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author | David Robillard <d@drobilla.net> | 2018-09-22 20:38:01 +0200 |
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committer | David Robillard <d@drobilla.net> | 2018-09-22 20:38:58 +0200 |
commit | 4db67120efca2d4c200d2e1ba5cf3d7b97cab97e (patch) | |
tree | 793630dd2a17b78d805dc4bc5cd50fbdd0ace3bd /lv2/event/event-helpers.h | |
parent | 160ecb9601c9687a1093e124e936dcbd78aef43c (diff) | |
download | lv2-4db67120efca2d4c200d2e1ba5cf3d7b97cab97e.tar.xz |
Install standard headers to simpler include paths
Diffstat (limited to 'lv2/event/event-helpers.h')
-rw-r--r-- | lv2/event/event-helpers.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/lv2/event/event-helpers.h b/lv2/event/event-helpers.h new file mode 100644 index 0000000..6eab3b6 --- /dev/null +++ b/lv2/event/event-helpers.h @@ -0,0 +1,265 @@ +/* + Copyright 2008-2015 David Robillard <http://drobilla.net> + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +/** + @file event-helpers.h Helper functions for the LV2 Event extension + <http://lv2plug.in/ns/ext/event>. +*/ + +#ifndef LV2_EVENT_HELPERS_H +#define LV2_EVENT_HELPERS_H + +#include <stdint.h> +#include <stdlib.h> +#include <string.h> + +#include "lv2/event/event.h" + +#ifdef __cplusplus +extern "C" { +#else +# include <stdbool.h> +#endif + +/** @file + * Helper functions for the LV2 Event extension + * <http://lv2plug.in/ns/ext/event>. + * + * These functions are provided for convenience only, use of them is not + * required for supporting lv2ev (i.e. the events extension is defined by the + * raw buffer format described in lv2_event.h and NOT by this API). + * + * Note that these functions are all static inline which basically means: + * do not take the address of these functions. */ + + +/** Pad a size to 64 bits (for event sizes) */ +static inline uint16_t +lv2_event_pad_size(uint16_t size) +{ + return (uint16_t)(size + 7U) & (uint16_t)(~7U); +} + + +/** Initialize (empty, reset..) an existing event buffer. + * The contents of buf are ignored entirely and overwritten, except capacity + * which is unmodified. */ +static inline void +lv2_event_buffer_reset(LV2_Event_Buffer* buf, + uint16_t stamp_type, + uint8_t* data) +{ + buf->data = data; + buf->header_size = sizeof(LV2_Event_Buffer); + buf->stamp_type = stamp_type; + buf->event_count = 0; + buf->size = 0; +} + + +/** Allocate a new, empty event buffer. */ +static inline LV2_Event_Buffer* +lv2_event_buffer_new(uint32_t capacity, uint16_t stamp_type) +{ + const size_t size = sizeof(LV2_Event_Buffer) + capacity; + LV2_Event_Buffer* buf = (LV2_Event_Buffer*)malloc(size); + if (buf != NULL) { + buf->capacity = capacity; + lv2_event_buffer_reset(buf, stamp_type, (uint8_t *)(buf + 1)); + return buf; + } else { + return NULL; + } +} + + +/** An iterator over an LV2_Event_Buffer. + * + * Multiple simultaneous read iterators over a single buffer is fine, + * but changing the buffer invalidates all iterators (e.g. RW Lock). */ +typedef struct { + LV2_Event_Buffer* buf; + uint32_t offset; +} LV2_Event_Iterator; + + +/** Reset an iterator to point to the start of `buf`. + * @return True if `iter` is valid, otherwise false (buffer is empty) */ +static inline bool +lv2_event_begin(LV2_Event_Iterator* iter, + LV2_Event_Buffer* buf) +{ + iter->buf = buf; + iter->offset = 0; + return (buf->size > 0); +} + + +/** Check if `iter` is valid. + * @return True if `iter` is valid, otherwise false (past end of buffer) */ +static inline bool +lv2_event_is_valid(LV2_Event_Iterator* iter) +{ + return (iter->buf && (iter->offset < iter->buf->size)); +} + + +/** Advance `iter` forward one event. + * `iter` must be valid. + * @return True if `iter` is valid, otherwise false (reached end of buffer) */ +static inline bool +lv2_event_increment(LV2_Event_Iterator* iter) +{ + if (!lv2_event_is_valid(iter)) { + return false; + } + + LV2_Event* const ev = (LV2_Event*)( + (uint8_t*)iter->buf->data + iter->offset); + + iter->offset += lv2_event_pad_size( + (uint16_t)((uint16_t)sizeof(LV2_Event) + ev->size)); + + return true; +} + + +/** Dereference an event iterator (get the event currently pointed at). + * `iter` must be valid. + * `data` if non-NULL, will be set to point to the contents of the event + * returned. + * @return A Pointer to the event `iter` is currently pointing at, or NULL + * if the end of the buffer is reached (in which case `data` is + * also set to NULL). */ +static inline LV2_Event* +lv2_event_get(LV2_Event_Iterator* iter, + uint8_t** data) +{ + if (!lv2_event_is_valid(iter)) { + return NULL; + } + + LV2_Event* const ev = (LV2_Event*)( + (uint8_t*)iter->buf->data + iter->offset); + + if (data) + *data = (uint8_t*)ev + sizeof(LV2_Event); + + return ev; +} + + +/** Write an event at `iter`. + * The event (if any) pointed to by `iter` will be overwritten, and `iter` + * incremented to point to the following event (i.e. several calls to this + * function can be done in sequence without twiddling iter in-between). + * @return True if event was written, otherwise false (buffer is full). */ +static inline bool +lv2_event_write(LV2_Event_Iterator* iter, + uint32_t frames, + uint32_t subframes, + uint16_t type, + uint16_t size, + const uint8_t* data) +{ + if (!iter->buf) + return false; + + if (iter->buf->capacity - iter->buf->size < sizeof(LV2_Event) + size) + return false; + + LV2_Event* const ev = (LV2_Event*)( + (uint8_t*)iter->buf->data + iter->offset); + + ev->frames = frames; + ev->subframes = subframes; + ev->type = type; + ev->size = size; + memcpy((uint8_t*)ev + sizeof(LV2_Event), data, size); + ++iter->buf->event_count; + + size = lv2_event_pad_size((uint16_t)(sizeof(LV2_Event) + size)); + iter->buf->size += size; + iter->offset += size; + + return true; +} + + +/** Reserve space for an event in the buffer and return a pointer to + the memory where the caller can write the event data, or NULL if there + is not enough room in the buffer. */ +static inline uint8_t* +lv2_event_reserve(LV2_Event_Iterator* iter, + uint32_t frames, + uint32_t subframes, + uint16_t type, + uint16_t size) +{ + const uint16_t total_size = (uint16_t)(sizeof(LV2_Event) + size); + if (iter->buf->capacity - iter->buf->size < total_size) + return NULL; + + LV2_Event* const ev = (LV2_Event*)( + (uint8_t*)iter->buf->data + iter->offset); + + ev->frames = frames; + ev->subframes = subframes; + ev->type = type; + ev->size = size; + ++iter->buf->event_count; + + const uint16_t padded_size = lv2_event_pad_size(total_size); + iter->buf->size += padded_size; + iter->offset += padded_size; + + return (uint8_t*)ev + sizeof(LV2_Event); +} + + +/** Write an event at `iter`. + * The event (if any) pointed to by `iter` will be overwritten, and `iter` + * incremented to point to the following event (i.e. several calls to this + * function can be done in sequence without twiddling iter in-between). + * @return True if event was written, otherwise false (buffer is full). */ +static inline bool +lv2_event_write_event(LV2_Event_Iterator* iter, + const LV2_Event* ev, + const uint8_t* data) +{ + const uint16_t total_size = (uint16_t)(sizeof(LV2_Event) + ev->size); + if (iter->buf->capacity - iter->buf->size < total_size) + return false; + + LV2_Event* const write_ev = (LV2_Event*)( + (uint8_t*)iter->buf->data + iter->offset); + + *write_ev = *ev; + memcpy((uint8_t*)write_ev + sizeof(LV2_Event), data, ev->size); + ++iter->buf->event_count; + + const uint16_t padded_size = lv2_event_pad_size(total_size); + iter->buf->size += padded_size; + iter->offset += padded_size; + + return true; +} + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* LV2_EVENT_HELPERS_H */ |