/*  IPUSH.C is a simple gif animation script using server a push technique. 
 *  it is based on Rob McCools hack DOIT.C and contains much of the original 
 *  code.  I have modified it to allow for the image name, number of frames
 *  and the refresh rate to be sent as paramters.  The ONLY line that needs
 *  to be edited in this code is the IMAGEPATH below.  Set this directory to
 *  where you keep the image files. 
 *
 *  USAGE:  <img src="http://www.blah.com/cgi-bin/ipush?name+x+y
 *          name = the prefix of all the gifs in an animation.
 *          x = the number of gifs in the animation.
 *          y = refresh rate of the animation.  try 1 to start with.
 * 
 *         i.e. <img src="http://www.blah.com/cgi-bin/ipush?dog+8+1>
 *              would server the images dog1.gif through dog8.gif with a
 *              refresh rate of 1.
 *
 *   Hope you enjoy!!!
 *   
 *   Chris Stephens  stephenc@pcmail.cbil.vcu.edu
 *   http://darkwing.cbil.vcu.edu/cworld/cworld.gmml
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdio.h>

#define HEADER \
"Content-type: multipart/x-mixed-replace;boundary=ThisRandomString\n" \

#define IMAGEPATH "../htdocs/cworld/"
#define RANDOMSTRING "\n--ThisRandomString\n"
#define ENDSTRING "\n--ThisRandomString--\n"
#define CTSTRING "Content-type: image/gif\n\n"

int main(int argc, char *argv[])
{
    struct stat fi;
    char fn[32];
    caddr_t fp;
    int x;
    int fd;
    int lastimage;
    int refresh;

    if(write(STDOUT_FILENO, HEADER, strlen(HEADER)) == -1)
        exit(0);
    if(write(STDOUT_FILENO, RANDOMSTRING, strlen(RANDOMSTRING)) == -1)
        exit(0);
    sscanf(argv[2],"%d",&lastimage);
    sscanf(argv[3],"%d",&refresh);
    x = 1;

    while(1) {
        sleep(refresh);
        if(write(STDOUT_FILENO, CTSTRING, strlen(CTSTRING)) == -1)
            exit(0);
        sprintf(fn, "%s%s%d.gif",IMAGEPATH,argv[1], x);
        if( (fd = open(fn, O_RDONLY)) == -1)
            continue;
        fstat(fd, &fi);
        fp = mmap(NULL, fi.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        if(fp == (caddr_t) -1)
            exit(0);
        if(write(STDOUT_FILENO, (void *) fp, fi.st_size) == -1)
            exit(0);
        munmap(fp, fi.st_size);
        close(fd);
        if(write(STDOUT_FILENO, RANDOMSTRING, strlen(RANDOMSTRING)) == -1)
            exit(0);
        if(x == lastimage) goto thats_it;
        else ++x;
    }

thats_it:
    exit (0);
}