/*
 * Lengen Copyright 2005 Michael John Wensley
 * This program reads from standard in until there is no more to read.
 * It then outputs the length of data read in bytes followed by the data itself.
 *
 * The purpose of this program is to wrap CGI output so
 * that web servers may do http pipelining for greater efficiency.
 *
 * To compile: gcc -o lengen lengen.c
 */

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

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

extern int optind, opterr, optopt;
static struct option long_options[] = {
	{"help", 0, 0, 'h'},
	{"http", 0, 0, 'w'},
	{"gopher", 0, 0, 'g'},
	{0, 0, 0, 0}
};


int main(argc, argv) 
int argc;
char *argv[];
{
	char c;
	char format = ' ';
	int capacity = 4;
	int size = 0;
	int option_index = 0;

	opterr = 0;
	while ((c = getopt_long(argc, argv, "hwg", long_options, &option_index)) != -1) {
		switch(c) {
			case 'h':
				printf("lengen Copyright 2005 Michael John Wensley\n");
				printf("This program reads in a file on standard in, calculates its length\n");
				printf("then outputs that followed by the file on the standard out.\n");
				printf("\n");
				printf("Use --http or -w for HTTP/1.1 style Content-Length.\n");
				printf("Use --gopher or -g for Gopher Plus style length\n");
				return EXIT_SUCCESS;
				;;
			case 'w':
				format = 'w';
				break;
				;;
			case 'g':
				format = 'g';
				break;
				;;
			default:
				fprintf(stderr, "Usage: %s [--help|--http|--gopher]\n", argv[0]);
				return EXIT_FAILURE;
		}
	}
			
	void *ram = 0;
	while (! feof(stdin)) {

		/* buffer full...? double the capacity like java does */
		if (size == capacity) capacity *= 2;
		
		ram = realloc(ram, capacity);
		if (ram == 0) {
			perror("lengen out of ram");
			return EXIT_FAILURE;
		}
		clearerr(stdin);
		size += fread(ram + size, 1, capacity - size, stdin);
		if (ferror(stdin)) {
			perror("lengen problem with stdin");
			return EXIT_FAILURE;
		}
	}
	switch(format) {
		/* gopherplus style */
		case 'g':
		printf("+%d\n", size);
		break
		;;
		/* http style */
		case 'w':
		printf("Content-Length: %d\r\n\r\n", size);
		break;;
		default:
		printf("%d\n", size);
		break;
	}
	fwrite(ram, 1, size, stdout);
	return EXIT_SUCCESS;
}