error/except.h

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/* Author: Andrew Schein   for emacs: -*- c++ -*- */


#ifndef NPS_EXCEPT_H
#define NPS_EXCEPT_H
#include <setjmp.h>
#include "../msg.h"

typedef struct Nps_exc_t {
  char *name;      
  char backtrace; 
} Nps_exc_t;

struct Nps_exc_frame_t {
  struct Nps_exc_frame_t *prev;
  jmp_buf target;
  const char *file;
  long line;
  char *msg;
  const Nps_exc_t *exc;
};

typedef struct Nps_exc_frame_t Nps_exc_frame_t;

enum { Nps_exc_entered=0, Nps_exc_thrown, Nps_exc_handled};

/* things to declare in except.c */
extern Nps_exc_frame_t *Nps_exc_stack;

void nps_throw(const Nps_exc_t *e,const char *file, long line,const char*,...);


#define THROW(e,...) nps_throw(&(e),__FILE__,__LINE__,"" __VA_ARGS__)
#define RETHROW         nps_throw(Nps_exc_stack->exc,Nps_exc_stack->file,   \
                                  Nps_exc_stack->line, Nps_exc_stack->msg)

#define TRY do {                                                        \
  volatile int Nps_exc_flag;                                            \
  Nps_exc_frame_t  curr_layer;                                          \
  curr_layer.msg = NULL; /* non-null is a signal */                     \
  curr_layer.prev  = Nps_exc_stack;                                     \
  Nps_exc_stack    = &curr_layer;                                       \
  Nps_exc_flag     = setjmp(Nps_exc_stack->target);                     \
  if (Nps_exc_flag == Nps_exc_entered) {

/* add check */
#define END_TRY                                                         \
  if (Nps_exc_flag == Nps_exc_entered) {                                \
    if (Nps_exc_stack != &curr_layer)                                   \
      MSG(DIE-1,"Exception Stack Corruption.\n");                       \
    if (Nps_exc_stack->msg) free(Nps_exc_stack->msg);                   \
    Nps_exc_stack = Nps_exc_stack->prev;                                \
  }                                                                     \
  } if (Nps_exc_flag == Nps_exc_thrown) THROW(*(Nps_exc_stack->exc));   \
  } while(0)

#define CATCH(e)                                                        \
  if (Nps_exc_flag == Nps_exc_entered) Nps_exc_stack = Nps_exc_stack->prev; \
  } else if (Nps_exc_stack->exc == &(e)) {                              \
  Nps_exc_flag = Nps_exc_handled;                                       \
  

/* #define RETURN switch (EXC_(stack) = EXC_(stack)->prev,0) default: return */


#endif

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