// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : identify.c
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies DiscImageChef format disk images.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library 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
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2019 Natalia Portillo
// ****************************************************************************/

#include <dicformat.h>
#include <errno.h>
#include <stdio.h>

//! Identifies a file as dicformat, using path
/*!
 *
 * @param filename path to the file to identify
 * @return If positive, confidence value, with 100 being maximum confidentiality, and 0 not recognizing the file.
 * If negative, error value
 */
int identify(const char *filename)
{
    FILE *stream;

    stream = fopen(filename, "rb");

    if(stream == NULL) return errno;

    int ret = identifyStream(stream);

    fclose(stream);

    return ret;
}

//! Identifies a file as dicformat, using an already existing stream
/*!
 *
 * @param imageStream stream of the file to identify
 * @return If positive, confidence value, with 100 being maximum confidentiality, and 0 not recognizing the file.
 * If negative, error value
 */
int identifyStream(FILE *imageStream)
{
    fseek(imageStream, 0, SEEK_SET);

    DicHeader header;

    size_t ret = fread(&header, sizeof(DicHeader), 1, imageStream);

    if(ret < sizeof(DicHeader)) return 0;

    if(header.identifier == DIC_MAGIC && header.imageMajorVersion <= DICF_VERSION) return 100;

    return 0;
}