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

#include <barrelfish/capabilities.h>
#include <barrelfish/debug.h>
#include <barrelfish/ram_alloc.h>
#include <barrelfish/vspace_common.h>
#include <barrelfish_kpi/types.h>
#include <errors/errno.h>

static void show_ram_available(const char* prefix) {
    // From fish: display how much memory free in the system.
    errval_t err;
    genpaddr_t available, total;
    err = ram_available(&available, &total);
    if (err_is_fail(err)) {
        USER_PANIC_ERR(err, "ram_available in show_ram_available()");
    }
    printf("%s System memory: free: %" PRIuGENPADDR " bytes, "
           "total: %" PRIuGENPADDR " bytes\n",
           prefix, available, total);
}

size_t bytes_needed = ((size_t) 8192) * 1024 * 1024;  /* 8 GB */

int main() {
    show_ram_available("[BEFORE]");

    // allocate frame
    struct capref frame;
    size_t frame_size;
    errval_t err = frame_alloc(&frame, bytes_needed, &frame_size);
    if (err_is_fail(err)) {
        USER_PANIC_ERR(err, "frame_alloc in big_malloc:main()");
    }
    // Unsure, but documentation for frame_create mentions "minimum size".
    assert(frame_size >= bytes_needed);
    printf("Allocated frame of %zu bytes.\n", frame_size);

    // map frame
    void *virt_addr;
    err = vspace_map_one_frame(&virt_addr, frame_size, frame,
                               /* memobj */ NULL, /* vregion */ NULL);
    if (err_is_fail(err)) {
        USER_PANIC_ERR(err, "vspace_map_one_frame in big_malloc:main()");
    }
    printf("Mapped frame at %p.\n", virt_addr);

    // check we can touch it.
    memset(virt_addr, 0x12345678, frame_size);

    show_ram_available("[AFTER]");

    return 0;
}