Read media tag.

CMakeLists.txt

@@ -5,6 +5,6 @@ set(CMAKE_C_STANDARD 99)
 add_compile_definitions(__STDC_FORMAT_MACROS=1)
 
 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 src/open.c include/dicformat/context.h src/close.c include/dicformat/errors.h)
+            include/dicformat/decls.h include/dicformat/structs.h src/identify.c src/open.c include/dicformat/context.h src/close.c include/dicformat/errors.h src/read.c)
 
 include_directories(include include/dicformat)

include/dicformat/decls.h

@@ -41,5 +41,7 @@ void *open(const char *filepath);
 
 int close(void *context);
 
+unsigned char *read_media_tag(void *context, int tag);
+
 
 #endif //LIBDICFORMAT_DECLS_H

src/read.c

@@ -0,0 +1,65 @@
+// /***************************************************************************
+// The Disc Image Chef
+// ----------------------------------------------------------------------------
+//
+// Filename       : open.c
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : libdicformat.
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Handles opening 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>
+
+unsigned char *read_media_tag(void *context, int tag)
+{
+    if(context == NULL)
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    dicformatContext *ctx = context;
+
+    // TODO: Cast this field without casting the whole structure, as this can buffer overflow
+    // Not a libdicformat context
+    if(ctx->magic != DIC_MAGIC)
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    dataLinkedList *item = ctx->mediaTagsHead;
+
+    while(item != NULL)
+    {
+        if(item->type == tag)
+            return item->data;
+
+        item = item->next;
+    }
+
+    return NULL;
+}