/* lv2_event_helpers.h - Helper functions for the LV2 events extension. * * Copyright (C) 2008-2009 David Robillard * * 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 #include #include #include #include #include "lv2/lv2plug.in/ns/ext/event/event.h" /** @file * Helper functions for the LV2 Event extension * . * * 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 */ 113'>113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174
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