#ifndef SCM_CONTINUATIONS_INTERNAL_H
#define SCM_CONTINUATIONS_INTERNAL_H

/* Copyright 1995-1996,2000-2001,2006,2008-2010,2012-2014,2018,2025
     Free Software Foundation, Inc.

   This file is part of Guile.

   Guile 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 3 of the License, or
   (at your option) any later version.

   Guile 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 Guile.  If not, see
   <https://www.gnu.org/licenses/>.  */



#ifndef _WIN64
#include <setjmp.h>
#else
#include "libguile/setjump-win.h"
#endif

#include "libguile/gc.h"
#include "libguile/scm.h"
#include "libguile/throw.h"



struct scm_vm_cont;

struct scm_continuation
{
  scm_t_bits tag;
  jmp_buf jmpbuf;
#if SCM_HAVE_AUXILIARY_STACK
  void *auxiliary_stack;
  unsigned long auxiliary_stack_size;
#endif
  SCM root;                 /* continuation root identifier.  */
  struct scm_vm_cont *vm_cont; /* vm's stack and regs */

  /* The offset from the live stack location to this copy.  This is
     used to adjust pointers from within the copied stack to the stack
     itself.

     Thus, when you read a pointer from the copied stack that points
     into the live stack, you need to add OFFSET so that it points
     into the copy.
  */
  ptrdiff_t offset;

  size_t num_stack_items;   /* size of the saved stack.  */
  SCM_STACKITEM stack[];    /* copied stack of size num_stack_items.  */ 
};

static inline int
scm_is_continuation (SCM c)
{
  return SCM_HAS_TYP16 (c, scm_tc16_continuation);
}

static inline struct scm_continuation*
scm_to_continuation (SCM c)
{
  if (!scm_is_continuation (c))
    abort ();

  return (struct scm_continuation*) SCM_UNPACK_POINTER (c);
}

static inline SCM
scm_from_continuation (struct scm_continuation* c)
{
  return SCM_PACK_POINTER (c);
}




SCM_INTERNAL SCM
scm_i_make_continuation (scm_thread *thread, struct scm_vm_cont *vm_cont);
SCM_INTERNAL void scm_i_reinstate_continuation (struct scm_continuation *cont,
                                                uint8_t *mra) SCM_NORETURN;

SCM_INTERNAL int scm_i_continuation_to_frame (SCM cont,
                                              struct scm_frame *frame);
SCM_INTERNAL int scm_i_print_continuation (SCM cont, SCM port,
                                           scm_print_state *state);

SCM_INTERNAL SCM
scm_i_with_continuation_barrier (scm_t_catch_body body,
				 void *body_data,
				 scm_t_catch_handler handler,
				 void *handler_data,
				 scm_t_catch_handler pre_unwind_handler,
				 void *pre_unwind_handler_data);

SCM_INTERNAL void scm_init_continuations (void);

#endif  /* SCM_CONTINUATIONS_INTERNAL_H */