2 * UCW Library -- Fast Buffered I/O
4 * (c) 1997--2007 Martin Mares <mj@ucw.cz>
5 * (c) 2004 Robert Spalek <robert@ucw.cz>
7 * This software may be freely distributed and used according to the terms
8 * of the GNU Lesser General Public License.
11 #ifndef _UCW_FASTBUF_H
12 #define _UCW_FASTBUF_H
18 * Generic buffered I/O. You supply hooks to be called for low-level operations
19 * (swapping of buffers, seeking and closing), we do the rest.
21 * Buffer layout when reading:
23 * +----------------+---------------------------+
24 * | read data | free space |
25 * +----------------+---------------------------+
27 * buffer bptr bstop bufend
29 * After the last character is read, bptr == bstop and buffer refill
30 * is deferred to the next read attempt. This gives us an easy way
31 * how to implement bungetc().
35 * +--------+--------------+--------------------+
36 * | unused | written data | free space |
37 * +--------+--------------+--------------------+
39 * buffer bstop bptr bufend
43 * - You can mix reads and writes on the same stream, but you must
44 * call bflush() in between and remember that the file position
45 * points after the flushed buffer which is not necessarily the same
46 * as after the data you've read.
47 * - The spout/refill hooks can change not only bptr and bstop, but also
48 * the location of the buffer; fb-mem.c takes advantage of it.
49 * - In some cases, the user of the bdirect interface can be allowed to modify
50 * the data in the buffer to avoid unnecessary copying. If the back-end
51 * allows such modifications, it can set can_overwrite_buffer accordingly:
52 * * 0 if no modification is allowed,
53 * * 1 if the user can modify the buffer on the condition that
54 * the modifications will be undone before calling the next
56 * * 2 if the user is allowed to overwrite the data in the buffer
57 * if bdirect_read_commit_modified() is called afterwards.
58 * In this case, the back-end must be prepared for trimming
59 * of the buffer which is done by the commit function.
63 byte is_fastbuf[0]; /* Dummy field for checking of type casts */
64 byte *bptr, *bstop; /* Access pointers */
65 byte *buffer, *bufend; /* Start and end of the buffer */
66 byte *name; /* File name for error messages */
67 sh_off_t pos; /* Position of bstop in the file */
68 int (*refill)(struct fastbuf *); /* Get a buffer with new data */
69 void (*spout)(struct fastbuf *); /* Write buffer data to the file */
70 int (*seek)(struct fastbuf *, sh_off_t, int); /* Slow path for bseek(), buffer already flushed; returns success */
71 void (*close)(struct fastbuf *); /* Close the stream */
72 int (*config)(struct fastbuf *, uns, int); /* Configure the stream */
73 int can_overwrite_buffer; /* Can the buffer be altered? (see discussion above) 0=never, 1=temporarily, 2=permanently */
76 /* FastIO on standard files (specify buffer size 0 to enable mmaping) */
78 struct fastbuf *bopen(byte *name, uns mode, uns buflen);
79 struct fastbuf *bopen_try(byte *name, uns mode, uns buflen);
80 struct fastbuf *bopen_tmp(uns buflen);
81 struct fastbuf *bfdopen(int fd, uns buflen);
82 struct fastbuf *bfdopen_shared(int fd, uns buflen);
83 void bfilesync(struct fastbuf *b);
85 #define TEMP_FILE_NAME_LEN 256
86 void temp_file_name(byte *name);
88 /* FastIO on in-memory streams */
90 struct fastbuf *fbmem_create(unsigned blocksize); /* Create stream and return its writing fastbuf */
91 struct fastbuf *fbmem_clone_read(struct fastbuf *); /* Create reading fastbuf */
93 /* FastIO on memory mapped files */
95 struct fastbuf *bopen_mm(byte *name, uns mode);
97 /* FastIO on files opened with O_DIRECT (see fb-direct.c for description) */
100 struct fastbuf *fbdir_open(byte *name, uns mode, struct asio_queue *io_queue);
101 struct fastbuf *fbdir_open_try(byte *name, uns mode, struct asio_queue *io_queue);
102 struct fastbuf *fbdir_open_fd(int fd, struct asio_queue *io_queue);
103 struct fastbuf *fbdir_open_tmp(struct asio_queue *io_queue);
105 /* FastIO on files with run-time parametrization */
114 extern struct cf_section fbpar_cf;
116 struct fastbuf *fbpar_open(byte *name, int mode, struct fb_params *params);
117 struct fastbuf *fbpar_open_try(byte *name, int mode, struct fb_params *params);
118 struct fastbuf *fbpar_open_fd(int fd, struct fb_params *params);
119 struct fastbuf *fbpar_open_tmp(struct fb_params *params);
121 /* FastI on file descriptors with limit */
123 struct fastbuf *bopen_limited_fd(int fd, uns bufsize, uns limit);
125 /* FastIO on static buffers */
127 void fbbuf_init_read(struct fastbuf *f, byte *buffer, uns size, uns can_overwrite);
128 void fbbuf_init_write(struct fastbuf *f, byte *buffer, uns size);
130 fbbuf_count_written(struct fastbuf *f)
132 return f->bptr - f->bstop;
135 /* FastIO on recyclable growing buffers */
137 struct fastbuf *fbgrow_create(unsigned basic_size);
138 void fbgrow_reset(struct fastbuf *b); /* Reset stream and prepare for writing */
139 void fbgrow_rewind(struct fastbuf *b); /* Prepare for reading */
141 /* FastO with atomic writes for multi-threaded programs */
145 struct fb_atomic_file *af;
146 byte *expected_max_bptr;
149 #define FB_ATOMIC(f) ((struct fb_atomic *)(f)->is_fastbuf)
151 struct fastbuf *fbatomic_open(byte *name, struct fastbuf *master, uns bufsize, int record_len);
152 void fbatomic_internal_write(struct fastbuf *b);
155 fbatomic_commit(struct fastbuf *b)
157 if (b->bptr >= ((struct fb_atomic *)b)->expected_max_bptr)
158 fbatomic_internal_write(b);
161 /* Configuring stream parameters */
163 int bconfig(struct fastbuf *f, uns type, int data);
165 #define BCONFIG_IS_TEMP_FILE 0
167 /* Universal functions working on all fastbuf's */
169 void bclose(struct fastbuf *f);
170 void bflush(struct fastbuf *f);
171 void bseek(struct fastbuf *f, sh_off_t pos, int whence);
172 void bsetpos(struct fastbuf *f, sh_off_t pos);
173 void brewind(struct fastbuf *f);
174 sh_off_t bfilesize(struct fastbuf *f); // -1 if not seekable
176 static inline sh_off_t btell(struct fastbuf *f)
178 return f->pos + (f->bptr - f->bstop);
181 int bgetc_slow(struct fastbuf *f);
182 static inline int bgetc(struct fastbuf *f)
184 return (f->bptr < f->bstop) ? (int) *f->bptr++ : bgetc_slow(f);
187 int bpeekc_slow(struct fastbuf *f);
188 static inline int bpeekc(struct fastbuf *f)
190 return (f->bptr < f->bstop) ? (int) *f->bptr : bpeekc_slow(f);
193 static inline void bungetc(struct fastbuf *f)
198 void bputc_slow(struct fastbuf *f, uns c);
199 static inline void bputc(struct fastbuf *f, uns c)
201 if (f->bptr < f->bufend)
208 bavailr(struct fastbuf *f)
210 return f->bstop - f->bptr;
214 bavailw(struct fastbuf *f)
216 return f->bufend - f->bptr;
219 uns bread_slow(struct fastbuf *f, void *b, uns l, uns check);
220 static inline uns bread(struct fastbuf *f, void *b, uns l)
224 memcpy(b, f->bptr, l);
229 return bread_slow(f, b, l, 0);
232 static inline uns breadb(struct fastbuf *f, void *b, uns l)
236 memcpy(b, f->bptr, l);
241 return bread_slow(f, b, l, 1);
244 void bwrite_slow(struct fastbuf *f, void *b, uns l);
245 static inline void bwrite(struct fastbuf *f, void *b, uns l)
249 memcpy(f->bptr, b, l);
253 bwrite_slow(f, b, l);
256 byte *bgets(struct fastbuf *f, byte *b, uns l); /* Non-std */
257 int bgets_nodie(struct fastbuf *f, byte *b, uns l);
258 byte *bgets0(struct fastbuf *f, byte *b, uns l);
262 uns bgets_bb(struct fastbuf *f, struct bb_t *b, uns limit);
263 byte *bgets_mp(struct fastbuf *f, struct mempool *mp);
265 struct bgets_stk_struct {
267 byte *old_buf, *cur_buf, *src;
268 uns old_len, cur_len, src_len;
270 void bgets_stk_init(struct bgets_stk_struct *s);
271 void bgets_stk_step(struct bgets_stk_struct *s);
272 #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; })
275 bputs(struct fastbuf *f, byte *b)
277 bwrite(f, b, strlen(b));
281 bputs0(struct fastbuf *f, byte *b)
283 bwrite(f, b, strlen(b)+1);
287 bputsn(struct fastbuf *f, byte *b)
293 void bbcopy_slow(struct fastbuf *f, struct fastbuf *t, uns l);
295 bbcopy(struct fastbuf *f, struct fastbuf *t, uns l)
297 if (bavailr(f) >= l && bavailw(t) >= l)
299 memcpy(t->bptr, f->bptr, l);
304 bbcopy_slow(f, t, l);
307 int bskip_slow(struct fastbuf *f, uns len);
308 static inline int bskip(struct fastbuf *f, uns len)
310 if (bavailr(f) >= len)
316 return bskip_slow(f, len);
319 /* Direct I/O on buffers */
322 bdirect_read_prepare(struct fastbuf *f, byte **buf)
324 if (f->bptr == f->bstop && !f->refill(f))
326 *buf = NULL; // This is not needed, but it helps to get rid of spurious warnings
334 bdirect_read_commit(struct fastbuf *f, byte *pos)
340 bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
343 f->buffer = pos; /* Avoid seeking backwards in the buffer */
347 bdirect_write_prepare(struct fastbuf *f, byte **buf)
349 if (f->bptr == f->bufend)
356 bdirect_write_commit(struct fastbuf *f, byte *pos)
361 /* Formatted output */
363 int bprintf(struct fastbuf *b, char *msg, ...) FORMAT_CHECK(printf,2,3);
364 int vbprintf(struct fastbuf *b, char *msg, va_list args);