Formatting currency in Drupal Commerce

A project I've been involved in uses Drupal Commerce (DC) to manage currency and products.  Here's how to format "normal" values to be DC friendly.  Reason for doing so?  DC stores amount fields as INTEGER.  For instance, an amount of USD99 is stored as 9900 in the table.

There are several functions which you need to make this happen.

• commerce_default_currency - Obtains default currency for the site (http://api.drupalcommerce.org/api/Drupal%20Commerce/sites%21all%21modules%21commerce%21commerce.module/function/commerce_default_currency/DC).  This is one of the required parameters which is to be passed to conversion function.

• commerce_currency_decimal_to_amount - Function to convert price amount to integer amount for DB storage (http://api.drupalcommerce.org/api/Drupal%20Commerce/sites%21all%21modules%21commerce%21commerce.module/function/commerce_currency_decimal_to_amount/DC).  Using this function is straight forward.  Assuming we want to store the value of 300 in the DB, we simply call it using the following params: 

commerce_currency_decimal_to_amount(300, commerce_default_currency());

• commerce_currency_format - Formats currency value from DB for display on page (http://api.drupalcommerce.org/api/Drupal%20Commerce/sites%21all%21modules%21commerce%21commerce.module/function/commerce_currency_format/DC).  This does the opposite of what the previous function does.  Once we obtain the DB value, we call this function to get the displayable value e.g. USD300.00