/*
- * 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 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;
}
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)
}
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)
}
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)
{
}
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)
}
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)
{
}
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)
{
}
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)
{
}
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)
{
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)
{
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');
}
+/* 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)