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 -1;
}

int Csubstr(char *haystack, int start, int len, char *out)
{
    int i;
    for(i=0; i<len; i++)
    {
        out[i] = haystack[start+i];
    }
    return 0;
}

char *Csplit(char *haystack, const char *needle, char *out)
{
    int start, end, offset, i;
    //match start
    if(0 == memcmp(haystack, needle, strlen(needle)))
    {
        start = Cstrpos(haystack, needle);
        if(-1 == start)
        {
            return NULL;
        }
    }
    else
    {
        start = 0;    
    }
    end   = Cstrpos(haystack+start, needle);
    if(-1 == end)
    {
        end = strlen(haystack) - start;
    }
    offset = end;
    
    for(i=0; i<offset; i++)
    {
        out[i] = haystack[i];
    }
    haystack += i+1; 
    
    return haystack;
}

int main(int argc, char **argv)
{
    //char *str = "123,456,789"; //2个测试字符串
    char *str = "123";
    cout<<str<<endl;
    
    int pos1;
    pos1 = Cstrpos(str, ",");
    cout<<pos1<<endl;
    
    char out[10] = {0};
    
    //Csubstr(str, 1, 3, out);
    //cout<<out<<endl;
    
    cout<<"+++++++++++++++++++++"<<endl;
    
    memset(out, 0, 10);
    str = Csplit(str, ",", out);
    cout<<out<<endl;
    
    cout<<"+++++++++++++++++++++"<<endl;
    
    memset(out, 0, 10);
    str = Csplit(str, ",", out);
    cout<<out<<endl;
    
    
    cout<<"+++++++++++++++++++++"<<endl;
    
    memset(out, 0, 10);
    str = Csplit(str, ",", out);
    cout<<out<<endl;
        
    cout<<"+++++++++++++++++++++"<<endl;
    
    memset(out, 0, 10);
    str = Csplit(str, ",", out);
    cout<<out<<endl;
    
    return 0;
}

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 + 1);
    
    if(! copy)
    {
        logd("malloc error 
");
        return ;
    }
    
    memset(copy, 0, len + 1);
    strcpy(copy, str);
    start = copy;
    end   = start + len - 1;
    
    while(end >= start)
    {
        if(! isgraph(*end))
        {
            *end = '';
            end--;
        }
        else
        {
            break;
        }
    }
    
    len   = strlen(copy);
    end   = start + len - 1;
    while(start <= end)
    {
        if(! isgraph(*start))
        {
            start++;
        }
        else
        {
            break;
        }
    }

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