Merge with git+ssh://cvs.ucw.cz/projects/sherlock/GIT/sherlock.git#v3.8

[libucw.git] / lib / fastbuf.h

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index 2948830ee4e0331e305a9c5a9ceb66486ca738db..905d046d134689c2a86a2a795dd7d46a56280abc 100644 (file)
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,11 +1,15 @@
 /*
 /*

- *     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>
 
 #ifndef EOF
 #include <stdio.h>


@@ -16,7 +20,8 @@
 #include "lib/unaligned.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:
  *
  *
  *  Buffer layout when reading:
  *


@@ -32,52 +37,96 @@
  *
  *  When writing:
  *
  *
  *  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 {
  */
 
 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 */
   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 (*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 *bopen_tmp(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_tmp(uns buflen);
+struct fastbuf *bfdopen(int fd, uns buflen);
+struct fastbuf *bfdopen_shared(int fd, uns buflen);
+void bfilesync(struct fastbuf *b);

 
 /* 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 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);
+
+/* 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;
+}
+
+/* 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);
 /* 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)
 {
 
 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);
 }
 
 int bgetc_slow(struct fastbuf *f);


@@ -106,11 +155,23 @@ static inline void bputc(struct fastbuf *f, uns c)
     bputc_slow(f, 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;
 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;
     {
       w = GET_U16(f->bptr);
       f->bptr += 2;


@@ -124,7 +185,7 @@ u32 bgetl_slow(struct fastbuf *f);
 static inline u32 bgetl(struct fastbuf *f)
 {
   u32 l;
 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;
     {
       l = GET_U32(f->bptr);
       f->bptr += 4;


@@ -138,7 +199,7 @@ u64 bgetq_slow(struct fastbuf *f);
 static inline u64 bgetq(struct fastbuf *f)
 {
   u64 l;
 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;
     {
       l = GET_U64(f->bptr);
       f->bptr += 8;


@@ -152,7 +213,7 @@ u64 bget5_slow(struct fastbuf *f);
 static inline u64 bget5(struct fastbuf *f)
 {
   u64 l;
 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;
     {
       l = GET_U40(f->bptr);
       f->bptr += 5;


@@ -165,7 +226,7 @@ static inline u64 bget5(struct fastbuf *f)
 void bputw_slow(struct fastbuf *f, uns w);
 static inline void bputw(struct fastbuf *f, uns w)
 {
 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;
     {
       PUT_U16(f->bptr, w);
       f->bptr += 2;


@@ -177,7 +238,7 @@ 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)
 {
 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;
     {
       PUT_U32(f->bptr, l);
       f->bptr += 4;


@@ -189,7 +250,7 @@ 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)
 {
 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;
     {
       PUT_U64(f->bptr, l);
       f->bptr += 8;


@@ -201,7 +262,7 @@ 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)
 {
 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;
     {
       PUT_U40(f->bptr, l);
       f->bptr += 5;


@@ -213,7 +274,7 @@ 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)
 {
 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;
     {
       memcpy(b, f->bptr, l);
       f->bptr += l;


@@ -225,7 +286,7 @@ static inline uns bread(struct fastbuf *f, void *b, uns l)
 
 static inline uns breadb(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;
     {
       memcpy(b, f->bptr, l);
       f->bptr += l;


@@ -238,7 +299,7 @@ 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)
 {
 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;
     {
       memcpy(f->bptr, b, l);
       f->bptr += l;


@@ -248,6 +309,7 @@ static inline void bwrite(struct fastbuf *f, void *b, uns l)
 }
 
 byte *bgets(struct fastbuf *f, byte *b, uns l);        /* Non-std */
 }
 
 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
 byte *bgets0(struct fastbuf *f, byte *b, uns l);
 
 static inline void


@@ -269,6 +331,32 @@ bputsn(struct fastbuf *f, byte *b)
   bputc(f, '\n');
 }
 
   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
 /* I/O on addr_int_t */
 
 #ifdef CPU_64BIT_POINTERS


@@ -281,8 +369,49 @@ bputsn(struct fastbuf *f, byte *b)
 
 /* Direct I/O on buffers */
 
 
 /* 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
 
 #endif