Add open() and close() skeletons that only recognize the image as a correct one.

CMakeLists.txt

@@ -4,6 +4,6 @@ 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 src/identify.c)
+            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_directories(include include/dicformat)

include/dicformat.h

@@ -33,9 +33,14 @@
 #ifndef LIBDICFORMAT_DICFORMAT_H
 #define LIBDICFORMAT_DICFORMAT_H
 
+#define LIBDICFORMAT_MAJOR_VERSION 1
+#define LIBDICFORMAT_MINOR_VERSION 0
+
+#include "dicformat/errors.h"
 #include "dicformat/consts.h"
 #include "dicformat/enums.h"
 #include "dicformat/decls.h"
 #include "dicformat/structs.h"
+#include "dicformat/context.h"
 
 #endif //LIBDICFORMAT_DICFORMAT_H

include/dicformat/context.h

@@ -0,0 +1,20 @@
+//
+// Created by claunia on 17/03/19.
+//
+
+#ifndef LIBDICFORMAT_CONTEXT_H
+#define LIBDICFORMAT_CONTEXT_H
+
+#include <stdint.h>
+#include <stdio.h>
+
+typedef struct dicformatContext
+{
+    uint64_t  magic;
+    uint8_t   libraryMajorVersion;
+    uint8_t   libraryMinorVersion;
+    FILE      *imageStream;
+    DicHeader header;
+} dicformatContext;
+
+#endif //LIBDICFORMAT_CONTEXT_H

include/dicformat/decls.h

@@ -37,4 +37,9 @@ int identify(const char *filename);
 
 int identifyStream(FILE *imageStream);
 
+void *open(const char *filepath);
+
+int close(void *context)
+
+
 #endif //LIBDICFORMAT_DECLS_H

include/dicformat/errors.h

@@ -0,0 +1,12 @@
+//
+// Created by claunia on 17/03/19.
+//
+
+#ifndef LIBDICFORMAT_ERRORS_H
+#define LIBDICFORMAT_ERRORS_H
+
+#define DICF_ERROR_NOT_DICFORMAT -1
+#define DICF_ERROR_FILE_TOO_SMALL -2
+#define DICF_ERROR_INCOMPATIBLE_VERSION -2
+
+#endif //LIBDICFORMAT_ERRORS_H

src/close.c

@@ -0,0 +1,62 @@
+// /***************************************************************************
+// The Disc Image Chef
+// ----------------------------------------------------------------------------
+//
+// Filename       : close.c
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : libdicformat.
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Handles closing 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 <stdio.h>
+#include <dicformat.h>
+#include <malloc.h>
+#include <errno.h>
+
+int close(void *context)
+{
+    if(context == NULL)
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    dicformatContext *ctx = context;
+
+    // TODO: Cast this field without casting the whole structure, as this can buffer overlow
+    // Not a libdicformat context
+    if(ctx->magic != DIC_MAGIC)
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    if(ctx->imageStream != NULL)
+        fclose(ctx->imageStream);
+
+    free(context);
+
+    return 0;
+}

src/open.c

@@ -0,0 +1,95 @@
+// /***************************************************************************
+// 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 <stdio.h>
+#include <dicformat.h>
+#include <malloc.h>
+#include <errno.h>
+
+void *open(const char *filepath)
+{
+    dicformatContext *ctx = malloc(sizeof(dicformatContext));
+    int              errorNo;
+    size_t           readBytes;
+
+    if(ctx == NULL)
+        return NULL;
+
+    ctx->imageStream = fopen(filepath, "rb");
+
+    if(ctx->imageStream == NULL)
+    {
+        errorNo = errno;
+        free(ctx);
+        errno = errorNo;
+
+        return NULL;
+    }
+
+    fseek(ctx->imageStream, 0, SEEK_SET);
+    readBytes = fread(&ctx->header, sizeof(DicHeader), 1, ctx->imageStream);
+
+    if(readBytes != sizeof(DicHeader))
+    {
+        free(ctx);
+        errno = DICF_ERROR_FILE_TOO_SMALL;
+
+        return NULL;
+    }
+
+    if(ctx->header.identifier != DIC_MAGIC)
+    {
+        free(ctx);
+        errno = DICF_ERROR_NOT_DICFORMAT;
+
+        return NULL;
+    }
+
+    if(ctx->header.imageMajorVersion > DICF_VERSION)
+    {
+        free(ctx);
+        errno = DICF_ERROR_INCOMPATIBLE_VERSION;
+
+        return NULL;
+    }
+
+    ctx->magic               = DIC_MAGIC;
+    ctx->libraryMajorVersion = LIBDICFORMAT_MAJOR_VERSION;
+    ctx->libraryMinorVersion = LIBDICFORMAT_MINOR_VERSION;
+
+    fprintf(stderr,
+            "libdicformat: Opened image version %d.%d",
+            ctx->header.imageMajorVersion,
+            ctx->header.imageMinorVersion);
+
+    return ctx;
+}