extcss3

extcss3 is a fast PHP7 extension for the handling of CSS3 strings (see W3C Candidate Recommendation). It supports preprocessing, tokenizing and minifying. Furthermore, extcss3 implements an API that can be used to analyse, augment or correct the style sheet while it is being processed.

Library Features

• Written in pure C99.
• Doesn't require any external libraries.
• Implements an intervention API.
• PHP 7 and PHP 7.1 ready.

Minifying Features

• Removes unnecessary whitespace, comments and semicolons.
• Removes invalid or empty declarations and qualified rules.
• Color name transformations (e.g. MediumSpringGreen to #00FA9A).
• Hexadecimal color transformations (e.g. #FF0000 to red).
• Function transformations (e.g. rgb(255, 255, 255) to #FFF).
• Minifying of numeric values (e.g. 005 to 5 or 0.1em to .1em).
• Optional: Removal of vendor-prefixed declarations.

Current Limitations

• The CSS string must be UTF-8 encoded.
• String and URL tokens are returned to the registered callbacks with quotes ("xxx" or 'xxx') as given in the original CSS string.
• The code compiles and runs on Linux systems. Other platforms have not been tested.

PHP Class (CSS3Processor)

public CSS3Processor::__construct(void) : CSS3Processor

• Constructs a new CSS3Processor object.
• Throws exceptions on errors.

public CSS3Processor::setModifier(int $type, callable $callback) : bool

• Registers a callback for the given token $type that will be called during tokenisation. The callback gets an info array of the current token and context.
• The callback should return a string with a (new) value that replaces the given token in the result string. If the return value is not a string, the original value is left unmodified.
• The parameter $type can be set to any of the extcss3 Type Constants listed below that are marked as modifiable.
• Only one modifier callback per token type is possible. Any subsequent call to ::setModifier() replaces previously set callbacks for the same type.
• Returns true on success.
• Throws exceptions on errors.

public CSS3Processor::dump(string $css) : string

• Applies preprocessing and the registered modifiers to $css and returns the resulting string.
• Throws exceptions on errors.

public CSS3Processor::minify(string $css [, array $vendors ]) : string

• Returns the minimized result string considering the registered modifiers and the blacklist of vendor prefixes given in the $vendors array.
• Throws exceptions on errors.

PHP Class Constants

Type Constants

• TYPE_IDENT 1
• TYPE_FUNCTION 2
• TYPE_AT_KEYWORD 3
• TYPE_HASH 4
• TYPE_STRING 5 (modifiable)
• TYPE_BAD_STRING 6 (modifiable)
• TYPE_URL 7 (modifiable)
• TYPE_BAD_URL 8 (modifiable)
• TYPE_DELIM 9
• TYPE_NUMBER 10
• TYPE_PERCENTAGE 11
• TYPE_DIMENSION 12
• TYPE_UNICODE_RANGE 13
• TYPE_INCLUDE_MATCH 14
• TYPE_DASH_MATCH 15
• TYPE_PREFIX_MATCH 16
• TYPE_SUFFIX_MATCH 17
• TYPE_SUBSTR_MATCH 18
• TYPE_COLUMN 19
• TYPE_WS 20
• TYPE_CDO 21
• TYPE_CDC 22
• TYPE_COLON 23
• TYPE_SEMICOLON 24
• TYPE_COMMA 25
• TYPE_BR_RO 26
• TYPE_BR_RC 27
• TYPE_BR_SO 28
• TYPE_BR_SC 29
• TYPE_BR_CO 30
• TYPE_BR_CC 31
• TYPE_COMMENT 32 (modifiable)
• TYPE_EOF 33

Flag Constants

• FLAG_ID 1
• FLAG_UNRESTRICTED 2
• FLAG_INTEGER 3
• FLAG_NUMBER 4
• FLAG_STRING 5
• FLAG_AT_URL_STRING 6

Exception Code Constants

• ERR_MEMORY 1
• ERR_BYTES_CORRUPTION 2
• ERR_NULL_PTR 3
• ERR_INV_PARAM 4

Examples

$css = file_get_contents('style.css');

try {
	$proc = new \CSS3Processor();

	$min = $proc->minify($css, ['-ms', '-moz', '-o']);
} catch (Exception $e) {
	...
}

More examples coming soon...