From 723306c417b3b0f8e6a3904906d6c5612cace432 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Sun, 4 Jun 2023 14:36:25 +0200 Subject: libio: Move istream_t precache logic into backend implementation The end goal is to remove direct buffer access from the istream_t interfaces and make that opaque. For the tar implementation, this already safes us needless buffer copying, as we essentially allow the user to read-through from the underlying stream. Signed-off-by: David Oberhollenzer --- lib/io/src/unix/istream.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'lib/io/src/unix') diff --git a/lib/io/src/unix/istream.c b/lib/io/src/unix/istream.c index f8cffad..24b18d6 100644 --- a/lib/io/src/unix/istream.c +++ b/lib/io/src/unix/istream.c @@ -20,15 +20,25 @@ static int file_precache(istream_t *strm) ssize_t ret; size_t diff; - while (strm->buffer_used < sizeof(file->buffer)) { + if (strm->buffer_offset >= strm->buffer_used) { + strm->buffer_offset = 0; + strm->buffer_used = 0; + } else if (strm->buffer_offset > 0) { + memmove(strm->buffer, + strm->buffer + strm->buffer_offset, + strm->buffer_used - strm->buffer_offset); + + strm->buffer_used -= strm->buffer_offset; + strm->buffer_offset = 0; + } + + while (!strm->eof && strm->buffer_used < sizeof(file->buffer)) { diff = sizeof(file->buffer) - strm->buffer_used; ret = read(file->fd, strm->buffer + strm->buffer_used, diff); - if (ret == 0) { + if (ret == 0) strm->eof = true; - break; - } if (ret < 0) { if (errno == EINTR) -- cgit v1.2.3