fcb.c

#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include "fcb.h"
#include "defs.h"
#include "global.h"
#include "mount.h"

struct FCB_map
{
    uint8_t drive;

    char filename[8];
    char extension[3];

    int host_fd;

    struct FCB_map* prev;
    struct FCB_map* next;
} * FCB_items = NULL;

bool fcb_matches(struct FCB* fcb, struct FCB_map* map)
{
    return fcb->drive == map->drive
           && !strncmp(fcb->filename, map->filename, 8)
           && !strncmp(fcb->extension, map->extension, 3);
}

uint8_t fcb_close(struct FCB* fcb)
{
    for (struct FCB_map* cur = FCB_items; cur; cur = cur->next)
    {
        if (fcb_matches(fcb, cur))
        {
            if (cur->prev)
            {
                cur->prev->next = cur->next;
            }

            if (cur->next)
            {
                cur->next->prev = cur->prev;
            }

            close(cur->host_fd);
            free(cur);

            return ERR_SUCCESS;
        }
    }

    return ERR_FCB_UNAVAILABLE;
}

uint8_t fcb_open(struct FCB* fcb)
{
    dbgprintf("Opening FCB / %d (%c:) / %.8s.%.3s\n", fcb->drive, fix_drive(fcb->drive) + 'A', fcb->filename,
           fcb->extension);

    for (struct FCB_map* cur = FCB_items; cur; cur = cur->next)
    {
        if (fcb_matches(fcb, cur))
        {
            return ERR_SUCCESS;
            dbgprintf("File already open\n");
            return ERR_UNABLE_TO_COMPLETE_FILE_OPERATION;
        }
    }

    char fname[16];
    fcb_filename(fcb, fname);

    dbgprintf("Absolute filename: %s\n", fname);

    char fixed[512];
    mount_str_to_real(fname, fixed);

    dbgprintf("Real filename: %s\n", fixed);

    int host_fd = open(fixed, O_RDWR);
    if (host_fd < 0)
    {   // failed to open
        dbgprintf("Unable to open file\n");
        return ERR_UNABLE_TO_COMPLETE_FILE_OPERATION;
    }

    struct FCB_map* map = calloc(1, sizeof(struct FCB_map));

    map->drive = fcb->drive;
    memcpy(map->filename, fcb->filename, 8);
    memcpy(map->extension, fcb->extension, 3);
    map->host_fd = host_fd;

    fcb->current_block = 0;
    fcb->record_size = 0x80;

    if (!FCB_items)
    {
        FCB_items = map;
        return ERR_SUCCESS;
    }

    struct FCB_map* cur = FCB_items;
    while (cur->next)
        cur = cur->next;

    cur->next = map;
    map->prev = cur;

    return ERR_SUCCESS;
}

void fcb_filename(struct FCB* fcb, char* fname)
{
    memset(fname, 0, 16);
    fname[0] = fix_drive(fcb->drive) + 'A';
    fname[1] = ':';
    fname[2] = '\\';
    strncat(fname, fcb->filename, 8);

    for (int i = 10; i >= 4; i--)
    {
        if (fname[i] != ' ')
            break;
        fname[i] = 0;
    }

    strcat(fname, ".");
    strncat(fname, fcb->extension, 3);

    for (int i = 14; i >= 12; i--)
    {
        if (fname[i] != ' ')
            break;
        fname[i] = 0;
    }
}

int fcb_get_fd(struct FCB* fcb)
{
    for (struct FCB_map* cur = FCB_items; cur; cur = cur->next)
    {
        if (fcb_matches(fcb, cur))
        {
            return cur->host_fd;
        }
    }

    return -1;
}

uint8_t fcb_find_first_next(struct FCB* fcb, bool first)
{
    return -1;
}