X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Ffastbuf.h;h=f1f0239ae8dac3177855a5919502d287e823353f;hb=7e769f8c4092b9538a497f0846a9165759b1fee2;hp=c367a1abdfccebe9f7c375f4bf9edb74b0d068a5;hpb=01ef9e1ec839ce2ad44b97d2ee1a97a67fe9f7c0;p=libucw.git

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index c367a1ab..f1f0239a 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -1,55 +1,98 @@
 /*
- *	Sherlock Library -- Fast File Buffering
+ *	Sherlock Library -- Fast Buffered I/O
  *
- *	(c) 1997--1999 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ *	(c) 1997--2000 Martin Mares <mj@ucw.cz>
  */
 
+#ifndef _SHERLOCK_FASTBUF_H
+#define _SHERLOCK_FASTBUF_H
+
 #ifndef EOF
 #include <stdio.h>
 #endif
 
+/*
+ *  Generic buffered I/O on a top of buffer swapping functions.
+ *
+ *  Buffer layout when reading:
+ *
+ *  +----------------+---------------------------+
+ *  | read data      | free space                |
+ *  +----------------+---------------------------+
+ *  ^        ^        ^                           ^
+ *  buffer   bptr     bstop                       bufend
+ *
+ *  After the last character is read, bptr == bstop and buffer refill
+ *  is deferred to the next read attempt. This gives us an easy way
+ *  how to implement bungetc().
+ *
+ *  When writing:
+ *
+ *  +----------------+---------------------------+
+ *  | written data   | free space                |
+ *  +----------------+---------------------------+
+ *  ^                 ^                           ^
+ *  buffer=bstop      bptr                        bufend
+ */
+
 struct fastbuf {
   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 standard portion of the buffer */
-  sh_off_t pos;				/* Position of bptr in the file */
-  sh_off_t fdpos;			/* Current position in the file */
-  int fd;				/* File descriptor */
+  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 ... */
+  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 */
 };
 
+/* 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);
+
+/* 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 */
+
+/* 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);
 
-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);
 }
 
 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, byte c)
 {
   *--f->bptr = c;
 }
 
 void bputc_slow(struct fastbuf *f, byte c);
-extern inline void bputc(struct fastbuf *f, byte c)
+static inline void bputc(struct fastbuf *f, byte c)
 {
   if (f->bptr < f->bufend)
     *f->bptr++ = c;
@@ -58,7 +101,7 @@ extern inline void bputc(struct fastbuf *f, byte c)
 }
 
 word bgetw_slow(struct fastbuf *f);
-extern inline word bgetw(struct fastbuf *f)
+static inline word bgetw(struct fastbuf *f)
 {
   word w;
   if (f->bptr + 2 <= f->bstop)
@@ -81,7 +124,7 @@ extern inline word bgetw(struct fastbuf *f)
 }
 
 u32 bgetl_slow(struct fastbuf *f);
-extern inline u32 bgetl(struct fastbuf *f)
+static inline u32 bgetl(struct fastbuf *f)
 {
   u32 l;
   if (f->bptr + 4 <= f->bstop)
@@ -104,7 +147,7 @@ extern inline u32 bgetl(struct fastbuf *f)
 }
 
 u64 bgetq_slow(struct fastbuf *f);
-extern inline u64 bgetq(struct fastbuf *f)
+static inline u64 bgetq(struct fastbuf *f)
 {
   if (f->bptr + 8 <= f->bstop)
     {
@@ -118,7 +161,7 @@ extern inline u64 bgetq(struct fastbuf *f)
 }
 
 u64 bget5_slow(struct fastbuf *f);
-extern inline u64 bget5(struct fastbuf *f)
+static inline u64 bget5(struct fastbuf *f)
 {
   u64 l;
   if (f->bptr + 5 <= f->bstop)
@@ -137,7 +180,7 @@ extern inline u64 bget5(struct fastbuf *f)
 }
 
 void bputw_slow(struct fastbuf *f, word w);
-extern inline void bputw(struct fastbuf *f, word w)
+static inline void bputw(struct fastbuf *f, word w)
 {
   if (f->bptr + 2 <= f->bufend)
     {
@@ -160,7 +203,7 @@ extern inline void bputw(struct fastbuf *f, word w)
 }
 
 void bputl_slow(struct fastbuf *f, u32 l);
-extern inline void bputl(struct fastbuf *f, u32 l)
+static inline void bputl(struct fastbuf *f, u32 l)
 {
   if (f->bptr + 4 <= f->bufend)
     {
@@ -187,7 +230,7 @@ extern inline void bputl(struct fastbuf *f, u32 l)
 }
 
 void bputq_slow(struct fastbuf *f, u64 l);
-extern inline void bputq(struct fastbuf *f, u64 l)
+static inline void bputq(struct fastbuf *f, u64 l)
 {
   if (f->bptr + 8 <= f->bufend)
     {
@@ -199,7 +242,7 @@ extern inline void bputq(struct fastbuf *f, u64 l)
 }
 
 void bput5_slow(struct fastbuf *f, u64 l);
-extern inline void bput5(struct fastbuf *f, u64 l)
+static inline void bput5(struct fastbuf *f, u64 l)
 {
   if (f->bptr + 5 <= f->bufend)
     {
@@ -224,20 +267,21 @@ extern inline void bput5(struct fastbuf *f, u64 l)
     bput5_slow(f, l);
 }
 
-void bread_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bread(struct fastbuf *f, void *b, uns l)
+uns bread_slow(struct fastbuf *f, void *b, uns l);
+static inline uns bread(struct fastbuf *f, void *b, uns l)
 {
   if (f->bptr + l <= f->bstop)
     {
       memcpy(b, f->bptr, l);
       f->bptr += l;
+      return l;
     }
   else
-    bread_slow(f, b, l);
+    return bread_slow(f, b, l);
 }
 
 void bwrite_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bwrite(struct fastbuf *f, void *b, uns l)
+static inline void bwrite(struct fastbuf *f, void *b, uns l)
 {
   if (f->bptr + l <= f->bufend)
     {
@@ -248,22 +292,29 @@ extern inline void bwrite(struct fastbuf *f, void *b, uns l)
     bwrite_slow(f, b, l);
 }
 
-void bbcopy(struct fastbuf *f, struct fastbuf *t, uns l);
 byte *bgets(struct fastbuf *f, byte *b, uns l);	/* Non-std */
 
-extern inline void
+static inline void
 bputs(struct fastbuf *f, byte *b)
 {
   bwrite(f, b, strlen(b));
 }
 
-extern inline void
+static inline void
 bputsn(struct fastbuf *f, byte *b)
 {
   bputs(f, b);
   bputc(f, '\n');
 }
 
+/* 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);
+
+/* 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)
@@ -275,3 +326,5 @@ bputsn(struct fastbuf *f, byte *b)
 #define bgetp(f) bgetl(f)
 #define bputp(f,l) bputl(f,l)
 #endif
+
+#endif