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Diffstat (limited to 'thirdparty/libwebsockets/include/libwebsockets/lws-ring.h')
| -rw-r--r-- | thirdparty/libwebsockets/include/libwebsockets/lws-ring.h | 305 |
1 files changed, 0 insertions, 305 deletions
diff --git a/thirdparty/libwebsockets/include/libwebsockets/lws-ring.h b/thirdparty/libwebsockets/include/libwebsockets/lws-ring.h deleted file mode 100644 index 9a5ec2e10b..0000000000 --- a/thirdparty/libwebsockets/include/libwebsockets/lws-ring.h +++ /dev/null @@ -1,305 +0,0 @@ -/* - * libwebsockets - small server side websockets and web server implementation - * - * Copyright (C) 2010-2018 Andy Green <andy@warmcat.com> - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation: - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, - * MA 02110-1301 USA - * - * included from libwebsockets.h - */ - -/** \defgroup lws_ring LWS Ringbuffer APIs - * ##lws_ring: generic ringbuffer struct - * - * Provides an abstract ringbuffer api supporting one head and one or an - * unlimited number of tails. - * - * All of the members are opaque and manipulated by lws_ring_...() apis. - * - * The lws_ring and its buffer is allocated at runtime on the heap, using - * - * - lws_ring_create() - * - lws_ring_destroy() - * - * It may contain any type, the size of the "element" stored in the ring - * buffer and the number of elements is given at creation time. - * - * When you create the ringbuffer, you can optionally provide an element - * destroy callback that frees any allocations inside the element. This is then - * automatically called for elements with no tail behind them, ie, elements - * which don't have any pending consumer are auto-freed. - * - * Whole elements may be inserted into the ringbuffer and removed from it, using - * - * - lws_ring_insert() - * - lws_ring_consume() - * - * You can find out how many whole elements are free or waiting using - * - * - lws_ring_get_count_free_elements() - * - lws_ring_get_count_waiting_elements() - * - * In addition there are special purpose optional byte-centric apis - * - * - lws_ring_next_linear_insert_range() - * - lws_ring_bump_head() - * - * which let you, eg, read() directly into the ringbuffer without needing - * an intermediate bounce buffer. - * - * The accessors understand that the ring wraps, and optimizes insertion and - * consumption into one or two memcpy()s depending on if the head or tail - * wraps. - * - * lws_ring only supports a single head, but optionally multiple tails with - * an API to inform it when the "oldest" tail has moved on. You can give - * NULL where-ever an api asks for a tail pointer, and it will use an internal - * single tail pointer for convenience. - * - * The "oldest tail", which is the only tail if you give it NULL instead of - * some other tail, is used to track which elements in the ringbuffer are - * still unread by anyone. - * - * - lws_ring_update_oldest_tail() - */ -///@{ -struct lws_ring; - -/** - * lws_ring_create(): create a new ringbuffer - * - * \param element_len: the size in bytes of one element in the ringbuffer - * \param count: the number of elements the ringbuffer can contain - * \param destroy_element: NULL, or callback to be called for each element - * that is removed from the ringbuffer due to the - * oldest tail moving beyond it - * - * Creates the ringbuffer and allocates the storage. Returns the new - * lws_ring *, or NULL if the allocation failed. - * - * If non-NULL, destroy_element will get called back for every element that is - * retired from the ringbuffer after the oldest tail has gone past it, and for - * any element still left in the ringbuffer when it is destroyed. It replaces - * all other element destruction code in your user code. - */ -LWS_VISIBLE LWS_EXTERN struct lws_ring * -lws_ring_create(size_t element_len, size_t count, - void (*destroy_element)(void *element)); - -/** - * lws_ring_destroy(): destroy a previously created ringbuffer - * - * \param ring: the struct lws_ring to destroy - * - * Destroys the ringbuffer allocation and the struct lws_ring itself. - */ -LWS_VISIBLE LWS_EXTERN void -lws_ring_destroy(struct lws_ring *ring); - -/** - * lws_ring_get_count_free_elements(): return how many elements can fit - * in the free space - * - * \param ring: the struct lws_ring to report on - * - * Returns how much room is left in the ringbuffer for whole element insertion. - */ -LWS_VISIBLE LWS_EXTERN size_t -lws_ring_get_count_free_elements(struct lws_ring *ring); - -/** - * lws_ring_get_count_waiting_elements(): return how many elements can be consumed - * - * \param ring: the struct lws_ring to report on - * \param tail: a pointer to the tail struct to use, or NULL for single tail - * - * Returns how many elements are waiting to be consumed from the perspective - * of the tail pointer given. - */ -LWS_VISIBLE LWS_EXTERN size_t -lws_ring_get_count_waiting_elements(struct lws_ring *ring, uint32_t *tail); - -/** - * lws_ring_insert(): attempt to insert up to max_count elements from src - * - * \param ring: the struct lws_ring to report on - * \param src: the array of elements to be inserted - * \param max_count: the number of available elements at src - * - * Attempts to insert as many of the elements at src as possible, up to the - * maximum max_count. Returns the number of elements actually inserted. - */ -LWS_VISIBLE LWS_EXTERN size_t -lws_ring_insert(struct lws_ring *ring, const void *src, size_t max_count); - -/** - * lws_ring_consume(): attempt to copy out and remove up to max_count elements - * to src - * - * \param ring: the struct lws_ring to report on - * \param tail: a pointer to the tail struct to use, or NULL for single tail - * \param dest: the array of elements to be inserted. or NULL for no copy - * \param max_count: the number of available elements at src - * - * Attempts to copy out as many waiting elements as possible into dest, from - * the perspective of the given tail, up to max_count. If dest is NULL, the - * copying out is not done but the elements are logically consumed as usual. - * NULL dest is useful in combination with lws_ring_get_element(), where you - * can use the element direct from the ringbuffer and then call this with NULL - * dest to logically consume it. - * - * Increments the tail position according to how many elements could be - * consumed. - * - * Returns the number of elements consumed. - */ -LWS_VISIBLE LWS_EXTERN size_t -lws_ring_consume(struct lws_ring *ring, uint32_t *tail, void *dest, - size_t max_count); - -/** - * lws_ring_get_element(): get a pointer to the next waiting element for tail - * - * \param ring: the struct lws_ring to report on - * \param tail: a pointer to the tail struct to use, or NULL for single tail - * - * Points to the next element that tail would consume, directly in the - * ringbuffer. This lets you write() or otherwise use the element without - * having to copy it out somewhere first. - * - * After calling this, you must call lws_ring_consume(ring, &tail, NULL, 1) - * which will logically consume the element you used up and increment your - * tail (tail may also be NULL there if you use a single tail). - * - * Returns NULL if no waiting element, or a const void * pointing to it. - */ -LWS_VISIBLE LWS_EXTERN const void * -lws_ring_get_element(struct lws_ring *ring, uint32_t *tail); - -/** - * lws_ring_update_oldest_tail(): free up elements older than tail for reuse - * - * \param ring: the struct lws_ring to report on - * \param tail: a pointer to the tail struct to use, or NULL for single tail - * - * If you are using multiple tails, you must use this API to inform the - * lws_ring when none of the tails still need elements in the fifo any more, - * by updating it when the "oldest" tail has moved on. - */ -LWS_VISIBLE LWS_EXTERN void -lws_ring_update_oldest_tail(struct lws_ring *ring, uint32_t tail); - -/** - * lws_ring_get_oldest_tail(): get current oldest available data index - * - * \param ring: the struct lws_ring to report on - * - * If you are initializing a new ringbuffer consumer, you can set its tail to - * this to start it from the oldest ringbuffer entry still available. - */ -LWS_VISIBLE LWS_EXTERN uint32_t -lws_ring_get_oldest_tail(struct lws_ring *ring); - -/** - * lws_ring_next_linear_insert_range(): used to write directly into the ring - * - * \param ring: the struct lws_ring to report on - * \param start: pointer to a void * set to the start of the next ringbuffer area - * \param bytes: pointer to a size_t set to the max length you may use from *start - * - * This provides a low-level, bytewise access directly into the ringbuffer - * allowing direct insertion of data without having to use a bounce buffer. - * - * The api reports the position and length of the next linear range that can - * be written in the ringbuffer, ie, up to the point it would wrap, and sets - * *start and *bytes accordingly. You can then, eg, directly read() into - * *start for up to *bytes, and use lws_ring_bump_head() to update the lws_ring - * with what you have done. - * - * Returns nonzero if no insertion is currently possible. - */ -LWS_VISIBLE LWS_EXTERN int -lws_ring_next_linear_insert_range(struct lws_ring *ring, void **start, - size_t *bytes); - -/** - * lws_ring_bump_head(): used to write directly into the ring - * - * \param ring: the struct lws_ring to operate on - * \param bytes: the number of bytes you inserted at the current head - */ -LWS_VISIBLE LWS_EXTERN void -lws_ring_bump_head(struct lws_ring *ring, size_t bytes); - -LWS_VISIBLE LWS_EXTERN void -lws_ring_dump(struct lws_ring *ring, uint32_t *tail); - -/* - * This is a helper that combines the common pattern of needing to consume - * some ringbuffer elements, move the consumer tail on, and check if that - * has moved any ringbuffer elements out of scope, because it was the last - * consumer that had not already consumed them. - * - * Elements that go out of scope because the oldest tail is now after them - * get garbage-collected by calling the destroy_element callback on them - * defined when the ringbuffer was created. - */ - -#define lws_ring_consume_and_update_oldest_tail(\ - ___ring, /* the lws_ring object */ \ - ___type, /* type of objects with tails */ \ - ___ptail, /* ptr to tail of obj with tail doing consuming */ \ - ___count, /* count of payload objects being consumed */ \ - ___list_head, /* head of list of objects with tails */ \ - ___mtail, /* member name of tail in ___type */ \ - ___mlist /* member name of next list member ptr in ___type */ \ - ) { \ - int ___n, ___m; \ - \ - ___n = lws_ring_get_oldest_tail(___ring) == *(___ptail); \ - lws_ring_consume(___ring, ___ptail, NULL, ___count); \ - if (___n) { \ - uint32_t ___oldest; \ - ___n = 0; \ - ___oldest = *(___ptail); \ - lws_start_foreach_llp(___type **, ___ppss, ___list_head) { \ - ___m = lws_ring_get_count_waiting_elements( \ - ___ring, &(*___ppss)->tail); \ - if (___m >= ___n) { \ - ___n = ___m; \ - ___oldest = (*___ppss)->tail; \ - } \ - } lws_end_foreach_llp(___ppss, ___mlist); \ - \ - lws_ring_update_oldest_tail(___ring, ___oldest); \ - } \ -} - -/* - * This does the same as the lws_ring_consume_and_update_oldest_tail() - * helper, but for the simpler case there is only one consumer, so one - * tail, and that tail is always the oldest tail. - */ - -#define lws_ring_consume_single_tail(\ - ___ring, /* the lws_ring object */ \ - ___ptail, /* ptr to tail of obj with tail doing consuming */ \ - ___count /* count of payload objects being consumed */ \ - ) { \ - lws_ring_consume(___ring, ___ptail, NULL, ___count); \ - lws_ring_update_oldest_tail(___ring, *(___ptail)); \ -} -///@} |