#include "nuklear.h"

#include "nuklear_internal.h"

/* ===============================================================

 *

 *                          PAGE ELEMENT

 *

 * ===============================================================*/

NK_LIB struct nk_page_element*

nk_create_page_element(struct nk_context *ctx)

{

    struct nk_page_element *elem;

    if (ctx->freelist) {

        /* unlink page element from free list */

        elem = ctx->freelist;

        ctx->freelist = elem->next;

    } else if (ctx->use_pool) {

        /* allocate page element from memory pool */

        elem = nk_pool_alloc(&ctx->pool);

        NK_ASSERT(elem);

        if (!elem) return 0;

    } else {

        /* allocate new page element from back of fixed size memory buffer */

        NK_STORAGE const nk_size size = sizeof(struct nk_page_element);

        NK_STORAGE const nk_size align = NK_ALIGNOF(struct nk_page_element);

        elem = (struct nk_page_element*)nk_buffer_alloc(&ctx->memory, NK_BUFFER_BACK, size, align);

        NK_ASSERT(elem);

        if (!elem) return 0;

    }

    nk_zero_struct(*elem);

    elem->next = 0;

    elem->prev = 0;

    return elem;

}

NK_LIB void

nk_link_page_element_into_freelist(struct nk_context *ctx,

    struct nk_page_element *elem)

{

    /* link table into freelist */

    if (!ctx->freelist) {

        ctx->freelist = elem;

    } else {

        elem->next = ctx->freelist;

        ctx->freelist = elem;

    }

}

NK_LIB void

nk_free_page_element(struct nk_context *ctx, struct nk_page_element *elem)

{

    /* we have a pool so just add to free list */

    if (ctx->use_pool) {

        nk_link_page_element_into_freelist(ctx, elem);

        return;

    }

    /* if possible remove last element from back of fixed memory buffer */

    {void *elem_end = (void*)(elem + 1);

    void *buffer_end = (nk_byte*)ctx->memory.memory.ptr + ctx->memory.size;

    if (elem_end == buffer_end)

        ctx->memory.size -= sizeof(struct nk_page_element);

    else nk_link_page_element_into_freelist(ctx, elem);}

}