@spec apply_mapping((non_neg_integer() -> non_neg_integer()) | nil, non_neg_integer()) ::
  non_neg_integer()

Apply a reorder mapping to a primary weight.

Arguments

• mapping_fn - a reorder mapping function from build_mapping/1, or nil.

• primary - the primary weight to remap.

Returns

The remapped primary weight, or the original if mapping_fn is nil.

Examples

iex> Cldr.Collation.Reorder.apply_mapping(nil, 0x2A00)
0x2A00

iex> mapping = Cldr.Collation.Reorder.build_mapping([:Grek, :Latn])
iex> remapped = Cldr.Collation.Reorder.apply_mapping(mapping, 0x2A00)
iex> is_integer(remapped)
true

@spec build_mapping([atom()]) :: (non_neg_integer() -> non_neg_integer()) | nil

Build a reorder mapping function from the given script codes.

Creates a function that remaps primary weights to reorder scripts. Core codes (space, punct, symbol, currency, digit) that are not explicitly listed are prepended automatically.

Arguments

• reorder_codes - a list of script code atoms (e.g., [:Grek, :Latn]). Supports ISO 15924 codes (:Latn, :Grek, :Cyrl) and special codes (:space, :punct, :symbol, :currency, :digit, :others).

Returns

• A function (primary :: integer()) -> integer() that remaps primary weights.
• nil if the list is empty or no valid mappings were found.

Examples

iex> Cldr.Collation.Reorder.build_mapping([])
nil

iex> mapping = Cldr.Collation.Reorder.build_mapping([:Grek, :Latn])
iex> is_function(mapping, 1)
true

@spec load_primary_to_fractional_lead() :: %{
  required(integer() | {:sub, integer()}) => non_neg_integer()
}

Load a mapping from allkeys integer primary weights to their fractional lead bytes and sub-bytes.

Parses FractionalUCA.txt data lines to extract both the fractional CE (which gives the lead byte and sub-byte) and the allkeys integer primary weight (from the comment portion).

The returned map has two types of entries:

• primary_weight => fractional_lead_byte - the script-identifying lead byte.
• {:sub, primary_weight} => fractional_sub_byte - the within-script sub-byte for preserving relative ordering during remapping.

Returns

A map %{integer() | {:sub, integer()} => non_neg_integer()}.

@spec load_script_ranges() :: %{
  required(String.t()) => {non_neg_integer(), non_neg_integer()}
}

Load the script-to-lead-byte-range mapping from FractionalUCA.txt.

Parses [top_byte ...] entries from the data file. Falls back to hardcoded defaults if the file is not found.

Returns

A map %{String.t() => {start_byte, end_byte}} where keys are lowercase script/group names and values are fractional lead byte range tuples.

Examples

iex> ranges = Cldr.Collation.Reorder.load_script_ranges()
iex> is_map(ranges)
true