basisu 0.1.0

A bit-exact pure-Rust Basis Universal texture transcoder (.ktx2 and .basis).
Documentation 
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//! BC7 format constant tables: the per-partition subset maps and the per-mode
//! bit-layout parameters needed to pack a BC7 block. Consumed by the
//! UASTC-to-BC7 transcoder's block packer.

/// Single-subset partition map: every one of the 16 texels is in subset 0.
pub static G_BC7_PARTITION1: [u8; 16] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

/// Two-subset partition maps: 64 patterns of 16 texels, each value the subset
/// (0 or 1) of that texel.
pub static G_BC7_PARTITION2: [u8; 1024] = [
    0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1,
    0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1,
    0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
    0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0,
    0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1,
    0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0,
    0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0,
    0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0,
    0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0,
    0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1,
    0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0,
    0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0,
    0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1,
    0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0,
    0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0,
    0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1,
    0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0,
    0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0,
    0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1,
    0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0,
    0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1,
    0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1,
    0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0,
    0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1,
];

/// Three-subset partition maps: 64 patterns of 16 texels, each value the subset
/// (0, 1, or 2) of that texel.
pub static G_BC7_PARTITION3: [u8; 1024] = [
    0, 0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 1, 2, 2, 2, 2, 0, 0, 0, 1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1,
    0, 0, 0, 0, 2, 0, 0, 1, 2, 2, 1, 1, 2, 2, 1, 1, 0, 2, 2, 2, 0, 0, 2, 2, 0, 0, 1, 1, 0, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 2, 2,
    0, 0, 2, 2, 0, 0, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2,
    0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2,
    0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2,
    0, 0, 1, 1, 0, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 2, 0, 0, 1, 1, 2, 0, 0, 1, 2, 2, 0, 0, 2, 2, 2, 0,
    0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 2, 1, 1, 2, 2, 0, 1, 1, 1, 0, 0, 1, 1, 2, 0, 0, 1, 2, 2, 0, 0,
    0, 0, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 1, 1, 1, 1,
    0, 1, 1, 1, 0, 1, 1, 1, 0, 2, 2, 2, 0, 2, 2, 2, 0, 0, 0, 1, 0, 0, 0, 1, 2, 2, 2, 1, 2, 2, 2, 1,
    0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 0, 0, 1, 1, 0, 0, 2, 2, 1, 0, 2, 2, 1, 0,
    0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2,
    0, 1, 1, 0, 1, 2, 2, 1, 1, 2, 2, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 2, 2, 1, 1, 2, 2, 1,
    0, 0, 2, 2, 1, 1, 0, 2, 1, 1, 0, 2, 0, 0, 2, 2, 0, 1, 1, 0, 0, 1, 1, 0, 2, 0, 0, 2, 2, 2, 2, 2,
    0, 0, 1, 1, 0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 1, 1, 0, 0, 0, 0, 2, 0, 0, 0, 2, 2, 1, 1, 2, 2, 2, 1,
    0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 2, 2, 2, 0, 2, 2, 2, 0, 0, 2, 2, 0, 0, 1, 2, 0, 0, 1, 1,
    0, 0, 1, 1, 0, 0, 1, 2, 0, 0, 2, 2, 0, 2, 2, 2, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0,
    0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 0, 0, 0, 0, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0,
    0, 1, 2, 0, 2, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1,
    0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2,
    0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 0, 0, 2, 2, 1, 1, 2, 2, 0, 0, 2, 2, 1, 1, 2, 2,
    0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 2, 2, 0, 1, 2, 2, 1, 0, 2, 2, 0, 1, 2, 2, 1,
    0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 0, 1, 0, 1, 0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1,
    0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 2, 2, 2, 2, 0, 2, 2, 2, 0, 1, 1, 1, 0, 2, 2, 2, 0, 1, 1, 1,
    0, 0, 0, 2, 1, 1, 1, 2, 0, 0, 0, 2, 1, 1, 1, 2, 0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2,
    0, 2, 2, 2, 0, 1, 1, 1, 0, 1, 1, 1, 0, 2, 2, 2, 0, 0, 0, 2, 1, 1, 1, 2, 1, 1, 1, 2, 0, 0, 0, 2,
    0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 1, 2,
    0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 2,
    0, 0, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2,
    0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 2, 2, 2, 1, 2, 2, 2, 0, 2, 2, 2, 1, 2, 2, 2,
    0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 1, 1, 1, 2, 0, 1, 1, 2, 2, 0, 1, 2, 2, 2, 0,
];

/// Texel index of the second subset's anchor for each two-subset partition. The
/// anchor texel omits its weight high bit, so the packer skips that bit there.
pub static G_BC7_ANCHOR_SECOND: [u8; 64] = [
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 2, 8, 2, 2, 8, 8, 15, 2, 8,
    2, 2, 8, 8, 2, 2, 15, 15, 6, 8, 2, 8, 15, 15, 2, 8, 2, 2, 2, 15, 15, 6, 6, 2, 6, 8, 15, 15, 2,
    2, 15, 15, 15, 15, 15, 2, 2, 15,
];

/// Texel index of the second subset's anchor for each three-subset partition.
pub static G_BC7_ANCHOR_THIRD_1: [u8; 64] = [
    3, 3, 15, 15, 8, 3, 15, 15, 8, 8, 6, 6, 6, 5, 3, 3, 3, 3, 8, 15, 3, 3, 6, 10, 5, 8, 8, 6, 8, 5,
    15, 15, 8, 15, 3, 5, 6, 10, 8, 15, 15, 3, 15, 5, 15, 15, 15, 15, 3, 15, 5, 5, 5, 8, 5, 10, 5,
    10, 8, 13, 15, 12, 3, 3,
];

/// Texel index of the third subset's anchor for each three-subset partition.
pub static G_BC7_ANCHOR_THIRD_2: [u8; 64] = [
    15, 8, 8, 3, 15, 15, 3, 8, 15, 15, 15, 15, 15, 15, 15, 8, 15, 8, 15, 3, 15, 8, 15, 8, 3, 15, 6,
    10, 15, 15, 10, 8, 15, 3, 15, 10, 10, 8, 9, 10, 6, 15, 8, 15, 3, 6, 6, 8, 15, 3, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 3, 15, 15, 8,
];

/// Subset count per BC7 mode (0..7).
pub static G_BC7_NUM_SUBSETS: [u8; 8] = [3, 2, 3, 2, 1, 1, 1, 2];

/// Bits of partition index per mode. 0 means the mode has no partition field.
pub static G_BC7_PARTITION_BITS: [u8; 8] = [4, 6, 6, 6, 0, 0, 0, 6];

/// Base color-weight bit count per mode. Mode 4's index-selector bit, when
/// set, adds one on top of this.
pub static G_BC7_COLOR_INDEX_BITCOUNT: [u8; 8] = [3, 3, 2, 2, 2, 2, 4, 2];

/// Alpha-weight bit count per mode; 0 for modes that share one weight set
/// across color and alpha.
pub static G_BC7_ALPHA_INDEX_BITCOUNT: [u8; 8] = [0, 0, 0, 0, 3, 2, 4, 2];

/// Whether a mode carries p-bits: an extra bit per endpoint (or per subset,
/// when shared) that acts as the low bit of all of that endpoint's channels.
pub static G_BC7_MODE_HAS_P_BITS: [u8; 8] = [1, 1, 0, 1, 0, 0, 1, 1];

/// Whether a mode's p-bits are shared across the two endpoints of a subset
/// rather than one per endpoint.
pub static G_BC7_MODE_HAS_SHARED_P_BITS: [u8; 8] = [0, 1, 0, 0, 0, 0, 0, 0];

/// Bits per color channel of each endpoint, before any p-bit, per mode.
pub static G_BC7_COLOR_PRECISION: [u8; 8] = [4, 6, 5, 7, 5, 7, 7, 5];

/// Bits per alpha channel of each endpoint per mode; 0 when the mode has no
/// separate alpha endpoints.
pub static G_BC7_ALPHA_PRECISION: [i8; 8] = [0, 0, 0, 0, 6, 8, 7, 5];