/*
- * Sherlock Library -- Fast File Buffering
+ * UCW Library -- Fast Buffered I/O
*
- * (c) 1997--1999 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 */
- sh_off_t pos; /* Position of bptr in the file */
- sh_off_t fdpos; /* Current position in the file */
- int fd; /* File descriptor */
+ 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 standard files (specify buffer size 0 to enable mmaping) */
+
+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(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(const char *name, uns mode);
+
+/* 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 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
+
+/* 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
-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);
+ 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);
}
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)
{
- *--f->bptr = c;
+ f->bptr--;
}
-void bputc_slow(struct fastbuf *f, byte c);
-extern inline void bputc(struct fastbuf *f, byte c)
+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)
{
- word w;
- if (f->bptr + 2 <= f->bstop)
- {
- byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
- w = * ((word *) p);
-#else
-#ifdef CPU_BIG_ENDIAN
- w = (p[0] << 8) | p[1];
-#else
- w = (p[1] << 8) | p[0];
-#endif
-#endif
- f->bptr += 2;
- return w;
- }
- else
- return bgetw_slow(f);
+ return f->bstop - f->bptr;
}
-u32 bgetl_slow(struct fastbuf *f);
-extern inline u32 bgetl(struct fastbuf *f)
+static inline uns
+bavailw(struct fastbuf *f)
{
- u32 l;
- if (f->bptr + 4 <= f->bstop)
- {
- byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
- l = * ((u32 *) p);
-#else
-#ifdef CPU_BIG_ENDIAN
- l = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
-#else
- l = (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
-#endif
-#endif
- f->bptr += 4;
- return l;
- }
- else
- return bgetl_slow(f);
+ return f->bufend - f->bptr;
}
-u64 bgetq_slow(struct fastbuf *f);
-extern inline u64 bgetq(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)
{
- if (f->bptr + 8 <= f->bstop)
+ if (bavailr(f) >= l)
{
- u64 l;
- memcpy(&l, f->bptr, 8);
- f->bptr += 8;
+ memcpy(b, f->bptr, l);
+ f->bptr += l;
return l;
}
else
- return bgetq_slow(f);
+ return bread_slow(f, b, l, 0);
}
-u64 bget5_slow(struct fastbuf *f);
-extern inline u64 bget5(struct fastbuf *f)
+static inline uns breadb(struct fastbuf *f, void *b, uns l)
{
- u64 l;
- if (f->bptr + 5 <= f->bstop)
+ if (bavailr(f) >= l)
{
- byte *p = f->bptr;
-#ifdef CPU_BIG_ENDIAN
- l = ((u64)p[0] << 32) | ((p[1] << 24) | (p[2] << 16) | (p[3] << 8) | p[4]);
-#else
- l = ((u64)p[4] << 32) | ((p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0]);
-#endif
- f->bptr += 5;
+ memcpy(b, f->bptr, l);
+ f->bptr += l;
return l;
}
else
- return bget5_slow(f);
+ return bread_slow(f, b, l, 1);
}
-void bputw_slow(struct fastbuf *f, word w);
-extern inline void bputw(struct fastbuf *f, word w)
+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 + 2 <= f->bufend)
+ if (bavailw(f) >= l)
{
- byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_WORDS
- * ((word *) p) = w;
-#else
-#ifdef CPU_BIG_ENDIAN
- p[0] = w >> 8U;
- p[1] = w;
-#else
- p[1] = w >> 8U;
- p[0] = w;
-#endif
-#endif
- f->bptr += 2;
+ memcpy(f->bptr, b, l);
+ f->bptr += l;
}
else
- bputw_slow(f, w);
+ bwrite_slow(f, b, l);
}
-void bputl_slow(struct fastbuf *f, u32 l);
-extern inline void bputl(struct fastbuf *f, u32 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)
{
- if (f->bptr + 4 <= f->bufend)
- {
- byte *p = f->bptr;
-#ifdef CPU_CAN_DO_UNALIGNED_LONGS
- * ((u32 *) p) = l;
-#else
-#ifdef CPU_BIG_ENDIAN
- p[0] = l >> 24U;
- p[1] = l >> 16U;
- p[2] = l >> 8U;
- p[3] = l;
-#else
- p[3] = l >> 24U;
- p[2] = l >> 16U;
- p[1] = l >> 8U;
- p[0] = l;
-#endif
-#endif
- f->bptr += 4;
- }
- else
- bputl_slow(f, l);
+ bwrite(f, b, strlen(b));
}
-void bputq_slow(struct fastbuf *f, u64 l);
-extern inline void bputq(struct fastbuf *f, u64 l)
+static inline void
+bputs0(struct fastbuf *f, const char *b)
{
- if (f->bptr + 8 <= f->bufend)
- {
- memcpy(f->bptr, &l, 8);
- f->bptr += 8;
- }
- else
- bputq_slow(f, l);
+ bwrite(f, b, strlen(b)+1);
}
-void bput5_slow(struct fastbuf *f, u64 l);
-extern inline void bput5(struct fastbuf *f, u64 l)
+static inline void
+bputsn(struct fastbuf *f, const char *b)
{
- if (f->bptr + 5 <= f->bufend)
+ 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)
{
- byte *p = f->bptr;
- u32 low = l;
-#ifdef CPU_BIG_ENDIAN
- p[0] = l >> 32;
- p[1] = low >> 24U;
- p[2] = low >> 16U;
- p[3] = low >> 8U;
- p[4] = low;
-#else
- p[4] = l >> 32;
- p[3] = low >> 24U;
- p[2] = low >> 16U;
- p[1] = low >> 8U;
- p[0] = low;
-#endif
- f->bptr += 5;
+ memcpy(t->bptr, f->bptr, l);
+ t->bptr += l;
+ f->bptr += l;
}
else
- bput5_slow(f, l);
+ bbcopy_slow(f, t, l);
}
-void bread_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bread(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->bstop)
+ if (bavailr(f) >= len)
{
- memcpy(b, f->bptr, l);
- f->bptr += l;
+ f->bptr += len;
+ return 1;
}
else
- bread_slow(f, b, l);
+ return bskip_slow(f, len);
}
-void bwrite_slow(struct fastbuf *f, void *b, uns l);
-extern inline void bwrite(struct fastbuf *f, void *b, uns l)
+/* Direct I/O on buffers */
+
+static inline uns
+bdirect_read_prepare(struct fastbuf *f, byte **buf)
{
- if (f->bptr + l <= f->bufend)
+ if (f->bptr == f->bstop && !f->refill(f))
{
- memcpy(f->bptr, b, l);
- f->bptr += l;
+ *buf = NULL; // This is not needed, but it helps to get rid of spurious warnings
+ return 0;
}
- else
- bwrite_slow(f, b, l);
+ *buf = f->bptr;
+ return bavailr(f);
}
-void bbcopy(struct fastbuf *f, struct fastbuf *t, uns l);
-byte *bgets(struct fastbuf *f, byte *b, uns l); /* Non-std */
+static inline void
+bdirect_read_commit(struct fastbuf *f, byte *pos)
+{
+ f->bptr = pos;
+}
-extern inline void
-bputs(struct fastbuf *f, byte *b)
+static inline void
+bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
{
- bwrite(f, b, strlen(b));
+ f->bptr = pos;
+ f->buffer = pos; /* Avoid seeking backwards in the buffer */
}
-extern inline void
-bputsn(struct fastbuf *f, byte *b)
+static inline uns
+bdirect_write_prepare(struct fastbuf *f, byte **buf)
{
- bputs(f, b);
- bputc(f, '\n');
+ 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;
}
-#ifdef SHERLOCK_CONFIG_LARGE_DB
-#define bgeto(f) bget5(f)
-#define bputo(f,l) bput5(f,l)
-#define bgetp(f) bgetq(f)
-#define bputp(f,l) bputq(f,l)
-#else
-#define bgeto(f) bgetl(f)
-#define bputo(f,l) bputl(f,l)
-#define bgetp(f) bgetl(f)
-#define bputp(f,l) bputl(f,l)
+/* 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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