2 * ustream - library for stream buffer management
4 * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
27 static void ustream_init_buf(struct ustream_buf
*buf
, int len
)
32 memset(buf
, 0, sizeof(*buf
));
33 buf
->data
= buf
->tail
= buf
->head
;
34 buf
->end
= buf
->head
+ len
;
38 static void ustream_add_buf(struct ustream_buf_list
*l
, struct ustream_buf
*buf
)
49 l
->data_tail
= l
->head
;
52 static bool ustream_can_alloc(struct ustream_buf_list
*l
)
54 if (l
->max_buffers
<= 0)
57 return (l
->buffers
< l
->max_buffers
);
60 static int ustream_alloc_default(struct ustream
*s
, struct ustream_buf_list
*l
)
62 struct ustream_buf
*buf
;
64 if (!ustream_can_alloc(l
))
67 buf
= malloc(sizeof(*buf
) + l
->buffer_len
+ s
->string_data
);
71 ustream_init_buf(buf
, l
->buffer_len
);
72 ustream_add_buf(l
, buf
);
77 static void ustream_free_buffers(struct ustream_buf_list
*l
)
79 struct ustream_buf
*buf
= l
->head
;
82 struct ustream_buf
*next
= buf
->next
;
92 void ustream_free(struct ustream
*s
)
97 uloop_timeout_cancel(&s
->state_change
);
98 ustream_free_buffers(&s
->r
);
99 ustream_free_buffers(&s
->w
);
102 static void ustream_state_change_cb(struct uloop_timeout
*t
)
104 struct ustream
*s
= container_of(t
, struct ustream
, state_change
);
107 ustream_free_buffers(&s
->w
);
112 void ustream_init_defaults(struct ustream
*s
)
114 #define DEFAULT_SET(_f, _default) \
120 DEFAULT_SET(s
->r
.alloc
, ustream_alloc_default
);
121 DEFAULT_SET(s
->w
.alloc
, ustream_alloc_default
);
123 DEFAULT_SET(s
->r
.min_buffers
, 1);
124 DEFAULT_SET(s
->r
.max_buffers
, 1);
125 DEFAULT_SET(s
->r
.buffer_len
, 4096);
127 DEFAULT_SET(s
->w
.min_buffers
, 2);
128 DEFAULT_SET(s
->w
.max_buffers
, -1);
129 DEFAULT_SET(s
->w
.buffer_len
, 256);
133 s
->state_change
.cb
= ustream_state_change_cb
;
134 s
->write_error
= false;
136 s
->eof_write_done
= false;
146 static bool ustream_should_move(struct ustream_buf_list
*l
, struct ustream_buf
*buf
, int len
)
151 /* nothing to squeeze */
152 if (buf
->data
== buf
->head
)
155 maxlen
= buf
->end
- buf
->head
;
156 offset
= buf
->data
- buf
->head
;
158 /* less than half is available */
159 if (offset
> maxlen
/ 2)
162 /* less than 32 bytes data but takes more than 1/4 space */
163 if (buf
->tail
- buf
->data
< 32 && offset
> maxlen
/ 4)
166 /* more buf is already in list or can be allocated */
167 if (buf
!= l
->tail
|| ustream_can_alloc(l
))
170 /* no need to move if len is available at the tail */
171 return (buf
->end
- buf
->tail
< len
);
174 static void ustream_free_buf(struct ustream_buf_list
*l
, struct ustream_buf
*buf
)
179 if (buf
== l
->data_tail
)
180 l
->data_tail
= buf
->next
;
185 if (--l
->buffers
>= l
->min_buffers
) {
191 ustream_init_buf(buf
, buf
->end
- buf
->head
);
192 ustream_add_buf(l
, buf
);
195 static void __ustream_set_read_blocked(struct ustream
*s
, unsigned char val
)
197 bool changed
= !!s
->read_blocked
!= !!val
;
199 s
->read_blocked
= val
;
201 s
->set_read_blocked(s
);
204 void ustream_set_read_blocked(struct ustream
*s
, bool set
)
206 unsigned char val
= s
->read_blocked
& ~READ_BLOCKED_USER
;
209 val
|= READ_BLOCKED_USER
;
211 __ustream_set_read_blocked(s
, val
);
214 void ustream_consume(struct ustream
*s
, int len
)
216 struct ustream_buf
*buf
= s
->r
.head
;
221 s
->r
.data_bytes
-= len
;
222 if (s
->r
.data_bytes
< 0)
226 struct ustream_buf
*next
= buf
->next
;
227 int buf_len
= buf
->tail
- buf
->data
;
235 ustream_free_buf(&s
->r
, buf
);
239 __ustream_set_read_blocked(s
, s
->read_blocked
& ~READ_BLOCKED_FULL
);
242 static void ustream_fixup_string(struct ustream
*s
, struct ustream_buf
*buf
)
250 static bool ustream_prepare_buf(struct ustream
*s
, struct ustream_buf_list
*l
, int len
)
252 struct ustream_buf
*buf
;
256 if (ustream_should_move(l
, buf
, len
)) {
257 int len
= buf
->tail
- buf
->data
;
259 memmove(buf
->head
, buf
->data
, len
);
260 buf
->data
= buf
->head
;
261 buf
->tail
= buf
->data
+ len
;
264 ustream_fixup_string(s
, buf
);
266 /* some chunks available at the tail */
267 if (buf
->tail
!= buf
->end
)
269 /* next buf available */
271 l
->data_tail
= buf
->next
;
276 if (!ustream_can_alloc(l
))
279 if (l
->alloc(s
, l
) < 0)
282 l
->data_tail
= l
->tail
;
286 char *ustream_reserve(struct ustream
*s
, int len
, int *maxlen
)
288 struct ustream_buf
*buf
;
290 if (!ustream_prepare_buf(s
, &s
->r
, len
)) {
291 __ustream_set_read_blocked(s
, s
->read_blocked
| READ_BLOCKED_FULL
);
296 buf
= s
->r
.data_tail
;
297 *maxlen
= buf
->end
- buf
->tail
;
301 void ustream_fill_read(struct ustream
*s
, int len
)
303 struct ustream_buf
*buf
= s
->r
.data_tail
;
307 s
->r
.data_bytes
+= len
;
312 maxlen
= buf
->end
- buf
->tail
;
318 ustream_fixup_string(s
, buf
);
320 s
->r
.data_tail
= buf
;
325 s
->notify_read(s
, n
);
328 char *ustream_get_read_buf(struct ustream
*s
, int *buflen
)
334 len
= s
->r
.head
->tail
- s
->r
.head
->data
;
336 data
= s
->r
.head
->data
;
345 int ustream_read(struct ustream
*s
, char *buf
, int buflen
)
352 chunk
= ustream_get_read_buf(s
, &chunk_len
);
355 if (chunk_len
> buflen
- len
)
356 chunk_len
= buflen
- len
;
357 memcpy(buf
+ len
, chunk
, chunk_len
);
358 ustream_consume(s
, chunk_len
);
360 } while (len
< buflen
);
365 static void ustream_write_error(struct ustream
*s
)
368 ustream_state_change(s
);
369 s
->write_error
= true;
372 bool ustream_write_pending(struct ustream
*s
)
374 struct ustream_buf
*buf
= s
->w
.head
;
380 while (buf
&& s
->w
.data_bytes
) {
381 struct ustream_buf
*next
= buf
->next
;
382 int maxlen
= buf
->tail
- buf
->data
;
384 len
= s
->write(s
, buf
->data
, maxlen
, !!buf
->next
);
386 ustream_write_error(s
);
394 s
->w
.data_bytes
-= len
;
400 ustream_free_buf(&s
->w
, buf
);
405 s
->notify_write(s
, wr
);
407 if (s
->eof
&& wr
&& !s
->w
.data_bytes
)
408 ustream_state_change(s
);
410 return !s
->w
.data_bytes
;
413 static int ustream_write_buffered(struct ustream
*s
, const char *data
, int len
, int wr
)
415 struct ustream_buf_list
*l
= &s
->w
;
416 struct ustream_buf
*buf
;
420 if (!ustream_prepare_buf(s
, &s
->w
, len
))
425 maxlen
= buf
->end
- buf
->tail
;
429 memcpy(buf
->tail
, data
, maxlen
);
434 l
->data_bytes
+= maxlen
;
440 int ustream_write(struct ustream
*s
, const char *data
, int len
, bool more
)
442 struct ustream_buf_list
*l
= &s
->w
;
448 if (!l
->data_bytes
) {
449 wr
= s
->write(s
, data
, len
, more
);
454 ustream_write_error(s
);
462 return ustream_write_buffered(s
, data
, len
, wr
);
465 #define MAX_STACK_BUFLEN 256
467 int ustream_vprintf(struct ustream
*s
, const char *format
, va_list arg
)
469 struct ustream_buf_list
*l
= &s
->w
;
472 int wr
, maxlen
, buflen
;
477 if (!l
->data_bytes
) {
478 buf
= alloca(MAX_STACK_BUFLEN
);
480 maxlen
= vsnprintf(buf
, MAX_STACK_BUFLEN
, format
, arg2
);
482 if (maxlen
< MAX_STACK_BUFLEN
) {
483 wr
= s
->write(s
, buf
, maxlen
, false);
485 ustream_write_error(s
);
493 return ustream_write_buffered(s
, buf
, maxlen
, wr
);
495 buf
= malloc(maxlen
+ 1);
498 wr
= vsnprintf(buf
, maxlen
+ 1, format
, arg
);
499 wr
= ustream_write(s
, buf
, wr
, false);
505 if (!ustream_prepare_buf(s
, l
, 1))
508 buf
= l
->data_tail
->tail
;
509 buflen
= l
->data_tail
->end
- buf
;
512 maxlen
= vsnprintf(buf
, buflen
, format
, arg2
);
519 l
->data_tail
->tail
+= wr
;
524 buf
= malloc(maxlen
+ 1);
527 maxlen
= vsnprintf(buf
, maxlen
+ 1, format
, arg
);
528 wr
= ustream_write_buffered(s
, buf
+ wr
, maxlen
- wr
, wr
);
534 int ustream_printf(struct ustream
*s
, const char *format
, ...)
542 va_start(arg
, format
);
543 ret
= ustream_vprintf(s
, format
, arg
);