http server v0.1_http_webapp.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
/*-----------------------------------------------------------------

functionname: file_exist
param:  NA
return: NA
author: xxxx
    
    check if file is exist in webapp
    history:    
    create by xxxx, 2014.1.08, add simple abilities
-------------------------------------------------------------*/
int file_exist(char* url)
{
    int ret;
    int len = 0;
    char* path= NULL;

    if(url == NULL)
        return -1;
    
    len = strlen(url);
    if(len  <= 0)
        return -1;
    
    path = (char*)malloc(len);
    strncpy(path, url, len);
    
    printf("[%s]\n", path);
    // remove blanks on head and tailof url
    ret = access(path, R_OK);
    if(ret == -1)
        perror("uri not exist");
        
    free(path);
    return ret;     
    
}


long get_file_size(FILE* fs)
{
    if(fs == NULL)
        return -1;
    
    fseek(fs, 0, SEEK_END);
    return ftell(fs);
}


char *itoa(int num, char *str, int radix)
{
        //0的情况
        if (num==0)
        {
                str[0]='0';
                str[1]='\0';
                return str;
        }

        char string[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        char* ptr = str;
        int i;
        int j;


        while (num)
        {
                *ptr++ = string[num % radix];
                num /= radix;

                if (num < radix)
                {
                        *ptr++ = string[num];
                        *ptr = '\0';
                        break;
                }
        }
        //两边对调
        j = ptr - str - 1;

        for (i = 0; i < (ptr - str) / 2; i++)
        {
                int temp = str[i];
                str[i] = str[j];
                str[j--] = temp;
        }

        return str;
}

int io_write(int fd, void *usrbuf, int n) 
{
    int nleft = n;
    int nwritten;
    char *bufp = usrbuf;

    while (nleft > 0) {
    if ((nwritten = write(fd, bufp, nleft)) <= 0) {
        if (errno == EINTR)  /* interrupted by sig handler return */
        nwritten = 0;    /* and call write() again */
        else
        return -1;       /* errorno set by write() */
    }
    nleft -= nwritten;
    bufp += nwritten;
    }
    return n;
}

#ifndef __HTTP_WEBAPP_H
#define __HTTP_WEBAPP_H


int file_exist(char* url);
long get_file_size(FILE* fs);
int io_write(int fd, void *usrbuf, int n);
char *itoa(int num, char *str, int radix);

#endif