#include <stdio.h>
#include <stdlib.h>
#include "types.h"
#include "DmaBuffer.h"

#define ALIGN_DOWN(v, align) ((v)&(-align))
#define ALIGN_UP(v, align)   ALIGN_DOWN((v)+((align)-1), align)

void*
new_align(int alignment, int size)
{
    char *nonalign;
    char *align;

    nonalign = new char[size + sizeof(void*) + alignment - 1];
    align = (char*)(ALIGN_UP((unsigned long)nonalign+sizeof(void*),alignment));
    *((void**)align - 1) = (void*)nonalign;

    return align;
}

void
free_align(void *ptr)
{
    char *real;

    if (ptr != NULL) {
        real = (char*)(*((void**)(ptr)-1));
        delete real;
    }
}

DmaBuffer::DmaBuffer(int size)
{
    buffer[0] = malloc(size);
    buffer[1] = malloc(size);

    //posix_memalign(&buffer[0], DEFAULT_ALIGNMENT, size);
    //posix_memalign(&buffer[1], DEFAULT_ALIGNMENT, size);

    //buffer[0] = new_align(DEFAULT_ALIGNMENT, size);
    //buffer[1] = new_align(DEFAULT_ALIGNMENT, size);

    flag = 0;
}

DmaBuffer::~DmaBuffer(void)
{
    //free(buffer[0]);
    //free(buffer[1]);
    free_align(buffer[0]);
    free_align(buffer[1]);
}

void
DmaBuffer::swap_buffer(void)
{
    flag ^= 1;
}

void
DmaBuffer::get_buffer(void *_dst)
{
    void **dst = (void**)_dst;
    *dst = buffer[flag];
}