Added iso_lib_is_compatible() function.

libisofs/libisofs.h

@@ -557,6 +557,14 @@ int iso_image_new(const char *name, IsoImage **image);
  */
 void iso_lib_version(int *major, int *minor, int *micro);
 
+/**
+ * Check if the library is ABI compatible with the given version.
+ * 
+ * @return 
+ *      1 lib is compatible, 0 is not.
+ */
+int iso_lib_is_compatible(int major, int minor, int micro);
+
 /**
  * Creates an IsoWriteOpts for writing an image. You should set the options
  * desired with the correspondent setters.

libisofs/util.c

@@ -1248,3 +1248,17 @@ void iso_lib_version(int *major, int *minor, int *micro)
     *minor = LIBISOFS_MINOR_VERSION;
     *micro = LIBISOFS_MICRO_VERSION;
 }
+
+int iso_lib_is_compatible(int major, int minor, int micro)
+{
+    int cmajor, cminor, cmicro;
+    
+    /* for now, the rule is that library is compitable if requested
+     * version is lower */
+    iso_lib_version(&cmajor, &cminor, &cmicro);
+
+    return cmajor > major 
+           || (cmajor == major 
+               && (cminor > minor 
+                   || (cminor == minor && cmicro >= micro)));
+}