Add identification.

CMakeLists.txt

@@ -3,6 +3,7 @@ project(libdicformat C)
 
 set(CMAKE_C_STANDARD 99)
 
-add_library(libdicformat SHARED include/dicformat/consts.h include/dicformat/enums.h include/dic.h include/dicformat.h include/dicformat/decls.h include/dicformat/structs.h)
+add_library(libdicformat SHARED include/dicformat/consts.h include/dicformat/enums.h include/dic.h include/dicformat.h
+            include/dicformat/decls.h include/dicformat/structs.h src/identify.c)
 
 include_directories(include include/dicformat)

include/dicformat.h

@@ -35,5 +35,7 @@
 
 #include "dicformat/consts.h"
 #include "dicformat/enums.h"
+#include "dicformat/decls.h"
+#include "dicformat/structs.h"
 
 #endif //LIBDICFORMAT_DICFORMAT_H

include/dicformat/decls.h

@@ -33,4 +33,8 @@
 #ifndef LIBDICFORMAT_DECLS_H
 #define LIBDICFORMAT_DECLS_H
 
+int identify(const char *filename);
+
+int identifyStream(FILE *imageStream);
+
 #endif //LIBDICFORMAT_DECLS_H

src/identify.c

@@ -0,0 +1,82 @@
+// /***************************************************************************
+// 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 <errno.h>
+#include <stdio.h>
+#include <dicformat.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;
+}