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)
48 l->data_tail = l->head;
51 static bool ustream_can_alloc(struct ustream_buf_list *l)
53 if (l->max_buffers <= 0)
56 return (l->buffers < l->max_buffers);
59 static int ustream_alloc_default(struct ustream *s, struct ustream_buf_list *l)
61 struct ustream_buf *buf;
63 if (!ustream_can_alloc(l))
66 buf = malloc(sizeof(*buf) + l->buffer_len + s->string_data);
67 ustream_init_buf(buf, l->buffer_len);
68 ustream_add_buf(l, buf);
73 static void ustream_free_buffers(struct ustream_buf_list *l)
75 struct ustream_buf *buf = l->head;
78 struct ustream_buf *next = buf->next;
88 void ustream_free(struct ustream *s)
93 uloop_timeout_cancel(&s->state_change);
94 ustream_free_buffers(&s->r);
95 ustream_free_buffers(&s->w);
96 s->write_error = false;
101 static void ustream_state_change_cb(struct uloop_timeout *t)
103 struct ustream *s = container_of(t, struct ustream, state_change);
106 ustream_free_buffers(&s->w);
111 void ustream_init_defaults(struct ustream *s)
113 #define DEFAULT_SET(_f, _default) \
119 DEFAULT_SET(s->r.alloc, ustream_alloc_default);
120 DEFAULT_SET(s->w.alloc, ustream_alloc_default);
122 DEFAULT_SET(s->r.min_buffers, 1);
123 DEFAULT_SET(s->r.max_buffers, 1);
124 DEFAULT_SET(s->r.buffer_len, 4096);
126 DEFAULT_SET(s->w.min_buffers, 2);
127 DEFAULT_SET(s->w.max_buffers, -1);
128 DEFAULT_SET(s->w.buffer_len, 256);
132 s->state_change.cb = ustream_state_change_cb;
135 static bool ustream_should_move(struct ustream_buf_list *l, struct ustream_buf *buf, int len)
140 if (buf->data == buf->head)
143 maxlen = buf->end - buf->head;
144 offset = buf->data - buf->head;
146 if (offset > maxlen / 2)
149 if (buf->tail - buf->data < 32 && offset > maxlen / 4)
152 if (buf != l->tail || ustream_can_alloc(l))
155 return (buf->end - buf->tail < len);
158 static void ustream_free_buf(struct ustream_buf_list *l, struct ustream_buf *buf)
163 if (buf == l->data_tail)
164 l->data_tail = buf->next;
169 if (--l->buffers >= l->min_buffers) {
175 ustream_init_buf(buf, buf->end - buf->head);
176 ustream_add_buf(l, buf);
179 static void __ustream_set_read_blocked(struct ustream *s, unsigned char val)
181 bool changed = !!s->read_blocked != !!val;
183 s->read_blocked = val;
185 s->set_read_blocked(s);
188 void ustream_set_read_blocked(struct ustream *s, bool set)
190 unsigned char val = s->read_blocked & ~READ_BLOCKED_USER;
193 val |= READ_BLOCKED_USER;
195 __ustream_set_read_blocked(s, val);
198 void ustream_consume(struct ustream *s, int len)
200 struct ustream_buf *buf = s->r.head;
205 s->r.data_bytes -= len;
206 if (s->r.data_bytes < 0)
210 struct ustream_buf *next = buf->next;
211 int buf_len = buf->tail - buf->data;
219 ustream_free_buf(&s->r, buf);
223 __ustream_set_read_blocked(s, s->read_blocked & ~READ_BLOCKED_FULL);
226 static void ustream_fixup_string(struct ustream *s, struct ustream_buf *buf)
234 static bool ustream_prepare_buf(struct ustream *s, struct ustream_buf_list *l, int len)
236 struct ustream_buf *buf;
240 if (ustream_should_move(l, buf, len)) {
241 int len = buf->tail - buf->data;
243 memmove(buf->head, buf->data, len);
244 buf->data = buf->head;
245 buf->tail = buf->data + len;
248 ustream_fixup_string(s, buf);
250 if (buf->tail != buf->end)
254 if (buf && buf->next) {
255 l->data_tail = buf->next;
259 if (!ustream_can_alloc(l))
262 if (l->alloc(s, l) < 0)
265 l->data_tail = l->tail;
269 char *ustream_reserve(struct ustream *s, int len, int *maxlen)
271 struct ustream_buf *buf = s->r.head;
273 if (!ustream_prepare_buf(s, &s->r, len)) {
274 __ustream_set_read_blocked(s, s->read_blocked | READ_BLOCKED_FULL);
279 buf = s->r.data_tail;
280 *maxlen = buf->end - buf->tail;
284 void ustream_fill_read(struct ustream *s, int len)
286 struct ustream_buf *buf = s->r.data_tail;
290 s->r.data_bytes += len;
295 maxlen = buf->end - buf->tail;
301 ustream_fixup_string(s, buf);
303 s->r.data_tail = buf;
308 s->notify_read(s, n);
311 char *ustream_get_read_buf(struct ustream *s, int *buflen)
317 len = s->r.head->tail - s->r.head->data;
318 data = s->r.head->data;
330 static void ustream_write_error(struct ustream *s)
332 s->write_error = true;
333 ustream_state_change(s);
336 bool ustream_write_pending(struct ustream *s)
338 struct ustream_buf *buf = s->w.head;
344 while (buf && s->w.data_bytes) {
345 struct ustream_buf *next = buf->next;
346 int maxlen = buf->tail - buf->data;
348 len = s->write(s, buf->data, maxlen, !!buf->next);
350 ustream_write_error(s);
358 s->w.data_bytes -= len;
364 ustream_free_buf(&s->w, buf);
369 s->notify_write(s, wr);
371 if (s->eof && wr && !s->w.data_bytes)
372 ustream_state_change(s);
374 return !s->w.data_bytes;
377 static int ustream_write_buffered(struct ustream *s, const char *data, int len, int wr)
379 struct ustream_buf_list *l = &s->w;
380 struct ustream_buf *buf;
382 bool has_data = !!s->w.data_bytes;
385 if (!ustream_prepare_buf(s, &s->w, len))
390 maxlen = buf->end - buf->tail;
394 memcpy(buf->tail, data, maxlen);
399 l->data_bytes += maxlen;
402 if (s->poll && !has_data)
408 int ustream_write(struct ustream *s, const char *data, int len, bool more)
410 struct ustream_buf_list *l = &s->w;
416 if (!l->data_bytes) {
417 wr = s->write(s, data, len, more);
422 ustream_write_error(s);
430 return ustream_write_buffered(s, data, len, wr);
433 #define MAX_STACK_BUFLEN 256
435 int ustream_vprintf(struct ustream *s, const char *format, va_list arg)
437 struct ustream_buf_list *l = &s->w;
440 int wr, maxlen, buflen;
445 if (!l->data_bytes) {
446 buf = alloca(MAX_STACK_BUFLEN);
448 maxlen = vsnprintf(buf, MAX_STACK_BUFLEN, format, arg2);
450 if (maxlen < MAX_STACK_BUFLEN) {
451 wr = s->write(s, buf, maxlen, false);
453 ustream_write_error(s);
461 return ustream_write_buffered(s, buf, maxlen, wr);
463 buf = malloc(maxlen + 1);
464 wr = vsnprintf(buf, maxlen + 1, format, arg);
465 wr = ustream_write(s, buf, wr, false);
471 if (!ustream_prepare_buf(s, l, 1))
474 buf = l->data_tail->tail;
475 buflen = l->data_tail->end - buf;
478 maxlen = vsnprintf(buf, buflen, format, arg2);
485 l->data_tail->tail += wr;
490 buf = malloc(maxlen + 1);
491 maxlen = vsnprintf(buf, maxlen + 1, format, arg);
492 wr = ustream_write_buffered(s, buf + wr, maxlen - wr, wr);
498 int ustream_printf(struct ustream *s, const char *format, ...)
506 va_start(arg, format);
507 ret = ustream_vprintf(s, format, arg);