X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffastbuf.h;h=abcf7118499f0a76a66b5ab1b4a0aa3e11f03e1f;hb=a46de3a8cefbe34d11b389687e2ca310bd81fcfe;hp=c6e6e333d4ebd288440cf9a803ab4d54afbf8760;hpb=c982330d65a5ff8930682b250612ea135db2d4f6;p=libucw.git

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index c6e6e333..abcf7118 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,22 +1,28 @@
 /*
- *	Sherlock Library -- Fast Buffered I/O
+ *	UCW Library -- Fast Buffered I/O
  *
- *	(c) 1997--2000 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.
  */
 
-#ifndef _SHERLOCK_FASTBUF_H
-#define _SHERLOCK_FASTBUF_H
+#ifndef _UCW_FASTBUF_H
+#define _UCW_FASTBUF_H
 
 #ifndef EOF
 #include <stdio.h>
 #endif
 
 #include <string.h>
+#include <alloca.h>
 
 #include "lib/unaligned.h"
 
 /*
- *  Generic buffered I/O on a top of buffer swapping functions.
+ *  Generic buffered I/O. You supply hooks to be called for low-level operations
+ *  (swapping of buffers, seeking and closing), we do the rest.
  *
  *  Buffer layout when reading:
  *
@@ -32,51 +38,134 @@
  *
  *  When writing:
  *
- *  +----------------+---------------------------+
- *  | written data   | free space                |
- *  +----------------+---------------------------+
- *  ^                 ^                           ^
- *  buffer=bstop      bptr                        bufend
+ *  +--------+--------------+--------------------+
+ *  | unused | written data | free space         |
+ *  +--------+--------------+--------------------+
+ *  ^         ^              ^                    ^
+ *  buffer    bstop          bptr                 bufend
+ *
+ *  Dirty tricks:
+ *
+ *    - You can mix reads and writes on the same stream, but you must
+ *	call bflush() in between and remember that the file position
+ *	points after the flushed buffer which is not necessarily the same
+ *	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 {
+  byte is_fastbuf[0];			/* Dummy field for checking of type casts */
   byte *bptr, *bstop;			/* Access pointers */
   byte *buffer, *bufend;		/* Start and end of the buffer */
   byte *name;				/* File name for error messages */
-  uns buflen;				/* Size of the buffer */
-  sh_off_t pos;				/* Position of buffer start in the file */
-  sh_off_t fdpos;			/* Current position in the non-buffered file */
-  int fd;				/* File descriptor, -1 if not a real file */
-  int is_temp_file;			/* Is a temporary file, delete on close */
-  void *lldata;				/* Data private to access functions below */
-  void *llpos;				/* ... continued ... */
+  sh_off_t pos;				/* Position of bstop in the file */
   int (*refill)(struct fastbuf *);	/* Get a buffer with new data */
   void (*spout)(struct fastbuf *);	/* Write buffer data to the file */
   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 */
+/* FastIO on standard files (specify buffer size 0 to enable mmaping) */
 
-struct fastbuf *bopen(byte *name, uns mode, uns buffer);
-struct fastbuf *bfdopen(int fd, uns buffer);
-void bbcopy(struct fastbuf *f, struct fastbuf *t, uns l);
+struct fastbuf *bopen(byte *name, uns mode, uns buflen);
+struct fastbuf *bopen_try(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);
+void bfilesync(struct fastbuf *b);
+
+#define TEMP_FILE_NAME_LEN 256
+void temp_file_name(byte *name);
 
 /* FastIO on in-memory streams */
 
 struct fastbuf *fbmem_create(unsigned blocksize);	/* Create stream and return its writing fastbuf */
 struct fastbuf *fbmem_clone_read(struct fastbuf *);	/* Create reading fastbuf */
 
+/* FastIO on memory mapped files */
+
+struct fastbuf *bopen_mm(byte *name, uns mode);
+
+/* FastIO on files opened with O_DIRECT (see fb-direct.c for description) */
+
+struct asio_queue;
+struct fastbuf *fbdir_open(byte *name, uns mode, struct asio_queue *io_queue);
+struct fastbuf *fbdir_open_try(byte *name, uns mode, struct asio_queue *io_queue);
+struct fastbuf *fbdir_open_fd(int fd, struct asio_queue *io_queue);
+struct fastbuf *fbdir_open_tmp(struct asio_queue *io_queue);
+
+/* 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, uns can_overwrite);
+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;
+}
+
+/* FastIO on recyclable growing buffers */
+
+struct fastbuf *fbgrow_create(unsigned basic_size);
+void fbgrow_reset(struct fastbuf *b);			/* Reset stream and prepare for writing */
+void fbgrow_rewind(struct fastbuf *b);			/* Prepare for reading */
+
+/* FastO with atomic writes for multi-threaded programs */
+
+struct fb_atomic {
+  struct fastbuf fb;
+  struct fb_atomic_file *af;
+  byte *expected_max_bptr;
+  uns slack_size;
+};
+#define FB_ATOMIC(f) ((struct fb_atomic *)(f)->is_fastbuf)
+
+struct fastbuf *fbatomic_open(byte *name, struct fastbuf *master, uns bufsize, int record_len);
+void fbatomic_internal_write(struct fastbuf *b);
+
+static inline void
+fbatomic_commit(struct fastbuf *b)
+{
+  if (b->bptr >= ((struct fb_atomic *)b)->expected_max_bptr)
+    fbatomic_internal_write(b);
+}
+
+/* Configuring stream parameters */
+
+int bconfig(struct fastbuf *f, uns type, int data);
+
+#define BCONFIG_IS_TEMP_FILE 0
+
 /* Universal functions working on all fastbuf's */
 
 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);
+sh_off_t bfilesize(struct fastbuf *f);
 
 static inline sh_off_t btell(struct fastbuf *f)
 {
-  return f->pos + (f->bptr - f->buffer);
+  return f->pos + (f->bptr - f->bstop);
 }
 
 int bgetc_slow(struct fastbuf *f);
@@ -105,11 +194,23 @@ static inline void bputc(struct fastbuf *f, uns c)
     bputc_slow(f, c);
 }
 
+static inline uns
+bavailr(struct fastbuf *f)
+{
+  return f->bstop - f->bptr;
+}
+
+static inline uns
+bavailw(struct fastbuf *f)
+{
+  return f->bufend - f->bptr;
+}
+
 int bgetw_slow(struct fastbuf *f);
 static inline int bgetw(struct fastbuf *f)
 {
   int w;
-  if (f->bptr + 2 <= f->bstop)
+  if (bavailr(f) >= 2)
     {
       w = GET_U16(f->bptr);
       f->bptr += 2;
@@ -123,7 +224,7 @@ u32 bgetl_slow(struct fastbuf *f);
 static inline u32 bgetl(struct fastbuf *f)
 {
   u32 l;
-  if (f->bptr + 4 <= f->bstop)
+  if (bavailr(f) >= 4)
     {
       l = GET_U32(f->bptr);
       f->bptr += 4;
@@ -137,7 +238,7 @@ u64 bgetq_slow(struct fastbuf *f);
 static inline u64 bgetq(struct fastbuf *f)
 {
   u64 l;
-  if (f->bptr + 8 <= f->bstop)
+  if (bavailr(f) >= 8)
     {
       l = GET_U64(f->bptr);
       f->bptr += 8;
@@ -151,7 +252,7 @@ u64 bget5_slow(struct fastbuf *f);
 static inline u64 bget5(struct fastbuf *f)
 {
   u64 l;
-  if (f->bptr + 5 <= f->bstop)
+  if (bavailr(f) >= 5)
     {
       l = GET_U40(f->bptr);
       f->bptr += 5;
@@ -164,7 +265,7 @@ static inline u64 bget5(struct fastbuf *f)
 void bputw_slow(struct fastbuf *f, uns w);
 static inline void bputw(struct fastbuf *f, uns w)
 {
-  if (f->bptr + 2 <= f->bufend)
+  if (bavailw(f) >= 2)
     {
       PUT_U16(f->bptr, w);
       f->bptr += 2;
@@ -176,7 +277,7 @@ static inline void bputw(struct fastbuf *f, uns w)
 void bputl_slow(struct fastbuf *f, u32 l);
 static inline void bputl(struct fastbuf *f, u32 l)
 {
-  if (f->bptr + 4 <= f->bufend)
+  if (bavailw(f) >= 4)
     {
       PUT_U32(f->bptr, l);
       f->bptr += 4;
@@ -188,7 +289,7 @@ static inline void bputl(struct fastbuf *f, u32 l)
 void bputq_slow(struct fastbuf *f, u64 l);
 static inline void bputq(struct fastbuf *f, u64 l)
 {
-  if (f->bptr + 8 <= f->bufend)
+  if (bavailw(f) >= 8)
     {
       PUT_U64(f->bptr, l);
       f->bptr += 8;
@@ -200,7 +301,7 @@ static inline void bputq(struct fastbuf *f, u64 l)
 void bput5_slow(struct fastbuf *f, u64 l);
 static inline void bput5(struct fastbuf *f, u64 l)
 {
-  if (f->bptr + 5 <= f->bufend)
+  if (bavailw(f) >= 5)
     {
       PUT_U40(f->bptr, l);
       f->bptr += 5;
@@ -212,7 +313,7 @@ static inline void bput5(struct fastbuf *f, u64 l)
 uns bread_slow(struct fastbuf *f, void *b, uns l, uns check);
 static inline uns bread(struct fastbuf *f, void *b, uns l)
 {
-  if (f->bptr + l <= f->bstop)
+  if (bavailr(f) >= l)
     {
       memcpy(b, f->bptr, l);
       f->bptr += l;
@@ -224,7 +325,7 @@ static inline uns bread(struct fastbuf *f, void *b, uns l)
 
 static inline uns breadb(struct fastbuf *f, void *b, uns l)
 {
-  if (f->bptr + l <= f->bstop)
+  if (bavailr(f) >= l)
     {
       memcpy(b, f->bptr, l);
       f->bptr += l;
@@ -237,7 +338,7 @@ static inline uns breadb(struct fastbuf *f, void *b, uns l)
 void bwrite_slow(struct fastbuf *f, void *b, uns l);
 static inline void bwrite(struct fastbuf *f, void *b, uns l)
 {
-  if (f->bptr + l <= f->bufend)
+  if (bavailw(f) >= l)
     {
       memcpy(f->bptr, b, l);
       f->bptr += l;
@@ -247,8 +348,23 @@ 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);
 
+struct mempool;
+struct bb_t;
+uns bgets_bb(struct fastbuf *f, struct bb_t *b, uns limit);
+byte *bgets_mp(struct fastbuf *f, struct mempool *mp);
+
+struct bgets_stk_struct {
+  struct fastbuf *f;
+  byte *old_buf, *cur_buf, *src;
+  uns old_len, cur_len, src_len;
+};
+void bgets_stk_init(struct bgets_stk_struct *s);
+void bgets_stk_step(struct bgets_stk_struct *s);
+#define bgets_stk(fb) ({ struct bgets_stk_struct _s; _s.f = (fb); for (bgets_stk_init(&_s); _s.cur_len; _s.cur_buf = alloca(_s.cur_len), bgets_stk_step(&_s)); _s.cur_buf; })
+
 static inline void
 bputs(struct fastbuf *f, byte *b)
 {
@@ -268,6 +384,32 @@ bputsn(struct fastbuf *f, byte *b)
   bputc(f, '\n');
 }
 
+void bbcopy_slow(struct fastbuf *f, struct fastbuf *t, uns l);
+static inline void
+bbcopy(struct fastbuf *f, struct fastbuf *t, uns l)
+{
+  if (bavailr(f) >= l && bavailw(t) >= l)
+    {
+      memcpy(t->bptr, f->bptr, l);
+      t->bptr += l;
+      f->bptr += l;
+    }
+  else
+    bbcopy_slow(f, t, l);
+}
+
+int bskip_slow(struct fastbuf *f, uns len);
+static inline int bskip(struct fastbuf *f, uns len)
+{
+  if (bavailr(f) >= len)
+    {
+      f->bptr += len;
+      return 1;
+    }
+  else
+    return bskip_slow(f, len);
+}
+
 /* I/O on addr_int_t */
 
 #ifdef CPU_64BIT_POINTERS
@@ -280,8 +422,49 @@ bputsn(struct fastbuf *f, byte *b)
 
 /* Direct I/O on buffers */
 
-int bdirect_read(struct fastbuf *f, byte **buf);
-int bdirect_write_prepare(struct fastbuf *f, byte **buf);
-void bdirect_write_commit(struct fastbuf *f, byte *pos);
+static inline uns
+bdirect_read_prepare(struct fastbuf *f, byte **buf)
+{
+  if (f->bptr == f->bstop && !f->refill(f))
+    {
+      *buf = NULL;  // This is not needed, but it helps to get rid of spurious warnings
+      return 0;
+    }
+  *buf = f->bptr;
+  return bavailr(f);
+}
+
+static inline void
+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)
+{
+  if (f->bptr == f->bufend)
+    f->spout(f);
+  *buf = f->bptr;
+  return bavailw(f);
+}
+
+static inline void
+bdirect_write_commit(struct fastbuf *f, byte *pos)
+{
+  f->bptr = pos;
+}
+
+/* Formatted output */
+
+int bprintf(struct fastbuf *b, char *msg, ...) FORMAT_CHECK(printf,2,3);
+int vbprintf(struct fastbuf *b, char *msg, va_list args);
 
 #endif