event-helpers.h

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/*
  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.
*/

 
#ifndef LV2_EVENT_HELPERS_H
#define LV2_EVENT_HELPERS_H
 
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
 
#include "event.h"
 
#ifdef __cplusplus
extern "C" {
#else
#    include <stdbool.h>
#endif

 

static inline uint16_t
lv2_event_pad_size(uint16_t size)
{
        return (uint16_t)(size + 7U) & (uint16_t)(~7U);
}
 

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;
}
 

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;
        }
}
 

typedef struct {
        LV2_Event_Buffer* buf;
        uint32_t          offset;
} LV2_Event_Iterator;
 

static inline bool
lv2_event_begin(LV2_Event_Iterator* iter,
                LV2_Event_Buffer*   buf)
{
        iter->buf = buf;
        iter->offset = 0;
        return (buf->size > 0);
}
 

static inline bool
lv2_event_is_valid(LV2_Event_Iterator* iter)
{
        return (iter->buf && (iter->offset < iter->buf->size));
}
 

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;
}
 

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;
}
 

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;
}
 

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);
}
 

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 */