{"id":376,"date":"2010-07-02T15:05:49","date_gmt":"2010-07-02T06:05:49","guid":{"rendered":"http:\/\/labs.gree.jp\/blog\/?p=376"},"modified":"2021-04-27T15:03:16","modified_gmt":"2021-04-27T06:03:16","slug":"post376","status":"publish","type":"post","link":"https:\/\/labs.gree.jp\/blog\/2010\/07\/376\/","title":{"rendered":"PHP\u3068\u4ef2\u826f\u304f\u306a\u308d\u3046 \u2212 empty()\u3068define() \u2212"},"content":{"rendered":"<h3 id=\"hs_43e35782a085abb360d4968e58969419_header_0\"> \u306f\u3058\u3081\u306b<\/h3>\n<p>\u3053\u3093\u306b\u3061\u306f\u3001\u30b0\u30ea\u30fc\u3067\u30a8\u30f3\u30b8\u30cb\u30a2\u3092\u3084\u3063\u3066\u3044\u308b\u68b6\u539f\u3068\u7533\u3057\u307e\u3059\u3002<br \/>\n\u4eca\u65e5\u306f\u3001\u4ee5\u524dPHP\u306b\u3064\u3044\u3066\u6c17\u306b\u306a\u3063\u3066\u8abf\u3079\u305f\u3053\u3068\u306b\u3064\u3044\u3066\u3001\u7d39\u4ecb\u3057\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002<br \/>\n\u656c\u9060\u3055\u308c\u304c\u3061\u306aPHP\u3067\u3059\u304c\u3001\u4e2d\u8eab\u3092\u77e5\u308b\u3068\u81ea\u7136\u3068\u611b\u7740\u304c\u6e67\u3044\u3066\u304d\u307e\u3059\u3002<\/p>\n<h3 id=\"hs_43e35782a085abb360d4968e58969419_header_1\"> empty()\u306b\u3064\u3044\u3066<\/h3>\n<p>empty()\u3068\u8a00\u3048\u3070\u3001PHP\u304c\u8a87\u308b7\u4e0d\u601d\u8b70\u95a2\u6570\u306e\u3072\u3068\u3064\u3067\u3059\u3002<\/p>\n<ul>\n<li> <a href=\"http:\/\/www.php.net\/manual\/ja\/types.comparisons.php\">http:\/\/www.php.net\/manual\/ja\/types.comparisons.php<\/a><\/li>\n<\/ul>\n<p>\u3053\u3061\u3089\u306b\u3042\u308b\u901a\u308a\u3001\u3069\u3046\u3057\u3066true\u306b\u306a\u308b\u306e\u304bfalse\u306b\u306a\u308b\u306e\u304b\u4e0d\u660e\u306a\u70b9\u304c\u591a\u3044\u95a2\u6570\u3067\u3059\u3002<\/p>\n<p>empty()\u304c\u547c\u3070\u308c\u308b\u7b87\u6240\u3092\u898b\u3066\u307f\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n<ul>\n<li> php-5.3.2\/Zend\/zend_vm_execute.h<\/li>\n<\/ul>\n<pre class=\"superpre c\">\n22701 static int ZEND_FASTCALL  ZEND_ISSET_ISEMPTY_VAR_SPEC_CV_HANDLER(ZEND_OPCODE_HANDLER_ARGS)\n22751   switch (opline->extended_value & ZEND_ISSET_ISEMPTY_MASK) {\n22752     case ZEND_ISSET:\n22753       if (isset && Z_TYPE_PP(value) == IS_NULL) {\n22754         Z_LVAL(EX_T(opline->result.u.var).tmp_var) = 0;\n22755       } else {\n22756         Z_LVAL(EX_T(opline->result.u.var).tmp_var) = isset;\n22757       }\n22758       break;\n22759     case ZEND_ISEMPTY:\n22760       if (!isset || !i_zend_is_true(*value)) {\n22761         Z_LVAL(EX_T(opline->result.u.var).tmp_var) = 1;\n22762       } else {\n22763         Z_LVAL(EX_T(opline->result.u.var).tmp_var) = 0;\n22764       }\n22765       break;\n22766   }<\/pre>\n<p>22759\u884c\u76ee\u304b\u3089empty\u306e\u51e6\u7406\u306b\u306a\u308a\u307e\u3059\u3002<br \/>\n isset()\u304cfalse\u306a\u3082\u306e\u306fempty()\u3067\u306ftrue\u306b\u306a\u308a\u307e\u3059\u3002<br \/>\n isset()\u3067true\u306a\u3082\u306e\u306b\u306f\u3001i_zend_is_true()\u3067\u30c1\u30a7\u30c3\u30af\u304c\u884c\u308f\u308c\u307e\u3059\u3002<\/p>\n<h4 id=\"hs_43e35782a085abb360d4968e58969419_header_2\"> i_zend_is_true()\u306b\u3064\u3044\u3066<\/h4>\n<p>i_zend_is_true()\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<ul>\n<li> php-5.3.2\/Zend\/zend_execute.h<\/li>\n<\/ul>\n<p>i_zend_is_true()\u306fzend_execute.h\u306b\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<pre class=\"superpre c\">\n80 static inline int i_zend_is_true(zval *op)\n81 {\n82   int result;\n83\n84   switch (Z_TYPE_P(op)) {\n85     case IS_NULL:\n86       result = 0;\n87       break;\n88     case IS_LONG:\n89     case IS_BOOL:\n90     case IS_RESOURCE:\n91       result = (Z_LVAL_P(op)?1:0);\n92       break;\n93     case IS_DOUBLE:\n94       result = (Z_DVAL_P(op) ? 1 : 0);\n95       break;\n96     case IS_STRING:\n97       if (Z_STRLEN_P(op) == 0\n98         || (Z_STRLEN_P(op)==1 && Z_STRVAL_P(op)[0]=='0')) {\n99         result = 0;\n100       } else {\n101         result = 1;\n102       }\n103       break;\n104     case IS_ARRAY:\n105       result = (zend_hash_num_elements(Z_ARRVAL_P(op))?1:0);\n106       break;\n107     case IS_OBJECT:\n108       if(IS_ZEND_STD_OBJECT(*op)) {\n109         TSRMLS_FETCH();\n110\n111         if (Z_OBJ_HT_P(op)->cast_object) {\n112           zval tmp;\n113           if (Z_OBJ_HT_P(op)->cast_object(op, &tmp, IS_BOOL TSRMLS_CC) == SUCCESS) {\n114             result = Z_LVAL(tmp);\n115             break;\n116           }\n117         } else if (Z_OBJ_HT_P(op)->get) {\n118           zval *tmp = Z_OBJ_HT_P(op)->get(op TSRMLS_CC);\n119           if(Z_TYPE_P(tmp) != IS_OBJECT) {\n120             \/* for safety - avoid loop *\/\n121             convert_to_boolean(tmp);\n122             result = Z_LVAL_P(tmp);\n123             zval_ptr_dtor(&tmp);\n124             break;\n125           }\n126         }\n127       }\n128       result = 1;\n129       break;\n130     default:\n131       result = 0;\n132       break;\n133   }\n134   return result;\n135 }<\/pre>\n<p>\u95a2\u6570\u3092\u898b\u3066\u307f\u308b\u3068\u3001\u5909\u6570\u306e\u578b\u5225\u306b\u30c1\u30a7\u30c3\u30af\u3057\u3066\u308b\u306e\u304c\u308f\u304b\u308a\u307e\u3059\u3002<br \/>\ni_zend_is_true()\u306fempty()\u3067\u306f\u53cd\u8ee2\u3057\u3066\u8a55\u4fa1\u3055\u308c\u308b\u3053\u3068\u3092\u8e0f\u307e\u3048\u3066\u3001<br \/>\n\u914d\u5217\u306e\u5834\u5408\u3001105\u884c\u76ee\u3067zend_hash_num_elements\u304c\u7a7a\u3067\u3042\u308c\u3070empty()\u306ftrue\u306b\u306a\u3063\u305f\u308a\u3001<br \/>\n\u6587\u5b57\u5217\u306e\u5834\u5408\u300197\u300198\u884c\u76ee\u3067\u6587\u5b57\u5217\u306e\u9577\u3055\u304c0\u306e\u3068\u304d\u3068\u6587\u5b57\u5217\u306e\u9577\u3055\u304c1\u306e\u3068\u304d\u3067\u3082\u4e2d\u8eab\u304c'0'\u3067\u3042\u308c\u3070empty()\u306ftrue\u306b\u306a\u3063\u305f\u308a\u3068\u3044\u3046\u5b9f\u88c5\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n<h3 id=\"hs_43e35782a085abb360d4968e58969419_header_3\"> \u5b9a\u6570\u306e\u8a71\u3068TRUE, FALSE, NULL\u306b\u3064\u3044\u3066 <\/h3>\n<p>\u6b21\u306f\u5b9a\u6570\u306e\u8a71\u3068TRUE, FALSE, NULL\u304c\u306a\u306b\u3082\u306e\u304b\u306b\u3064\u3044\u3066\u3067\u3059\u3002<\/p>\n<p>PHP\u4e0a\u3067\u4f7f\u3063\u3066\u307f\u308b\u3068\u3001<\/p>\n<pre class=\"superpre php\">\nvar_dump(TRUE);\nvar_dump(FALSE);\nvar_dump(NULL);<\/pre>\n<pre class=\"superpre \">\nbool(true)\nbool(false)\nNULL<\/pre>\n<p>\u3068\u306a\u3063\u3066\u3001\u8ad6\u7406\u578b\u3068NULL\u3092\u5b9a\u7fa9\u3059\u308b\u5b9a\u6570\u3067\u3059\u3002<\/p>\n<ul>\n<li> <a href=\"http:\/\/www.php.net\/manual\/ja\/reserved.constants.php\">http:\/\/www.php.net\/manual\/ja\/reserved.constants.php<\/a><\/li>\n<\/ul>\n<p>\u3053\u3061\u3089\u306b\u66f8\u304b\u308c\u3066\u3044\u308b\u901a\u308a\u5b9a\u7fa9\u6e08\u307f\u306e\u5b9a\u6570\u3068\u3057\u3066\u77e5\u3089\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<p>\u3069\u3053\u3067\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u308b\u304b\u3092\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<br \/>\nTRUE\u3001FALSE\u3001NULL\u306fzend_constants.c\u306ezend_register_standard_constants()\u5185\u3067\u5b9a\u6570\u3068\u3057\u3066\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<ul>\n<li> php-5.3.2\/Zend\/zend_constants.c<\/li>\n<\/ul>\n<pre class=\"superpre c\">\n96 void zend_register_standard_constants(TSRMLS_D)\n97 {\n\n118     zend_constant c;\n119\n120     c.flags = CONST_PERSISTENT | CONST_CT_SUBST;\n121     c.module_number = 0;\n122\n123     c.name = zend_strndup(ZEND_STRL(\"TRUE\"));\n124     c.name_len = sizeof(\"TRUE\");\n125     c.value.value.lval = 1;\n126     c.value.type = IS_BOOL;\n127     zend_register_constant(&c TSRMLS_CC);\n128\n129     c.name = zend_strndup(ZEND_STRL(\"FALSE\"));\n130     c.name_len = sizeof(\"FALSE\");\n131     c.value.value.lval = 0;\n132     c.value.type = IS_BOOL;\n133     zend_register_constant(&c TSRMLS_CC);\n134\n135     c.name = zend_strndup(ZEND_STRL(\"NULL\"));\n136     c.name_len = sizeof(\"NULL\");\n137     c.value.type = IS_NULL;\n138     zend_register_constant(&c TSRMLS_CC);<\/pre>\n<p>\u95a2\u6570\u306e\u4e2d\u8eab\u3092\u8997\u3044\u3066\u307f\u308b\u3068\u3001zend_constant\u306b 123\u3001129\u3001135\u884c\u76ee\u3067\u305d\u308c\u305e\u308c\u306e\u5b9a\u6570\u306e\u540d\u524d\u3092name\u306b\u3001 \u307e\u305f\u305d\u308c\u305e\u308c\u306evalue\u3001type\u3092\u5165\u308c\u3066 zend_register_constant()\u3092\u901a\u3057\u3066\u5b9a\u6570\u3068\u3057\u3066\u5b9a\u7fa9\u3055\u308c\u307e\u3059\u3002<br \/>\nzend_register_constant()\u306f\u5b9a\u6570\u306e\u767b\u9332\u3092\u884c\u3046\u95a2\u6570\u3067\u3059\u3002<\/p>\n<h4 id=\"hs_43e35782a085abb360d4968e58969419_header_4\"> define()\u306b\u3064\u3044\u3066 <\/h4>\n<p>\u3053\u3053\u3067PHP\u4e0a\u3067\u5b9a\u6570\u3092\u5b9a\u7fa9\u3059\u308b\u969b\u306b\u7528\u3044\u308bdefine\u95a2\u6570\u306b\u3064\u3044\u3066\u898b\u3066\u307f\u307e\u3059\u3002<\/p>\n<ul>\n<li> php-5.3.2\/Zend\/zend_builtin_functions.c<\/li>\n<\/ul>\n<pre class=\"superpre c\">\n623 ZEND_FUNCTION(define)\n\n633   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, \"sz|b\", &name, &name_len, &val, &non_cs) == FAILURE) {\n634     return;\n635   }\n\n637   if(non_cs) {\n638     case_sensitive = 0;\n639   }\n\n678   c.value = *val;\n679   zval_copy_ctor(&c.value);\n680   if (val_free) {\n681     zval_ptr_dtor(&val_free);\n682   }\n683   c.flags = case_sensitive; \/* non persistent *\/\n684   c.name = zend_strndup(name, name_len);\n685   c.name_len = name_len+1;\n686   c.module_number = PHP_USER_CONSTANT;\n687   if (zend_register_constant(&c TSRMLS_CC) == SUCCESS) {\n688     RETURN_TRUE;\n689   } else {\n690     RETURN_FALSE;\n691   }\n<\/pre>\n<p>define()\u3067\u3082\u540c\u3058\u304f\u3001zend_register_constant()\u3092\u901a\u3057\u3066\u5b9a\u6570\u306e\u5b9a\u7fa9\u3092\u884c\u3063\u3066\u3044\u307e\u3059\u3002 \u5148\u7a0b\u3068\u9055\u3046\u3068\u3053\u308d\u306fzend_constant.flags\u306b\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3059\u308b\u304b\u306e\u30d5\u30e9\u30b0\u304cdefine()\u306e\u5f15\u6570\u306b\u3088\u308a\u30bb\u30c3\u30c8\u3067\u304d\u307e\u3059\u3002 \u305d\u306e\u305f\u3081\u3001TRUE, FALSE, NULL\u306f\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u533a\u5225\u3057\u306a\u3044\u5b9a\u6570\u3068\u3057\u3066\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002 \u305d\u3053\u3067\u5927\u6587\u5b57\u5c0f\u6587\u5b57\u3092\u6df7\u305c\u3066\u3001<\/p>\n<pre class=\"superpre php\">\nvar_dump(TRUE);\nvar_dump(True);\nvar_dump(TrUe);\nvar_dump(true);<\/pre>\n<p>\u3092\u5b9f\u884c\u3059\u308b\u3068<\/p>\n<pre class=\"superpre \">\nbool(true)\nbool(true)\nbool(true)\nbool(true)<\/pre>\n<p>\u3068\u3059\u3079\u3066\u540c\u3058\u5024\u306b\u306a\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3059\u3002<\/p>\n<h4 id=\"hs_43e35782a085abb360d4968e58969419_header_5\"> zend_register_constant()\u306b\u3064\u3044\u3066<\/h4>\n<p>zend_register_constant()\u3067\u5b9a\u6570\u304c\u767b\u9332\u3055\u308c\u308b\u51e6\u7406\u3092\u898b\u3066\u307f\u307e\u3059\u3002<\/p>\n<ul>\n<li> php-5.3.2\/Zend\/zend_constatns.c<\/li>\n<\/ul>\n<pre class=\"superpre c\">\n411 ZEND_API int zend_register_constant(zend_constant *c TSRMLS_DC)\n412 {\n413   char *lowercase_name = NULL;\n414   char *name;\n415   int ret = SUCCESS;\n416 \n417 #if 0\n418   printf(\"Registering constant for module %d\\n\", c->module_number);\n419 #endif\n420 \n421   if (!(c->flags & CONST_CS)) {\n422     \/* keep in mind that c->name_len already contains the '\\0' *\/\n423     lowercase_name = estrndup(c->name, c->name_len-1);\n424     zend_str_tolower(lowercase_name, c->name_len-1);\n425     name = lowercase_name;\n426   } else { \n427     char *slash = strrchr(c->name, '\\\\');\n428     if(slash) {\n429       lowercase_name = estrndup(c->name, c->name_len-1);\n430       zend_str_tolower(lowercase_name, slash-c->name);\n431       name = lowercase_name;\n432     } else {\n433       name = c->name;\n434     }\n435   } \n\n438       zend_hash_add(EG(zend_constants), name, c->name_len, (void *) c, sizeof(zend_constant), NULL)==FAILURE) {<\/pre>\n<p>zend_constatnt->flags\u306bCONST_CS\u304c\u3064\u3044\u3066\u3044\u306a\u3044\u3068\u5b9a\u6570\u540d\u306fzend_str_tolower\u3092\u901a\u3057\u3066\u5c0f\u6587\u5b57\u306b\u5909\u63db\u3055\u308c\u307e\u3059\u3002<br \/>\n\u6700\u5f8c\u306bzend_hash_add\u3092\u4f7f\u3063\u3066zend_constants\u306b\u5b9a\u6570\u304c\u767b\u9332\u3055\u308c\u307e\u3059\u3002<\/p>\n<h4 id=\"hs_43e35782a085abb360d4968e58969419_header_6\"> zend_get_constant()\u306b\u3064\u3044\u3066<\/h4>\n<ul>\n<li> php-5.3.2\/Zend\/zend_get_constant.c<\/li>\n<\/ul>\n<pre class=\"superpre c\">\n224 ZEND_API int zend_get_constant(const char *name, uint name_len, zval *result TSRMLS_DC)\n225 {\n226   zend_constant *c;\n227   int retval = 1;\n228   char *lookup_name;\n229\n230   if (zend_hash_find(EG(zend_constants), name, name_len+1, (void **) &c) == FAILURE) {\n231     lookup_name = zend_str_tolower_dup(name, name_len);\n232\n233     if (zend_hash_find(EG(zend_constants), lookup_name, name_len+1, (void **) &c)==SUCCESS) {\n234       if (c->flags & CONST_CS) {\n235         retval=0;\n236       }\n237     }<\/pre>\n<p>\u5b9a\u6570\u3092\u53c2\u7167\u3059\u308b\u3068\u304d\u306fzend_get_constant()\u304c\u547c\u3070\u308c\u3066\u307e\u3059\u3002<br \/>\n\u307e\u305a\u306f\u6e21\u3055\u308c\u305f\u5b9a\u6570\u540d\u3067\u691c\u7d22\u3057\u3001\u30d2\u30c3\u30c8\u3057\u306a\u3051\u308c\u3070\u5c0f\u6587\u5b57\u306b\u5909\u63db\u3057\u3066\u518d\u5ea6\u691c\u7d22\u3092\u884c\u306a\u3044\u307e\u3059\u3002<br \/>\n\u3053\u306e\u3068\u304d\u30d2\u30c3\u30c8\u3057\u305f\u3082\u306e\u306b\u3064\u3044\u3066\u306fCONST_CS\u30d5\u30e9\u30b0\u304c\u7acb\u3063\u3066\u3044\u308c\u3070\u5c0f\u6587\u5b57\u5909\u63db\u5f8c\u306e\u691c\u7d22\u306f\u7121\u52b9\u306b\u306a\u3063\u3066\u307e\u3059\u3002<\/p>\n<h3 id=\"hs_43e35782a085abb360d4968e58969419_header_7\"> \u3055\u3044\u3054\u306b<\/h3>\n<p>\u4eca\u56de\u306fPHP\u4e0a\u3067\u306e\u5b9a\u6570\u306e\u8a71\u3068empty()\u306b\u3064\u3044\u3066\u7c21\u5358\u306b\u7d39\u4ecb\u3057\u307e\u3057\u305f\u3002<br \/>\n\u6b21\u56de\u306farray\u95a2\u6570\u306b\u3064\u3044\u3066\u7d39\u4ecb\u3057\u305f\u3044\u3068\u601d\u3044\u307e\u3059\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u306f\u3058\u3081\u306b \u3053\u3093\u306b\u3061\u306f\u3001\u30b0\u30ea\u30fc\u3067\u30a8\u30f3\u30b8\u30cb\u30a2\u3092\u3084\u3063\u3066\u3044\u308b\u68b6\u539f\u3068\u7533\u3057\u307e\u3059\u3002 \u4eca\u65e5\u306f\u3001\u4ee5\u524dPHP\u306b\u3064\u3044\u3066\u6c17\u306b\u306a\u3063\u3066\u8abf\u3079\u305f\u3053\u3068\u306b\u3064\u3044\u3066\u3001\u7d39\u4ecb\u3057\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002 \u656c\u9060\u3055\u308c\u304c\u3061\u306aPHP\u3067\u3059\u304c\u3001\u4e2d\u8eab\u3092\u77e5\u308b\u3068\u81ea\u7136\u3068\u611b\u7740\u304c\u6e67\u3044\u3066\u304d\u307e\u3059\u3002 e [&hellip;]<\/p>\n","protected":false},"author":105,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[9],"tags":[8],"class_list":["post-376","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-info","tag-php"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/posts\/376","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/users\/105"}],"replies":[{"embeddable":true,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/comments?post=376"}],"version-history":[{"count":3,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/posts\/376\/revisions"}],"predecessor-version":[{"id":21130,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/posts\/376\/revisions\/21130"}],"wp:attachment":[{"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/media?parent=376"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/categories?post=376"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/labs.gree.jp\/blog\/wp-json\/wp\/v2\/tags?post=376"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}