#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include "evtqueue.h"


void InitEvtQueue(EvtQueue *queue)
{
    queue->events = NULL;
    queue->maxsize = 0;
    queue->size = 0;
    queue->pos = 0;
}

void ResetEvtQueue(EvtQueue *queue)
{
    free(queue->events);
    queue->events = NULL;
    queue->maxsize = 0;
    queue->size = 0;
    queue->pos = 0;
}

ALenum InsertEvtQueue(EvtQueue *queue, const MidiEvent *evt)
{
    ALsizei pos;

    if(queue->maxsize == queue->size)
    {
        if(queue->pos > 0)
        {
            /* Queue has some stale entries, remove them to make space for more
             * events. */
            memmove(&queue->events[0], &queue->events[queue->pos],
                    (queue->size-queue->pos)*sizeof(queue->events[0]));
            queue->size -= queue->pos;
            queue->pos = 0;
        }
        else
        {
            /* Queue is full, double the allocated space. */
            void *temp = NULL;
            ALsizei newsize;

            newsize = (queue->maxsize ? (queue->maxsize<<1) : 16);
            if(newsize > queue->maxsize)
                temp = realloc(queue->events, newsize * sizeof(queue->events[0]));
            if(!temp)
                return AL_OUT_OF_MEMORY;

            queue->events = temp;
            queue->maxsize = newsize;
        }
    }

    pos = queue->pos;
    if(queue->size > 0)
    {
        ALsizei high = queue->size - 1;
        while(pos < high)
        {
            ALsizei mid = pos + (high-pos)/2;
            if(queue->events[mid].time < evt->time)
                pos = mid + 1;
            else
                high = mid;
        }
        while(pos < queue->size && queue->events[pos].time <= evt->time)
            pos++;

        if(pos < queue->size)
            memmove(&queue->events[pos+1], &queue->events[pos],
                    (queue->size-pos)*sizeof(queue->events[0]));
    }

    queue->events[pos] = *evt;
    queue->size++;

    return AL_NO_ERROR;
}