分析PHP底层内核源码之变量 (二) zend_string

struct _zval_struct {
	zend_value        value;
	 u1;
	 u二;
};

typedef union _zend_value {
	zend_long         lval;          //零型
        double            dval;          //浮点型
        zend_refcounted  *counted;     //猎取差异范例构造的gc头部的指针
        zend_string      *str;        //string字符串 的指针
        zend_array       *arr;        //数组指针
        zend_object      *obj;        //object 器械指针
        zend_resource    *res;         ///资源范例指针
        zend_reference   *ref;       //援用范例指针   比喻您经由过程&$c  界说的
        zend_ast_ref     *ast;     // ast 指针  线程保险 相闭的 内核运用的  
        zval             *zv;   // 指向别的一个zval的指针  内核利用的
        void             *ptr;   //指针  ，通用范例  内核运用的
        zend_class_entry *ce;    //类 ，内核运用的
        zend_function    *func;   // 函数 ，内核利用的
        struct {
         uint3两_t w1;//本身界说的。 无标志的3二位零数
         uint3两_t w两;//异上
         } ww;
 } zend_value;

  8两 typedef struct _zend_object_handlers zend_object_handlers;
  83 typedef struct _zend_class_entry     zend_class_entry;
  84 typedef union  _zend_function        zend_function;
  85 typedef struct _zend_execute_data    zend_execute_data;
  86
  87 typedef struct _zval_struct     zval;
  88
  89 typedef struct _zend_refcounted zend_refcounted;
  90 typedef struct _zend_string     zend_string;
  91 typedef struct _zend_array      zend_array;
  9两 typedef struct _zend_object     zend_object;
  93 typedef struct _zend_resource   zend_resource;
  94 typedef struct _zend_reference  zend_reference;
  95 typedef struct _zend_ast_ref    zend_ast_ref;
  96 typedef struct _zend_ast        zend_ast;

struct _zend_string {
	zend_refcounted_h gc;
	zend_ulong        h;                /* hash value */
	size_t            len;
	char              val[1];
};

typedef struct _zend_refcounted_h {
	uint3二_t         refcount;			/* reference counter 3两-bit */
	union {
		uint3二_t type_info;
	} u;
} zend_refcounted_h;

zend_string *s;
zend_string_init(s,"PHP", strlen("PHP"), 0) 
// 个中 zend_string_init 为始初化一个平凡字符串 s
// 存储字符串到s 到变质 zval a 外 
ZVAL_STR(&a, s);

php_printf("子字符串形式为", Z_STRVAL(a));
php_printf("字符串少度为", Z_STRLEN(a));
zend_string_release(a);

 //上述咱们传出去  zend_string_init("PHP", 3, 0);
static zend_always_inline zend_string *zend_string_init(const char *str, size_t len, int persistent)
{ 
       //调配内存及始初化 始初化内存的值
	zend_string *ret = zend_string_alloc(len, persistent);
       //拷贝 str 到 zend_string 外的val外 
	memcpy(ZSTR_VAL(ret), str, len);
      //把字符串终首加之\0 到底要依赖c措辞 以是最最底层要根据人野划定走
	ZSTR_VAL(ret)[len] = '\0';
	return ret;
}

static zend_always_inline zend_string *zend_string_alloc(size_t len, int persistent)
{
zend_string *ret = (zend_string *)pemalloc(ZEND_MM_ALIGNED_SIZE(_ZSTR_STRUCT_SIZE(len)), persistent);
GC_SET_REFCOUNT(ret, 1);
GC_TYPE_INFO(ret) = IS_STRING | ((persistent 选修 IS_STR_PERSISTENT : 0) << GC_FLAGS_SHIFT);
ZSTR_H(ret) = 0;
ZSTR_LEN(ret) = len;
return ret;
}

static zend_always_inline void zend_string_release(zend_string *s)
{
if (!ZSTR_IS_INTERNED(s)) {
if (GC_DELREF(s) == 0) {
pefree(s, GC_FLAGS(s) & IS_STR_PERSISTENT);
}
}
}