From: Martin Mares <mj@ucw.cz>
Date: Fri, 27 Sep 2002 21:45:40 +0000 (+0000)
Subject: When writing, the data needn't start at the beginning of the buffer.
X-Git-Tag: holmes-import~1335
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=2a5686e35c9d6be6cefe22d49cfff6d23ec2e842;p=libucw.git

When writing, the data needn't start at the beginning of the buffer.
(We need this for fb-mmap since the buffer is always page aligned.)
---

diff --git a/lib/fastbuf.c b/lib/fastbuf.c
index 2631be06..d976730d 100644
--- a/lib/fastbuf.c
+++ b/lib/fastbuf.c
@@ -24,13 +24,10 @@ void bclose(struct fastbuf *f)
 
 void bflush(struct fastbuf *f)
 {
-  if (f->bptr != f->buffer)
-    {					/* Have something to flush */
-      if (f->bstop > f->buffer)		/* Read data? */
-	f->bptr = f->bstop = f->buffer;
-      else				/* Write data... */
-	f->spout(f);
-    }
+  if (f->bptr > f->bstop)
+    f->spout(f);
+  else if (f->bstop > f->buffer)
+    f->bptr = f->bstop = f->buffer;
 }
 
 inline void bsetpos(struct fastbuf *f, sh_off_t pos)
diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index 4f6c5e66..1f502ce5 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -36,11 +36,11 @@
  *
  *  When writing:
  *
- *  +----------------+---------------------------+
- *  | written data   | free space                |
- *  +----------------+---------------------------+
- *  ^                 ^                           ^
- *  buffer=bstop      bptr                        bufend
+ *  +--------+--------------+--------------------+
+ *  | unused | written data | free space         |
+ *  +--------+--------------+--------------------+
+ *  ^         ^              ^                    ^
+ *  buffer    bstop          bptr                 bufend
  *
  *  Dirty tricks:
  *