[翻譯][php擴展開發與嵌入式]第2章-變數的裡裡外外

typedef struct _zval_struct {  
    zval_value  value;  
    zend_uint   refcount;  
    zend_uchar  type;  
    zend_uchar  is_ref;  
} zval;

typedef union _zvalue_value {  
    long                    lval;  
    double              dval;  
    struct {  
        char        *val;  
        int     len;  
    }                   str;  
    HashTable           *ht;  
    zend_object_value       obj;  
} zvalue_value;

void describe_zval(zval *foo)  
{  
    if (foo->type == IS_NULL) {  
        php_printf("The variable is NULL");  
    } else {  
        php_printf("The variable is of type %d", foo->type);  
    }  
}

void describe_zval(zval *foo)  
{  
    if (Z_TYPE_P(foo) == IS_NULL) {  
        php_printf("The variable is NULL");  
    } else {  
        php_printf("The variable is of type %d",  
                            Z_TYPE_P(foo));  
    }  
}

void display_values(zval boolzv, zval *longpzv,  
                zval **doubleppzv)  
{  
    if (Z_TYPE(boolzv) == IS_BOOL) {  
        php_printf("The value of the boolean is: %s\n",  
            Z_BVAL(boolzv) ? "true" : "false");  
    }  
    if (Z_TYPE_P(longpzv) == IS_LONG) {  
        php_printf("The value of the long is: %ld\n",  
            Z_LVAL_P(longpzv));  
    }  
    if (Z_TYPE_PP(doubleppzv) == IS_DOUBLE) {  
        php_printf("The value of the double is: %f\n",  
            Z_DVAL_PP(doubleppzv));  
    }  
}

void display_string(zval *zstr)  
{  
    if (Z_TYPE_P(zstr) != IS_STRING) {  
        php_printf("The wrong datatype was passed!\n");  
        return;  
    }  
    PHPWRITE(Z_STRVAL_P(zstr), Z_STRLEN_P(zstr));  
}

ZVAL_NULL(pvz);                   Z_TYPE_P(pzv) = IS_NULL;

ZVAL_BOOL(pzv, b);                Z_TYPE_P(pzv) = IS_BOOL;  
                                  Z_BVAL_P(pzv) = b ? 1 : 0;  
ZVAL_TRUE(pzv);                   ZVAL_BOOL(pzv, 1);  
ZVAL_FALSE(pzv);                  ZVAL_BOOL(pzv, 0);

ZVAL_LONG(pzv, l);                Z_TYPE_P(pzv) = IS_LONG;  
                                  Z_LVAL_P(pzv) = l;  
ZVAL_DOUBLE(pzv, d);              Z_TYPE_P(pzv) = IS_DOUBLE;  
                                  Z_DVAL_P(pzv) = d;

ZVAL_STRINGL(pzv,str,len,dup);    Z_TYPE_P(pzv) = IS_STRING;  
                                  Z_STRLEN_P(pzv) = len;  
                                  if (dup) {  
                                      Z_STRVAL_P(pzv) =  
                                            estrndup(str, len + 1);  
                                  } else {  
                                     Z_STRVAL_P(pzv) = str;  
                                  }  
ZVAL_STRING(pzv, str, dup);       ZVAL _STRINGL(pzv, str,  
                                                strlen(str), dup);

ZVAL_RESOURCE(pzv, res);          Z_TYPE_P(pzv) = IS_RESOURCE;  
                                  Z_RESVAL_P(pzv) = res;

static void eae_001_zval_dump_real(zval *z, int level) {  
    HashTable   *ht;  
    int         ret;  
    char        *key;  
    uint        index;  
    zval        **pData;  
  
    switch ( Z_TYPE_P(z) ) {  
        case IS_NULL:  
            php_printf("%*stype = null, refcount = %d%s\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", is_ref " : "");  
            break;  
        case IS_BOOL:  
            php_printf("%*stype = bool, refcount = %d%s, value = %s\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", 
            is_ref " : "", Z_BVAL_P(z) ? "true" : "false");  
            break;  
        case IS_LONG:  
            php_printf("%*stype = long, refcount = %d%s, value = %ld\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", 
            is_ref " : "", Z_LVAL_P(z));  
            break;  
        case IS_STRING:  
            php_printf("%*stype = string, refcount = %d%s, value = \"%s\", len = %d\n", level * 4, "", Z_REFCOUNT_P(z), 
            Z_ISREF_P(z) ? ", is_ref " : "", Z_STRVAL_P(z), Z_STRLEN_P(z));  
            break;  
        case IS_DOUBLE:  
            php_printf("%*stype = double, refcount = %d%s, value = %0.6f\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", 
            is_ref " : "", Z_DVAL_P(z));  
            break;  
        case IS_RESOURCE:  
            php_printf("%*stype = resource, refcount = %d%s, resource_id = %d\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", 
            is_ref " : "", Z_RESVAL_P(z));  
            break;  
        case IS_ARRAY:  
            ht      = Z_ARRVAL_P(z);  
  
            zend_hash_internal_pointer_reset(ht);  
            php_printf("%*stype = array, refcount = %d%s, value = %s\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", 
            is_ref " : "", HASH_KEY_NON_EXISTANT != zend_hash_has_more_elements(ht) ? "" : "empty");  
            while ( HASH_KEY_NON_EXISTANT != (ret = zend_hash_get_current_key(ht, &key, &index, 0)) ) {  
                if ( HASH_KEY_IS_STRING == ret ) {  
                    php_printf("%*skey is string \"%s\"", (level + 1) * 4, "", key);  
                } else if ( HASH_KEY_IS_LONG == ret ) {  
                    php_printf("%*skey is long %d", (level + 1) * 4, "", index);  
                }  
                ret = zend_hash_get_current_data(ht, &pData);  
                eae_001_zval_dump_real(*pData, level + 1);  
                zend_hash_move_forward(ht);  
            }  
            zend_hash_internal_pointer_end(Z_ARRVAL_P(z));  
            break;  
        case IS_OBJECT:  
            php_printf("%*stype = object, refcount = %d%s\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", is_ref " : "");  
            break;  
        default:  
            php_printf("%*sunknown type, refcount = %d%s\n", level * 4, "", Z_REFCOUNT_P(z), Z_ISREF_P(z) ? ", is_ref " : "");  
            break;  
    }  
}  
  
PHP_FUNCTION(eae_001_zval_dump)  
{  
    zval    *z;  
  
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z", &z) == FAILURE) {  
        return;  
    }  
  
    eae_001_zval_dump_real(z, 0);  
  
    RETURN_NULL();  
}  
  
PHP_FUNCTION(eae_001_zval_make)  
{  
    zval    *z;  
  
    MAKE_STD_ZVAL(z);  
  
    ZVAL_NULL(z);  
    eae_001_zval_dump_real(z, 0);  
  
    ZVAL_TRUE(z);  
    eae_001_zval_dump_real(z, 0);  
  
    ZVAL_FALSE(z);  
    eae_001_zval_dump_real(z, 0);  
  
    ZVAL_LONG(z, 100);  
    eae_001_zval_dump_real(z, 0);  
  
    ZVAL_DOUBLE(z, 100.0);  
    eae_001_zval_dump_real(z, 0);  
  
    ZVAL_STRING(z, "100", 0);  
    eae_001_zval_dump_real(z, 0);  
}

struct _zend_execution_globals {  
    ...  
    HashTable symbol_table;  
    HashTable *active_symbol_table;  
    ...  
};

/* php实现 */  
<?php $foo = &#39;bar&#39;; ?>  
  
/* C实现 */  
{  
    zval *fooval;  
  
    MAKE_STD_ZVAL(fooval);  
    ZVAL_STRING(fooval, "bar", 1);  
    ZEND_SET_SYMBOL(EG(active_symbol_table), "foo", fooval);  
}

{  
    zval **fooval;  
  
    if (zend_hash_find(EG(active_symbol_table),  
                       "foo", sizeof("foo"),  
                       (void**)&fooval) == SUCCESS) {  
        php_printf("Got the value of $foo!");  
    } else {  
        php_printf("$foo is not defined.");  
    }  
}

void display_zval(zval *value)  
{  
    switch (Z_TYPE_P(value)) {  
        case IS_NULL:  
            /* NULLs are echoed as nothing */  
            break;  
        case IS_BOOL:  
            if (Z_BVAL_P(value)) {  
                php_printf("1");  
            }  
            break;  
        case IS_LONG:  
            php_printf("%ld", Z_LVAL_P(value));  
            break;  
        case IS_DOUBLE:  
            php_printf("%f", Z_DVAL_P(value));  
            break;  
        case IS_STRING:  
            PHPWRITE(Z_STRVAL_P(value), Z_STRLEN_P(value));  
            break;  
        case IS_RESOURCE:  
            php_printf("Resource #%ld", Z_RESVAL_P(value));  
            break;  
        case IS_ARRAY:  
            php_printf("Array");  
            break;  
        case IS_OBJECT:  
            php_printf("Object");  
            break;  
        default:  
            /* Should never happen in practice, 
             * but it's dangerous to make assumptions 
             */  
             php_printf("Unknown");  
             break;  
    }  
}

void display_zval(zval *value)  
{  
    convert_to_string(value);  
    PHPWRITE(Z_STRVAL_P(value), Z_STRLEN_P(value));  
}