/*
** ObjectiveAmiga: Encoding of types for Objective C
** See GNU:lib/libobjam/ReadMe for details
*/


#include <ctype.h>

#include <libraries/objc.h>
#include <clib/objc_protos.h>

#include "misc.h" /* For the ANSI function emulations */


#define MAX(X, Y)                    \
  ({ typeof(X) __x = (X), __y = (Y); \
     (__x > __y ? __x : __y); })

#define MIN(X, Y)                    \
  ({ typeof(X) __x = (X), __y = (Y); \
     (__x < __y ? __x : __y); })


static inline int
atoi (const char* str)
{
  int res = 0;
  
  while (isdigit (*str))
    res *= 10, res += (*str++ - '0');

  return res;
}

/*
  return the size of an object specified by type 
*/

int
objc_sizeof_type(const char* type)
{
  switch(*type) {
  case _C_ID:
    return sizeof(id);
    break;

  case _C_CLASS:
    return sizeof(OCClass*);
    break;

  case _C_SEL:
    return sizeof(SEL);
    break;

  case _C_CHR:
    return sizeof(char);
    break;
    
  case _C_UCHR:
    return sizeof(unsigned char);
    break;

  case _C_SHT:
    return sizeof(short);
    break;

  case _C_USHT:
    return sizeof(unsigned short);
    break;

  case _C_INT:
    return sizeof(int);
    break;

  case _C_UINT:
    return sizeof(unsigned int);
    break;

  case _C_LNG:
    return sizeof(long);
    break;

  case _C_ULNG:
    return sizeof(unsigned long);
    break;

  case _C_PTR:
  case _C_ATOM:
  case _C_CHARPTR:
    return sizeof(char*);
    break;

  case _C_ARY_B:
    {
      int len = atoi(type+1);
      while (isdigit(*++type));
      return len*objc_aligned_size (type);
    }
    break; 

  case _C_STRUCT_B:
    {
      int acc_size = 0;
      int align;
      while (*type != _C_STRUCT_E && *type++ != '='); /* skip "<name>=" */
      while (*type != _C_STRUCT_E);
	{
	  align = objc_alignof_type (type);       /* padd to alignment */
	  if ((acc_size % align) != 0)
	    acc_size += align - (acc_size % align);
	  acc_size += objc_sizeof_type (type);   /* add component size */
	  type = objc_skip_typespec (type);	         /* skip component */
	}
      return acc_size;
    }

  case _C_UNION_B:
    {
      int max_size = 0;
      while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
      while (*type != _C_UNION_E)
	{
	  max_size = MAX (max_size, objc_sizeof_type (type));
	  type = objc_skip_typespec (type);
	}
      return max_size;
    }
    
  default:
    printf("objc_sizeof_type: cannot parse typespec: %s\n", type);
    abort();
  }
}


/*
  Return the alignment of an object specified by type 
*/

int
objc_alignof_type(const char* type)
{
  switch(*type) {
  case _C_ID:
    return __alignof__(id);
    break;

  case _C_CLASS:
    return __alignof__(OCClass*);
    break;
    
  case _C_SEL:
    return __alignof__(SEL);
    break;

  case _C_CHR:
    return __alignof__(char);
    break;
    
  case _C_UCHR:
    return __alignof__(unsigned char);
    break;

  case _C_SHT:
    return __alignof__(short);
    break;

  case _C_USHT:
    return __alignof__(unsigned short);
    break;

  case _C_INT:
    return __alignof__(int);
    break;

  case _C_UINT:
    return __alignof__(unsigned int);
    break;

  case _C_LNG:
    return __alignof__(long);
    break;

  case _C_ULNG:
    return __alignof__(unsigned long);
    break;

  case _C_ATOM:
  case _C_CHARPTR:
    return __alignof__(char*);
    break;

  case _C_ARY_B:
    while (isdigit(*++type)) /* do nothing */;
    return objc_alignof_type (type);
      
  case _C_STRUCT_B:
    {
      struct { int x; double y; } fooalign;
      while(*type != _C_STRUCT_E && *type++ != '=') /* do nothing */;
      if (*type != _C_STRUCT_E)
	return MAX (objc_alignof_type (type), __alignof__ (fooalign));
      else
	return __alignof__ (fooalign);
    }

  case _C_UNION_B:
    {
      int maxalign = 0;
      while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
      while (*type != _C_UNION_E)
	{
	  maxalign = MAX (maxalign, objc_alignof_type (type));
	  type = objc_skip_typespec (type);
	}
      return maxalign;
    }
    
  default:
    abort();
  }
}

/*
  The aligned size if the size rounded up to the nearest alignment.
*/

int
objc_aligned_size (const char* type)
{
  int size = objc_sizeof_type (type);
  int align = objc_alignof_type (type);

  if ((size % align) != 0)
    return size + align - (size % align);
  else
    return size;
}

/*
  The size rounded up to the nearest integral of the wordsize, taken
  to be the size of a void*.
*/

int 
objc_promoted_size (const char* type)
{
  int size = objc_sizeof_type (type);
  int wordsize = sizeof (void*);

  if ((size % wordsize) != 0)
    return size + wordsize - (size % wordsize);
  else
    return size;
}

/*
  Skip type qualifiers.  These may eventually precede typespecs
  occuring in method prototype encodings.
*/

inline const char*
objc_skip_type_qualifiers (const char* type)
{
  while (*type == _C_CONST
	 || *type == _C_IN 
	 || *type == _C_INOUT
	 || *type == _C_OUT 
	 || *type == _C_BYCOPY
	 || *type == _C_ONEWAY)
    {
      type += 1;
    }
  return type;
}

  
/*
  Skip one typespec element.  If the typespec is prepended by type
  qualifiers, these are skipped as well.
*/

const char* 
objc_skip_typespec (const char* type)
{
  type = objc_skip_type_qualifiers (type);
  
  switch (*type) {

  case _C_ID:
    /* An id may be annotated by the actual type if it is known
       with the @"ClassName" syntax */

    if (*++type != '"')
      return type;
    else
      {
	while (*++type != '"') /* do nothing */;
	return type + 1;
      }

    /* The following are one character type codes */
  case _C_CLASS:
  case _C_SEL:
  case _C_CHR:
  case _C_UCHR:
  case _C_CHARPTR:
  case _C_ATOM:
  case _C_SHT:
  case _C_USHT:
  case _C_INT:
  case _C_UINT:
  case _C_LNG:
  case _C_ULNG:
  case _C_FLT:
  case _C_DBL:
  case _C_VOID:
    return ++type;
    break;

  case _C_ARY_B:
    /* skip digits, typespec and closing ']' */
    
    while(isdigit(*++type));
    type = objc_skip_typespec(type);
    if (*type == _C_ARY_E)
      return ++type;
    else
      abort();

  case _C_STRUCT_B:
    /* skip name, and elements until closing '}'  */
    
    while (*type != _C_STRUCT_E && *type++ != '=');
    while (*type != _C_STRUCT_E) { type = objc_skip_typespec (type); }
    return ++type;

  case _C_UNION_B:
    /* skip name, and elements until closing ')'  */
    
    while (*type != _C_UNION_E && *type++ != '=');
    while (*type != _C_UNION_E) { type = objc_skip_typespec (type); }
    return ++type;

  case _C_PTR:
    /* Just skip the following typespec */
    
    return objc_skip_typespec (++type);
    
  default:
    abort();
  }
}

/*
  Skip an offset as part of a method encoding.  This is prepended by a
  '+' if the argument is passed in registers.
*/
inline const char* 
objc_skip_offset (const char* type)
{
  if (*type == '+') type++;
  while(isdigit(*++type));
  return type;
}

/*
  Skip an argument specification of a method encoding.
*/
const char*
objc_skip_argspec (const char* type)
{
  type = objc_skip_typespec (type);
  type = objc_skip_offset (type);
  return type;
}

/*
  Return the number of arguments that the method MTH expects.
  Note that all methods need two implicit arguments `self' and
  `_cmd'. 
*/
int
method_get_number_of_arguments (struct objc_method* mth)
{
  int i = 0;
  const char* type = mth->method_types;
  while (*type)
    {
      type = objc_skip_argspec (type);
      i += 1;
    }
  return i - 1;
}

/*
  Return the size of the argument block needed on the stack to invoke
  the method MTH.  This may be zero, if all arguments are passed in
  registers.
*/

int method_get_sizeof_arguments (struct objc_method* mth)
{
  const char* type = objc_skip_typespec (mth->method_types);
  return atoi (type);
}

/*
  Return a pointer to the next argument of ARGFRAME.  type points to
  the last argument.  Typical use of this look like:

  {
    char *datum, *type; 
    for (datum = method_get_first_argument (method, argframe, &type);
         datum; datum = method_get_next_argument (argframe, &type))
      {
        unsigned flags = objc_get_type_qualifiers (type);
        type = objc_skip_type_qualifiers (type);
	if (*type != _C_PTR)
          [portal encodeData: datum ofType: type];
	else
	  {
	    if ((flags & _F_IN) == _F_IN)
              [portal encodeData: *(char**)datum ofType: ++type];
	  }
      }
  }
*/  

char*
method_get_next_argument (arglist_t argframe,
			  const char **type)
{
  const char *t = objc_skip_argspec (*type);

  if (*t == '\0')
    return 0;

  *type = t;
  t = objc_skip_typespec (t);

  if (*t == '+')
    return argframe->arg_regs + atoi (++t);
  else
    return argframe->arg_ptr + atoi (t);
}

/*
  Return a pointer to the value of the first argument of the method 
  described in M with the given argumentframe ARGFRAME.  The type
  is returned in TYPE.  type must be passed to successive calls of 
  method_get_next_argument.
*/
char*
method_get_first_argument (struct objc_method* m,
			   arglist_t argframe, 
			   const char** type)
{
  *type = m->method_types;
  return method_get_next_argument (argframe, type);
}

/*
   Return a pointer to the ARGth argument of the method
   M from the frame ARGFRAME.  The type of the argument
   is returned in the value-result argument TYPE 
*/

char*
method_get_nth_argument (struct objc_method* m,
			 arglist_t argframe, int arg, 
			 const char **type)
{
  const char* t = objc_skip_argspec (m->method_types);

  if (arg > method_get_number_of_arguments (m))
    return 0;

  while (arg--)
    t = objc_skip_argspec (t);
  
  *type = t;
  t = objc_skip_typespec (t);

  if (*t == '+')
    return argframe->arg_regs + atoi (++t);
  else
    return argframe->arg_ptr + atoi (t);
}

unsigned
objc_get_type_qualifiers (const char* type)
{
  unsigned res = 0;
  BOOL flag = YES;

  while (flag)
    switch (*type++)
      {
      case _C_CONST:  res |= _F_CONST; break;
      case _C_IN:     res |= _F_IN; break;
      case _C_INOUT:  res |= _F_INOUT; break;
      case _C_OUT:    res |= _F_OUT; break;
      case _C_BYCOPY: res |= _F_BYCOPY; break;
      case _C_ONEWAY: res |= _F_ONEWAY; break;
      default: flag = NO;
    }

  return res;
}