PCRE接口pcre_fullinfo混合子模式调用结果

NGINX中使用PCRE最为正则表达式的解析接口,对编译和解析过程中的一些点进行了测试验证

PCRE接口pcre_fullinfo()的描述在这个链接中有详细的描述,这里对接口的一些

链接 http://mushclient.com/pcre/index.html

这里描述一下命名子模式(named subpattern)和非命名子模式(numbering subpattern)混合使用的情况接口

PCRE_INFO_CAPTURECOUNT: 得到的是所有子模式的个数,包含上述的两种子模式个数;

PCRE_INFO_NAMECOUNT: 得到的是命名子模式的个数,不包括非命名子模式的个数;

PCRE_INFO_NAMETABLE:

对于只有命名子模式的情况,例如文档描述的一个例子:

 (?<date> (?<year>(\d\d)?\d\d) - (?<month>\d\d) - (?<day>\d\d) )

 00 01 d  a  t  e  00 ??  00 05 d  a  y  00 ?? ??  00 04 m  o  n  t  h  00  00 02 y  e  a  r  00 ??

而对于混合模式;例子如下,注意开头的两个数字,就是说capture的数字是和非命名子模式一起排列的,也就是根据左括号的先后排列的:

(eeeee)(?<abb> exception)(?<adfa>xydz)(ddddd)\k<abb>\1\2

{captures 4 

named_captures 2 
name_size 7}

 
0 2 abb?? 
0 3 adfa 

测试例子

#include <stdlib.h>#include <pcre.h>#define NGX_REGEX_CASELESS    PCRE_CASELESStypedef struct {    pcre        *code;    pcre_extra  *extra;} ngx_regex_t;int main(){    pcre  *re;    char       *errstr;    int  erroff;    int captures =0, named_captures, name_size;    char  *name;    char  *data = "(eeeee)(?<abb> exception)(?<adfa>xydz)(ddddd)\\k<abb>\\1\\2";    int n, i;    char  *p;     printf("%s \n", data);    p = data;    printf("%s \n", p);    re = pcre_compile(data, PCRE_CASELESS, &errstr, &erroff, NULL);    if(NULL == re)    {        printf("compile pcre failed\n");        return 0;    }        n = pcre_fullinfo(re, NULL, PCRE_INFO_CAPTURECOUNT, &captures);    if(n < 0)    {         printf("pcre_fullinfo PCRE_INFO_CAPTURECOUNT failed %d \n", n);         return 0;    }                 printf(" captures %d \n", captures);    n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMECOUNT, &named_captures);    if(n < 0)    {         printf("pcre_fullinfo PCRE_INFO_NAMECOUNT failed %d \n", n);         return 0;    }    printf("named_captures %d \n", named_captures);    n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMEENTRYSIZE, &name_size);     if(n < 0)     {          printf("pcre_fullinfo PCRE_INFO_NAMEENTRYSIZE failed %d \n", n);           return 0;      }     printf("name_size %d \n", name_size);     n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMETABLE, &name);    if(n < 0)    {       printf("pcre_fullinfo PCRE_INFO_NAMETABLE failed %d \n", n);       return 0;      }    p =name;    int j;   for(j = 0; j < named_captures; j++)   {        for(i = 0; i <2; i++)        {                    printf("%x ", p[i]);              }                      printf("%s \n", &p[2]);        p += name_size;        }    return 1;}