#include <al/macros.h>

#include "buffer.h"

#define NNWT_BUFFER_SIZE KB(1)
#define NNWT_BUFFER_GROW ((size_t)al_grow_step)

void nn_buffer_init(struct nn_buffer *buffer)
{
    buffer->size = 0;
    buffer->alloc = 0;
    buffer->data = NULL;
}

void nn_buffer_ensure_space(struct nn_buffer *buffer, size_t size)
{
    al_assert(size > 0);
    if (size > buffer->alloc) {
        buffer->alloc = (size <= NNWT_BUFFER_SIZE) ? NNWT_BUFFER_SIZE :
            (size + NNWT_BUFFER_GROW) & ~NNWT_BUFFER_GROW;
        buffer->data = (u8 *)al_realloc(buffer->data, buffer->alloc);
    }
}

void nn_buffer_shrink_to_size(struct nn_buffer *buffer)
{
    buffer->alloc = 0;
    nn_buffer_ensure_space(buffer, buffer->size);
}

void nn_buffer_write(struct nn_buffer *buffer, void *data, size_t index, size_t size)
{
    al_assert(buffer->size <= buffer->alloc);
    size_t reach = index + size;
    if (reach > buffer->size) {
        nn_buffer_ensure_space(buffer, reach);
        buffer->size = reach;
    }
    al_memcpy(&buffer->data[index], data, size);
}

void nn_buffer_append(struct nn_buffer *buffer, void *data, size_t size)
{
    nn_buffer_write(buffer, data, buffer->size, size);
}

u8 *nn_buffer_get_ptr(struct nn_buffer *buffer, size_t index)
{
    return buffer->data + index;
}

void nn_buffer_read(struct nn_buffer *buffer, void *ptr, size_t index, size_t size)
{
    al_assert(index + size <= buffer->size);
    al_memcpy(ptr, &buffer->data[index], size);
}

void nn_buffer_free(struct nn_buffer *buffer)
{
    if (buffer->alloc) al_free(buffer->data);
}