X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffastbuf.h;h=9878beeb1593580664f27b5be370e8b088bba60c;hb=ec085c955731db594926666e9bc6bdbbc1f5be9e;hp=d5ca3e717ef7709d52ac46c4f3900ec4d5cffca0;hpb=168c1f2ddcb8ce07248b4079b6398afe8c2d792a;p=libucw.git

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index d5ca3e71..9878beeb 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,15 +1,22 @@
 /*
- *	Sherlock Library -- Fast Buffered I/O
+ *	UCW Library -- Fast Buffered I/O
  *
- *	(c) 1997--2000 Martin Mares <mj@ucw.cz>
+ *	(c) 1997--2007 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 EOF
-#include <stdio.h>
-#endif
+#ifndef _UCW_FASTBUF_H
+#define _UCW_FASTBUF_H
+
+#include <string.h>
+#include <alloca.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:
  *
@@ -25,71 +32,198 @@
  *
  *  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 */
-  void *lldata;				/* Data private to access functions below */
-  void *llpos;				/* ... continued ... */
+  char *name;				/* File name for error messages */
+  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 */
+  int (*seek)(struct fastbuf *, sh_off_t, int);  /* Slow path for bseek(), buffer already flushed; returns success */
   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 files with run-time parametrization */
+
+enum fb_type {				/* Which back-end you want to use */
+  FB_STD,				/* Standard buffered I/O */
+  FB_DIRECT,				/* Direct I/O bypassing system caches (see fb-direct.c for description) */
+  FB_MMAP				/* Memory mapped files */
+};
+
+struct fb_params {
+  enum fb_type type;
+  uns buffer_size;
+  /* FB_STD only */
+  uns keep_back_buf;
+  /* FB_DIRECT only */
+  uns read_ahead;			
+  uns write_back;
+  struct asio_queue *asio;
+};
+
+struct cf_section;
+extern struct cf_section fbpar_cf;
+extern struct fb_params fbpar_def;
+
+struct fastbuf *bopen_file(const char *name, int mode, struct fb_params *params);	/* Use params==NULL for defaults */
+struct fastbuf *bopen_file_try(const char *name, int mode, struct fb_params *params);
+struct fastbuf *bopen_tmp_file(struct fb_params *params);
+struct fastbuf *bopen_fd(int fd, struct fb_params *params);
+
 /* FastIO on standard files */
 
-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 *bfdopen_internal(int fd, const char *name, uns buflen);
+struct fastbuf *bopen(const char *name, uns mode, uns buflen);
+struct fastbuf *bopen_try(const char *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(char *name);
+void bfix_tmp_file(struct fastbuf *fb, const char *name);
+
+/* Internal functions of some file back-ends */
+
+struct fastbuf *bfmmopen_internal(int fd, const char *name, uns mode);
+
+extern uns fbdir_cheat;
+struct asio_queue;
+struct fastbuf *fbdir_open_fd_internal(int fd, const char *name, struct asio_queue *io_queue, uns buffer_size, uns read_ahead, uns write_back);
 
 /* FastIO on in-memory streams */
 
-struct fastbuf *fbmem_create(unsigned blocksize);	/* Create stream and return its writing fastbuf */
+struct fastbuf *fbmem_create(uns blocksize);		/* Create stream and return its writing fastbuf */
 struct fastbuf *fbmem_clone_read(struct fastbuf *);	/* Create reading fastbuf */
 
+/* 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 on memory pools */
+
+struct mempool;
+struct fbpool {
+  struct fastbuf fb;
+  struct mempool *mp;
+};
+
+void fbpool_init(struct fbpool *fb);	/* Initialize a new fastbuf */
+void fbpool_start(struct fbpool *fb, struct mempool *mp, uns init_size);
+					/* Start a new continuous block and prepare for writing (see mp_start()) */
+void *fbpool_end(struct fbpool *fb);	/* Close the block and return its address (see mp_end()).
+					   The length can be determined with mp_size(mp, ptr). */
+
+/* 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(const char *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 */
+
+enum bconfig_type {
+  BCONFIG_IS_TEMP_FILE,
+  BCONFIG_KEEP_BACK_BUF,
+};
+
+int bconfig(struct fastbuf *f, uns type, int data);
+
 /* 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);		// -1 if not seekable
 
-extern 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);
-extern inline int bgetc(struct fastbuf *f)
+static inline int bgetc(struct fastbuf *f)
 {
   return (f->bptr < f->bstop) ? (int) *f->bptr++ : bgetc_slow(f);
 }
 
 int bpeekc_slow(struct fastbuf *f);
-extern inline int bpeekc(struct fastbuf *f)
+static inline int bpeekc(struct fastbuf *f)
 {
   return (f->bptr < f->bstop) ? (int) *f->bptr : bpeekc_slow(f);
 }
 
-extern inline void bungetc(struct fastbuf *f, byte c)
+static inline void bungetc(struct fastbuf *f)
 {
-  *--f->bptr = c;
+  f->bptr--;
 }
 
-void bputc_slow(struct fastbuf *f, byte c);
-extern inline void bputc(struct fastbuf *f, byte c)
+void bputc_slow(struct fastbuf *f, uns c);
+static inline void bputc(struct fastbuf *f, uns c)
 {
   if (f->bptr < f->bufend)
     *f->bptr++ = c;
@@ -97,222 +231,178 @@ extern inline void bputc(struct fastbuf *f, byte c)
     bputc_slow(f, c);
 }
 
-word bgetw_slow(struct fastbuf *f);
-extern inline word bgetw(struct fastbuf *f)
+static inline uns
+bavailr(struct fastbuf *f)
 {
-  word w;
-  if (f->bptr + 2 <= f->bstop)
-    {
-      byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
-      w = * ((word *) p);
-#else
-#ifdef CPU_BIG_ENDIAN
-      w = (p[0] << 8) | p[1];
-#else
-      w = (p[1] << 8) | p[0];
-#endif
-#endif
-      f->bptr += 2;
-      return w;
-    }
-  else
-    return bgetw_slow(f);
+  return f->bstop - f->bptr;
 }
 
-u32 bgetl_slow(struct fastbuf *f);
-extern inline u32 bgetl(struct fastbuf *f)
+static inline uns
+bavailw(struct fastbuf *f)
 {
-  u32 l;
-  if (f->bptr + 4 <= f->bstop)
-    {
-      byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
-      l = * ((u32 *) p);
-#else
-#ifdef CPU_BIG_ENDIAN
-      l = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
-#else
-      l = (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
-#endif
-#endif
-      f->bptr += 4;
-      return l;
-    }
-  else
-    return bgetl_slow(f);
+  return f->bufend - f->bptr;
 }
 
-u64 bgetq_slow(struct fastbuf *f);
-extern inline u64 bgetq(struct fastbuf *f)
+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 + 8 <= f->bstop)
+  if (bavailr(f) >= l)
     {
-      u64 l;
-      memcpy(&l, f->bptr, 8);
-      f->bptr += 8;
+      memcpy(b, f->bptr, l);
+      f->bptr += l;
       return l;
     }
   else
-    return bgetq_slow(f);
+    return bread_slow(f, b, l, 0);
 }
 
-u64 bget5_slow(struct fastbuf *f);
-extern inline u64 bget5(struct fastbuf *f)
+static inline uns breadb(struct fastbuf *f, void *b, uns l)
 {
-  u64 l;
-  if (f->bptr + 5 <= f->bstop)
+  if (bavailr(f) >= l)
     {
-      byte *p = f->bptr;
-#ifdef CPU_BIG_ENDIAN
-      l = ((u64)p[0] << 32) | (u32)((p[1] << 24) | (p[2] << 16) | (p[3] << 8) | p[4]);
-#else
-      l = ((u64)p[4] << 32) | (u32)((p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0]);
-#endif
-      f->bptr += 5;
+      memcpy(b, f->bptr, l);
+      f->bptr += l;
       return l;
     }
   else
-    return bget5_slow(f);
+    return bread_slow(f, b, l, 1);
 }
 
-void bputw_slow(struct fastbuf *f, word w);
-extern inline void bputw(struct fastbuf *f, word w)
+void bwrite_slow(struct fastbuf *f, const void *b, uns l);
+static inline void bwrite(struct fastbuf *f, const void *b, uns l)
 {
-  if (f->bptr + 2 <= f->bufend)
+  if (bavailw(f) >= l)
     {
-      byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
-      * ((word *) p) = w;
-#else
-#ifdef CPU_BIG_ENDIAN
-      p[0] = w >> 8U;
-      p[1] = w;
-#else
-      p[1] = w >> 8U;
-      p[0] = w;
-#endif
-#endif
-      f->bptr += 2;
+      memcpy(f->bptr, b, l);
+      f->bptr += l;
     }
   else
-    bputw_slow(f, w);
+    bwrite_slow(f, b, l);
 }
 
-void bputl_slow(struct fastbuf *f, u32 l);
-extern inline void bputl(struct fastbuf *f, u32 l)
+/*
+ *  Functions for reading of strings:
+ *
+ *     bgets()		reads a line, strip the trailing '\n' and return a pointer
+ *			to the terminating 0 or NULL on EOF. Dies if the line is too long.
+ *     bgets0()		does the same for 0-terminated strings.
+ *     bgets_nodie()	a variant of bgets() which returns either the length of the
+ *     			string (excluding the terminator) or -1 if the line does not fit
+ *     			in the buffer. In such cases, it returns after reading exactly `l'
+ *     			bytes of input.
+ *     bgets_bb()	a variant of bgets() which allocates the string in a growing buffer
+ *     bgets_mp()	the same, but in a mempool
+ *     bgets_stk()	the same, but on the stack by alloca()
+ */
+
+char *bgets(struct fastbuf *f, char *b, uns l);
+char *bgets0(struct fastbuf *f, char *b, uns l);
+int bgets_nodie(struct fastbuf *f, char *b, uns l);
+
+struct mempool;
+struct bb_t;
+uns bgets_bb(struct fastbuf *f, struct bb_t *b, uns limit);
+char *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, const char *b)
 {
-  if (f->bptr + 4 <= f->bufend)
-    {
-      byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
-      * ((u32 *) p) = l;
-#else
-#ifdef CPU_BIG_ENDIAN
-      p[0] = l >> 24U;
-      p[1] = l >> 16U;
-      p[2] = l >> 8U;
-      p[3] = l;
-#else
-      p[3] = l >> 24U;
-      p[2] = l >> 16U;
-      p[1] = l >> 8U;
-      p[0] = l;
-#endif
-#endif
-      f->bptr += 4;
-    }
-  else
-    bputl_slow(f, l);
+  bwrite(f, b, strlen(b));
 }
 
-void bputq_slow(struct fastbuf *f, u64 l);
-extern inline void bputq(struct fastbuf *f, u64 l)
+static inline void
+bputs0(struct fastbuf *f, const char *b)
 {
-  if (f->bptr + 8 <= f->bufend)
-    {
-      memcpy(f->bptr, &l, 8);
-      f->bptr += 8;
-    }
-  else
-    bputq_slow(f, l);
+  bwrite(f, b, strlen(b)+1);
 }
 
-void bput5_slow(struct fastbuf *f, u64 l);
-extern inline void bput5(struct fastbuf *f, u64 l)
+static inline void
+bputsn(struct fastbuf *f, const char *b)
 {
-  if (f->bptr + 5 <= f->bufend)
+  bputs(f, 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)
     {
-      byte *p = f->bptr;
-      u32 low = l;
-#ifdef CPU_BIG_ENDIAN
-      p[0] = l >> 32U;
-      p[1] = low >> 24U;
-      p[2] = low >> 16U;
-      p[3] = low >> 8U;
-      p[4] = low;
-#else
-      p[4] = l >> 32U;
-      p[3] = low >> 24U;
-      p[2] = low >> 16U;
-      p[1] = low >> 8U;
-      p[0] = low;
-#endif
-      f->bptr += 5;
+      memcpy(t->bptr, f->bptr, l);
+      t->bptr += l;
+      f->bptr += l;
     }
   else
-    bput5_slow(f, l);
+    bbcopy_slow(f, t, l);
 }
 
-void bread_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bread(struct fastbuf *f, void *b, uns l)
+int bskip_slow(struct fastbuf *f, uns len);
+static inline int bskip(struct fastbuf *f, uns len)
 {
-  if (f->bptr + l <= f->bstop)
+  if (bavailr(f) >= len)
     {
-      memcpy(b, f->bptr, l);
-      f->bptr += l;
+      f->bptr += len;
+      return 1;
     }
   else
-    bread_slow(f, b, l);
+    return bskip_slow(f, len);
 }
 
-void bwrite_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bwrite(struct fastbuf *f, void *b, uns l)
+/* Direct I/O on buffers */
+
+static inline uns
+bdirect_read_prepare(struct fastbuf *f, byte **buf)
 {
-  if (f->bptr + l <= f->bufend)
+  if (f->bptr == f->bstop && !f->refill(f))
     {
-      memcpy(f->bptr, b, l);
-      f->bptr += l;
+      *buf = NULL;  // This is not needed, but it helps to get rid of spurious warnings
+      return 0;
     }
-  else
-    bwrite_slow(f, b, l);
+  *buf = f->bptr;
+  return bavailr(f);
 }
 
-byte *bgets(struct fastbuf *f, byte *b, uns l);	/* Non-std */
+static inline void
+bdirect_read_commit(struct fastbuf *f, byte *pos)
+{
+  f->bptr = pos;
+}
 
-extern inline void
-bputs(struct fastbuf *f, byte *b)
+static inline void
+bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
 {
-  bwrite(f, b, strlen(b));
+  f->bptr = pos;
+  f->buffer = pos;	/* Avoid seeking backwards in the buffer */
 }
 
-extern inline void
-bputsn(struct fastbuf *f, byte *b)
+static inline uns
+bdirect_write_prepare(struct fastbuf *f, byte **buf)
 {
-  bputs(f, b);
-  bputc(f, '\n');
+  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;
 }
 
-/* Depending on compile-time configuration, we select the right function for reading/writing of file offsets */
-
-#ifdef SHERLOCK_CONFIG_LARGE_DB
-#define bgeto(f) bget5(f)
-#define bputo(f,l) bput5(f,l)
-#define bgetp(f) bgetq(f)
-#define bputp(f,l) bputq(f,l)
-#else
-#define bgeto(f) bgetl(f)
-#define bputo(f,l) bputl(f,l)
-#define bgetp(f) bgetl(f)
-#define bputp(f,l) bputl(f,l)
+/* Formatted output */
+
+int bprintf(struct fastbuf *b, const char *msg, ...) FORMAT_CHECK(printf,2,3);
+int vbprintf(struct fastbuf *b, const char *msg, va_list args);
+
 #endif