// public domain, no warranty.

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

#define	BUFSIZE	4096

static char	Buf_i[BUFSIZE], Buf_o[BUFSIZE];
static char	Description[] = "<description>";
static char	LocalTimeHeader[] = "[CDATA[";
static char	GlobalTimeHeader[] = "<br>(";

static	void	convert_description(void)
{
	int	n, pos, remain;
	char	*utime, *ltime, *p;

	ltime = strstr(Buf_i, LocalTimeHeader);
	utime = strstr(Buf_i, GlobalTimeHeader);
	if (utime == NULL || ltime == NULL) {
		goto no_convert;
	}

	p = strchr(utime, ')');
	if (p == NULL) {
		goto no_convert;
	}

	*utime = '\0';	/* terminate character for local time string */
	*p = '\0';	/* terminate character for global time string */

	ltime += sizeof(LocalTimeHeader) - 1;
	utime += sizeof(GlobalTimeHeader) - 1;

	while (utime != p) {
		switch (*p) {
		case	'/':
			*p = '-';
			break;
		case	' ':
			*p = 'T';
			break;
		default:
			/* do nothing */
			break;
		}

		p--;
	}

	remain = sizeof(Buf_o);
	pos = 0;

	n = snprintf(Buf_o + pos, remain, "<description>");
	remain -= n;
	pos += n;

	n = snprintf(Buf_o + pos, remain, "%s", ltime);
	remain -= n;
	pos += n;

	n = snprintf(Buf_o + pos, remain, "</description>\n");
	remain -= n;
	pos += n;

	n = snprintf(Buf_o + pos, remain, "<TimeStamp><when>");
	remain -= n;
	pos += n;

	n = snprintf(Buf_o + pos, remain, "%s", utime);
	remain -= n;
	pos += n;

	n = snprintf(Buf_o + pos, remain, ".000Z</when></TimeStamp>\n");
	remain -= n;
	pos += n;

	return;

no_convert:
	strcpy(Buf_o, Buf_i);
	return;
}

int	main(int argc, char *argv[])
{
	FILE	*fp;
	int	result;

	/* usage */
	if (argc < 2) {
		printf("usage: %s [filename]\n", argv[0]);
		result = EXIT_FAILURE;
		goto fin0;
	}

	/* open file */
	fp = fopen(argv[1], "r");
	if (fp == NULL) {
		printf("%s: file open error\n", argv[1]);
		result = EXIT_FAILURE;
		goto fin0;
	}

	/* read file/process */
	while (fgets(Buf_i, sizeof(Buf_i), fp) != NULL) {
		if (strncmp(Buf_i, Description, sizeof(Description) - 1)) {
			printf("%s", Buf_i);
		} else {
			convert_description();
			printf("%s", Buf_o);
		}
	}

fin1:
	fclose(fp);
fin0:
	return result;
}