Linux进阶篇：磁盘管理（二）：LVM的创建、格式化和使用

由于C语言的正则表达式API相对比较简易.默认API只有regcomp/regerror/regexec/regfree这些函数.相对于其他的高级语言中正则表达式所所能实现的功能(如:查找/替换)有所欠缺.所以想着自己写下一些需要的函数以备后续需要使用.

#ifndef _E_REGEX_INCLUDE
#define _E_REGEX_INCLUDE
#include <regex.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>

typedef int errno_t;

static size_t position = 0;

//functions prototype
char* regnext(regex_t* regex,char* content);
void _r_release(void);
bool regreplace(regex_t* regex,char** content,char* replacement);
void regreplaceAll(regex_t* regex,char** content,char* replacement);

int main(void){
	char* content = (char*)"sjdlf12323ldjslfjsjf133334";
	char* pattern = (char*)"([[:digit:]][[:digit:]])\\1";
	regex_t regex;
	errno_t state = regcomp(&regex,pattern,REG_EXTENDED);
	if(state){
		char* errbuf = calloc(20,sizeof(char));
		regerror(state,&regex,errbuf,20);
		fprintf(stderr,"Regex:%s compile failed.\n"
					   "Reason: %s\n",pattern,errbuf);
		free(errbuf);
		regfree(&regex);
		exit(EXIT_FAILURE);
	}
	
	printf("content: %s\n",content);
	char* replacement = (char*)"";
	regreplaceAll(&regex,&content,replacement);
	printf("content: %s\n",content);
    regfree(&regex);
}



//find next match
char* regnext(regex_t* regex,char* content){
	regmatch_t matches[regex->re_nsub + 1];
	errno_t state = regexec(regex,content,regex->re_nsub + 1,matches,0);
	if(state == REG_NOMATCH){
		_r_release();
		return NULL;
	}
	char* reval = (char*)calloc(matches[0].rm_eo - matches[0].rm_so + 1,sizeof(char));
	memcpy(reval,content + position + matches[0].rm_so,matches[0].rm_eo - matches[0].rm_so);
	position += matches[0].rm_eo;
	return reval;
}

//replace first
bool regreplace(regex_t* regex,char** content,char* replacement){
	regmatch_t matches[regex->re_nsub + 1];
	errno_t state = regexec(regex,*content,regex->re_nsub + 1,matches,0);
	if(state == REG_NOMATCH){
		return false;
	}
	char* newContent = (char*)calloc(strlen(*content) + strlen(replacement) - (matches[0].rm_eo - matches[0].rm_so),sizeof(char));
	size_t head = matches[0].rm_so;
	size_t middle = strlen(replacement);
	size_t end = strlen(*content) - matches[0].rm_eo;
	memcpy(newContent,*content,head);
	memcpy(newContent + head,replacement,middle);
	memcpy(newContent + head + middle,*content + matches[0].rm_eo,end);
	*content = newContent;
	return true;
}

//replace all
void regreplaceAll(regex_t* regex,char** content,char* replacement){
	for(;regreplace(regex,content,replacement););
}


void _r_release(void){
	position = 0;
}


#endif