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authorDavid Robillard <d@drobilla.net>2022-07-07 18:59:32 -0400
committerDavid Robillard <d@drobilla.net>2022-07-17 18:14:00 -0400
commit1eccbe4355685b322194df72b5de2382d5290b3b (patch)
tree0677b5c2f577a5024c351a164527f4bdd91a639b /include/lv2/event/event-helpers.h
parentd4a970f6962dda28133290194832b726b566ddab (diff)
downloadlv2-1eccbe4355685b322194df72b5de2382d5290b3b.tar.xz
Rearrange source tree to be directly usable by dependants
This allows the LV2 source distribution to be used as an include path for compilers and an LV2_PATH for applications, at the expense of self-contained bundles. That's a nice idea, but it made LV2 itself weird and annoying to depend on. This rearranges things so that directories in the source tree correspond more closely to installation directories. To make this possible, the "aux" directory in the documentation output has been changed to "style", to avoid the reserved name "aux" on Windows.
Diffstat (limited to 'include/lv2/event/event-helpers.h')
-rw-r--r--include/lv2/event/event-helpers.h255
1 files changed, 255 insertions, 0 deletions
diff --git a/include/lv2/event/event-helpers.h b/include/lv2/event/event-helpers.h
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+++ b/include/lv2/event/event-helpers.h
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+/*
+ Copyright 2008-2015 David Robillard <d@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.
+*/
+
+#ifndef LV2_EVENT_HELPERS_H
+#define LV2_EVENT_HELPERS_H
+
+/**
+ @file event-helpers.h Helper functions for the LV2 Event extension
+ <http://lv2plug.in/ns/ext/event>.
+*/
+
+#include "lv2/core/attributes.h"
+#include "lv2/event/event.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+LV2_DISABLE_DEPRECATION_WARNINGS
+
+/** @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) & ~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;
+ }
+ 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. */
+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*)(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*)(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*)(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*)(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*)(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;
+}
+
+LV2_RESTORE_WARNINGS
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* LV2_EVENT_HELPERS_H */