前面简单介绍了用C语言实现PHP扩展的步骤，见php扩展开发步骤示例，那个是扩展一个函数，这里讲述一下如何用C扩展PHP类。
准备实现的类如下：
class Rectangle{
private $_width;
private $_height;
public function __construct($width, $height){
$this->_width = $width;
$this->_height = $height;
}
public function clone(){
return new Rectangle($this->_width, $this->_height);
}
public function setWidth($width){
$this->_width = $width;
}
public function setHeight($height){
$this->_height = $height;
}
public function getWidth(){
return $this->_width;
}
public function getHeight(){
return $this->_height;
}
public function getArea(){
return $this->_width * $this->_height;
}
public function getCircle(){
return ($this->_width + $this->_height) * 2;
}
}
实现类扩展的步骤如下：(首先下载PHP源码，这里使用的是php-5.2.8)
1. 建立扩展骨架
cd php-5.2.8/ext
./ext_skel –extname=class_ext
2. 修改编译参数
cd php-5.2.8/ext/class_ext
vi config.m4
去掉
PHP_ARG_ENABLE(class_ext, whether to enable class_ext support,
和
[ –enable-class_ext Enable class_ext support])
两行前面的dnl，修改后为：
dnl Otherwise use enable:
PHP_ARG_ENABLE(class_ext, whether to enable class_ext support,
dnl Make sure that the comment is aligned:
[ –enable-class_ext Enable class_ext support])
3. 编写C代码
cd php-5.2.8/ext/class_ext
vi php_class_ext.h
在 PHP_FUNCTION(confirm_class_ext_compiled); 后面增加申明函数：
PHP_METHOD(Rectangle,__construct);
PHP_METHOD(Rectangle,clone);
PHP_METHOD(Rectangle,setWidth);
PHP_METHOD(Rectangle,setHeight);
PHP_METHOD(Rectangle,getWidth);
PHP_METHOD(Rectangle,getHeight);
PHP_METHOD(Rectangle,getArea);
PHP_METHDO(Rectangle,getCircle);
vi class_ext.c
#申明方法的参数，注册到函数表中
ZEND_BEGIN_ARG_INFO(arg_construct,2)
ZEND_ARG_INFO(0, width)
ZEND_ARG_INFO(0, height)
ZEND_END_ARG_INFO()
ZEND_BEGIN_ARG_INFO(arg_set_width,1)
ZEND_ARG_INFO(0, width)
ZEND_END_ARG_INFO()
ZEND_BEGIN_ARG_INFO(arg_set_height,1)
ZEND_ARG_INFO(0, height)
ZEND_END_ARG_INFO()
const zend_function_entry class_ext_functions[] = {
PHP_FE(confirm_class_ext_compiled, NULL)
PHP_ME(Rectangle, __construct, arg_construct, ZEND_ACC_CTOR|ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, clone, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, setWidth, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, setHeight, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, getWidth, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, getHeight, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, getArea, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Rectangle, getCircle, NULL, ZEND_ACC_PUBLIC)
{NULL, NULL, NULL} /* Must be the last line in class_ext_functions[] */
};
#其中ZEND_ACC_CTOR表示构造函数，ZEND_ACC_PUBLIC表示访问权限为PUBLIC。
#接下来，在模块初始化函数中注册并初始化类
zend_class_entry *Rectangle_ce; //zend内部类结构变量
PHP_MINIT_FUNCTION(class_ext)
{
zend_class_entry Rectangle;
INIT_CLASS_ENTRY(Rectanble, “Rectangle”, class_ext_functions); //第二个参数为类名，第三个参数为类的函数列表
Rectangle_ce = zend_register_internal_class_ex(&Rectangle, NULL, NULL TSRMLS_CC); //注册类
zend_declare_property_null(Rectangle_ce, ZEND_STRL(“_width”), ZEND_ACC_PRIVATE TSRMLS_CC); //初始化类的属性_width
zend_declare_property_null(Rectangle_ce, ZEND_STRL(“_height”), ZEND_ACC_PRIVATE TSRMLS_CC); //初始化类的属性_height
return SUCCESS;
}
#在文件最后增加类的成员函数的具体实现代码
PHP_METHOD(Rectangle, __construct)
{
long width,height;
if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, “ll”, &width, &height) == FAILURE){ //获取构造函数的两个函数参数_width和_height
WRONG_PARAM_COUNT;
}
if( width <= 0 ) {
width = 1; //如果_width为0，则赋默认值1
}
if( height <= 0 ) {
height = 1; //如果_height为0，则赋默认值1
}
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), width TSRMLS_CC); //更新类成员变量_width的值
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), height TSRMLS_CC); //更新类成员变量_height的值
RETURN_TRUE;
}
PHP_METHOD(Rectangle, clone)
{
zval *clone_obj;
zval *width,*height;
MAKE_STD_ZVAL(clone_obj);
object_init_ex(clone_obj, Rectangle_ce); //初始化对象，对象所属的类为Rectangle_ce
width = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), 0 TSRMLS_CC); //获取类成员变量_width的值
height = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), 0 TSRMLS_CC); //获取类成员变量_height的值
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), width TSRMLS_CC); //更新Rectangle_ce类对象clone_obj的属性值_width
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), height TSRMLS_CC); //更新Rectangle_ce类对象clone_obj的属性值_height
RETURN_ZVAL(clone_obj, 1, 0); //返回该对象
}
PHP_METHOD(Rectangle, setWidth()
{
long width;
if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, “l”, &width) == FAILURE){
WRONG_PARAM_COUNT;
}
if( width <= 0 ) {
width = 1;
}
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), width TSRMLS_CC); //更新类成员变量_width的值
RETURN_TRUE;
}
PHP_METHOD(Rectangle, setHeight()
{
long height;
if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, “l”, &height) == FAILURE){
WRONG_PARAM_COUNT;
}
if( height <= 0 ) {
height = 1;
}
zend_update_property_long(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), height TSRMLS_CC); //更新类成员变量_height的值
RETURN_TRUE;
}
PHP_METHOD(Rectangle, getWidth)
{
zval *zWidth;
long width;
zWidth = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), 0 TSRMLS_CC); //获取类成员变量_width的值
width = Z_LVAL_P(zWidth);
RETURN_LONG(width);
}
PHP_METHOD(Rectangle, getHeight)
{
zval *zHeight;
long height;
zHeight = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), 0 TSRMLS_CC);
height = Z_LVAL_P(zHeight);
RETURN_LONG(height);
}
PHP_METHOD(Rectangle, getArea)
{
zval *zWidth,*zHeight;
long width,height,area;
zWidth = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), 0 TSRMLS_CC);
zHeight = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), 0 TSRMLS_CC);
width = Z_LVAL_P(zWidth);
height = Z_LVAL_P(zHeight);
area = width * height;
RETURN_LONG(area);
}
PHP_METHOD(Rectangle, getCircle)
{
zval *zWidth,*zHeight;
long width,height,circle;
zWidth = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_width”), 0 TSRMLS_CC);
zHeight = zend_read_property(Z_OBJCE_P(getThis()), getThis(), ZEND_STRL(“_height”), 0 TSRMLS_CC);
width = Z_LVAL_P(zWidth);
height = Z_LVAL_P(zHeight);
circle = (width + height) * 2;
RETURN_LONG(circle);
}
4. 编译代码
cd php-5.2.8/ext/class_ext
/usr/local/php/bin/phpize
./configure –with-php-config=/usr/local/php/bin/php-config
make
make install
此时会在php的安装路径下产生一个so文件，比如
/usr/local/php/lib/php/extensions/no-debug-non-zts-20060613/class_ext.so
修改php.ini 添加扩展
extension_dir = “/usr/local/php/lib/php/extensions/no-debug-non-zts-20060613/”
[class_ext]
extension = class_ext.so
5. 测试代码
$width = -10;
$height = 12;
$rectangle = new Rectangle($width, $height);
$area = $rectangle->getArea();
var_dump($area);
$circle = $rectangle->getCircle();
var_dump($circle);
$clone = $rectangle->clone();
$_area = $clone->getArea();
var_dump($_area);
$clone->setWidth(100);
$clone->setHeight(200);
$_area = $clone->getArea();
var_dump($_area);
$width = $clone->getWidth();
var_dump($width);
$height = $clone->getHeight();
var_dump($height);
结果输出：
int(12)
int(26)
int(12)
int(20000)
int(100)
int(200)
6. Over！