X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Ffastbuf.h;h=1589843d5e3ccde0a701004ee893812b9a37c1af;hb=39d5e9acc6d93c07cbb408fe27144c8a485499ac;hp=9e974cf54ea4539b7c6d9f29d19b970f42c17246;hpb=d6279d601cfb3f86e0bbe3fb78b4daa9af824bf3;p=libucw.git

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index 9e974cf5..1589843d 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,23 +1,18 @@
 /*
- *	Sherlock Library -- Fast Buffered I/O
+ *	UCW Library -- Fast Buffered I/O
  *
- *	(c) 1997--2004 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 _SHERLOCK_FASTBUF_H
-#define _SHERLOCK_FASTBUF_H
-
-#ifndef EOF
-#include <stdio.h>
-#endif
+#ifndef _UCW_FASTBUF_H
+#define _UCW_FASTBUF_H
 
 #include <string.h>
-
-#include "lib/unaligned.h"
+#include <alloca.h>
 
 /*
  *  Generic buffered I/O. You supply hooks to be called for low-level operations
@@ -51,36 +46,53 @@
  *	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 */
+  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 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(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);
 
 /* 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 */
 
 /* FastIO on memory mapped files */
 
-struct fastbuf *bopen_mm(byte *name, uns mode);
+struct fastbuf *bopen_mm(const char *name, uns mode);
 
 /* FastI on file descriptors with limit */
 
@@ -88,7 +100,7 @@ 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_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)
@@ -96,21 +108,37 @@ 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(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 */
 
 int bconfig(struct fastbuf *f, uns type, int data);
 
 #define BCONFIG_IS_TEMP_FILE 0
-#define BCONFIG_CAN_OVERWRITE 1
-  /* Specifies whether the caller is allowed to perform the following optimized
-   * 0-copy write operation:
-   * 	- get the buffer by bdirect_read_prepare()
-   * 	- modify the buffer, e.g. by putting \0's inside
-   * 	- call bflush() to let the fastbuf know
-   * Values:
-   * 0: read-only memory
-   * 1: you can write into read-write memory, if you restore the original value
-   * 2: you can rewrite the original content */
 
 /* Universal functions working on all fastbuf's */
 
@@ -119,7 +147,7 @@ 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);
+sh_off_t bfilesize(struct fastbuf *f);		// -1 if not seekable
 
 static inline sh_off_t btell(struct fastbuf *f)
 {
@@ -152,114 +180,22 @@ static inline void bputc(struct fastbuf *f, uns c)
     bputc_slow(f, c);
 }
 
-int bgetw_slow(struct fastbuf *f);
-static inline int bgetw(struct fastbuf *f)
-{
-  int w;
-  if (f->bptr + 2 <= f->bstop)
-    {
-      w = GET_U16(f->bptr);
-      f->bptr += 2;
-      return w;
-    }
-  else
-    return bgetw_slow(f);
-}
-
-u32 bgetl_slow(struct fastbuf *f);
-static inline u32 bgetl(struct fastbuf *f)
-{
-  u32 l;
-  if (f->bptr + 4 <= f->bstop)
-    {
-      l = GET_U32(f->bptr);
-      f->bptr += 4;
-      return l;
-    }
-  else
-    return bgetl_slow(f);
-}
-
-u64 bgetq_slow(struct fastbuf *f);
-static inline u64 bgetq(struct fastbuf *f)
-{
-  u64 l;
-  if (f->bptr + 8 <= f->bstop)
-    {
-      l = GET_U64(f->bptr);
-      f->bptr += 8;
-      return l;
-    }
-  else
-    return bgetq_slow(f);
-}
-
-u64 bget5_slow(struct fastbuf *f);
-static inline u64 bget5(struct fastbuf *f)
-{
-  u64 l;
-  if (f->bptr + 5 <= f->bstop)
-    {
-      l = GET_U40(f->bptr);
-      f->bptr += 5;
-      return l;
-    }
-  else
-    return bget5_slow(f);
-}
-
-void bputw_slow(struct fastbuf *f, uns w);
-static inline void bputw(struct fastbuf *f, uns w)
-{
-  if (f->bptr + 2 <= f->bufend)
-    {
-      PUT_U16(f->bptr, w);
-      f->bptr += 2;
-    }
-  else
-    bputw_slow(f, w);
-}
-
-void bputl_slow(struct fastbuf *f, u32 l);
-static inline void bputl(struct fastbuf *f, u32 l)
-{
-  if (f->bptr + 4 <= f->bufend)
-    {
-      PUT_U32(f->bptr, l);
-      f->bptr += 4;
-    }
-  else
-    bputl_slow(f, l);
-}
-
-void bputq_slow(struct fastbuf *f, u64 l);
-static inline void bputq(struct fastbuf *f, u64 l)
+static inline uns
+bavailr(struct fastbuf *f)
 {
-  if (f->bptr + 8 <= f->bufend)
-    {
-      PUT_U64(f->bptr, l);
-      f->bptr += 8;
-    }
-  else
-    bputq_slow(f, l);
+  return f->bstop - f->bptr;
 }
 
-void bput5_slow(struct fastbuf *f, u64 l);
-static inline void bput5(struct fastbuf *f, u64 l)
+static inline uns
+bavailw(struct fastbuf *f)
 {
-  if (f->bptr + 5 <= f->bufend)
-    {
-      PUT_U40(f->bptr, l);
-      f->bptr += 5;
-    }
-  else
-    bput5_slow(f, l);
+  return f->bufend - f->bptr;
 }
 
 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;
@@ -271,7 +207,7 @@ 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;
@@ -281,10 +217,10 @@ static inline uns breadb(struct fastbuf *f, void *b, uns l)
     return bread_slow(f, b, l, 1);
 }
 
-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, const void *b, uns l);
+static inline void bwrite(struct fastbuf *f, const void *b, uns l)
 {
-  if (f->bptr + l <= f->bufend)
+  if (bavailw(f) >= l)
     {
       memcpy(f->bptr, b, l);
       f->bptr += l;
@@ -293,24 +229,53 @@ static inline void bwrite(struct fastbuf *f, void *b, uns l)
     bwrite_slow(f, b, 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);
+/*
+ *  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, byte *b)
+bputs(struct fastbuf *f, const char *b)
 {
   bwrite(f, b, strlen(b));
 }
 
 static inline void
-bputs0(struct fastbuf *f, byte *b)
+bputs0(struct fastbuf *f, const char *b)
 {
   bwrite(f, b, strlen(b)+1);
 }
 
 static inline void
-bputsn(struct fastbuf *f, byte *b)
+bputsn(struct fastbuf *f, const char *b)
 {
   bputs(f, b);
   bputc(f, '\n');
@@ -320,8 +285,7 @@ void bbcopy_slow(struct fastbuf *f, struct fastbuf *t, uns l);
 static inline void
 bbcopy(struct fastbuf *f, struct fastbuf *t, uns l)
 {
-  if (f->bptr + l <= f->bstop &&
-      t->bptr + l <= t->bufend)
+  if (bavailr(f) >= l && bavailw(t) >= l)
     {
       memcpy(t->bptr, f->bptr, l);
       t->bptr += l;
@@ -331,15 +295,17 @@ bbcopy(struct fastbuf *f, struct fastbuf *t, uns l)
     bbcopy_slow(f, t, l);
 }
 
-/* I/O on addr_int_t */
-
-#ifdef CPU_64BIT_POINTERS
-#define bputa(x,p) bputq(x,p)
-#define bgeta(x) bgetq(x)
-#else
-#define bputa(x,p) bputl(x,p)
-#define bgeta(x) bgetl(x)
-#endif
+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);
+}
 
 /* Direct I/O on buffers */
 
@@ -347,9 +313,12 @@ static inline uns
 bdirect_read_prepare(struct fastbuf *f, byte **buf)
 {
   if (f->bptr == f->bstop && !f->refill(f))
-    return 0;
+    {
+      *buf = NULL;  // This is not needed, but it helps to get rid of spurious warnings
+      return 0;
+    }
   *buf = f->bptr;
-  return f->bstop - f->bptr;
+  return bavailr(f);
 }
 
 static inline void
@@ -358,13 +327,20 @@ 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 f->bufend - f->bptr;
+  return bavailw(f);
 }
 
 static inline void
@@ -375,7 +351,7 @@ bdirect_write_commit(struct fastbuf *f, byte *pos)
 
 /* Formatted output */
 
-int bprintf(struct fastbuf *b, byte *msg, ...);
-int vbprintf(struct fastbuf *b, byte *msg, va_list args);
+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