Struct Geometry 

pub struct Geometry {

    pub variant: FatVariant,
    pub bytes_per_sector: u32,
    pub sectors_per_cluster: u32,
    pub cluster_size: u32,
    pub reserved_sectors: u32,
    pub num_fats: u32,
    pub fat_size_sectors: u32,
    pub root_entry_count: u32,
    pub total_sectors: u64,
    pub root_cluster: u32,
    pub count_of_clusters: u32,
    pub fat_start: u64,
    pub root_dir_start: u64,
    pub root_dir_bytes: u32,
    pub data_start: u64,
}

Resolved on-disk geometry of a FAT12/16/32 volume. All byte offsets are relative to the start of the volume (sector 0).

Fields

variant: FatVariant

Which FAT variant.

bytes_per_sector: u32

Bytes per logical sector (power of two, 512–4096).

sectors_per_cluster: u32

Sectors per cluster (power of two, 1–128).

cluster_size: u32

Cluster size in bytes.

reserved_sectors: u32

Count of reserved sectors preceding the first FAT.

num_fats: u32

Number of FAT copies.

fat_size_sectors: u32

Sectors occupied by one FAT.

root_entry_count: u32

FAT12/16 fixed root directory entry count (0 on FAT32).

total_sectors: u64

Total sectors in the volume.

root_cluster: u32

FAT32/exFAT first cluster of the root directory (0 on FAT12/16).

count_of_clusters: u32

Count of data clusters (drives the type decision).

fat_start: u64

Byte offset of the first FAT.

root_dir_start: u64

Byte offset of the FAT12/16 fixed root region (0 on FAT32).

root_dir_bytes: u32

Byte size of the FAT12/16 fixed root region (0 on FAT32).

data_start: u64

Byte offset of cluster 2 (start of the data region).

Implementations

impl Geometry

pub fn parse(boot: &[u8]) -> Result<Geometry>

Parse the BPB from the boot sector boot (at least 512 bytes).

Fails loud, naming the offending value, on any structurally invalid field — an invalid BPB is a bootstrap failure, never a silent default.

pub fn cluster_offset(&self, cluster: u32) -> Option<u64>

Byte offset of the first sector of cluster (>= 2) in the data region.

Trait Implementations

impl Clone for Geometry

fn clone(&self) -> Geometry

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Geometry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.