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);
110 void ustream_init_defaults(struct ustream *s)
112 #define DEFAULT_SET(_f, _default) \
118 DEFAULT_SET(s->r.alloc, ustream_alloc_default);
119 DEFAULT_SET(s->w.alloc, ustream_alloc_default);
121 DEFAULT_SET(s->r.min_buffers, 1);
122 DEFAULT_SET(s->r.max_buffers, 1);
123 DEFAULT_SET(s->r.buffer_len, 4096);
125 DEFAULT_SET(s->w.min_buffers, 2);
126 DEFAULT_SET(s->w.max_buffers, -1);
127 DEFAULT_SET(s->w.buffer_len, 256);
131 s->state_change.cb = ustream_state_change_cb;
134 static bool ustream_should_move(struct ustream_buf_list *l, struct ustream_buf *buf, int len)
139 if (buf->data == buf->head)
142 maxlen = buf->end - buf->head;
143 offset = buf->data - buf->head;
145 if (offset > maxlen / 2)
148 if (buf->tail - buf->data < 32 && offset > maxlen / 4)
151 if (buf != l->tail || ustream_can_alloc(l))
154 return (buf->end - buf->tail < len);
157 static void ustream_free_buf(struct ustream_buf_list *l, struct ustream_buf *buf)
162 if (buf == l->data_tail)
163 l->data_tail = buf->next;
168 if (--l->buffers >= l->min_buffers) {
174 ustream_init_buf(buf, buf->end - buf->head);
175 ustream_add_buf(l, buf);
178 static void __ustream_set_read_blocked(struct ustream *s, unsigned char val)
180 bool changed = !!s->read_blocked != !!val;
182 s->read_blocked = val;
184 s->set_read_blocked(s);
187 void ustream_set_read_blocked(struct ustream *s, bool set)
189 unsigned char val = s->read_blocked & ~READ_BLOCKED_USER;
192 val |= READ_BLOCKED_USER;
194 __ustream_set_read_blocked(s, val);
197 void ustream_consume(struct ustream *s, int len)
199 struct ustream_buf *buf = s->r.head;
204 s->r.data_bytes -= len;
205 if (s->r.data_bytes < 0)
209 struct ustream_buf *next = buf->next;
210 int buf_len = buf->tail - buf->data;
218 ustream_free_buf(&s->r, buf);
222 __ustream_set_read_blocked(s, s->read_blocked & ~READ_BLOCKED_FULL);
225 static void ustream_fixup_string(struct ustream *s, struct ustream_buf *buf)
233 static bool ustream_prepare_buf(struct ustream *s, struct ustream_buf_list *l, int len)
235 struct ustream_buf *buf;
239 if (ustream_should_move(l, buf, len)) {
240 int len = buf->tail - buf->data;
242 memmove(buf->head, buf->data, len);
243 buf->data = buf->head;
244 buf->tail = buf->data + len;
247 ustream_fixup_string(s, buf);
249 if (buf->tail != buf->end)
253 if (buf && buf->next) {
254 l->data_tail = buf->next;
258 if (!ustream_can_alloc(l))
261 if (l->alloc(s, l) < 0)
264 l->data_tail = l->tail;
268 char *ustream_reserve(struct ustream *s, int len, int *maxlen)
270 struct ustream_buf *buf = s->r.head;
272 if (!ustream_prepare_buf(s, &s->r, len)) {
273 __ustream_set_read_blocked(s, s->read_blocked | READ_BLOCKED_FULL);
278 buf = s->r.data_tail;
279 *maxlen = buf->end - buf->tail;
283 void ustream_fill_read(struct ustream *s, int len)
285 struct ustream_buf *buf = s->r.data_tail;
289 s->r.data_bytes += len;
294 maxlen = buf->end - buf->tail;
300 ustream_fixup_string(s, buf);
302 s->r.data_tail = buf;
307 s->notify_read(s, n);
310 char *ustream_get_read_buf(struct ustream *s, int *buflen)
316 len = s->r.head->tail - s->r.head->data;
317 data = s->r.head->data;
329 static void ustream_write_error(struct ustream *s)
331 s->write_error = true;
332 ustream_state_change(s);
335 bool ustream_write_pending(struct ustream *s)
337 struct ustream_buf *buf = s->w.head;
344 struct ustream_buf *next = buf->next;
345 int maxlen = buf->tail - buf->data;
347 len = s->write(s, buf->data, maxlen, !!buf->next);
349 ustream_write_error(s);
357 s->w.data_bytes -= len;
363 ustream_free_buf(&s->w, buf);
368 s->notify_write(s, wr);
370 if (s->eof && wr && !s->w.data_bytes)
371 ustream_state_change(s);
373 return !s->w.data_bytes;
376 static int ustream_write_buffered(struct ustream *s, const char *data, int len, int wr)
378 struct ustream_buf_list *l = &s->w;
379 struct ustream_buf *buf;
383 if (!ustream_prepare_buf(s, &s->w, len))
388 maxlen = buf->end - buf->tail;
392 memcpy(buf->tail, data, maxlen);
397 l->data_bytes += maxlen;
403 int ustream_write(struct ustream *s, const char *data, int len, bool more)
405 struct ustream_buf_list *l = &s->w;
411 if (!l->data_bytes) {
412 wr = s->write(s, data, len, more);
417 ustream_write_error(s);
425 return ustream_write_buffered(s, data, len, wr);
428 #define MAX_STACK_BUFLEN 256
430 int ustream_vprintf(struct ustream *s, const char *format, va_list arg)
432 struct ustream_buf_list *l = &s->w;
435 int wr, maxlen, buflen;
437 if (!l->data_bytes) {
438 buf = alloca(MAX_STACK_BUFLEN);
440 maxlen = vsnprintf(buf, MAX_STACK_BUFLEN, format, arg2);
442 if (maxlen < MAX_STACK_BUFLEN) {
443 wr = s->write(s, buf, maxlen, false);
445 ustream_write_error(s);
453 return ustream_write_buffered(s, buf, maxlen, wr);
455 buf = malloc(maxlen + 1);
456 wr = vsnprintf(buf, maxlen + 1, format, arg);
457 wr = ustream_write(s, buf, wr, false);
463 if (!ustream_prepare_buf(s, l, 1))
466 buf = l->data_tail->tail;
467 buflen = l->data_tail->end - buf;
470 maxlen = vsnprintf(buf, buflen, format, arg2);
477 l->data_tail->tail += wr;
482 buf = malloc(maxlen + 1);
483 maxlen = vsnprintf(buf, maxlen + 1, format, arg);
484 wr = ustream_write_buffered(s, buf + wr, maxlen - wr, wr);
490 int ustream_printf(struct ustream *s, const char *format, ...)
495 va_start(arg, format);
496 ret = ustream_vprintf(s, format, arg);