diff options
Diffstat (limited to 'exfat/mkfs/fat.c')
-rw-r--r-- | exfat/mkfs/fat.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/exfat/mkfs/fat.c b/exfat/mkfs/fat.c new file mode 100644 index 000000000..82feff8ba --- /dev/null +++ b/exfat/mkfs/fat.c @@ -0,0 +1,86 @@ +/* + fat.c (09.11.10) + File Allocation Table creation code. + + Copyright (C) 2011, 2012 Andrew Nayenko + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <unistd.h> +#include "fat.h" +#include "cbm.h" +#include "uct.h" +#include "rootdir.h" + +static off64_t fat_alignment(void) +{ + return (off64_t) 128 * get_sector_size(); +} + +static off64_t fat_size(void) +{ + return get_volume_size() / get_cluster_size() * sizeof(cluster_t); +} + +static cluster_t fat_write_entry(struct exfat_dev* dev, cluster_t cluster, + cluster_t value) +{ + le32_t fat_entry = cpu_to_le32(value); + if (exfat_write(dev, &fat_entry, sizeof(fat_entry)) < 0) + { + exfat_error("failed to write FAT entry 0x%x", value); + return 0; + } + return cluster + 1; +} + +static cluster_t fat_write_entries(struct exfat_dev* dev, cluster_t cluster, + uint64_t length) +{ + cluster_t end = cluster + DIV_ROUND_UP(length, get_cluster_size()); + + while (cluster < end - 1) + { + cluster = fat_write_entry(dev, cluster, cluster + 1); + if (cluster == 0) + return 0; + } + return fat_write_entry(dev, cluster, EXFAT_CLUSTER_END); +} + +static int fat_write(struct exfat_dev* dev) +{ + cluster_t c = 0; + + if (!(c = fat_write_entry(dev, c, 0xfffffff8))) /* media type */ + return 1; + if (!(c = fat_write_entry(dev, c, 0xffffffff))) /* some weird constant */ + return 1; + if (!(c = fat_write_entries(dev, c, cbm.get_size()))) + return 1; + if (!(c = fat_write_entries(dev, c, uct.get_size()))) + return 1; + if (!(c = fat_write_entries(dev, c, rootdir.get_size()))) + return 1; + + return 0; +} + +const struct fs_object fat = +{ + .get_alignment = fat_alignment, + .get_size = fat_size, + .write = fat_write, +}; |