지역 사회 배우다 도구 라이브러리 여가
찾다
한국어
집 > php教程 > php手册 > 본문

深入PHP内核之in_array，php内核in_array

WBOY
풀어 주다： 2016-06-13 08:51:27
원래의
1251명이 탐색했습니다.

深入PHP内核之in_array，php内核in_array

无意中看到一段代码

1、a.php

<?php
$y="12";
$x = array();
for($j=0;$j<50000;$j++){
    $x[]= "{$j}";
}

for($i=0;$i<30000;$i++){
    if(in_array($y,$x,true)){
        continue;
    }
}
?>
로그인 후 복사

测试

[root@dev tmp]# time php a.php

real    0m0.101s
user    0m0.080s
sys     0m0.013s
로그인 후 복사

2、b.php

<?php                                                                                                                                                                                        
$y="1800";
$x = array();
for($j=0;$j<50000;$j++){
    $x[]= "{$j}";
}
 
for($i=0;$i<30000;$i++){
    if(in_array($y,$x)){
        continue;
    }   
}
로그인 후 복사

测试

[root@dev tmp]# time php b.php 

real    0m9.517s
user    0m4.486s
sys     0m0.015s
로그인 후 복사

需要9s

对于b.php 有严重的效率问题，跟踪测试一下好了

[root@dev tmp]# ltrace -c  php b.php     
% time     seconds  usecs/call     calls      function
------ ----------- ----------- --------- --------------------
 52.92  175.486683         224    780155 strtol
 33.34  110.550182    55275091         2 __libc_start_main
  6.33   20.999979         177    118479 memcpy
  3.56   11.819558         234     50394 __ctype_b_loc
  1.66    5.510564         285     19294 free
  1.42    4.704605      156820        30 dlopen
  0.43    1.416750          76     18430 malloc
  0.13    0.422050          76      5510 strlen
  0.08    0.258620          76      3375 __ctype_tolower_loc
  0.04    0.137245          77      1770 strrchr
  0.02    0.067158          76       880 strcasecmp
  0.02    0.059222          76       776 calloc
  0.01    0.034591       17295         2 getprotobyname
  0.01    0.031099          76       407 realloc
  0.01    0.021277          77       276 memset
  0.00    0.011502         383        30 dlclose
  0.00    0.010671          85       125 
  0.00    0.006806          73        93 fileno
  0.00    0.006095          76        80 strncasecmp
  0.00    0.005397          77        70 strchr
  0.00    0.005139         160        32 ftell
  0.00    0.004405         137        32 fclose
  0.00    0.003644         104        35 __fxstat
  0.00    0.003432         107        32 fopen
  0.00    0.003103         107        29 munmap
  0.00    0.003062          78        39 getenv
  0.00    0.003031         104        29 mmap
  0.00    0.003027         104        29 isatty
  0.00    0.002825         104        27 __xstat
  0.00    0.002468          82        30 dlsym
  0.00    0.002167          74        29 sysconf
  0.00    0.001956          75        26 _setjmp
  0.00    0.001419         109        13 __lxstat
  0.00    0.001294          76        17 memchr
  0.00    0.001125        1125         1 SYS_clone
  0.00    0.001099        1099         1 tzset
  0.00    0.001098        1098         1 exit
  0.00    0.001075        1075         1 ERR_load_crypto_strings
  0.00    0.000986         986         1 using_history
  0.00    0.000837         837         1 SYS_exit_group
  0.00    0.000606          75         8 __strdup
  0.00    0.000596          74         8 strcmp
  0.00    0.000591          73         8 __memcpy_chk
  0.00    0.000457          76         6 fflush
  0.00    0.000326         108         3 getcwd
  0.00    0.000309          77         4 __errno_location
  0.00    0.000271         271         1 setlocale
  0.00    0.000271         271         1 scandir
  0.00    0.000238          79         3 __sprintf_chk
  0.00    0.000222         111         2 signal
  0.00    0.000206         206         1 SSL_library_init
  0.00    0.000186         186         1 fgetc
  0.00    0.000155         155         1 ERR_load_ERR_strings
  0.00    0.000154          77         2 xmlSetGenericErrorFunc
  0.00    0.000151          75         2 __strtok_r
  0.00    0.000151          75         2 xmlParserInputBufferCreateFilenameDefault
  0.00    0.000148         148         1 xmlInitParser
  0.00    0.000147          73         2 xmlOutputBufferCreateFilenameDefault
  0.00    0.000130         130         1 OpenSSL_add_all_ciphers
  0.00    0.000122         122         1 EVP_cleanup
  0.00    0.000112         112         1 access
  0.00    0.000109         109         1 rewind
  0.00    0.000106         106         1 OPENSSL_add_all_algorithms_noconf
  0.00    0.000105         105         1 sigprocmask
  0.00    0.000093          93         1 gnu_get_libc_version
  0.00    0.000090          90         1 OpenSSL_add_all_digests
  0.00    0.000084          84         1 xmlCleanupParser
  0.00    0.000081          81         1 xmlRelaxNGCleanupTypes
  0.00    0.000079          79         1 xmlSetStructuredErrorFunc
  0.00    0.000078          78         1 SSL_get_ex_new_index
  0.00    0.000077          77         1 __gmp_set_memory_functions
  0.00    0.000076          76         1 ERR_load_EVP_strings
  0.00    0.000076          76         1 pcre_version
  0.00    0.000075          75         1 X509_get_default_cert_area
  0.00    0.000075          75         1 strstr
  0.00    0.000074          74         1 sigemptyset
  0.00    0.000074          74         1 __xmlParserVersion
  0.00    0.000074          74         1 time
  0.00    0.000074          74         1 xmlResetLastError
  0.00    0.000074          74         1 strncmp
  0.00    0.000073          73         1 sigaddset
------ ----------- ----------- --------- --------------------
100.00  331.614442               1000662 total
로그인 후 복사

我们发现 strtol 占用了大量的时间

查一下库函数

/*
函数名: strtol 
功  能: 将串转换为长整数 
用  法: long strtol(char *str, char **endptr, int base); 
程序例: 
*/

#include <stdlib.h> 
#include <stdio.h> 

int main(void) 
{ 
   char *string = "87654321", *endptr; 
   long lnumber; 

   /* strtol converts string to long integer  */ 
   lnumber = strtol(string, &endptr, 10); 
   printf("string = %s  long = %ld\n", string, lnumber); 

   return 0; 
}
로그인 후 복사

所以应该是源代码中有大量的类型转换

关于in_array

in_array是这个样子的

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )
로그인 후 복사

在 haystack 中搜索 needle，如果没有设置 strict 则使用宽松的比较。

needle

待搜索的值。如果 needle 是字符串，则比较是区分大小写的。

haystack

这个数组。

strict

如果第三个参数 strict 的值为 TRUE 则 in_array() 函数还会检查 needle 的类型是否和 haystack 中的相同。

那么我看一下源代码

第一步 在ext/standard/array.c 文件中

/* }}} */                                                      
                                                               
/* {{{ proto bool in_array(mixed needle, array haystack [, bool strict])
   Checks if the given value exists in the array */            
PHP_FUNCTION(in_array)                                         
{                                                              
    php_search_array(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);     
}                                                              
/* }}} */                                                      
                                                               
/* {{{ proto mixed array_search(mixed needle, array haystack [, bool strict])
   Searches the array for a given value and returns the corresponding key if successful */
PHP_FUNCTION(array_search)                                     
{                                                              
    php_search_array(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);     
}                                                              
/* }}} */
로그인 후 복사

顺便看到了array_search，原来和in_array的内部实现基本一致

其中函数的参数 在./zend.h中

#define INTERNAL_FUNCTION_PARAM_PASSTHRU ht, return_value, return_value_ptr, this_ptr, return_value_used TSRMLS_CC
로그인 후 복사

第二步 在ext/standard/array.c 文件中 查看php_search_array原型

/* void php_search_array(INTERNAL_FUNCTION_PARAMETERS, int behavior)
 * 0 = return boolean
 * 1 = return key
 */      
static void php_search_array(INTERNAL_FUNCTION_PARAMETERS, int behavior) /* {{{ */
{        
    zval *value,            /* value to check for */
         *array,            /* array to check in */
         **entry,           /* pointer to array entry */
         res;              /* comparison result */
    HashPosition pos;        /* hash iterator */
    zend_bool strict = 0;     /* strict comparison or not */
    ulong num_key;
    uint str_key_len;
    char *string_key;
    int (*is_equal_func)(zval *, zval *, zval * TSRMLS_DC) = is_equal_function;
         
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "za|b", &value, &array, &strict) == FAILURE) {
        return;
    }    
         
    if (strict) {
        is_equal_func = is_identical_function;
    }    
         
    zend_hash_internal_pointer_reset_ex(Z_ARRVAL_P(array), &pos);
    while (zend_hash_get_current_data_ex(Z_ARRVAL_P(array), (void **)&entry, &pos) == SUCCESS) {
        is_equal_func(&res, value, *entry TSRMLS_CC);
        if (Z_LVAL(res)) {
            if (behavior == 0) {
                RETURN_TRUE;
            } else {
                /* Return current key */
                switch (zend_hash_get_current_key_ex(Z_ARRVAL_P(array), &string_key, &str_key_len, &num_key, 0, &pos)) {
                    case HASH_KEY_IS_STRING:
                        RETURN_STRINGL(string_key, str_key_len - 1, 1);
                        break;
                    case HASH_KEY_IS_LONG:
                        RETURN_LONG(num_key);
                        break;
                }
            }
        }
        zend_hash_move_forward_ex(Z_ARRVAL_P(array), &pos);
    }    
         
    RETURN_FALSE;
}        
/* }}} */
         
/* {{{ proto bool in_array(mixed needle, array haystack [, bool strict])
   Checks if the given value exists in the array */
로그인 후 복사

我们发现 strict 这个值的不同有两种比较方式，看一下两个函数的不同之处

is_identical_function 检查类型是否相同

ZEND_API int is_identical_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{        
   Z_TYPE_P(result) = IS_BOOL;
   if (Z_TYPE_P(op1) != Z_TYPE_P(op2)) {
      Z_LVAL_P(result) = 0;
      return SUCCESS;
   }    
   switch (Z_TYPE_P(op1)) {
      case IS_NULL:
         Z_LVAL_P(result) = 1;
         break;
      case IS_BOOL:
      case IS_LONG:
      case IS_RESOURCE:
         Z_LVAL_P(result) = (Z_LVAL_P(op1) == Z_LVAL_P(op2));
         break;
      case IS_DOUBLE:
         Z_LVAL_P(result) = (Z_DVAL_P(op1) == Z_DVAL_P(op2));
         break;
      case IS_STRING:
         Z_LVAL_P(result) = ((Z_STRLEN_P(op1) == Z_STRLEN_P(op2))
            && (!memcmp(Z_STRVAL_P(op1), Z_STRVAL_P(op2), Z_STRLEN_P(op1))));
         break;
      case IS_ARRAY:
         Z_LVAL_P(result) = (Z_ARRVAL_P(op1) == Z_ARRVAL_P(op2) 
            zend_hash_compare(Z_ARRVAL_P(op1), Z_ARRVAL_P(op2), (compare_func_t) hash_zval_identical_function, 1 TSRMLS_CC)==0);
         break;
      case IS_OBJECT:
         if (Z_OBJ_HT_P(op1) == Z_OBJ_HT_P(op2)) {
            Z_LVAL_P(result) = (Z_OBJ_HANDLE_P(op1) == Z_OBJ_HANDLE_P(op2));
         } else {
            Z_LVAL_P(result) = 0;
         }
         break;
      default:
         Z_LVAL_P(result) = 0;
         return FAILURE;
   }    
   return SUCCESS;
}        
/* }}} */
로그인 후 복사

is_equal_function 不检查类型是否相同，所以需要隐式转换

ZEND_API int is_equal_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{        
   if (compare_function(result, op1, op2 TSRMLS_CC) == FAILURE) {
      return FAILURE;
   }    
   ZVAL_BOOL(result, (Z_LVAL_P(result) == 0));
   return SUCCESS;
}        
/* }}} */
로그인 후 복사

==》compare_function

ZEND_API int compare_function(zval *result, zval *op1, zval *op2 TSRMLS_DC) /* {{{ */
{            
   int ret; 
   int converted = 0;
   zval op1_copy, op2_copy;
   zval *op_free;
             
   while (1) {
      switch (TYPE_PAIR(Z_TYPE_P(op1), Z_TYPE_P(op2))) {
         case TYPE_PAIR(IS_LONG, IS_LONG):
            ZVAL_LONG(result, Z_LVAL_P(op1)>Z_LVAL_P(op2)?1:(Z_LVAL_P(op1)<Z_LVAL_P(op2)?-1:0)); 
            return SUCCESS;
              
         case TYPE_PAIR(IS_DOUBLE, IS_LONG):
            Z_DVAL_P(result) = Z_DVAL_P(op1) - (double)Z_LVAL_P(op2);
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_LONG, IS_DOUBLE):
            Z_DVAL_P(result) = (double)Z_LVAL_P(op1) - Z_DVAL_P(op2);
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_DOUBLE, IS_DOUBLE):
            if (Z_DVAL_P(op1) == Z_DVAL_P(op2)) {
               ZVAL_LONG(result, 0);
            } else {
               Z_DVAL_P(result) = Z_DVAL_P(op1) - Z_DVAL_P(op2);
               ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
            }
            return SUCCESS;
            
         case TYPE_PAIR(IS_ARRAY, IS_ARRAY):
            zend_compare_arrays(result, op1, op2 TSRMLS_CC);
            return SUCCESS;
            
         case TYPE_PAIR(IS_NULL, IS_NULL):
            ZVAL_LONG(result, 0);
            return SUCCESS;
            
         case TYPE_PAIR(IS_NULL, IS_BOOL):
            ZVAL_LONG(result, Z_LVAL_P(op2) ? -1 : 0);
            return SUCCESS;
             
         case TYPE_PAIR(IS_BOOL, IS_NULL):
            ZVAL_LONG(result, Z_LVAL_P(op1) ? 1 : 0);
            return SUCCESS;
             
         case TYPE_PAIR(IS_BOOL, IS_BOOL):
            ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_STRING, IS_STRING):
            zendi_smart_strcmp(result, op1, op2);
            return SUCCESS;
             
         case TYPE_PAIR(IS_NULL, IS_STRING):
            ZVAL_LONG(result, zend_binary_strcmp("", 0, Z_STRVAL_P(op2), Z_STRLEN_P(op2)));
            return SUCCESS;
             
         case TYPE_PAIR(IS_STRING, IS_NULL):
            ZVAL_LONG(result, zend_binary_strcmp(Z_STRVAL_P(op1), Z_STRLEN_P(op1), "", 0));
            return SUCCESS;
             
         case TYPE_PAIR(IS_OBJECT, IS_NULL):
            ZVAL_LONG(result, 1);
            return SUCCESS;
             
         case TYPE_PAIR(IS_NULL, IS_OBJECT):
            ZVAL_LONG(result, -1);
            return SUCCESS;
             
         case TYPE_PAIR(IS_OBJECT, IS_OBJECT):
            /* If both are objects sharing the same comparision handler then use is */
            if (Z_OBJ_HANDLER_P(op1,compare_objects) == Z_OBJ_HANDLER_P(op2,compare_objects)) {
               if (Z_OBJ_HANDLE_P(op1) == Z_OBJ_HANDLE_P(op2)) {
                  /* object handles are identical, apparently this is the same object */
                  ZVAL_LONG(result, 0);
                  return SUCCESS;
               }
               ZVAL_LONG(result, Z_OBJ_HT_P(op1)->compare_objects(op1, op2 TSRMLS_CC));
               return SUCCESS;
            }
            /* break missing intentionally */
             
         default:
            if (Z_TYPE_P(op1) == IS_OBJECT) {
               if (Z_OBJ_HT_P(op1)->get) {
                  op_free = Z_OBJ_HT_P(op1)->get(op1 TSRMLS_CC);
                  ret = compare_function(result, op_free, op2 TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op2) != IS_OBJECT && Z_OBJ_HT_P(op1)->cast_object) {
                  ALLOC_INIT_ZVAL(op_free);
                  if (Z_OBJ_HT_P(op1)->cast_object(op1, op_free, Z_TYPE_P(op2) TSRMLS_CC) == FAILURE) {
                     ZVAL_LONG(result, 1);
                     zend_free_obj_get_result(op_free TSRMLS_CC);
                     return SUCCESS;
                  }
                  ret = compare_function(result, op_free, op2 TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               }
            }
            if (Z_TYPE_P(op2) == IS_OBJECT) {
               if (Z_OBJ_HT_P(op2)->get) {
                  op_free = Z_OBJ_HT_P(op2)->get(op2 TSRMLS_CC);
                  ret = compare_function(result, op1, op_free TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op1) != IS_OBJECT && Z_OBJ_HT_P(op2)->cast_object) {
                  ALLOC_INIT_ZVAL(op_free);
                  if (Z_OBJ_HT_P(op2)->cast_object(op2, op_free, Z_TYPE_P(op1) TSRMLS_CC) == FAILURE) {
                     ZVAL_LONG(result, -1);
                     zend_free_obj_get_result(op_free TSRMLS_CC);
                     return SUCCESS;
                  }
                  ret = compare_function(result, op1, op_free TSRMLS_CC);
                  zend_free_obj_get_result(op_free TSRMLS_CC);
                  return ret;
               } else if (Z_TYPE_P(op1) == IS_OBJECT) {
                  ZVAL_LONG(result, 1);
                  return SUCCESS;
               }
            }
            if (!converted) {
               if (Z_TYPE_P(op1) == IS_NULL) {
                  zendi_convert_to_boolean(op2, op2_copy, result);
                  ZVAL_LONG(result, Z_LVAL_P(op2) ? -1 : 0);
                  return SUCCESS;
               } else if (Z_TYPE_P(op2) == IS_NULL) {
                  zendi_convert_to_boolean(op1, op1_copy, result);
                  ZVAL_LONG(result, Z_LVAL_P(op1) ? 1 : 0);
                  return SUCCESS;
               } else if (Z_TYPE_P(op1) == IS_BOOL) {
                  zendi_convert_to_boolean(op2, op2_copy, result);
                  ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
                  return SUCCESS;
               } else if (Z_TYPE_P(op2) == IS_BOOL) {
                  zendi_convert_to_boolean(op1, op1_copy, result);
                  ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(op1) - Z_LVAL_P(op2)));
                  return SUCCESS;
               } else {
                  zendi_convert_scalar_to_number(op1, op1_copy, result);
                  zendi_convert_scalar_to_number(op2, op2_copy, result);
                  converted = 1;
               }
            } else if (Z_TYPE_P(op1)==IS_ARRAY) {
               ZVAL_LONG(result, 1);
               return SUCCESS;
            } else if (Z_TYPE_P(op2)==IS_ARRAY) {
               ZVAL_LONG(result, -1);
               return SUCCESS;
            } else if (Z_TYPE_P(op1)==IS_OBJECT) {
               ZVAL_LONG(result, 1);
               return SUCCESS;
            } else if (Z_TYPE_P(op2)==IS_OBJECT) {
               ZVAL_LONG(result, -1);
               return SUCCESS;
            } else {
               ZVAL_LONG(result, 0);
               return FAILURE;
            }
      }     
   }         
}             
/* }}} */
로그인 후 복사

接着看一下array 和string 怎么比较的

==》zend_hash_compare 在Zend/zend_hash.c中

ZEND_API int zend_hash_compare(HashTable *ht1, HashTable *ht2, compare_func_t compar, zend_bool ordered TSRMLS_DC)
{            
     Bucket *p1, *p2 = NULL;
     int result;
     void *pData2;
             
     IS_CONSISTENT(ht1);
     IS_CONSISTENT(ht2);
             
     HASH_PROTECT_RECURSION(ht1);.
     HASH_PROTECT_RECURSION(ht2);.
             
     result = ht1->nNumOfElements - ht2->nNumOfElements;
     if (result!=0) {
          HASH_UNPROTECT_RECURSION(ht1);.
          HASH_UNPROTECT_RECURSION(ht2);.
          return result;
     }        
             
     p1 = ht1->pListHead;
     if (ordered) {
          p2 = ht2->pListHead;
     }         
             
     while (p1) {
          if (ordered && !p2) {
               HASH_UNPROTECT_RECURSION(ht1);.
               HASH_UNPROTECT_RECURSION(ht2);.
               return 1; /* That's not supposed to happen */
          }    
          if (ordered) {
               if (p1->nKeyLength==0 && p2->nKeyLength==0) { /* numeric indices */
                    result = p1->h - p2->h;
                    if (result!=0) {
                         HASH_UNPROTECT_RECURSION(ht1);.
                         HASH_UNPROTECT_RECURSION(ht2);.
                         return result;
                    }
               } else { /* string indices */
                    result = p1->nKeyLength - p2->nKeyLength;
                    if (result!=0) {
                         HASH_UNPROTECT_RECURSION(ht1);.
                         HASH_UNPROTECT_RECURSION(ht2);.
                         return result;
                    }
                    result = memcmp(p1->arKey, p2->arKey, p1->nKeyLength);
                    if (result!=0) {
                         HASH_UNPROTECT_RECURSION(ht1);.
                         HASH_UNPROTECT_RECURSION(ht2);.
                         return result;
                    }
               }
               pData2 = p2->pData;
          } else {
               if (p1->nKeyLength==0) { /* numeric index */
                    if (zend_hash_index_find(ht2, p1->h, &pData2)==FAILURE) {
                         HASH_UNPROTECT_RECURSION(ht1);.
                         HASH_UNPROTECT_RECURSION(ht2);.
                         return 1;
                    }
               } else { /* string index */
                    if (zend_hash_quick_find(ht2, p1->arKey, p1->nKeyLength, p1->h, &pData2)==FAILURE) { 
                         HASH_UNPROTECT_RECURSION(ht1);.
                         HASH_UNPROTECT_RECURSION(ht2);.
                         return 1;
                    }
               } 
          }     
          result = compar(p1->pData, pData2 TSRMLS_CC);
          if (result!=0) {
               HASH_UNPROTECT_RECURSION(ht1);.
               HASH_UNPROTECT_RECURSION(ht2);.
               return result;
          }     
          p1 = p1->pListNext;
          if (ordered) {
               p2 = p2->pListNext;
          }     
     }         
               
     HASH_UNPROTECT_RECURSION(ht1);.
     HASH_UNPROTECT_RECURSION(ht2);.
     return 0; 
}
로그인 후 복사

==》还有一个 zendi_smart_strcmp 在Zend/zend_operators.c中

ZEND_API void zendi_smart_strcmp(zval *result, zval *s1, zval *s2) /* {{{ */
{    
     int ret1, ret2;
     int oflow1, oflow2;
     long lval1, lval2;
     double dval1, dval2;
     
     if ((ret1=is_numeric_string_ex(Z_STRVAL_P(s1), Z_STRLEN_P(s1), &lval1, &dval1, 0, &oflow1)) &&
          (ret2=is_numeric_string_ex(Z_STRVAL_P(s2), Z_STRLEN_P(s2), &lval2, &dval2, 0, &oflow2))) {
#if ULONG_MAX == 0xFFFFFFFF
          if (oflow1 != 0 && oflow1 == oflow2 && dval1 - dval2 == 0. &&
               ((oflow1 == 1 && dval1 > 9007199254740991. /*0x1FFFFFFFFFFFFF*/)
                    (oflow1 == -1 && dval1 < -9007199254740991.))) {
#else
          if (oflow1 != 0 && oflow1 == oflow2 && dval1 - dval2 == 0.) {
#endif
               /* both values are integers overflown to the same side, and the
                * double comparison may have resulted in crucial accuracy lost */
               goto string_cmp;
          }
          if ((ret1==IS_DOUBLE)      (ret2==IS_DOUBLE)) {
               if (ret1!=IS_DOUBLE) {
                    if (oflow2) {
                         /* 2nd operand is integer > LONG_MAX (oflow2==1) or < LONG_MIN (-1) */
                         ZVAL_LONG(result, -1 * oflow2);
                         return;
                    }
                    dval1 = (double) lval1;
               } else if (ret2!=IS_DOUBLE) {
                    if (oflow1) {
                         ZVAL_LONG(result, oflow1);
                         return;
                    }
                    dval2 = (double) lval2;
               } else if (dval1 == dval2 && !zend_finite(dval1)) {
                    /* Both values overflowed and have the same sign,
                     * so a numeric comparison would be inaccurate */
                    goto string_cmp;
               }
               Z_DVAL_P(result) = dval1 - dval2;
               ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_DVAL_P(result)));
          } else { /* they both have to be long's */
               ZVAL_LONG(result, lval1 > lval2 ? 1 : (lval1 < lval2 ? -1 : 0));
          }
     } else {
string_cmp:
          Z_LVAL_P(result) = zend_binary_zval_strcmp(s1, s2);
          ZVAL_LONG(result, ZEND_NORMALIZE_BOOL(Z_LVAL_P(result)));
     }
}   
/* }}} *
로그인 후 복사

我们这个类型转换函数 is_numeric_string_ex 在 Zend/zend_operators.h

继续跟踪

==》is_numeric_string_ex

static inline zend_uchar is_numeric_string_ex(const char *str, int length, long *lval, double *dval, int allow_errors, int *oflow_info)
{
     const char *ptr;
     int base = 10, digits = 0, dp_or_e = 0;
     double local_dval;
     zend_uchar type;
 
     if (!length) {
          return 0;
     }
 
     if (oflow_info != NULL) {
          *oflow_info = 0;
     }
 
     /* Skip any whitespace
      * This is much faster than the isspace() function */
     while (*str == ' '      *str == '\t'      *str == '\n'      *str == '\r'      *str == '\v'      *str == '\f') {
          str++;
          length--;
     }
     ptr = str;
 
     if (*ptr == '-'      *ptr == '+') {
          ptr++;
     }
 
     if (ZEND_IS_DIGIT(*ptr)) {
          /* Handle hex numbers
           * str is used instead of ptr to disallow signs and keep old behavior */
          if (length > 2 && *str == '0' && (str[1] == 'x'      str[1] == 'X')) {
               base = 16;
               ptr += 2;
          }
 
          /* Skip any leading 0s */
          while (*ptr == '0') {
               ptr++;
          }
 
          /* Count the number of digits. If a decimal point/exponent is found,
           * it's a double. Otherwise, if there's a dval or no need to check for
           * a full match, stop when there are too many digits for a long */
          for (type = IS_LONG; !(digits >= MAX_LENGTH_OF_LONG && (dval      allow_errors == 1)); digits++, ptr++) {
check_digits:
               if (ZEND_IS_DIGIT(*ptr)      (base == 16 && ZEND_IS_XDIGIT(*ptr))) {
                    continue;
               } else if (base == 10) {
                    if (*ptr == '.' && dp_or_e < 1) {
                         goto process_double;
                    } else if ((*ptr == 'e'      *ptr == 'E') && dp_or_e < 2) {
                         const char *e = ptr + 1;
 
                         if (*e == '-'      *e == '+') {
                              ptr = e++;
                         }
                         if (ZEND_IS_DIGIT(*e)) {
                              goto process_double;
                         }
                    }
               }
 
               break;
          }
 
          if (base == 10) {
               if (digits >= MAX_LENGTH_OF_LONG) {
                    if (oflow_info != NULL) {
                         *oflow_info = *str == '-' ? -1 : 1;
                    }
                    dp_or_e = -1;
                    goto process_double;
               }
          } else if (!(digits < SIZEOF_LONG * 2      (digits == SIZEOF_LONG * 2 && ptr[-digits] <= '7'))) {
               if (dval) {
                    local_dval = zend_hex_strtod(str, &ptr);
               }
               if (oflow_info != NULL) {
                    *oflow_info = 1;
               }
               type = IS_DOUBLE;
          }
     } else if (*ptr == '.' && ZEND_IS_DIGIT(ptr[1])) {
process_double:
          type = IS_DOUBLE;
 
          /* If there's a dval, do the conversion; else continue checking
           * the digits if we need to check for a full match */
          if (dval) {
               local_dval = zend_strtod(str, &ptr);
          } else if (allow_errors != 1 && dp_or_e != -1) {
               dp_or_e = (*ptr++ == '.') ? 1 : 2;
               goto check_digits;
          }
     } else {
          return 0;
     }
 
     if (ptr != str + length) {
          if (!allow_errors) {
               return 0;
          }
          if (allow_errors == -1) {
               zend_error(E_NOTICE, "A non well formed numeric value encountered");
          }
     }
 
     if (type == IS_LONG) {
          if (digits == MAX_LENGTH_OF_LONG - 1) {
               int cmp = strcmp(&ptr[-digits], long_min_digits);
 
               if (!(cmp < 0      (cmp == 0 && *str == '-'))) {
                    if (dval) {
                         *dval = zend_strtod(str, NULL);
                    }
                    if (oflow_info != NULL) {
                         *oflow_info = *str == '-' ? -1 : 1;
                    }
 
                    return IS_DOUBLE;
               }
          }
 
          if (lval) {
               *lval = strtol(str, NULL, base);
          }
 
          return IS_LONG;
     } else {
          if (dval) {
               *dval = local_dval;
          }
 
          return IS_DOUBLE;
     }
}
로그인 후 복사

type == IS_LONG时果然有这个代码

截取这一段代码

&hellip;&hellip;
if (type == IS_LONG) {
     if (digits == MAX_LENGTH_OF_LONG - 1) {
          int cmp = strcmp(&ptr[-digits], long_min_digits);

          if (!(cmp < 0      (cmp == 0 && *str == '-'))) {
               if (dval) {
                    *dval = zend_strtod(str, NULL);
               }
               if (oflow_info != NULL) {
                    *oflow_info = *str == '-' ? -1 : 1;
               }

               return IS_DOUBLE;
          }
     }

     if (lval) {
          *lval = strtol(str, NULL, base);
     }

     return IS_LONG;
}
&hellip;&hellip;
로그인 후 복사

原来如此  strtol 在这里的

관련 라벨：
include
원천：php.cn
이전 기사：一段phpcurl代码，phpcurl代码 다음 기사：PHP递归创建多级目录，php递归
본 웹사이트의 성명
본 글의 내용은 네티즌들의 자발적인 기여로 작성되었으며, 저작권은 원저작자에게 있습니다. 본 사이트는 이에 상응하는 법적 책임을 지지 않습니다. 표절이나 침해가 의심되는 콘텐츠를 발견한 경우 admin@php.cn으로 문의하세요.
저자별 최신 기사
최신 이슈
mysql의 jpg 이미지를 html에 추가 서문으로서 저는 이것에 대해 매우 생소하기 때문에 어리석은 질문일 수도 있습니다. 그러나... 저는 "상점"에 대한 제품 정보를 저장하는 데이터...
에서 2024-04-02 13:27:34
0
1
344
관련 주제
더>
인기 추천
인기 튜토리얼
더>
관련 튜토리얼
인기 추천
최신 강좌
최신 다운로드
더>
웹 효과
웹사이트 소스 코드
웹사이트 자료
프론트엔드 템플릿