Linux API使用 - 正則表達式regex

使用那麼多的接口了，開始從正則開始記錄吧，還是得養成記錄的習慣，將已經寫好的代碼放出來，這纔是你自己的，同時也是大家的。

#include <regex.h>

int main()
{
    int status ,i;
	int cflags = REG_EXTENDED;
	regmatch_t pmatch[10];
	const size_t nmatch = 10;
	regex_t reg;
	char match[100];
	//char data[10][100] = {0};
	char data[nmatch][100];
	memset(data,0x0,sizeof(data));
	//printf("sizeof data %d\n", sizeof(data));
	const char * pattern = "^[^:]+: *([a-zA-Z]) *, *([\-]*[0-9]+) *, *Speed *: *([0-9]+) *, *Acc *: *([0-9]+)$";
	//const char * pattern = "^[^:]+: *([a-zA-Z]) *, *([\-|0-9][0-9]*) *, *Speed *: *([0-9]+) *, *Acc *: *([0-9]+)$";
	char * buf = "SingleAxis : x, -100 ,   Speed: 30,Acc : 30";
	regcomp(&reg,pattern,cflags);//編譯正則模式
	status = regexec(&reg,buf,nmatch,pmatch,0);//執行正則表達式和緩存的比較
	if(status == REG_NOMATCH)
		printf("No match\n");
	else if (0 == status)
	{
		for(int i=0; i < 10 && pmatch[i].rm_so != -1; i++) {
		    int len = pmatch[i].rm_eo - pmatch[i].rm_so;
		    printf("i %d => len:%d\n",i,len);
		    if(len) {
		        memset(match,'\0',sizeof(match));
		        memcpy(match, buf + pmatch[i].rm_so,len);
		        // get axis distance speed acc from i == 1
		        printf("match %d:%s\n",i,match);
		        if(i >= 1) {
			        printf("ready to copy to data[%d] addr %p\n",i-1,data[i-1]);
			        printf("len now is %d\n", len);
		        	memcpy(data[i-1],match,len);
		        	printf("length:%d\n",strlen(data[i-1]));
		        	printf("data[%d]:%s\n",i,data[i-1]);
		        }
		    }
		}
	}
}

簡要的使用流程按照如上形式即可，這裏對正則表達式做一些說明。
注意：

1. regexec 需要判斷結果
2. pmatch數組中存放者匹配的結果
3. 如果需要類似python中的group的功能，需要在匹配表達式中加上()
4. regmatch_t結構體中的rm_eo,rm_so分別表明了匹配的開始和結束，兩者相減 表明了匹配的長度

運行結果：

i 0 => len:43
match 0:SingleAxis : x, -100 ,   Speed: 30,Acc : 30
i 1 => len:1
match 1:x
ready to copy to data[0] addr 0x7ffef92cc340
len now is 1
length:1
data[1]:x
i 2 => len:4
match 2:-100
ready to copy to data[1] addr 0x7ffef92cc3a4
len now is 4
length:4
data[2]:-100
i 3 => len:2
match 3:30
ready to copy to data[2] addr 0x7ffef92cc408
len now is 2
length:2
data[3]:30
i 4 => len:2
match 4:30
ready to copy to data[3] addr 0x7ffef92cc46c
len now is 2
length:2
data[4]:30