Re: [boost] [IOStreams] windowing in mapped_file

From: Frank Birbacher (bloodymir.crap_at_[hidden])
Date: 2007-09-03 18:30:44

Hi!

Benjamin Collins schrieb:
>  class window_manager {
>  public:
>      struct iterator {
>          operator++() {
>              if(current_ptr+1 >= current_map_end)
>                  // remap file to the next block, re-adjust pointers
>          }
> 
>          operator--() {
>              if(current_ptr-1 <= current_map_begin)
>                  // remap file to the previous block, re-adjust pointers
>          }

How is that different from using "buffers"? The regular std::fstream
shows just this behavior: when reading it fills a buffer; when the end
of the buffer is reached it loads the next part of the file into memory,
and so on. The only difference is that writing to a memory location does
not implicitly change the file content. But do you need this kind of
random access for writing?

Frank