X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=inline;f=lib%2Ffastbuf.h;h=45ce06916f0c388831a57d3293104a810a684c61;hb=997624f88f37bec5cb96cf9fc3b3cac05ccc6ed8;hp=a370c45be8995155190b5eb61079812a685178e4;hpb=0fcb09840c756fc67ba5e572c25f5304e639f54c;p=libucw.git

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index a370c45b..45ce0691 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,7 +1,8 @@
 /*
  *	Sherlock Library -- Fast Buffered I/O
  *
- *	(c) 1997--2002 Martin Mares <mj@ucw.cz>
+ *	(c) 1997--2004 Martin Mares <mj@ucw.cz>
+ *	(c) 2004 Robert Spalek <robert@ucw.cz>
  *
  *	This software may be freely distributed and used according to the terms
  *	of the GNU Lesser General Public License.
@@ -15,7 +16,6 @@
 #endif
 
 #include <string.h>
-#include <stdarg.h>
 
 #include "lib/unaligned.h"
 
@@ -51,6 +51,17 @@
  *	as after the data you've read.
  *    - The spout/refill hooks can change not only bptr and bstop, but also
  *	the location of the buffer; fb-mem.c takes advantage of it.
+ *    - In some cases, the user of the bdirect interface can be allowed to modify
+ *	the data in the buffer to avoid unnecessary copying. If the back-end
+ *	allows such modifications, it can set can_overwrite_buffer accordingly:
+ *		*  0 if no modification is allowed,
+ *		*  1 if the user can modify the buffer on the condition that
+ *		     the modifications will be undone before calling the next
+ *		     fastbuf operation
+ *		*  2 if the user is allowed to overwrite the data in the buffer
+ *		     if bdirect_read_commit_modified() is called afterwards.
+ *		     In this case, the back-end must be prepared for trimming
+ *		     of the buffer which is done by the commit function.
  */
 
 struct fastbuf {
@@ -64,14 +75,15 @@ struct fastbuf {
   void (*seek)(struct fastbuf *, sh_off_t, int);  /* Slow path for bseek(), buffer already flushed */
   void (*close)(struct fastbuf *);	/* Close the stream */
   int (*config)(struct fastbuf *, uns, int);	/* Configure the stream */
+  int can_overwrite_buffer;		/* Can the buffer be altered? (see discussion above) 0=never, 1=temporarily, 2=permanently */
 };
 
 /* FastIO on standard files (specify buffer size 0 to enable mmaping) */
 
-struct fastbuf *bopen(byte *name, uns mode, uns buffer);
-struct fastbuf *bopen_tmp(uns buffer);
-struct fastbuf *bfdopen(int fd, uns buffer);
-struct fastbuf *bfdopen_shared(int fd, uns buffer);
+struct fastbuf *bopen(byte *name, uns mode, uns buflen);
+struct fastbuf *bopen_tmp(uns buflen);
+struct fastbuf *bfdopen(int fd, uns buflen);
+struct fastbuf *bfdopen_shared(int fd, uns buflen);
 
 /* FastIO on in-memory streams */
 
@@ -82,6 +94,20 @@ struct fastbuf *fbmem_clone_read(struct fastbuf *);	/* Create reading fastbuf */
 
 struct fastbuf *bopen_mm(byte *name, uns mode);
 
+/* FastI on file descriptors with limit */
+
+struct fastbuf *bopen_limited_fd(int fd, uns bufsize, uns limit);
+
+/* FastIO on static buffers */
+
+void fbbuf_init_read(struct fastbuf *f, byte *buffer, uns size);
+void fbbuf_init_write(struct fastbuf *f, byte *buffer, uns size);
+static inline uns
+fbbuf_count_written(struct fastbuf *f)
+{
+  return f->bptr - f->bstop;
+}
+
 /* Configuring stream parameters */
 
 int bconfig(struct fastbuf *f, uns type, int data);
@@ -94,6 +120,8 @@ void bclose(struct fastbuf *f);
 void bflush(struct fastbuf *f);
 void bseek(struct fastbuf *f, sh_off_t pos, int whence);
 void bsetpos(struct fastbuf *f, sh_off_t pos);
+void brewind(struct fastbuf *f);
+void bskip(struct fastbuf *f, uns len);
 
 static inline sh_off_t btell(struct fastbuf *f)
 {
@@ -268,6 +296,7 @@ static inline void bwrite(struct fastbuf *f, void *b, uns l)
 }
 
 byte *bgets(struct fastbuf *f, byte *b, uns l);	/* Non-std */
+int bgets_nodie(struct fastbuf *f, byte *b, uns l);
 byte *bgets0(struct fastbuf *f, byte *b, uns l);
 
 static inline void
@@ -331,6 +360,13 @@ bdirect_read_commit(struct fastbuf *f, byte *pos)
   f->bptr = pos;
 }
 
+static inline void
+bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
+{
+  f->bptr = pos;
+  f->buffer = pos;	/* Avoid seeking backwards in the buffer */
+}
+
 static inline uns
 bdirect_write_prepare(struct fastbuf *f, byte **buf)
 {