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.
65 struct fastbuf { /** Fastbuf structure **/
66 byte is_fastbuf[0]; /** Dummy field for checking of type casts **/
67 byte *bptr, *bstop; /** Access pointers **/
68 byte *buffer, *bufend; /** Start and end of the buffer **/
69 char *name; /** File name for error messages **/
70 ucw_off_t pos; /** Position of bstop in the file **/
71 int (*refill)(struct fastbuf *); /** Get a buffer with new data **/
72 void (*spout)(struct fastbuf *); /** Write buffer data to the file **/
73 int (*seek)(struct fastbuf *, ucw_off_t, int); /** Slow path for bseek(), buffer already flushed; returns success **/
74 void (*close)(struct fastbuf *); /** Close the stream **/
75 int (*config)(struct fastbuf *, uns, int); /** Configure the stream **/
76 int can_overwrite_buffer; /** Can the buffer be altered? (see discussion above) 0=never, 1=temporarily, 2=permanently **/
79 /* FastIO on files with several configurable back-ends */
81 enum fb_type { /** Which back-end you want to use **/
82 FB_STD, /** Standard buffered I/O **/
83 FB_DIRECT, /** Direct I/O bypassing system caches (see +fb-direct.c+ for a description) **/
84 FB_MMAP /** Memory mapped files **/
87 struct fb_params { /** **/
88 enum fb_type type; /** **/
89 uns buffer_size; /** 0 for default size **/
90 uns keep_back_buf; /** FB_STD: optimize for bi-directional access **/
91 uns read_ahead; /** FB_DIRECT options **/
92 uns write_back; /** **/
93 struct asio_queue *asio; /** **/
97 extern struct cf_section fbpar_cf; /** Config **/
98 extern struct fb_params fbpar_def; /** Default parameters **/
102 * Use +@params = NULL+ for defaults.
104 struct fastbuf *bopen_file(const char *name, int mode, struct fb_params *params);
105 struct fastbuf *bopen_file_try(const char *name, int mode, struct fb_params *params); /** Tries to open a file (does not die, if unsuccessful) **/
107 * Opens a temporary file.
108 * It is placed with other temp filenames and deleted when closed.
110 struct fastbuf *bopen_tmp_file(struct fb_params *params);
111 struct fastbuf *bopen_fd_name(int fd, struct fb_params *params, const char *name);
112 static inline struct fastbuf *bopen_fd(int fd, struct fb_params *params)
114 return bopen_fd_name(fd, params, NULL);
117 /* FastIO on standard files (shortcuts for FB_STD) */
119 struct fastbuf *bopen(const char *name, uns mode, uns buflen);
120 struct fastbuf *bopen_try(const char *name, uns mode, uns buflen);
121 struct fastbuf *bopen_tmp(uns buflen);
122 struct fastbuf *bfdopen(int fd, uns buflen);
123 struct fastbuf *bfdopen_shared(int fd, uns buflen);
124 void bfilesync(struct fastbuf *b);
126 /* Temporary files */
128 #define TEMP_FILE_NAME_LEN 256
129 void temp_file_name(char *name_buf, int *open_flags);
130 void bfix_tmp_file(struct fastbuf *fb, const char *name);
131 int open_tmp(char *name_buf, int open_flags, int mode);
133 /* Internal functions of some file back-ends */
135 struct fastbuf *bfdopen_internal(int fd, const char *name, uns buflen);
136 struct fastbuf *bfmmopen_internal(int fd, const char *name, uns mode);
138 extern uns fbdir_cheat;
140 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);
142 void bclose_file_helper(struct fastbuf *f, int fd, int is_temp_file);
144 /* FastIO on in-memory streams */
146 struct fastbuf *fbmem_create(uns blocksize); /* Create stream and return its writing fastbuf */
147 struct fastbuf *fbmem_clone_read(struct fastbuf *); /* Create reading fastbuf */
149 /* FastI on file descriptors with limit */
151 struct fastbuf *bopen_limited_fd(int fd, uns bufsize, uns limit);
153 /* FastIO on static buffers */
155 void fbbuf_init_read(struct fastbuf *f, byte *buffer, uns size, uns can_overwrite);
156 void fbbuf_init_write(struct fastbuf *f, byte *buffer, uns size);
158 fbbuf_count_written(struct fastbuf *f)
160 return f->bptr - f->bstop;
163 /* FastIO on recyclable growing buffers */
165 struct fastbuf *fbgrow_create(unsigned basic_size);
166 void fbgrow_reset(struct fastbuf *b); /* Reset stream and prepare for writing */
167 void fbgrow_rewind(struct fastbuf *b); /* Prepare for reading */
169 /* FastO on memory pools */
177 void fbpool_init(struct fbpool *fb); /* Initialize a new fastbuf */
178 void fbpool_start(struct fbpool *fb, struct mempool *mp, uns init_size);
179 /* Start a new continuous block and prepare for writing (see mp_start()) */
180 void *fbpool_end(struct fbpool *fb); /* Close the block and return its address (see mp_end()).
181 The length can be determined with mp_size(mp, ptr). */
183 /* FastO with atomic writes for multi-threaded programs */
187 struct fb_atomic_file *af;
188 byte *expected_max_bptr;
191 #define FB_ATOMIC(f) ((struct fb_atomic *)(f)->is_fastbuf)
193 struct fastbuf *fbatomic_open(const char *name, struct fastbuf *master, uns bufsize, int record_len);
194 void fbatomic_internal_write(struct fastbuf *b);
197 fbatomic_commit(struct fastbuf *b)
199 if (b->bptr >= ((struct fb_atomic *)b)->expected_max_bptr)
200 fbatomic_internal_write(b);
203 /* Configuring stream parameters */
206 BCONFIG_IS_TEMP_FILE, /* 0=normal file, 1=temporary file, 2=shared fd */
207 BCONFIG_KEEP_BACK_BUF, /* Optimize for bi-directional access */
210 int bconfig(struct fastbuf *f, uns type, int data);
212 /* Universal functions working on all fastbuf's */
214 void bclose(struct fastbuf *f);
215 void bflush(struct fastbuf *f);
216 void bseek(struct fastbuf *f, ucw_off_t pos, int whence);
217 void bsetpos(struct fastbuf *f, ucw_off_t pos);
218 void brewind(struct fastbuf *f);
219 ucw_off_t bfilesize(struct fastbuf *f); /* -1 if not seekable */
221 static inline ucw_off_t btell(struct fastbuf *f)
223 return f->pos + (f->bptr - f->bstop);
226 int bgetc_slow(struct fastbuf *f);
227 static inline int bgetc(struct fastbuf *f)
229 return (f->bptr < f->bstop) ? (int) *f->bptr++ : bgetc_slow(f);
232 int bpeekc_slow(struct fastbuf *f);
233 static inline int bpeekc(struct fastbuf *f)
235 return (f->bptr < f->bstop) ? (int) *f->bptr : bpeekc_slow(f);
238 static inline void bungetc(struct fastbuf *f)
243 void bputc_slow(struct fastbuf *f, uns c);
244 static inline void bputc(struct fastbuf *f, uns c)
246 if (f->bptr < f->bufend)
253 bavailr(struct fastbuf *f)
255 return f->bstop - f->bptr;
259 bavailw(struct fastbuf *f)
261 return f->bufend - f->bptr;
264 uns bread_slow(struct fastbuf *f, void *b, uns l, uns check);
265 static inline uns bread(struct fastbuf *f, void *b, uns l)
269 memcpy(b, f->bptr, l);
274 return bread_slow(f, b, l, 0);
277 static inline uns breadb(struct fastbuf *f, void *b, uns l)
281 memcpy(b, f->bptr, l);
286 return bread_slow(f, b, l, 1);
289 void bwrite_slow(struct fastbuf *f, const void *b, uns l);
290 static inline void bwrite(struct fastbuf *f, const void *b, uns l)
294 memcpy(f->bptr, b, l);
298 bwrite_slow(f, b, l);
302 * Functions for reading of strings:
304 * bgets() reads a line, strip the trailing '\n' and return a pointer
305 * to the terminating 0 or NULL on EOF. Dies if the line is too long.
306 * bgets0() does the same for 0-terminated strings.
307 * bgets_nodie() a variant of bgets() which returns either the length of the
308 * string (excluding the terminator) or -1 if the line does not fit
309 * in the buffer. In such cases, it returns after reading exactly `l'
311 * bgets_bb() a variant of bgets() which allocates the string in a growing buffer
312 * bgets_mp() the same, but in a mempool
313 * bgets_stk() the same, but on the stack by alloca()
316 char *bgets(struct fastbuf *f, char *b, uns l);
317 char *bgets0(struct fastbuf *f, char *b, uns l);
318 int bgets_nodie(struct fastbuf *f, char *b, uns l);
322 uns bgets_bb(struct fastbuf *f, struct bb_t *b, uns limit);
323 char *bgets_mp(struct fastbuf *f, struct mempool *mp);
325 struct bgets_stk_struct {
327 byte *old_buf, *cur_buf, *src;
328 uns old_len, cur_len, src_len;
330 void bgets_stk_init(struct bgets_stk_struct *s);
331 void bgets_stk_step(struct bgets_stk_struct *s);
332 #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; })
335 bputs(struct fastbuf *f, const char *b)
337 bwrite(f, b, strlen(b));
341 bputs0(struct fastbuf *f, const char *b)
343 bwrite(f, b, strlen(b)+1);
347 bputsn(struct fastbuf *f, const char *b)
353 void bbcopy_slow(struct fastbuf *f, struct fastbuf *t, uns l);
355 bbcopy(struct fastbuf *f, struct fastbuf *t, uns l)
357 if (bavailr(f) >= l && bavailw(t) >= l)
359 memcpy(t->bptr, f->bptr, l);
364 bbcopy_slow(f, t, l);
367 int bskip_slow(struct fastbuf *f, uns len);
368 static inline int bskip(struct fastbuf *f, uns len)
370 if (bavailr(f) >= len)
376 return bskip_slow(f, len);
379 /* Direct I/O on buffers */
382 bdirect_read_prepare(struct fastbuf *f, byte **buf)
384 if (f->bptr == f->bstop && !f->refill(f))
386 *buf = NULL; // This is not needed, but it helps to get rid of spurious warnings
394 bdirect_read_commit(struct fastbuf *f, byte *pos)
400 bdirect_read_commit_modified(struct fastbuf *f, byte *pos)
403 f->buffer = pos; /* Avoid seeking backwards in the buffer */
407 bdirect_write_prepare(struct fastbuf *f, byte **buf)
409 if (f->bptr == f->bufend)
416 bdirect_write_commit(struct fastbuf *f, byte *pos)
421 /* Formatted output */
423 int bprintf(struct fastbuf *b, const char *msg, ...) FORMAT_CHECK(printf,2,3);
424 int vbprintf(struct fastbuf *b, const char *msg, va_list args);