/*
* Sherlock Library -- Fast Buffered I/O
*
- * (c) 1997--2000 Martin Mares <mj@ucw.cz>
+ * (c) 1997--2002 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#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:
*
*
* 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.
*/
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 */
- 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 */
/* FastIO on standard files */
+struct fb_file {
+ struct fastbuf fb;
+ int fd; /* File descriptor, -1 if not a real file */
+ int is_temp_file; /* 0=normal file, 1=temporary file, delete on close, -1=shared FD */
+};
+#define FB_FILE(f) ((struct fb_file *)(f)->is_fastbuf)
+
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 *bfdopen_shared(int fd, uns buffer);
+#define FB_IS_TEMP_FILE(f) FB_FILE(f)->is_temp_file
/* FastIO on in-memory streams */
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);
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 (f->bptr + l <= f->bstop &&
+ t->bptr + l <= t->bufend)
+ {
+ memcpy(t->bptr, f->bptr, l);
+ t->bptr += l;
+ f->bptr += l;
+ }
+ else
+ bbcopy_slow(f, t, l);
+}
+
/* I/O on addr_int_t */
#ifdef CPU_64BIT_POINTERS
/* 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 int
+bdirect_read_prepare(struct fastbuf *f, byte **buf)
+{
+ if (f->bptr == f->bstop && !f->refill(f))
+ return EOF;
+ *buf = f->bptr;
+ return f->bstop - f->bptr;
+}
+
+static inline void
+bdirect_read_commit(struct fastbuf *f, byte *pos)
+{
+ f->bptr = pos;
+}
+
+static inline int
+bdirect_write_prepare(struct fastbuf *f, byte **buf)
+{
+ if (f->bptr == f->bufend)
+ f->spout(f);
+ *buf = f->bptr;
+ return f->bufend - f->bptr;
+}
+
+static inline void
+bdirect_write_commit(struct fastbuf *f, byte *pos)
+{
+ f->bptr = pos;
+}
#endif