/*
  * exceptions4c lightweight version 1.0
  *
  * Copyright (c) 2013 Guillermo Calvo
  * Licensed under the GNU Lesser General Public License
  */
 
 #ifndef EXCEPTIONS4C_LITE
 #define EXCEPTIONS4C_LITE
 
 #include <stddef.h>
 #include <setjmp.h>
 
 /* Maximum number of nested `try` blocks */
 #ifndef E4C_MAX_FRAMES
 # define E4C_MAX_FRAMES 16
 #endif
 
 /* Maximum length (in bytes) of an exception message */
 #ifndef E4C_MESSAGE_SIZE
 # define E4C_MESSAGE_SIZE 128
 #endif
 
 /* Exception handling keywords: try/catch/finally/throw */
 #ifndef E4C_NOKEYWORDS
 # define try E4C_TRY
 # define catch(type) E4C_CATCH(type)
 # define finally E4C_FINALLY
 # define throw(type, message) E4C_THROW(type, message)
 #endif
 
 /* Represents an exception type */
 struct e4c_exception_type{
     const char * name;
     const char * default_message;
     const struct e4c_exception_type * supertype;
 };
 
 /* Declarations and definitions of exception types */
 #define E4C_DECLARE_EXCEPTION(name) extern const struct e4c_exception_type name
 #define E4C_DEFINE_EXCEPTION(name, default_message, supertype) const struct e4c_exception_type name = { #name, default_message, &supertype }
 
 /* Predefined exception types */
 E4C_DECLARE_EXCEPTION(RuntimeException);
 E4C_DECLARE_EXCEPTION(NullPointerException);
 E4C_DECLARE_EXCEPTION(ClustalOmegaException);
 
 /* Represents an instance of an exception type */
 struct e4c_exception{
     char message[E4C_MESSAGE_SIZE];
     const char * file;
     int line;
     const struct e4c_exception_type * type;
 };
 
 /* Retrieve current thrown exception */
 #define E4C_EXCEPTION e4c.err
 
 /* Returns whether current exception is of a given type */
 #define E4C_IS_INSTANCE_OF(t) ( e4c.err.type == &t || e4c_extends(e4c.err.type, &t) )
 
 /* Implementation details */
 #define E4C_TRY if(e4c_try(E4C_INFO) && setjmp(e4c.jump[e4c.frames - 1]) >= 0) while(e4c_hook(0)) if(e4c.frame[e4c.frames].stage == e4c_trying)
 #define E4C_CATCH(type) else if(e4c.frame[e4c.frames].stage == e4c_catching && E4C_IS_INSTANCE_OF(type) && e4c_hook(1))
 #define E4C_FINALLY else if(e4c.frame[e4c.frames].stage == e4c_finalizing)
 #define E4C_THROW(type, message) e4c_throw(&type, E4C_INFO, message)
 #ifndef NDEBUG
 # define E4C_INFO __FILE__, __LINE__
 #else
 # define E4C_INFO NULL, 0
 #endif
 
 enum e4c_stage{e4c_beginning, e4c_trying, e4c_catching, e4c_finalizing, e4c_done};
 extern struct e4c_context{jmp_buf jump[E4C_MAX_FRAMES]; struct e4c_exception err; struct{unsigned char stage; unsigned char uncaught;} frame[E4C_MAX_FRAMES + 1]; int frames;} e4c;
 extern int e4c_try(const char * file, int line);
 extern int e4c_hook(int is_catch);
 extern int e4c_extends(const struct e4c_exception_type * child, const struct e4c_exception_type * parent);
 extern void e4c_throw(const struct e4c_exception_type * exception_type, const char * file, int line, const char * message);
 
 # endif