a2kit 4.4.1

Retro disk image and language utility
Documentation 
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//! ## Sector Skewing Module
//! 
//! This contains all the sector skew tables.  Some disk images are organized in a way
//! where this information is needed to find a sector.

/// Get the interleave ratio from a *physical* skew table.
/// Will panic if the largest id occurs first or table is bad.
pub fn get_phys_interleave(table: &[usize]) -> usize {
    let first = table[0];
    for rep in 1..table.len() {
        if table[rep]==first+1 {
            return rep;
        }
    }
    panic!("bad physical skew table");
}

/// Skew table for native 8 inch CP/M v1 disks
pub const CPM_1_LSEC_TO_PSEC: [u8;26] = [1,7,13,19,25,5,11,17,23,3,9,15,21,2,8,14,20,26,6,12,18,24,4,10,16,22];
/// Skew table for Nabu 8 inch CP/M disks
pub const CPM_LSEC_TO_NABU_PSEC: [u8;26] = [1,8,15,22,3,10,17,24,5,12,19,26,7,14,21,2,9,16,23,4,11,18,25,6,13,20];
/// Skew table for Osborne 5.25 inch SSSD disks
pub const CPM_LSEC_TO_OSB1_PSEC: [u8;10] = [1,3,5,7,9,2,4,6,8,10];
/// Take CP/M logical sector to DOS logical sector; the offset within the DOS sector is obtained by another table.
pub const CPM_LSEC_TO_DOS_LSEC: [usize;32] = [0,0,6,6,12,12,3,3,9,9,15,15,14,14,5,5,11,11,2,2,8,8,7,7,13,13,4,4,10,10,1,1];
/// Take CP/M logical sector to DOS physical sector; the offset within the DOS sector is obtained by another table.
pub const CPM_LSEC_TO_DOS_PSEC: [usize;32] = [0,0,3,3,6,6,9,9,12,12,15,15,2,2,5,5,8,8,11,11,14,14,1,1,4,4,7,7,10,10,13,13];
/// Take CP/M logical sector to offset within DOS logical sector
pub const CPM_LSEC_TO_DOS_OFFSET: [usize;32] = [0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128,0,128];

/// 3.5 inch disk physical sector skew by zone; inner zone tables are padded to 12 entries
pub const D35_PHYSICAL: [[usize;12];5] = [
    [0,3,6,9,1,4,7,10,2,5,8,11],
    [0,3,6,9,1,4,7,10,2,5,8,0xff],
    [0,5,3,8,1,6,4,9,2,7,0xff,0xff],
    [0,7,5,3,1,8,6,4,2,0xff,0xff,0xff],
    [0,2,4,6,1,3,5,7,0xff,0xff,0xff,0xff],
];

/// Physical sector skew used by DOS 3.2
pub const DOS32_PHYSICAL: [usize;13] = [0,10,7,4,1,11,8,5,2,12,9,6,3];
/// Translate DOS 3.3 logical sector to physical sector
pub const DOS_LSEC_TO_DOS_PSEC: [usize;16] = [0,13,11,9,7,5,3,1,14,12,10,8,6,4,2,15];
/// Translate DOS 3.3 physical sector to logical sector
pub const DOS_PSEC_TO_DOS_LSEC: [usize;16] = [0,7,14,6,13,5,12,4,11,3,10,2,9,1,8,15];