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

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