Include lv2-event headers directly.

1 files changed, 243 insertions, 0 deletions

diff --git a/lv2/event-helpers.h b/lv2/event-helpers.h
new file mode 100644
index 0000000..b14f7d9
--- /dev/null
+++ b/lv2/event-helpers.h
@@ -0,0 +1,243 @@
+/* lv2_event_helpers.h - Helper functions for the LV2 events extension.
+ *
+ * Copyright (C) 2008-2009 David Robillard <http://drobilla.net>
+ *
+ * This header 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This header 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 header; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
+ */
+
+#ifndef LV2_EVENT_HELPERS_H
+#define LV2_EVENT_HELPERS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "event.h"
+
+/** @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 (size + 7) & (~7);
+}
+
+
+/** 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)
+{
+	LV2_Event_Buffer* buf = (LV2_Event_Buffer*)malloc(sizeof(LV2_Event_Buffer) + capacity);
+	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 @a buf.
+ * @return True if @a 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 @a iter is valid.
+ * @return True if @a iter is valid, otherwise false (past end of buffer) */
+static inline bool
+lv2_event_is_valid(LV2_Event_Iterator* iter)
+{
+	return (iter->offset < iter->buf->size);
+}
+
+
+/** Advance @a iter forward one event.
+ * @a iter must be valid.
+ * @return True if @a iter is valid, otherwise false (reached end of buffer) */
+static inline bool
+lv2_event_increment(LV2_Event_Iterator* iter)
+{
+	assert(lv2_event_is_valid(iter));
+
+	LV2_Event* const ev = (LV2_Event*)(
+			(uint8_t*)iter->buf->data + iter->offset);
+
+	iter->offset += lv2_event_pad_size(sizeof(LV2_Event) + ev->size);
+
+	return true;
+}
+
+
+/** Dereference an event iterator (get the event currently pointed at).
+ * @a iter must be valid.
+ * @a data if non-NULL, will be set to point to the contents of the event
+ *         returned.
+ * @return A Pointer to the event @a iter is currently pointing at, or NULL
+ *         if the end of the buffer is reached (in which case @a data is
+ *         also set to NULL). */
+static inline LV2_Event*
+lv2_event_get(LV2_Event_Iterator* iter,
+              uint8_t**           data)
+{
+	assert(lv2_event_is_valid(iter));
+
+	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 @a iter.
+ * The event (if any) pointed to by @a iter will be overwritten, and @a 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->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(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)
+{
+	size = lv2_event_pad_size(size);
+	if (iter->buf->capacity - iter->buf->size < sizeof(LV2_Event) + 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;
+
+	size = lv2_event_pad_size(sizeof(LV2_Event) + size);
+	iter->buf->size += size;
+	iter->offset    += size;
+
+	return (uint8_t*)ev + sizeof(LV2_Event);
+}
+
+
+/** Write an event at @a iter.
+ * The event (if any) pointed to by @a iter will be overwritten, and @a 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)
+{
+	if (iter->buf->capacity - iter->buf->size < sizeof(LV2_Event) + ev->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 size = lv2_event_pad_size(sizeof(LV2_Event) + ev->size);
+	iter->buf->size += size;
+	iter->offset    += size;
+
+	return true;
+}
+
+#endif /* LV2_EVENT_HELPERS_H */
+