/*

 * Soft:        Perform a GET query to a remote HTTP/HTTPS server.

 *              Set a timer to compute global remote server response

 *              time.

 *

 * Part:        HTML stream parser utility functions.

 *

 * Authors:     Alexandre Cassen, <acassen@linux-vs.org>

 *

 *              This program is distributed in the hope that it will be useful,

 *              but WITHOUT ANY WARRANTY; without even the implied warranty of

 *              MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 *              See the GNU General Public License for more details.

 *

 *              This program is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 * Copyright (C) 2001-2017 Alexandre Cassen, <acassen@gmail.com>

 */

#include "config.h"

#include <string.h>

#include <stdlib.h>

#include <stdint.h>

#include "html.h"

#include "memory.h"

/* HTTP header tag */

#define CONTENT_LENGTH	"Content-Length:"

/* Return the http header content length */

size_t extract_content_length(const char *buffer, size_t size)

{

	char *clen = strstr(buffer, CONTENT_LENGTH);

	size_t len;

	char *end;

	/* Pattern not found */

	if (!clen || clen > buffer + size)

		return SIZE_MAX;

	/* Content-Length extraction */

	len = strtoul(clen + strlen(CONTENT_LENGTH), &end, 10);

	if (*end)

		return SIZE_MAX;

	return len;

}

/*

 * Return the http header error code. According

 * to rfc2616.6.1 status code is between HTTP_Version

 * and Reason_Phrase, separated by space caracter.

 */

#include "logger.h"

int extract_status_code(const char *buffer, size_t size)

{

	const char *buf_end = buffer + size;

	char *end;

	unsigned long code;

	/* Status-Code extraction */

	while (buffer < buf_end && *buffer != ' ' && *buffer != '\r')

		buffer++;

	if (*buffer != ' ')

		return 0;

	buffer++;

	if (buffer + 3 >= buf_end || *buffer == ' ' || buffer[3] != ' ')

		return 0;

	code = strtoul(buffer, &end, 10);	// This line causes a strict-overflow=4 warning with gcc 5.4.0

	if (buffer + 3 != end)

		return 0;

	return code;

}

/* simple function returning a pointer to the html buffer begin */

const char * __attribute__ ((pure))

extract_html(const char *buffer, size_t size_buffer)

{

	const char *end = buffer + size_buffer;

	const char *cur;

	for (cur = buffer; cur + 3 < end; cur++)

		if (*cur == '\r' && *(cur+1) == '\n'

		    && *(cur+2) == '\r' && *(cur+3) == '\n')

			return cur + 4;

	return NULL;

}