archive.c

gcc库的原代码,对编程有很大帮助.

      else if ((buf & _B_NUMBER) == 1)
	len = (*stream->read)(stream->physical, val, 1);

      else
	__objc_fatal("expected 8bit unsigned int, got %dbit int",
		     (int)(buf&_B_NUMBER)*8);
    }
  return len;
}

__inline__ int
objc_read_short (struct objc_typed_stream* stream, short* value)
{
  unsigned char buf[sizeof(short)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	{
	  int pos = 1;
	  int nbytes = buf[0] & _B_NUMBER;
	  if (nbytes > sizeof (short))
	    __objc_fatal("expected short, got bigger (%dbits)", nbytes*8);
	  len = (*stream->read)(stream->physical, buf+1, nbytes);
	  (*value) = 0;
	  while (pos <= nbytes)
	    (*value) = ((*value)*0x100) + buf[pos++];
	  if (buf[0] & _B_SIGN)
	    (*value) = -(*value);
	}
    }
  return len;
}

__inline__ int
objc_read_unsigned_short (struct objc_typed_stream* stream,
			  unsigned short* value)
{
  unsigned char buf[sizeof(unsigned short)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	{
	  int pos = 1;
	  int nbytes = buf[0] & _B_NUMBER;
	  if (nbytes > sizeof (short))
	    __objc_fatal("expected short, got int or bigger");
	  len = (*stream->read)(stream->physical, buf+1, nbytes);
	  (*value) = 0;
	  while (pos <= nbytes)
	    (*value) = ((*value)*0x100) + buf[pos++];
	}
    }
  return len;
}


__inline__ int
objc_read_int (struct objc_typed_stream* stream, int* value)
{
  unsigned char buf[sizeof(int)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	{
	  int pos = 1;
	  int nbytes = buf[0] & _B_NUMBER;
	  if (nbytes > sizeof (int))
	    __objc_fatal("expected int, got bigger");
	  len = (*stream->read)(stream->physical, buf+1, nbytes);
	  (*value) = 0;
	  while (pos <= nbytes)
	    (*value) = ((*value)*0x100) + buf[pos++];
	  if (buf[0] & _B_SIGN)
	    (*value) = -(*value);
	}
    }
  return len;
}

__inline__ int
objc_read_long (struct objc_typed_stream* stream, long* value)
{
  unsigned char buf[sizeof(long)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	{
	  int pos = 1;
	  int nbytes = buf[0] & _B_NUMBER;
	  if (nbytes > sizeof (long))
	    __objc_fatal("expected long, got bigger");
	  len = (*stream->read)(stream->physical, buf+1, nbytes);
	  (*value) = 0;
	  while (pos <= nbytes)
	    (*value) = ((*value)*0x100) + buf[pos++];
	  if (buf[0] & _B_SIGN)
	    (*value) = -(*value);
	}
    }
  return len;
}

__inline__ int
__objc_read_nbyte_uint (struct objc_typed_stream* stream,
		       unsigned int nbytes, unsigned int* val)
{
  int len, pos = 0;
  unsigned char buf[sizeof(unsigned int)+1];

  if (nbytes > sizeof (int))
    __objc_fatal("expected int, got bigger");

  len = (*stream->read)(stream->physical, buf, nbytes);
  (*val) = 0;
  while (pos < nbytes)
    (*val) = ((*val)*0x100) + buf[pos++];
  return len;
}
  

__inline__ int
objc_read_unsigned_int (struct objc_typed_stream* stream,
			unsigned int* value)
{
  unsigned char buf[sizeof(unsigned int)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	len = __objc_read_nbyte_uint (stream, (buf[0] & _B_VALUE), value);

    }
  return len;
}

int
__objc_read_nbyte_ulong (struct objc_typed_stream* stream,
		       unsigned int nbytes, unsigned long* val)
{
  int len, pos = 0;
  unsigned char buf[sizeof(unsigned long)+1];

  if (nbytes > sizeof (long))
    __objc_fatal("expected long, got bigger");

  len = (*stream->read)(stream->physical, buf, nbytes);
  (*val) = 0;
  while (pos < nbytes)
    (*val) = ((*val)*0x100) + buf[pos++];
  return len;
}
  

__inline__ int
objc_read_unsigned_long (struct objc_typed_stream* stream,
			unsigned long* value)
{
  unsigned char buf[sizeof(unsigned long)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      if ((buf[0] & _B_CODE) == _B_SINT)
	(*value) = (buf[0] & _B_VALUE);

      else
	len = __objc_read_nbyte_ulong (stream, (buf[0] & _B_VALUE), value);

    }
  return len;
}

__inline__ int
objc_read_string (struct objc_typed_stream* stream,
		  char** string)
{
  unsigned char buf[sizeof(unsigned int)+1];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      unsigned long key = 0;

      if ((buf[0]&_B_CODE) == _B_RCOMM)	/* register following */
	{
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  len = (*stream->read)(stream->physical, buf, 1);
	}

      switch (buf[0]&_B_CODE) {
      case _B_SSTR:
	{
	  int length = buf[0]&_B_VALUE;
	  (*string) = (char*)__objc_xmalloc(length+1);
	  if (key)
	    hash_add (&stream->stream_table, LONG2PTR(key), *string);
	  len = (*stream->read)(stream->physical, *string, length);
	  (*string)[length] = '\0';
	}
	break;

      case _B_UCOMM:
	{
	  char *tmp;
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  tmp = hash_value_for_key (stream->stream_table, LONG2PTR (key));
	  *string = __objc_xmalloc (strlen(tmp) + 1);
	  strcpy (*string, tmp);
	}
	break;

      case _B_NSTR:
	{
	  unsigned int nbytes = buf[0]&_B_VALUE;
	  len = __objc_read_nbyte_uint(stream, nbytes, &nbytes);
	  if (len) {
	    (*string) = (char*)__objc_xmalloc(nbytes+1);
	    if (key)
	      hash_add (&stream->stream_table, LONG2PTR(key), *string);
	    len = (*stream->read)(stream->physical, *string, nbytes);
	    (*string)[nbytes] = '\0';
	  }
	}
	break;
	
      default:
	__objc_fatal("expected string, got opcode %c\n", (buf[0]&_B_CODE));
      }
    }

  return len;
}


int
objc_read_object (struct objc_typed_stream* stream, id* object)
{
  unsigned char buf[sizeof (unsigned int)];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      SEL read_sel = sel_get_any_uid ("read:");
      unsigned long key = 0;

      if ((buf[0]&_B_CODE) == _B_RCOMM)	/* register common */
	{
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  len = (*stream->read)(stream->physical, buf, 1);
	}

      if (buf[0] == (_B_EXT | _BX_OBJECT))
	{
	  Class class;

	  /* get class */
	  len = objc_read_class (stream, &class);

	  /* create instance */
	  (*object) = class_create_instance(class);

	  /* register? */
	  if (key)
	    hash_add (&stream->object_table, LONG2PTR(key), *object);

	  /* send -read: */
	  if (__objc_responds_to (*object, read_sel))
	    (*get_imp(class, read_sel))(*object, read_sel, stream);

	  /* check null-byte */
	  len = (*stream->read)(stream->physical, buf, 1);
	  if (buf[0] != '\0')
	    __objc_fatal("expected null-byte, got opcode %c", buf[0]);
	}

      else if ((buf[0]&_B_CODE) == _B_UCOMM)
	{
	  if (key)
	    __objc_fatal("cannot register use upcode...");
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  (*object) = hash_value_for_key (stream->object_table, LONG2PTR(key));
	}

      else if (buf[0] == (_B_EXT | _BX_OBJREF))	/* a forward reference */
	{
	  struct objc_list* other;
	  len = objc_read_unsigned_long (stream, &key);
	  other = (struct objc_list*)hash_value_for_key (stream->object_refs, LONG2PTR(key));
	  hash_add (&stream->object_refs, LONG2PTR(key), (void*)list_cons(object, other));
	}

      else if (buf[0] == (_B_EXT | _BX_OBJROOT)) /* a root object */
	{
	  if (key)
	    __objc_fatal("cannot register root object...");
	  len = objc_read_object (stream, object);
	  __objc_finish_read_root_object (stream);
	}

      else
	__objc_fatal("expected object, got opcode %c", buf[0]);
    }
  return len;
}

static int
objc_read_class (struct objc_typed_stream* stream, Class* class)
{
  unsigned char buf[sizeof (unsigned int)];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      unsigned long key = 0;

      if ((buf[0]&_B_CODE) == _B_RCOMM)	/* register following */
	{
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  len = (*stream->read)(stream->physical, buf, 1);
	}

      if (buf[0] == (_B_EXT | _BX_CLASS))
	{
	  char* class_name;
	  unsigned long version;

	  /* get class */
	  len = objc_read_string (stream, &class_name);
	  (*class) = objc_get_class(class_name);
	  free (class_name);

	  /* register */
	  if (key)
	    hash_add (&stream->stream_table, LONG2PTR(key), *class);

	  objc_read_unsigned_long(stream, &version);
	  hash_add (&stream->class_table, (*class)->name, (void*)version);
	}

      else if ((buf[0]&_B_CODE) == _B_UCOMM)
	{
	  if (key)
	    __objc_fatal("cannot register use upcode...");
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  (*class) = hash_value_for_key (stream->stream_table, LONG2PTR(key));
	  if (!*class)
	    __objc_fatal("cannot find class for key %lu", key);
	}

      else
	__objc_fatal("expected class, got opcode %c", buf[0]);
    }
  return len;
}

int
objc_read_selector (struct objc_typed_stream* stream, SEL* selector)
{
  unsigned char buf[sizeof (unsigned int)];
  int len;
  if ((len = (*stream->read)(stream->physical, buf, 1)))
    {
      unsigned long key = 0;

      if ((buf[0]&_B_CODE) == _B_RCOMM)	/* register following */
	{
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  len = (*stream->read)(stream->physical, buf, 1);
	}

      if (buf[0] == (_B_EXT|_BX_SEL)) /* selector! */
	{
	  char* selector_name;

	  /* get selector */
	  len = objc_read_string (stream, &selector_name);
	  /* To handle NULL selectors */
	  if (0 == strlen(selector_name))
	    {
	      (*selector) = (SEL)0;
	      return 0;
	    }
	  else 
	    (*selector) = sel_get_any_uid(selector_name);
	  free (selector_name);

	  /* register */
	  if (key)
	    hash_add (&stream->stream_table, LONG2PTR(key), (void*)*selector);
	}

      else if ((buf[0]&_B_CODE) == _B_UCOMM)
	{
	  if (key)
	    __objc_fatal("cannot register use upcode...");
	  len = __objc_read_nbyte_ulong(stream, (buf[0] & _B_VALUE), &key);
	  (*selector) = hash_value_for_key (stream->stream_table, LONG2PTR(key));
	}

      else
	__objc_fatal("expected selector, got opcode %c", buf[0]);
    }
  return len;
}

/*
** USER LEVEL FUNCTIONS
*/

/*
** Write one object, encoded in TYPE and pointed to by DATA to the
** typed stream STREAM.  
*/

int
objc_write_type(TypedStream* stream, const char* type, const void* data)
{
  switch(*type) {
  case _C_ID:
    return objc_write_object (stream, *(id*)data);
    break;

  case _C_CLASS:
    return objc_write_class (stream, *(Class*)data);
    break;

  case _C_SEL:
    return objc_write_selector (stream, *(SEL*)data);
    break;

  case _C_CHR:
    return objc_write_char(stream, *(char*)data);
    break;
    
  case _C_UCHR:
    return objc_write_unsigned_char(stream, *(unsigned char*)data);
    break;

  case _C_SHT:
    return objc_write_short(stream, *(short*)data);
    break;

  case _C_USHT:
    return objc_write_unsigned_short(stream, *(unsigned short*)data);
    break;

  case _C_INT:
    return objc_write_int(stream, *(int*)data);
    break;

  case _C_UINT:
    return objc_write_unsigned_int(stream, *(unsigned int*)data);
    break;

  case _C_LNG:
    return objc_write_long(stream, *(long*)data);
    break;

  case _C_ULNG:
    return objc_write_unsigned_long(stream, *(unsigned long*)data);
    break;

  case _C_CHARPTR:
    return objc_write_string (stream, *(char**)data, strlen(*(char**)data));
    break;

  case _C_ATOM:
    return objc_write_string_atomic (stream, *(char**)data, strlen(*(char**)data));
    break;

  case _C_ARY_B:
    {
      int len = atoi(type+1);
      while (isdigit(*++type));
      return objc_write_array (stream, type, len, data);
    }
    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 */
	  acc_size += ROUND (acc_size, align);
	  objc_write_type (stream, type, ((char*)data)+acc_size);
	  acc_size += objc_sizeof_type (type);   /* add component size */
	  type = objc_skip_typespec (type);	 /* skip component */
	}
      return 1;
    }

  default:
    fprintf(stderr, "objc_write_type: cannot parse typespec: %s\n", type);
    abort();
  }
}

/*
** Read one object, encoded in TYPE and pointed to by DATA to the
** typed stream STREAM.  DATA specifies the address of the types to
** read.  Expected type is checked against the type actually present
** on the stream. 
*/

int
objc_read_type(TypedStream* stream, const char* type, void* data)
{
  char c;
  switch(c = *type) {
  case _C_ID:
    return objc_read_object (stream, (id*)data);
    break;

  case _C_CLASS:
    return objc_read_class (stream, (Class*)data);
    break;

  case _C_SEL:
    return objc_read_selector (stream, (SEL*)data);
    break;