php内置函数分析array_diff()

 1 PHP_FUNCTION(array_diff) 2 { 3 ????zval *args; 4 ????int argc, i; 5 ????uint32_t num; 6 ????HashTable exclude; 7 ????zval *value; 8 ????zend_string *str, *key; 9 ????zend_long idx;10 ????zval dummy;11 12 ????// 至少两个参数13 ????if (ZEND_NUM_ARGS() < 2) {14 ????????php_error_docref(NULL, E_WARNING, "at least 2 parameters are required, %d given", ZEND_NUM_ARGS());15 ????????return;16 ????}17 ????// 类型描述符：* ?variable arguments list (0 or more)18 ????// 类型描述符：+ ?variable arguments list (1 or more)19 ????// 参数存放在数组args中，argc保存参数个数20 ????if (zend_parse_parameters(ZEND_NUM_ARGS(), "+", &args, &argc) == FAILURE) {21 ????????return;22 ????}23 24 ????// 第一个参数不是数组，则报错25 ????if (Z_TYPE(args[0]) != IS_ARRAY) {26 ????????php_error_docref(NULL, E_WARNING, "Argument #1 is not an array");27 ????????RETURN_NULL(); // 返回NULL28 ????}29 30 ????/* count number of elements */31 ????// 检查所有参数是否是数组32 ????num = 0;33 ????for (i = 1; i < argc; i++) {34 ????????if (Z_TYPE(args[i]) != IS_ARRAY) {35 ????????????php_error_docref(NULL, E_WARNING, "Argument #%d is not an array", i + 1);36 ????????????RETURN_NULL(); // 返回NULL37 ????????}38 ????????num += zend_hash_num_elements(Z_ARRVAL(args[i])); // 所有参数数组的元素个数累加39 ????}40 41 ????// 元素个数num为0，返回第一个参数数组（空数组）42 ????if (num == 0) {43 ????????ZVAL_COPY(return_value, &args[0]);44 ????????return;45 ????}46 47 ????ZVAL_NULL(&dummy);48 ????/* create exclude map */49 ????zend_hash_init(&exclude, num, NULL, NULL, 0);50 ????// 从第二个数组开始,所以数组元素保存到exclude51 ????for (i = 1; i < argc; i++) {52 ????????// 遍历数组53 ????????ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL(args[i]), value) {54 ????????????str = zval_get_string(value); // 数组元素值转为字符串55 ????????????zend_hash_add(&exclude, str, &dummy); // 56 ????????????zend_string_release(str);57 ????????} ZEND_HASH_FOREACH_END();58 ????}59 60 ????/* copy all elements of first array that are not in exclude set */61 ????// 初始化返回值数组，大小和第一个数组一致。62 ????array_init_size(return_value, zend_hash_num_elements(Z_ARRVAL(args[0])));63 ????// 循环遍历第一个数组64 ????ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL(args[0]), idx, key, value) {65 ????????str = zval_get_string(value); // 元素值转为字符串66 ????????if (!zend_hash_exists(&exclude, str)) { // exclude中找不到该值67 ????????????// 插入到返回值数组中（差集），键名保留不变。68 ????????????if (key) {69 ????????????????value = zend_hash_add_new(Z_ARRVAL_P(return_value), key, value);70 ????????????} else {71 ????????????????value = zend_hash_index_add_new(Z_ARRVAL_P(return_value), idx, value);72 ????????????}73 ????????????zval_add_ref(value);74 ????????}75 ????????zend_string_release(str);76 ????} ZEND_HASH_FOREACH_END();77 78 ????zend_hash_destroy(&exclude);79 }