Graham McIntire
b0832e5a9c
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45 lines
1.5 KiB
Elixir
45 lines
1.5 KiB
Elixir
defmodule Aprsme.Callsign do
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@moduledoc """
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Validation and normalization for APRS source identifiers.
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RF callsigns follow AX.25's shorter shape, while APRS-IS also carries
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application and gateway identifiers. Validation therefore enforces a
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conservative transport-safe character set and length without rejecting
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established APRS-IS identifiers.
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"""
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@safe_identifier_regex ~r/^[A-Z0-9]+(?:-[A-Z0-9]+)*$/
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@spec valid?(term()) :: boolean()
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def valid?(callsign) when is_binary(callsign) do
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normalized = normalize(callsign)
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byte_size(normalized) in 1..20 and Regex.match?(@safe_identifier_regex, normalized)
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end
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def valid?(_callsign), do: false
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@spec normalize(term()) :: String.t()
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def normalize(callsign) when is_binary(callsign), do: callsign |> String.trim() |> String.upcase()
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def normalize(_callsign), do: ""
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@spec matches?(term(), term()) :: boolean()
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def matches?(left, right), do: normalize(left) == normalize(right)
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@spec extract_base(term()) :: String.t()
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def extract_base(callsign), do: callsign |> extract_parts() |> elem(0)
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@spec extract_ssid(term()) :: String.t()
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def extract_ssid(callsign), do: callsign |> extract_parts() |> elem(1)
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@spec extract_parts(term()) :: {String.t(), String.t()}
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def extract_parts(callsign) when is_binary(callsign) do
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normalized = normalize(callsign)
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case Regex.run(~r/^(.*)-([0-9]+)$/, normalized) do
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[_, base, ssid] -> {base, ssid}
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_ -> {normalized, "0"}
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end
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end
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def extract_parts(_callsign), do: {"", "0"}
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end
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