纯C 实现 strpos substr strspilt str_trim

在C 语言中没有C++ 好用的 spilt 方法 (STL 带的也不怎么好用)

 #include <stdio.h>
 #include <string.h>
 #include <iostream>
 using namespace std;

 int Cstrpos(char *haystack, const char *needle)
 {
     char *p;
     p = strstr(haystack, needle);
     if(p)
     {
         return p - haystack;
     }
     return -;
 }

 int Csubstr(char *haystack, int start, int len, char *out)
 {
     int i;
     for(i=; i<len; i++)
     {
         out[i] = haystack[start+i];
     }
     return ;
 }

 char *Csplit(char *haystack, const char *needle, char *out)
 {
     int start, end, offset, i;
     //match start
     if( == memcmp(haystack, needle, strlen(needle)))
     {
         start = Cstrpos(haystack, needle);
         if(- == start)
         {
             return NULL;
         }
     }
     else
     {
         start = ;
     }
     end   = Cstrpos(haystack+start, needle);
     if(- == end)
     {
         end = strlen(haystack) - start;
     }
     offset = end;

     for(i=; i<offset; i++)
     {
         out[i] = haystack[i];
     }
     haystack += i+; 

     return haystack;
 }

 int main(int argc, char **argv)
 {
     //char *str = "123,456,789"; //2个测试字符串
     char *str = "";
     cout<<str<<endl;

     int pos1;
     pos1 = Cstrpos(str, ",");
     cout<<pos1<<endl;

     char out[] = {};

     //Csubstr(str, 1, 3, out);
     //cout<<out<<endl;

     cout<<"+++++++++++++++++++++"<<endl;

     memset(out, , );
     str = Csplit(str, ",", out);
     cout<<out<<endl;

     cout<<"+++++++++++++++++++++"<<endl;

     memset(out, , );
     str = Csplit(str, ",", out);
     cout<<out<<endl;

     cout<<"+++++++++++++++++++++"<<endl;

     memset(out, , );
     str = Csplit(str, ",", out);
     cout<<out<<endl;

     cout<<"+++++++++++++++++++++"<<endl;

     memset(out, , );
     str = Csplit(str, ",", out);
     cout<<out<<endl;

     return ;
 }

因为也包含了测试程序 使用 cout 输出，所以使用 g++ 编译，执行。但3个函数是 可以移值到 ARM 、 KEIL、STM32 中的。

测试123,456,789

测试123

这个，目前还有一个缺点，分隔符只支持1个字符。

补发一个，实现的 str_trim 函数  需要头文件 #include <ctype.h>

 static void str_trim(char *str)
 {
     int len;
     char *copy;
     char *end, *start;

     len   = strlen(str);
     copy  = (char *)malloc(len + );

     if(! copy)
     {
         logd("malloc error \n");
         return ;
     }

     memset(copy, , len + );
     strcpy(copy, str);
     start = copy;
     end   = start + len - ;

     while(end >= start)
     {
         if(! isgraph(*end))
         {
             *end = '\0';
             end--;
         }
         else
         {
             break;
         }
     }

     len   = strlen(copy);
     end   = start + len - ;
     while(start <= end)
     {
         if(! isgraph(*start))
         {
             start++;
         }
         else
         {
             break;
         }
     }

     strcpy(str, start);
     free(copy);
 }