From 9386d0717a7477bf094cc9b1a034ae7aae3a2f67 Mon Sep 17 00:00:00 2001 From: Yousong Zhou Date: Thu, 4 Jun 2015 21:41:40 +0800 Subject: [PATCH] ustream: tweak ustream_prepare_buf() a bit. No functional change. - Reuse existing NULL check on buf. - Add some comments for ease of reading the code. Signed-off-by: Yousong Zhou --- ustream.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/ustream.c b/ustream.c index fc93bc2..e7ee9f0 100644 --- a/ustream.c +++ b/ustream.c @@ -145,21 +145,26 @@ static bool ustream_should_move(struct ustream_buf_list *l, struct ustream_buf * int maxlen; int offset; + /* nothing to squeeze */ if (buf->data == buf->head) return false; maxlen = buf->end - buf->head; offset = buf->data - buf->head; + /* less than half is available */ if (offset > maxlen / 2) return true; + /* less than 32 bytes data but takes more than 1/4 space */ if (buf->tail - buf->data < 32 && offset > maxlen / 4) return true; + /* more buf is already in list or can be allocated */ if (buf != l->tail || ustream_can_alloc(l)) return false; + /* no need to move if len is available at the tail */ return (buf->end - buf->tail < len); } @@ -255,13 +260,14 @@ static bool ustream_prepare_buf(struct ustream *s, struct ustream_buf_list *l, i if (l == &s->r) ustream_fixup_string(s, buf); } + /* some chunks available at the tail */ if (buf->tail != buf->end) return true; - } - - if (buf && buf->next) { - l->data_tail = buf->next; - return true; + /* next buf available */ + if (buf->next) { + l->data_tail = buf->next; + return true; + } } if (!ustream_can_alloc(l)) -- 2.30.2