Class: Cosmos::BufferedFile

Inherits:
File show all
Defined in:
ext/cosmos/ext/buffered_file/buffered_file.c

Constant Summary

Constants inherited from File

File::NON_ASCII_PRINTABLE

Instance Method Summary collapse

Methods inherited from File

build_timestamped_filename, find_in_search_path, is_ascii?

Constructor Details

#initialize(*args) ⇒ Object

Initialize the BufferedFile. Takes the same args as File



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# File 'ext/cosmos/ext/buffered_file/buffered_file.c', line 30

static VALUE buffered_file_initialize(int argc, VALUE* argv, VALUE self) {
  rb_call_super(argc, argv);
  rb_ivar_set(self, id_ivar_buffer, rb_str_new2(""));
  rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(0));
  return self;
}

Instance Method Details

#pos ⇒ Object

Get the current file position



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# File 'ext/cosmos/ext/buffered_file/buffered_file.c', line 94

static VALUE buffered_file_pos(VALUE self) {
  volatile VALUE parent_pos = rb_call_super(0, NULL);
  long long ll_pos = NUM2LL(parent_pos);
  long buffer_length = RSTRING_LEN(rb_ivar_get(self, id_ivar_buffer));
  long buffer_index = FIX2INT(rb_ivar_get(self, id_ivar_buffer_index));
  return LL2NUM(ll_pos - (long long)(buffer_length - buffer_index));
}

#read(arg_length) ⇒ Object

Read using an internal buffer to avoid system calls



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# File 'ext/cosmos/ext/buffered_file/buffered_file.c', line 38

static VALUE buffered_file_read(VALUE self, VALUE arg_length) {
  long length = FIX2INT(arg_length);
  volatile VALUE buffer = rb_ivar_get(self, id_ivar_buffer);
  long buffer_length = RSTRING_LEN(buffer);
  long buffer_index = FIX2INT(rb_ivar_get(self, id_ivar_buffer_index));
  volatile VALUE result = Qnil;
  volatile VALUE super_arg = Qnil;

  if (length <= (buffer_length - buffer_index)) {
    /* Return part of the buffer without having to go to the OS */
    result = rb_str_substr(buffer, buffer_index, length);
    buffer_index += length;
    rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(buffer_index));
    return result;
  } else if (length > BUFFER_SIZE) {
    /* Reading more than our buffer */
    if (buffer_length > 0) {
      if (buffer_index > 0) {
        rb_funcall(buffer, id_method_slice_bang, 1, rb_range_new(INT2FIX(0), INT2FIX(buffer_index - 1), Qfalse));
        buffer_length = RSTRING_LEN(buffer);
        buffer_index = 0;
        rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(0));
      }
      super_arg = INT2FIX(length - buffer_length);
      rb_str_append(buffer, rb_funcall(rb_call_super(1, (VALUE*) &super_arg), id_method_to_s, 0));
      return rb_funcall(buffer, id_method_slice_bang, 1, rb_const_get(cBufferedFile, id_const_ALL_RANGE));
    } else {
      return rb_call_super(1, &arg_length);
    }
  } else {
    /* Read into the buffer */
    if (buffer_index > 0) {
      rb_funcall(buffer, id_method_slice_bang, 1, rb_range_new(INT2FIX(0), INT2FIX(buffer_index - 1), Qfalse));
      buffer_length = RSTRING_LEN(buffer);
      buffer_index = 0;
      rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(0));
    }
    super_arg = INT2FIX(BUFFER_SIZE - buffer_length);
    rb_str_append(buffer, rb_funcall(rb_call_super(1, (VALUE*) &super_arg), id_method_to_s, 0));
    buffer_length = RSTRING_LEN(buffer);
    if (buffer_length <= 0) {
      return Qnil;
    }

    if (length <= buffer_length) {
      result = rb_str_substr(buffer, buffer_index, length);
      buffer_index += length;
      rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(buffer_index));
      return result;
    } else {
      return rb_funcall(buffer, id_method_slice_bang, 1, rb_const_get(cBufferedFile, id_const_ALL_RANGE));
    }
  }
}

#seek(*args) ⇒ Object

Seek to a given file position



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# File 'ext/cosmos/ext/buffered_file/buffered_file.c', line 103

static VALUE buffered_file_seek(int argc, VALUE* argv, VALUE self) {
  volatile VALUE amount = Qnil;
  volatile VALUE whence = Qnil;
  long buffer_index = 0;
  volatile VALUE super_args[2] = {Qnil, Qnil};

  switch (argc)
  {
    case 1:
      amount = argv[0];
      whence = BUFFERED_FILE_SEEK_SET;
      break;

    case 2:
      amount = argv[0];
      whence = argv[1];
      break;

    default:
      /* Invalid number of arguments given - let super handle */
      return rb_call_super(argc, argv);
  };

  if (whence == BUFFERED_FILE_SEEK_CUR) {
    buffer_index = FIX2INT(rb_ivar_get(self, id_ivar_buffer_index)) + FIX2INT(amount);
    if ((buffer_index >= 0) && (buffer_index < RSTRING_LEN(rb_ivar_get(self, id_ivar_buffer)))) {
      rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(buffer_index));
      return INT2FIX(0);
    }
    super_args[0] = rb_funcall(self, id_method_pos, 0);
    super_args[1] = BUFFERED_FILE_SEEK_SET;
    rb_call_super(2, (VALUE*) super_args);
  }

  rb_funcall(rb_ivar_get(self, id_ivar_buffer), id_method_clear, 0);
  rb_ivar_set(self, id_ivar_buffer_index, INT2FIX(0));
  return rb_call_super(argc, argv);
}