding to ship your cargo to another country. We discuss these options below.

Most services will offer you a pick up and drop off scheme where the company will collect your possessions, pack them accordingly (so that fragile items do not break etc), transport them to the cargo ship which will then transport them to their destination.

At the destination the same company (if they have a depot / office) or an affiliate company will collect the possessions and transport them to their new home.

When transporting cargo you need to take into account the size and the weight of everything to be transported as there are different types of containers that can be used to transport the items.

Barrels/drums are used for small items that are less likely to break and easy to pack into smaller spaces. These are usually the cheapest way when transporting items. A lot of people tend to use this way when they want to ship items to their families overseas without having to actually take the items there themselves.

Small crates are the next way of shipping items overseas. These are usually used again for smaller items but are a bit more fragile and will either need the extra space or extra protection when being transported. These can be used for items such as small beside Lamps, DVD players or small TVs, vacuum cleaners, computers, coffee tables, etc, etc.

Larger crates are used for large items that need a lot of space or needs to be in a fixed position for transport because of it being fragile. Items that could be stored in a large crate could be from bigger televisions, small desks or tables, chairs, stools, or floor lamps to lawnmowers, ladders, gym equipment and large kitchen appliances.

Containers are the biggest thing you can choose when shipping your possessions abroad. Containers are more expensive but they are worth it when you need to ship a lot of items. Containers do come in different lengths but the height is more or less the same. Containers can be used to house things from cars to king size beds and can fit most things that you own in them.

Companies usually charge for the transportation of your possessions by calculating the weight of what is being transported. The cost usually covers everything from labour, transportation to and from the ship and includes the shipping itself, to the hire of the crate or container itself and fuel costs.

We feel that shipping overseas is the best and cheapest way of moving your possessions from where you live to your new home.

About the Author

Global Shipping & Trading Ltd.

http://www.globalshippingandtrading.com/

TMS Furniture 40096BLK Nook Dining Table, Black $114.06 Color:Black Nook Table Product weight: 30lbs Made in China Care Instructions: Wipe with mild furniture cleanser…

Winsome Wood 94215 Night Stand Accent End Table, Antique Walnut $57.96 Finish/Color :Antique Walnut Night Stand / Accent Table Features simple design and plenty of storage. Includes one drawer and cabinet. Satin Nickle knob. Assembly required….

South Shore 3127-080 Cosmos Twin Mates Kids Bed, Black Onyx $175.22 Finish:Black Onyx/Charcoal, Size:Twin The Cosmos Twin Mate’s Bed provides a distinctly modern edge. Brushed nickel handles complement the items style. The design is in-line with one of the most sought-after looks, and the colours have been chosen to reflect today’s hottest trends. Three practical drawers Metal handles with a silver finish Box spring not required Smart glide drawer slides with…

Halogen 35 Watt 12 Volt JC Type G6.35 Bulb $3.00 Dimension: N/A Finish: Clear Material: Glass Halogen 35Watt 12Volt JC Type G6.35 Bulb 35Watt Incandescent. JC Type Bulb Bi-Pin (G6.35). …

13Watt 120Volt Single U Tube Compact Fluorescent Bulb $13.69 Dimension: 7.5″L Finish: Warm White Material: Glass 13Watt 120Volt Single U Tube Compact Fluorescent Bulb 9W/3000K Incandescent. PL Type Bulb (Plug-In) Bi-Pin Base..  …

Technorati Tags: design, floor lamps crate and barrel, furniture, home, lamp, lamps, lamps crate and barrel, table lamps crate and barrel

Tags: design, floor lamps crate and barrel, furniture, home, lamp, lamps, lamps crate and barrel, table lamps crate and barrel

Technorati Tags: decorative table lamps design, design, furniture, home, lighting, shopping

Tags: decorative table lamps design, design, furniture, home, lighting, shopping

Beautiful, Bright And Breezy Interior Design Ideas

Beautiful, bright and breezy rooms in which to relax and enjoy your favourite hobby or pass time are something we should all try to emulate! All very well if you have a spare room, if not a quiet corner of a living or dining room would be fine!

Those with a basement or attic could also utilise the space as long there is sufficient light and warmth. Major renovations can cost the earth, however with a little ingenuity a small space can be transform into a haven in which to relax and unwind.

To achieve a simple yet stunning look on a budget opt for stripped floor boards. If you are fed up with natural wood looks or if your floor boards are not in very good condition you could always paint them! Paint manufactures have developed paint which is designed to take the tough treatment floors can get or for a cheap alternative simply use an emulsion and repaint it when it begins to look tatty!

Choose a bright colour to inspire your hobby or pass times. Nautical themes are great for bringing a sense of fun and memories of the sea, holidays and sunny days. If your hobby is more sedate or you just want a space to relax with a book opt for neutral or pastel tones to create a sense of serenity.

Add simply and unfussy window dressings which allow masses of natural light to flood into the room. It is surprising just how much natural light there is even on overcast days! Keep to light weight curtains which offer a light and airy ambience to the room.

Select furniture which is comfortable and practical! One of the latest interior design trends is the ‘shabby chic’ look which enables you to have an a miss mash of odd pieces of furniture within the same room. Try and keep to only two colours for walls, ceilings and floors as this will enable you to inject colour by using natural products such as vases of seasonal flowers or brightly coloured cushions and throws.

Create wonderful lighting effects during the evenings with a collection of small and large Table Lamps. One key factor is to keep clutter to a minimum otherwise your dream space will end up looking like a ‘tip’ and whilst ‘shabby chic’ enables you to have old and new sitting side by side and look stunning, it does not give the go-ahead for mess!

The great thing about this style of room design is that it can be achieved on a very small budget. Scour junk shops, visit boots fairs and garage sales, take heed of the old saying ‘one man’s junk is another man’s treasure’!

If you need to invest in something new it should probably be a lamp as you need to be sure that it is safe and works!

Beautiful mirror lamps are a great way to achieve some wonderful diffused lighting effects. Opt for modern styles which have large white shades if you need plenty of good light to work by. Alternatively use small and delicate lamps for relaxation areas.

About the Author

Terrys Fabrics offer a wide range of curtains, fabrics and
Mirror Lamps

Technorati Tags: cheap modern table lamps, design, furniture, home, modern, shopping

Tags: cheap modern table lamps, design, furniture, home, modern, shopping

Tips for Safety of Kids

What should we do?

——————

1, Always keep the baby neat and clean.

2, Cut the nails properly with utmost care.

3, Wet nappy should be removed and parts should be cleaned with soap.

4, Take care of the genitals because fungal infection is common in that area. Parts should be kept dry.

5,Care of the scalp is very important.Fungal infections, dermatitis ect can be prevented by proper cleaning.

6,Tight dress can cause irritation, hence dress should be loose and should allow entry of air.

7,Room should have sufficient light and ventilation.It should be free from dust and insects.

8,Seperate bed preferably water proof is needed for kids .It should be arranged near mother’s bed.

9, Always keep some music making toys near the baby.

10, While carrying the baby support the head with hand.Since the neck muscles are weak sudden fall of head can be dangerous.

11, Mothers milk is the best nutrition for the baby,it also gives emotional attachment.Breast milk should be given as per the babies need preferably in mother sitting position.Proper cleaning of nipple is also necessary.Mother should take good nutritious diet throughout lactating period.

12, If there is some contraindication for breast feeding cows milk can be given.Feeding bottle should be cleaned with warm water and should be kept dry till next use.

13, Cows milk should be boiled and cooled.Some diseases like bovine tuberculosis,brucellosis ect spread through raw milk.

14, Some children are allergic to some substances like food,milk,dress,cosmetics ect.. Try to find out the material causing allergy and avoid such things.

15, Mosquito nets should be used regularly.Diseases like malaria,dengue ,filariasis,yellow fever and ect spread through mosquito bites. Mosquito bite can also produce skin eruptions with some allergic reactions.It also disturbes sound sleep.

16, A calm atmosphere should be maintained for a good sleep.Compared to adults infants need more sleep.It is said that growth hormone secretion is activated during sleep.

17, Growth developement,behavioral developement,motor developement,personal social developement,language developement ect should be noted down in relation to age. However parents need not be over anxious because slight variations are seen from individual to individual.

18,Assessment of growth by measuring height and weight is necessary.

19, In the early months of life infant may defecate after every feed.Proper toilet training should be given when the infant grows.The infant can be placed on the toilet seat by the age of ten months.

20, The toilet seat (potty seat) should be cleaned with antiseptic liquid before and after use.It should not be shared by other children.

21, If the baby shows some signs of distress like excessive crying,convulsions,fever with rigor,stiffness of neck,frequent vomiting and diarrhoea,bluish discolouration of the body,difficult breathing with grunting, ect pay attention and consult your doctor.

22,A first aid box should be kept in the room ,which should contain sterile cotton,dressing materials,antiseptic lotion and ointment and forceps.Seperate book should be maintained to note down the phone numbers of doctors, ambulance,police ect.

23,Child’s medicines should be kept in seperate box.Information regarding dose and mode of administration should be written in a paper and affixed on the box.

24, while driving keep the baby in seperate seat belt.

25, When you are going out with the baby keep an identity card with your phone number and address inside his small pocket.

26, When the infant starts walking always accompany him to prevent a fall and injuries thereby.

27, In emergencies take the first aid measures and take the victim to nearby hospital.

Choking :–The baby may swallow some solid objects and cause obstruction. Immediately make the baby to lie on the abdomen in head low position and press the abdomen backwards and towards the chest. Stroking the upper back is also useful. If no result call a trained person to take the material with the help of forceps.

Accidental poisoning:– Try to takeout the poisonous subatance and induce vomiting (except kerosine & acids). Wash the body with water to reduce absorption through skin.Identify the pioson and take the victim to the hospital.

Burns:–First of all remove the source of heat and put clean cold water.Burned cloaths should not be removed immediately. Cover the wound with sterile cotton and take to nearby hospital.

Wounds :–Clean the wound with clean water and stop the bleeding by compressing,raising the wound above the level of heart or use a tourniquet to compress blood vessels. Then dress the wound with sterile cotton and bandage and consult a doctor.

Drowning in bath tub:–Take the baby immediately and keep in head low position ,press the abdomen gentely or give a mouth to mouth sucking till the air way is clear. Give mouth to mouth breathing and cardiac massage and take the victim to the hospital.

Electric shock:–Stop the source of current. Then observe the victim,if no breathing give mouth to mouth breath along with cardiac massage and take to the hospital.

28, And the last but not the least, give your child maximum care, love and support to make him healthy and happy for ever.

What we should not do?

———————-

1, Never shake the baby, it can cause damage to the brain.

2,Don’t keep any small articles near the baby .

3,Sharp pointed articles like pen, pencil, ect should not be given to kids.

4,Avoid entry of water in to the ear while giving a bath.

5,Food should not be given forcibly when the baby is crying or coughing continuously.

6,Should not overfeed the baby.

7,Articles like mosquito repellents ,moth balls,ink,gum,medicines,ect should be kept away.

8,Avoid tight cloathings.

9,Should not be placed near the edge of the bed.

10,Should not give the baby to strangers and avoid close contact with others.

11,All electrical instruments should be kept away,and bed should not be arranged near electrical sockets and wires.

12,Kitchen is a dangerous place for children.Don’t keep them alone in the kitchen.

13,Water level in the bath tub should be minimum and don’t go for any other works(to attent phone call or calling bell ect) when the baby is in the tub.

14,Avoid smoking inside the house.

15,Should not allow pet animals to be in very close contact with the kids.(anti rabies injections should be given to pets and cut their nails properly)

16,When the child starts walking should not be kept alone on the upstairs and should not allow them to climb the steps.

17,Strong light should be avoided in the room.

18,When you are travelling don’t give the food articles given by co passengers.

19,Baby should not be allowed to crawl on the soil.

20,If you are sick or someone else is sick be away from the kids.

21,Dont take the baby to hospital wards,crowded market places and polluted dusty areas.

22,Table Lamp should not be kept near the kids,this will attract insects at night and cause problems.

23,Others medicine should not be given to the children.

24,Medicine which has crossed the expiery date should not be used.

About the Author

We provide free articles and information. Check us out at Free Articles

Philips 69151/60/48 LUMIWARE Color Changing LED Bottle Cooler, Transparent $180.00 Add a cool factor to any drink with the Philips LUMIWARE Cooler, a presentation bottle cooler featuring white and colored LEDs. The LUMIWARE Cooler casts a beautiful aura of gently glowing light, illuminating bottles with a magical touch. Choose a color and set the brightness to match your decor, occasion, or mood. Chic and versatile, the cooler works perfectly indoors or out. Its charging base me…

South Shore 3272-062 Lily Rose Night Table Kids Nightstand, $77.24 Finish:Romantic Pine This richly finished country night table will definitely bring magic to your daughter’s room. Its unique, ultra-stylish detailing gives this collection on undeniably romantic flair. Onepractical drawer Easily accessible open storage space Ceramic flower handle Decorative kick plate Smart glide drawer slidescomes withstops and built-in dampers 5-Year Warranty…

South Shore Furniture 3268-062 Jumper Night Stand $109.96 Finish:Classic Cherry The Jumper Nightstand will be a welcome presence throughout the various stages of your child’s life. The open cubby and the drawer provide ample bedside storage space. The side panels and mouldings are curved to accentuate the leg effect and the side mouldings are prevalent to create a dimensional look. One practical drawer Easily accessible open storage space Metal handl…

Kids Line Velour Changing Pad Cover, Mosaic Transport $10.99 The Mosaic Transport Nursery Fitted Crib Sheet features accents of boats, airplanes, trucks and cars in shades of brown and blue to compliment the nursery bedding collection….

Zutano Owls Velour Changing Pad Cover $15.99 Zutano Owls Velour Changing Pad CoverBaby will feel at ease during diaper changes while resting on top of this adorable elephant printed velour changing pad cover from Zutano….

Technorati Tags: design, flash, furniture, home, shopping, table lamp kids

Tags: design, flash, furniture, home, shopping, table lamp kids

Technorati Tags: design, desk lamps nz, furniture, home, modern, shopping

Tags: design, desk lamps nz, furniture, home, modern, shopping

Purchase Rawhide Chandelier Lamp Shades For Southwestern Interior Design

Deciding to use rawhide and leather chandelier lamp shades for your wrought iron Lamps is definitely the best way to get that fantastic western design you see in designer homes. Because they are an easy way to incorporate western style that combines well with wooden furniture and southwestern style accessories, many designers are choosing to use them in their home’s decor.

It is also very common to see these kinds of lamp shades used on large lamps in hunting lodges, western homes, and restaurants where a western or rustic design theme is used. You will probably be amazed at how easy it is to incorporate western design into your home by simply placing leather lamp shades on your chandelier lighting fixtures or other small lamps, or on lamps that require a smaller size western style lamp shade.

You will no doubt love the warm glow generated by the natural color of the rawhide and the welcoming ambiance it evokes no matter where you choose to place it. Rawhide chandelier lamp shades are without a doubt the best choice when wishing to design an elegant decorating flare without loosing western design.

A major reason these leather lamp shades are so sought-after for Spanish style chandeliers and other home lighting fixtures is because of the many options to choose from. When decorating with a particular color palette, you have the option of choosing a pig-skin shade in one of many colors to match, or the more rustic style rawhide shade.

It doesn’t matter which style of rawhide or leather chandelier lamp shades you need, you will certainly be happy with the style you can create with these shades. The fact that these chandelier shades are made by hand, gives them a certain uniqueness not found in commercially produced lamp shades.

Since they are each fitted with a special bulb clip, you will find it easy to turn even the smallest Desk Lamp or Table Lamp into a southwestern style lighting fixture. Try suspending a large wrought iron chandelier with leather chandelier lamp shades above an elegant dining table, or hung as the focal point in the front hall of a rustic style cabin.

You will like how it remarkably enhances your decor, bringing a welcoming environment and giving it a touch of rustic flare. It is the natural leather and rawhide that deepens the look of wood furnishings and rustic decor.

If you have been looking for the right lighting accessories to pair with rustic interior design, you will certainly enjoy the country style you can accomplish with leather shades. Because they are so versatile, chandelier shades will look amazing on lighting fixtures you already own, or on decorative metal chandeliers.

Not only do rustic chandelier shades give you the option of altering the style of your decorating, you will also enjoy how convenient it is to purchase them online. Find the perfect shade size for small lamps in several attractive styles and colors. You won’t come across a simpler way to add to the appeal of western home decorating than with the great style of rustic rawhide and leather chandelier lamp shades.

About the Author

Craig Chambers is the director of Mission Del Rey and offers free information online about purchasing rawhide chandelier lamp shades for southwestern style decor. For more information visit http://www.missiondelrey.com

Technorati Tags: design, diy, howto, natural wood table lamps, projects, woodworking

Tags: design, diy, howto, natural wood table lamps, projects, woodworking

Session of low-level optimization of memory usage in the C++ programs with the total exposure

It should be clear that all methods described in this article should be used very carefully and just in the exceptional cases: usually we have to pay for all low-level optimization elements that we used by flexibility, portability, clearness or scalability of the resulted application.

But if you have exactly that specific case and have no way back – than you’re welcome.

Author:
Victor Milokum,
Team Leader of Apriorit, Network Security direction.

Table of Content

1. The optimization of the “Concrete Factories” (variations about Pimpl idiom)
2. The optimization by “Arena”

“In computing, optimization is the process of modifying a system to make some aspect of it work more efficiently or use fewer resources. The system may be a single computer program, a collection of computers or even an entire network such as the Internet.
Although the word “optimization” shares the same root as “optimal,” it is rare for the process of optimization to produce a truly optimal system. Often there is no “one size fits all” design which works well in all cases, so engineers make trade-offs to optimize the attributes of greatest interest.
Donald Knuth made the following statement on optimization: “We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.” An alternative approach is to design first, code from the design and then profile/benchmark the resulting code to see which parts should be optimized.”

(c) wiki

The optimization of the “Concrete Factories”

I think that a lot of you repeatedly met the classic ”Factory” pattern – or “Concrete Factory” in GoF. terminology:

struct IObject
{
virtual ~IObject(){}
virtual void DoIt()=0;
};
class CFactory
{
public:
void CreateSmth(int objType, std::auto_ptr<IObject> * pResult)
{
if (iValue<0)
{
pResult->reset(new CObject1);
}
else
{
pResult->reset(new CObject2);
}
}
};

This pattern is great for avoiding endless if’s and switch’es through over the code, but it has one unpleasant disadvantage. It is concerned with excessive usage of dynamic memory that sometimes affects badly on the C++ program performance. We will try to cure this patter of it – with certain reservations of course.

Let’s follow the factory usage process again:

Action

Sense

std::auto_ptr<IObject> product;

We define some container for the production, the place where created object will be stored.

MySuperFactory.CreateSmth(1, &product);

We create an object in this container by means of the factory.

product->DoIt();

We use the object via the defined interface

mySuperContainer.Add( product );

or pass the container ownership to somebody else.

To optimize the described life cycle of the production we can use the following statements:

• The special form of the new operator – placement new – enables to create objects in the custom “row” buffer. For example:

char buffer[1024];
new(buffer)CObject(a,b,c);

It is very useful taking into account the fact that we can allocate the buffer more effectively than the standard new implementation does. But actually the using of placement new also adds some difficulties to the developer’s life:

• Row buffer should be aligned by the platform-dependant range;
• The destructor of the created object should be implemented manually.
• Stack is the great alternative for the heap. It would be tempting to use buffer on the stack as the container, i.e. to use  
  MyWrapperAroundLocalBuffer<ObjectSize, IObject> product;

  instead of the original

  std::auto_ptr<IObject> product;

  The main problem of the container on the stack creation is that it’s impossible to allocate an object of the custom (unknown while compiling) size in the standard C++.

• But as soon as our factory is the concrete one (and not an abstract) and we know about all of its production types, we certainly will be able to know the maximal size of the object-production on the compilation stage. For example we can use the type lists:

//——————————–
// typelist basics
//——————————–
template<class Head, class Tail>
struct Node
{
};
struct NullNode
{
};

We can develop the recursive compile-time function to calculate the maximal size of the object from the types in the list:

template <class List>
struct GetMaxSize
{
};
template <class Head, class Tail>
struct GetMaxSize<Node<Head, Tail> >
{
static const size_t TailSize = GetMaxSize<Tail>::Result;
static const size_t Result = (TailSize > sizeof(Head) )
? TailSize : sizeof(Head);
};
template <>
struct GetMaxSize<NullNode>
{
static const size_t Result = 0;
};

Then we can create the list of all possible production types for the factory CFactory:

typedef utils::Node<CObject1>,
utils::Node<CObject2>,
utils::NullNode
>
> ObjectList;
static const size_t MaxObjectSize = utils::GetMaxSize<ObjectList>::Result;

As the result now we can be 100% sure that each produced object will be placed in the buffer of MaxObjectSize (if we’ve developed the type list correctly, of course):

char buffer[ MaxObjectSize ];

It can be easily allocated in the stack.

• As far as our container should be able to store the objects of different types we have a right to expect some help from them in the form of the corresponding interface support:

struct IManageable
{
virtual ~IManageable(){}
virtual void DestroyObject(void * pObject)=0;
virtual void CreateAndSwap(void * pObject, int iMaxSize)=0;
virtual void CreateAndCopy(void * pObject, int iMaxSize)=0;
};

I.e. an object that wants to live in our container should be able to:

• • Destroy the objects of its type by the certain address;
  • Use the Create And Swap technology for passing object ownership (optional);
  • Use the Create And Copy technology for object copy creation (optional).

The structure of the container can be represented in the following scheme:

I.e. our container includes row buffer and two pointers to the different virtual bases of the object placed in the row buffer:

• Pointer to IManageable for the management of the object life cycle;
• Pointer to the user interface IObject which methods the factory user, in fact, wants to call.

As far as we don’t want to spend efforts on adding the support of the IManageable interface to the each production class it makes sense to develop the pattern manageable that will do it automatically:

// manageable control flags (iFlags field)
const int allow_std_swap = 1;
const int allow_copy = 2;
const int allow_all = 3;

// class manageable: wrapper, provides binary interface to manage object’s life
template<class ImplType, int iFlags>
class manageable:public IManageable, public ImplType
{
typedef manageable<ImplType, iFlags> ThisType;

virtual void DestroyObject(void * pObject)
{
((ThisType*)pObject)->~ThisType();
}
// CreateAndSwap
template<int iFlags>
void CreateAndSwapImpl(void * /*pObject*/, int /*iMaxSize*/)
{
throw std::runtime_error(“Swap method is not supported”);
}

template<>
void CreateAndSwapImpl<allow_std_swap>(void * pObject, int /*iMaxSize*/)
{
ThisType * pNewObject = new(pObject)ThisType();
pNewObject->swap(*this);
}

virtual void CreateAndSwap(void * pObject, int iMaxSize)
{
if (sizeof(ThisType)>iMaxSize)
throw std::runtime_error(“Object too large: swap method failed”);
CreateAndSwapImpl<iFlags & allow_std_swap>(pObject, iMaxSize);
}

// CreateAndCopy
template<int iFlags>
void CreateAndCopyImpl(void * /*pObject*/, int /*iMaxSize*/)
{
throw std::runtime_error(“Copy method is not supported”);
}
template<>
void CreateAndCopyImpl<allow_copy>(void * pObject, int /*iMaxSize*/)
{
new(pObject)ThisType(*this);
}

virtual void CreateAndCopy(void * pObject, int iMaxSize)
{
if (sizeof(ThisType)>iMaxSize)
throw std::runtime_error(“Object too large: copy method failed”);
CreateAndCopyImpl<iFlags & allow_copy>(pObject, iMaxSize);
}

public:
manageable()
{
}
template<class Type0>
manageable(Type0 param0)
: ImplType(param0)
{
}
};

The pattern is parameterized by object type and flags that define what methods should be supported. For example, if we specify the allow_copy flag then the compiler will require the constructor of coping from the object for the CreateAndCopy method implementation; similarly, if we specify the allow_swap flag then the CreateAndSwap function will be generated – it will be based on the method of the swap object, that we should develop ourselves.
So our optimized factory now looks as following:

class CFastConcreteFactory
{
public:
typedef utils::Node<utils::manageable<CObject1, utils::allow_copy>,
utils::Node<utils::manageable<CObject2, utils::allow_copy>,
utils::NullNode
>
> ObjectList;

static const size_t MaxObjectSize = utils::GetMaxSize<ObjectList>::Result;
typedef utils::CFastObject<MaxObjectSize, IObject> AnyObject;

void CreateSmth(int iValue, AnyObject * pResult)
{
if (iValue<0)
{
pResult->CreateByCopy(utils::manageable<CObject1,
utils::allow_copy>());
}
else
{
pResult->CreateByCopy(utils::manageable<CObject2,
utils::allow_copy>());
}
}
};

And it is as easy to use as the original one:

// usage sample
CFastConcreteFactory factory;
CFastConcreteFactory::AnyObject product;
factory.CreateSmth(-1, &product);
product->DoIt();
// copy sample
CFastConcreteFactory::AnyObject another_product;
product.Copy( &another_product );

But the functioning of our creation will be much faster (see fast_object_sample in the attachments).

All source, examples, performance and unit tests can be found in the lib
MakeItFaster in the attachments. There are also projects for VC++ 7.1 and VC++ 8.0.

See: cmnFastObjects.h, fast_object_sample

The optimization by «Arena»

The second optimization method proposed is much simpler but the scope of its application is a little bit smaller.

Let’s imagine that we have some iterative algorithm that repeats some action N times:

int mega_algorithm(int N)
{
int Count =0;
for(int i =0 ; i<N; ++i)
{
Count += DoSmth1( );
}
return Count;
}

Let’s suppose that two conditions are met:

• Algorithm doesn’t have any side effects;
• We can predict the maximal size of the dynamic memory allocated for an iteration (let’s name it MaxHeapUsage).

In this case we can use the “Arena” pattern for its optimization. The essence of the pattern is rather simple. For its implementation we:

• • replace the standard new/delete with our own ones;
  • register some buffer-arena pBuffer with MaxHeapUsage size before the algorithm starts and set the index pointing on the start of free space FreeIndex to 0;
  • in the new handlers we allocate memory directly in the buffer by moving FreeIndex on the allocation value. Naturally, we return ((char *) pBuffer + oldFreeIndex);
  • set FreeIndex to 0 after each iteration and so dispose all memory that iteration has allocated for its needs;
  • unregister our buffer-arena after algorithm finishes.

It’s very simple and effective. It’s also very dangerous pattern because it’s rather hard to guarantee the first condition fulfillment in the production code. But this pattern is good for calculation concerned tasks (for example in the game development).

When using STL containers the concrete instance of the arena can be referred to the container in such a way that the definition and usage of the container will be almost the same to those of the original one, for example:

typedef utils::arena_custom_map<int,int,
utils::CGrowingArena<1024> >::result Map1_type;
Map1_type map1;

for(int i = 0;i<iNumberOfElements;++i)
{
map1[i] = i+1;
}

In this example all memory for the object map1 is allocated in the extendable buffer CGrowingArena, allocated memory will be disposed in the destructor when destroying the object.

All source, examples, performance and unit tests can be found in the lib MakeItFaster in the attachments. There are also projects for VC++ 7.1 and VC++ 8.0.

See: cmnArena.h/ win32_arena_tests, win32_arena_sample

Download attachments.

About the Author

Technorati Tags: chemistry, design, reference, science, table of elements wiki, webdesign

Tags: chemistry, design, reference, science, table of elements wiki, webdesign

Lamps – And Now, Something Completely Different!

The Antique & Vintage Table Lamp Co specialise in antique table Lamp Lighting with an on-line range of unique, classic, antique and Vintage Lamps and lamp shades.

The “art” of interior design is generally seen as divided between modern contemporary, eclectic, or, classic /  traditional interior design.

Our home interiors are an important part of our lives and can offer a comfortable retreat from the busyness of the world we live in. 

Decorative Lamps, although a source of lighting, offer more than this basic function of providing light.  With this in mind, we have listed an unusual and very decorative, large pair of lamps, technically described as of, circular compressed, fluted form!  This particular style, although used here in a contemporary manner, is in fact, a very traditional and classic design. 

These impressive, red lacquered, mango wood lamps were hand made in Northern Thailand by a young Thai woman whose carving technique was passed down to her from her father. Mango wood is an unusual material and these lamps have been skillfully carved to take full advantage of the qualities of the material.

With an overall height of 25″ / 64cm (including shades) and an impressive 40″ / 102cm in diameter!

Although contemporary, it is sometimes surprising just how a striking pair of “knock-out” lamps like this, can work so well in a wide range of interior styles.

Decorative lighting is available in a wide range of styles and designs and The Antique & Vintage Table Lamp Co offer lamps in porcelain, cinnabar, glass, gilt wood and pottery. With lamps from China, Japan, England and France.

The Antique & Vintage Table Lamp Co specialise in antique Table Lamp Lighting with an on-line range of over 100 unique, antique and vintage lamps on view.

Lamps are shipped ready wired for the U.S, the U.K and Australia.

You are invited to visit their web site at www.antiquelampshop.com

© The Antique & Vintage Table Lamp Co 2009

  
About the Author

Maurice Robertson, principal of The Antique and Vintage Table Lamp Co , has had a lifetime’s association with antique porcelain and pottery,with his commercial experience spaning a period of 40 years,including as a valuer to the Australian Government’s Incentive to the Arts Scheme. His long experience with antique ceramics and glass also includes dealing with leading museums and numerous international private collections. He has extended his ceramics expertise into the quality Table Lamps seen on the company’s site, he is well known to local and international interior designers who have included many of his table lamps in their projects and has also supplied items of national interest to the official Sydney residence of the Australian Prime Minister.

Technorati Tags: design, furniture, home, lamps lighting antiques, lighting, vintage

Tags: design, furniture, home, lamps lighting antiques, lighting, vintage