PCRE、PCRE2 以及PCRE++ 使用教程
PCRE、PCRE2 以及PCRE++ 库的源码，PCER2 参考我的博客。
2.VS2008 建立一个win32 程序 ，工程名PcreDemo。
3.将所需的DLL 和 lib 拷贝进工程相应目录，并进行相关设置
4. pcre 简单使用
pcre *re;
const char *error;
int erroffset;
int ovector[OVECCOUNT];
int rc;
string strOrg = “I am hk!”;
string strRex = “\\b\\w+\\b“;
printf(“前言：以下例子只是非常简单的应用，仅供参考！\n pcreD.dll pcre2.dll pcre++.dll pcreD.lib pcre2.lib pcre++.lib 请按照文档网址自行下载并编译！\n”);
printf(“\n\n\n”);
printf(” PCRE 1 库 应用实例:\n\n”);
printf(“字符串是 : %s\n”, strOrg.c_str());
printf(“正则表达式是: %s\n\n\n”, strRex.c_str());
char *p = (char *) strOrg.c_str();
re = pcre_compile(strRex.c_str(), // pattern, 输入参数，将要被编译的字符串形式的正则表达式,
PCRE_CASELESS|PCRE_GLOBAL,// options, 输入参数，用来指定编译时的一些选项
&error, // errptr, 输出参数，用来输出错误信息
&erroffset, // erroffset, 输出参数，pattern中出错位置的偏移量
NULL); // tableptr, 输入参数，用来指定字符表，一般情况用NULL
// 返回值：被编译好的正则表达式的pcre内部表示结构
if (re == NULL) { //如果编译失败，返回错误信息
printf(“PCRE compilation failed at offset %d: %s\n”, erroffset, error);
return false;
}
rc = pcre_exec(re, NULL, p, strlen(p), 0, 0, ovector, OVECCOUNT);
if (rc < 0) { //如果没有匹配，返回错误信息
if (rc == PCRE_ERROR_NOMATCH)
printf(“Sorry, no match …\n”);
else
printf(“Matching error %d\n”, rc);
pcre_free(re);
return false;
}
while ( ( rc = pcre_exec(re, NULL, p, strlen(p), 0, 0, ovector, OVECCOUNT)) != PCRE_ERROR_NOMATCH )
{
char *substring_start = p + ovector[0];
int substring_length = ovector[1] – ovector[0];
char matched[1024];
memset( matched, 0, 1024 );
strncpy( matched, substring_start, substring_length );
//strDes = matched;
printf( “全部的匹配结果有:%s\n”, matched );
p += ovector[1];
if (*p == \’\0\’)
{
break;
}
}
pcre_free(re); // 编译正则表达式re 释放内存
5 .pcre2 简单使用
printf(” PCRE 2 库 应用实例:\n\n”);
int error_code = 0;
PCRE2_SIZE error_offset = 0;
int nOptions = 0;
// const char *pError;
string strOrg2 = “I am hk!”;
string strRex2 = “\\b\\w+\\b“;
printf(“字符串是 : %s\n”, strOrg2.c_str());
printf(“正则表达式是: %s\n\n\n”, strRex2.c_str());
//going to compile the regular expression pattern, and handle any errors that are detected
pcre2_code *recm = pcre2_compile(reinterpret_cast<PCRE2_SPTR>(strRex2.c_str()), PCRE2_ZERO_TERMINATED, 0 , &error_code, &error_offset, NULL);
//Compilation failed: print the error message and exit
if (re == NULL)
{
PCRE2_UCHAR buffer[256];
pcre2_get_error_message(error_code, buffer, sizeof(buffer));
printf(“PCRE2 compilation failed at offset %d: %s\n”, (int)error_offset,buffer);
return 1;
}
// Using this function ensures that the block is exactly the right size for the number of capturing parentheses in the pattern.
pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(recm, NULL);
int rc2 = 0;
int start_offset = 0;
unsigned int match_index = 0;
rc2= pcre2_match(recm, reinterpret_cast<PCRE2_SPTR>(strOrg2.c_str()), strOrg2.length(), start_offset, 0, match_data, NULL);
//if(rc < 0)
//{
//
//}
//else
//{
// int pos = start_offset;
// while ((rc = pcre2_match(re, reinterpret_cast<PCRE2_SPTR>(strStruff.c_str()), strStruff.length(), start_offset, 0, match_data, NULL)) > 0)
// {
// pos = start_offset;
// }
//}
if (rc2 < 0)
{
switch(rc2)
{
case PCRE2_ERROR_NOMATCH: printf(“No match\n”); break;
/*
Handle other special cases if you like
*/
default: printf(“Matching error %d\n”, rc2); break;
}
pcre2_match_data_free(match_data); /* Release memory used for the match */
pcre2_code_free(recm); /* data and the compiled pattern. */
return 1;
}
//going to compile the regular expression pattern, and handle any errors that are detected
while ((rc2 = pcre2_match(recm, reinterpret_cast<PCRE2_SPTR>(strOrg2.c_str()), strOrg2.length(), start_offset, 0, match_data, NULL)) > 0)
{
//Match succeded. Get a pointer to the output vector, where string offsets are stored.
PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
int i = 0;
for (i = 0; i < rc2; i++)
{
char *substring_start = (char *)strOrg2.c_str() + ovector[2*i];
int substring_length = ovector[2*i+1] – ovector[2*i];
char matched[1024];
memset( matched, 0, 1024 );
strncpy( matched, substring_start, substring_length );
printf( “全部匹配结果有 :%s\n”,matched );
}
start_offset = ovector[2*(i-1) + 1];
if ( strOrg2[start_offset] == \’\0\’)
{
break;
}
}
pcre2_match_data_free(match_data);
pcre2_code_free(recm);
6.pcre++简单使用
printf(” PCRE++库 应用实例：\n\n”);
/*
* define a string with a regular expression
*/
printf(“官方例子如下：\n”);
string expression = “(\\b\\w+\\b)”;
/*
* this is the string in which we want to search
*/
string stuff = “I am hk!”;
cout << ” searching in \”” << stuff << “\” for regex \””
<< expression << “\”:” << endl;
/*
* Create a new Pcre object, search case-insensitive (“i”)
*/
pcrepp::Pcre reg(expression, “i”);
/*
* see if the expression matched
*/
if(reg.search(stuff) == true) {
/*
* see if the expression generated any substrings
*/
if(reg.matches() >= 1) {
/*
* print out the number of substrings
*/
cout << ” generated ” << reg.matches() << ” substrings:” << endl;
/*
* iterate over the matched sub strings
*/
for(int pos=0; pos < reg.matches(); pos++) {
/* print out each substring */
cout << ” substring ” << pos << “: ” << reg[pos]; // also possible: reg.get_match(pos);
/* print out the start/end offset of the current substring
* within the searched string(stuff)
*/
cout << ” (start: ” << reg.get_match_start(pos) << “, end: “
<< reg.get_match_end(pos) << “)” << endl;
}
}
else {
/*
* we had a match, but it generated no substrings, for whatever reason
*/
cout << ” it matched, but there where no substrings.” << endl;
}
}
else {
/*
* no match at all
*/
cout << ” didn\’t match.” << endl;
}
printf(“我自己做相关封装如下：\n”);
pcrepp::Pcre regg(expression);
int npos = 0;
if ( !regg.search(stuff, npos))
{
return false;
}
while(regg.search(stuff, npos))
{
if(regg.matches() >= 1)
{
string strMatched = regg.get_match(0);
printf(“全部匹配结果有：%s\n”,strMatched.c_str());
npos = regg.get_match_end(0) + 1;
}
}
7. OK!完成啦，有什么问题大家可以给我留言哦！