/*
- * Sherlock Library -- Fast File Buffering
+ * UCW Library -- Fast Buffered I/O
*
- * (c) 1997 Martin Mares, <mj@atrey.karlin.mff.cuni.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. You supply hooks to be called for low-level operations
+ * (swapping of buffers, seeking and closing), we do the rest.
+ *
+ * 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:
+ *
+ * +--------+--------------+--------------------+
+ * | 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 standard portion of the buffer */
- uns pos; /* Position of bptr in the file */
- uns fdpos; /* Current position in the file */
- int fd; /* File descriptor */
+ 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 */
+ 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 */
};
-struct fastbuf *bopen(byte *name, uns mode, uns buffer);
-struct fastbuf *bfdopen(int fd, uns buffer);
+/* 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 *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(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
-void bseek(struct fastbuf *f, uns pos, int whence);
-void bsetpos(struct fastbuf *f, uns pos);
-
-extern inline uns 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);
}
-extern inline void bungetc(struct fastbuf *f, byte c)
+int bpeekc_slow(struct fastbuf *f);
+static inline int bpeekc(struct fastbuf *f)
{
- *--f->bptr = c;
+ return (f->bptr < f->bstop) ? (int) *f->bptr : bpeekc_slow(f);
}
-void bputc_slow(struct fastbuf *f, byte c);
-extern inline void bputc(struct fastbuf *f, byte c)
+static inline void bungetc(struct fastbuf *f)
+{
+ f->bptr--;
+}
+
+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;
bputc_slow(f, c);
}
-word bgetw_slow(struct fastbuf *f);
-extern inline word bgetw(struct fastbuf *f)
+static inline uns
+bavailr(struct fastbuf *f)
{
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
- word w;
- if (f->bptr + 2 <= f->bstop)
- {
- w = * ((word *) f->bptr);
- f->bptr += 2;
- return w;
- }
- else
- return bgetw_slow(f);
-#else
- word w = bgetc(f);
-#ifdef CPU_BIG_ENDIAN
- return (w << 8) | bgetc(f);
-#else
- return w | (bgetc(f) << 8);
-#endif
-#endif
+ return f->bstop - f->bptr;
+}
+
+static inline uns
+bavailw(struct fastbuf *f)
+{
+ return f->bufend - f->bptr;
}
-ulg bgetl_slow(struct fastbuf *f);
-extern inline ulg bgetl(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)
{
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
- ulg l;
- if (f->bptr + 4 <= f->bstop)
+ if (bavailr(f) >= l)
{
- l = * ((ulg *) f->bptr);
- f->bptr += 4;
+ memcpy(b, f->bptr, l);
+ f->bptr += l;
return l;
}
else
- return bgetl_slow(f);
-#else
- ulg l = bgetc(f);
-#ifdef CPU_BIG_ENDIAN
- l = (l << 8) | bgetc(f);
- l = (l << 8) | bgetc(f);
- return (l << 8) | bgetc(f);
-#else
- l = (bgetc(f) << 8) | l;
- l = (bgetc(f) << 16) | l;
- return (bgetc(f) << 24) | l;
-#endif
-#endif
+ return bread_slow(f, b, l, 0);
}
-void bputw_slow(struct fastbuf *f, word w);
-extern inline void bputw(struct fastbuf *f, word w)
+static inline uns breadb(struct fastbuf *f, void *b, uns l)
{
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
- if (f->bptr + 2 <= f->bufend)
+ if (bavailr(f) >= l)
{
- * ((word *) f->bptr) = w;
- f->bptr += 2;
+ memcpy(b, f->bptr, l);
+ f->bptr += l;
+ return l;
}
else
- bputw_slow(f, w);
-#else
-#ifdef CPU_BIG_ENDIAN
- bputc(f, w >> 8);
- bputc(f, w);
-#else
- bputc(f, w);
- bputc(f, w >> 8);
-#endif
-#endif
+ return bread_slow(f, b, l, 1);
}
-void bputl_slow(struct fastbuf *f, ulg l);
-extern inline void bputl(struct fastbuf *f, ulg l)
+void bwrite_slow(struct fastbuf *f, const void *b, uns l);
+static inline void bwrite(struct fastbuf *f, const void *b, uns l)
{
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
- if (f->bptr + 4 <= f->bufend)
+ if (bavailw(f) >= l)
{
- * ((ulg *) f->bptr) = l;
- f->bptr += 4;
+ memcpy(f->bptr, b, l);
+ f->bptr += l;
}
else
- bputl_slow(f, l);
-#else
-#ifdef CPU_BIG_ENDIAN
- bputc(f, l >> 24);
- bputc(f, l >> 16);
- bputc(f, l >> 8);
- bputc(f, l);
-#else
- bputc(f, l);
- bputc(f, l >> 8);
- bputc(f, l >> 16);
- bputc(f, l >> 24);
-#endif
-#endif
+ bwrite_slow(f, b, 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)
+{
+ bwrite(f, b, strlen(b));
+}
+
+static inline void
+bputs0(struct fastbuf *f, const char *b)
+{
+ bwrite(f, b, strlen(b)+1);
}
-void bread_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bread(struct fastbuf *f, void *b, uns l)
+static inline void
+bputsn(struct fastbuf *f, const char *b)
{
- if (f->bptr + l <= f->bstop)
+ 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)
{
- memcpy(b, f->bptr, l);
+ memcpy(t->bptr, f->bptr, l);
+ t->bptr += l;
f->bptr += l;
}
else
- bread_slow(f, b, l);
+ bbcopy_slow(f, t, l);
}
-void bwrite_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bwrite(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->bufend)
+ if (bavailr(f) >= len)
{
- memcpy(f->bptr, b, l);
- f->bptr += l;
+ f->bptr += len;
+ return 1;
}
else
- bwrite_slow(f, b, l);
+ return bskip_slow(f, len);
}
-void bbcopy(struct fastbuf *f, struct fastbuf *t, uns l);
+/* Direct I/O on buffers */
-extern inline byte * /* Non-standard */
-bgets(struct fastbuf *f, byte *b, uns l)
+static inline uns
+bdirect_read_prepare(struct fastbuf *f, byte **buf)
{
- byte *e = b + l - 1;
- int k;
-
- k = bgetc(f);
- if (k == EOF)
- return NULL;
- while (b < e)
+ if (f->bptr == f->bstop && !f->refill(f))
{
- if (k == '\n' || k == EOF)
- {
- *b = 0;
- return b;
- }
- *b++ = k;
- k = bgetc(f);
+ *buf = NULL; // This is not needed, but it helps to get rid of spurious warnings
+ return 0;
}
- die("%s: Line too long", f->name);
+ *buf = f->bptr;
+ return bavailr(f);
}
-extern inline void
-bputs(struct fastbuf *f, byte *b)
+static inline void
+bdirect_read_commit(struct fastbuf *f, byte *pos)
{
- while (*b)
- bputc(f, *b++);
+ f->bptr = pos;
}
-extern inline void
-bputsn(struct fastbuf *f, byte *b)
+static inline void
+bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
{
- bputs(f, b);
- bputc(f, '\n');
+ 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 bavailw(f);
+}
+
+static inline void
+bdirect_write_commit(struct fastbuf *f, byte *pos)
+{
+ f->bptr = pos;
}
+/* 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
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