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);
68 ustream_init_buf(buf, l->buffer_len);
69 ustream_add_buf(l, buf);
74 static void ustream_free_buffers(struct ustream_buf_list *l)
76 struct ustream_buf *buf = l->head;
79 struct ustream_buf *next = buf->next;
89 void ustream_free(struct ustream *s)
94 uloop_timeout_cancel(&s->state_change);
95 ustream_free_buffers(&s->r);
96 ustream_free_buffers(&s->w);
97 s->write_error = false;
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;
136 static bool ustream_should_move(struct ustream_buf_list *l, struct ustream_buf *buf, int len)
141 if (buf->data == buf->head)
144 maxlen = buf->end - buf->head;
145 offset = buf->data - buf->head;
147 if (offset > maxlen / 2)
150 if (buf->tail - buf->data < 32 && offset > maxlen / 4)
153 if (buf != l->tail || ustream_can_alloc(l))
156 return (buf->end - buf->tail < len);
159 static void ustream_free_buf(struct ustream_buf_list *l, struct ustream_buf *buf)
164 if (buf == l->data_tail)
165 l->data_tail = buf->next;
170 if (--l->buffers >= l->min_buffers) {
176 ustream_init_buf(buf, buf->end - buf->head);
177 ustream_add_buf(l, buf);
180 static void __ustream_set_read_blocked(struct ustream *s, unsigned char val)
182 bool changed = !!s->read_blocked != !!val;
184 s->read_blocked = val;
186 s->set_read_blocked(s);
189 void ustream_set_read_blocked(struct ustream *s, bool set)
191 unsigned char val = s->read_blocked & ~READ_BLOCKED_USER;
194 val |= READ_BLOCKED_USER;
196 __ustream_set_read_blocked(s, val);
199 void ustream_consume(struct ustream *s, int len)
201 struct ustream_buf *buf = s->r.head;
206 s->r.data_bytes -= len;
207 if (s->r.data_bytes < 0)
211 struct ustream_buf *next = buf->next;
212 int buf_len = buf->tail - buf->data;
220 ustream_free_buf(&s->r, buf);
224 __ustream_set_read_blocked(s, s->read_blocked & ~READ_BLOCKED_FULL);
227 static void ustream_fixup_string(struct ustream *s, struct ustream_buf *buf)
235 static bool ustream_prepare_buf(struct ustream *s, struct ustream_buf_list *l, int len)
237 struct ustream_buf *buf;
241 if (ustream_should_move(l, buf, len)) {
242 int len = buf->tail - buf->data;
244 memmove(buf->head, buf->data, len);
245 buf->data = buf->head;
246 buf->tail = buf->data + len;
249 ustream_fixup_string(s, buf);
251 if (buf->tail != buf->end)
255 if (buf && buf->next) {
256 l->data_tail = buf->next;
260 if (!ustream_can_alloc(l))
263 if (l->alloc(s, l) < 0)
266 l->data_tail = l->tail;
270 char *ustream_reserve(struct ustream *s, int len, int *maxlen)
272 struct ustream_buf *buf = s->r.head;
274 if (!ustream_prepare_buf(s, &s->r, len)) {
275 __ustream_set_read_blocked(s, s->read_blocked | READ_BLOCKED_FULL);
280 buf = s->r.data_tail;
281 *maxlen = buf->end - buf->tail;
285 void ustream_fill_read(struct ustream *s, int len)
287 struct ustream_buf *buf = s->r.data_tail;
291 s->r.data_bytes += len;
296 maxlen = buf->end - buf->tail;
302 ustream_fixup_string(s, buf);
304 s->r.data_tail = buf;
309 s->notify_read(s, n);
312 char *ustream_get_read_buf(struct ustream *s, int *buflen)
318 len = s->r.head->tail - s->r.head->data;
319 data = s->r.head->data;
331 static void ustream_write_error(struct ustream *s)
333 s->write_error = true;
334 ustream_state_change(s);
337 bool ustream_write_pending(struct ustream *s)
339 struct ustream_buf *buf = s->w.head;
345 while (buf && s->w.data_bytes) {
346 struct ustream_buf *next = buf->next;
347 int maxlen = buf->tail - buf->data;
349 len = s->write(s, buf->data, maxlen, !!buf->next);
351 ustream_write_error(s);
359 s->w.data_bytes -= len;
365 ustream_free_buf(&s->w, buf);
370 s->notify_write(s, wr);
372 if (s->eof && wr && !s->w.data_bytes)
373 ustream_state_change(s);
375 return !s->w.data_bytes;
378 static int ustream_write_buffered(struct ustream *s, const char *data, int len, int wr)
380 struct ustream_buf_list *l = &s->w;
381 struct ustream_buf *buf;
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;
405 int ustream_write(struct ustream *s, const char *data, int len, bool more)
407 struct ustream_buf_list *l = &s->w;
413 if (!l->data_bytes) {
414 wr = s->write(s, data, len, more);
419 ustream_write_error(s);
427 return ustream_write_buffered(s, data, len, wr);
430 #define MAX_STACK_BUFLEN 256
432 int ustream_vprintf(struct ustream *s, const char *format, va_list arg)
434 struct ustream_buf_list *l = &s->w;
437 int wr, maxlen, buflen;
442 if (!l->data_bytes) {
443 buf = alloca(MAX_STACK_BUFLEN);
445 maxlen = vsnprintf(buf, MAX_STACK_BUFLEN, format, arg2);
447 if (maxlen < MAX_STACK_BUFLEN) {
448 wr = s->write(s, buf, maxlen, false);
450 ustream_write_error(s);
458 return ustream_write_buffered(s, buf, maxlen, wr);
460 buf = malloc(maxlen + 1);
461 wr = vsnprintf(buf, maxlen + 1, format, arg);
462 wr = ustream_write(s, buf, wr, false);
468 if (!ustream_prepare_buf(s, l, 1))
471 buf = l->data_tail->tail;
472 buflen = l->data_tail->end - buf;
475 maxlen = vsnprintf(buf, buflen, format, arg2);
482 l->data_tail->tail += wr;
487 buf = malloc(maxlen + 1);
488 maxlen = vsnprintf(buf, maxlen + 1, format, arg);
489 wr = ustream_write_buffered(s, buf + wr, maxlen - wr, wr);
495 int ustream_printf(struct ustream *s, const char *format, ...)
503 va_start(arg, format);
504 ret = ustream_vprintf(s, format, arg);