diff options
Diffstat (limited to 'lib/kernel/src/ram_file.erl')
| -rw-r--r-- | lib/kernel/src/ram_file.erl | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl index 0230cb4e0a..2bfb2cd021 100644 --- a/lib/kernel/src/ram_file.erl +++ b/lib/kernel/src/ram_file.erl @@ -28,7 +28,7 @@ %% Specialized file operations -export([get_size/1, get_file/1, set_file/2, get_file_close/1]). --export([compress/1, uncompress/1, uuencode/1, uudecode/1]). +-export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]). -export([open_mode/1]). %% used by ftp-file @@ -71,6 +71,7 @@ -define(RAM_FILE_UUENCODE, 35). -define(RAM_FILE_UUDECODE, 36). -define(RAM_FILE_SIZE, 37). +-define(RAM_FILE_ADVISE, 38). %% Open modes for RAM_FILE_OPEN -define(RAM_FILE_MODE_READ, 1). @@ -91,6 +92,14 @@ -define(RAM_FILE_RESP_NUMBER, 3). -define(RAM_FILE_RESP_INFO, 4). +%% POSIX file advises +-define(POSIX_FADV_NORMAL, 0). +-define(POSIX_FADV_RANDOM, 1). +-define(POSIX_FADV_SEQUENTIAL, 2). +-define(POSIX_FADV_WILLNEED, 3). +-define(POSIX_FADV_DONTNEED, 4). +-define(POSIX_FADV_NOREUSE, 5). + %% -------------------------------------------------------------------------- %% Generic file contents operations. %% @@ -352,6 +361,28 @@ uudecode(#file_descriptor{module = ?MODULE, data = Port}) -> uudecode(#file_descriptor{}) -> {error, enotsup}. +advise(#file_descriptor{module = ?MODULE, data = Port}, Offset, + Length, Advise) -> + Cmd0 = <<?RAM_FILE_ADVISE, Offset:64/signed, Length:64/signed>>, + case Advise of + normal -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NORMAL:32/signed>>); + random -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_RANDOM:32/signed>>); + sequential -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_SEQUENTIAL:32/signed>>); + will_need -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_WILLNEED:32/signed>>); + dont_need -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_DONTNEED:32/signed>>); + no_reuse -> + call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NOREUSE:32/signed>>); + _ -> + {error, einval} + end; +advise(#file_descriptor{}, _Offset, _Length, _Advise) -> + {error, enotsup}. + %%%----------------------------------------------------------------- |