Changes: https://mm.icann.org/pipermail/tz-announce/2017-October/000047.html MFC after: 2 days
157 lines
4.1 KiB
Awk
157 lines
4.1 KiB
Awk
# Convert tzdata source into a smaller version of itself.
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# Contributed by Paul Eggert. This file is in the public domain.
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# This is not a general-purpose converter; it is designed for current tzdata.
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# 'zic' should treat this script's output as if it were identical to
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# this script's input.
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# Return a new rule name.
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# N_RULE_NAMES keeps track of how many rule names have been generated.
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function gen_rule_name(alphabet, base, rule_name, n, digit)
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{
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alphabet = ""
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alphabet = alphabet "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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alphabet = alphabet "abcdefghijklmnopqrstuvwxyz"
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alphabet = alphabet "!$%&'()*+,./:;<=>?@[\\]^_`{|}~"
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base = length(alphabet)
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rule_name = ""
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n = n_rule_names++
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do {
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n -= rule_name && n <= base
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digit = n % base
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rule_name = substr(alphabet, digit + 1, 1) rule_name
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n = (n - digit) / base
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} while (n);
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return rule_name
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}
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# Process an input line and save it for later output.
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function process_input_line(line, field, end, i, n, startdef)
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{
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# Remove comments, normalize spaces, and append a space to each line.
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sub(/#.*/, "", line)
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line = line " "
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gsub(/[[:space:]]+/, " ", line)
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# Abbreviate keywords. Do not abbreviate "Link" to just "L",
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# as pre-2017c zic erroneously diagnoses "Li" as ambiguous.
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sub(/^Link /, "Li ", line)
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sub(/^Rule /, "R ", line)
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sub(/^Zone /, "Z ", line)
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# SystemV rules are not needed.
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if (line ~ /^R SystemV /) return
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# Replace FooAsia rules with the same rules without "Asia", as they
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# are duplicates.
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if (match(line, /[^ ]Asia /)) {
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if (line ~ /^R /) return
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line = substr(line, 1, RSTART) substr(line, RSTART + 5)
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}
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# Abbreviate times.
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while (match(line, /[: ]0+[0-9]/))
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line = substr(line, 1, RSTART) substr(line, RSTART + RLENGTH - 1)
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while (match(line, /:0[^:]/))
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line = substr(line, 1, RSTART - 1) substr(line, RSTART + 2)
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# Abbreviate weekday names. Do not abbreviate "Sun" and "Sat", as
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# pre-2017c zic erroneously diagnoses "Su" and "Sa" as ambiguous.
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while (match(line, / (last)?(Mon|Wed|Fri)[ <>]/)) {
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end = RSTART + RLENGTH
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line = substr(line, 1, end - 4) substr(line, end - 1)
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}
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while (match(line, / (last)?(Tue|Thu)[ <>]/)) {
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end = RSTART + RLENGTH
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line = substr(line, 1, end - 3) substr(line, end - 1)
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}
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# Abbreviate "max", "only" and month names.
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# Do not abbreviate "min", as pre-2017c zic erroneously diagnoses "mi"
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# as ambiguous.
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gsub(/ max /, " ma ", line)
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gsub(/ only /, " o ", line)
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gsub(/ Jan /, " Ja ", line)
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gsub(/ Feb /, " F ", line)
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gsub(/ Apr /, " Ap ", line)
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gsub(/ Aug /, " Au ", line)
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gsub(/ Sep /, " S ", line)
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gsub(/ Oct /, " O ", line)
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gsub(/ Nov /, " N ", line)
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gsub(/ Dec /, " D ", line)
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# Strip leading and trailing space.
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sub(/^ /, "", line)
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sub(/ $/, "", line)
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# Remove unnecessary trailing zero fields.
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sub(/ 0+$/, "", line)
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# Remove unnecessary trailing days-of-month "1".
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if (match(line, /[[:alpha:]] 1$/))
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line = substr(line, 1, RSTART)
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# Remove unnecessary trailing " Ja" (for January).
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sub(/ Ja$/, "", line)
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n = split(line, field)
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# Abbreviate rule names.
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i = field[1] == "Z" ? 4 : field[1] == "Li" ? 0 : 2
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if (i && field[i] ~ /^[^-+0-9]/) {
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if (!rule[field[i]])
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rule[field[i]] = gen_rule_name()
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field[i] = rule[field[i]]
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}
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# If this zone supersedes an earlier one, delete the earlier one
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# from the saved output lines.
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startdef = ""
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if (field[1] == "Z")
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zonename = startdef = field[2]
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else if (field[1] == "Li")
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zonename = startdef = field[3]
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else if (field[1] == "R")
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zonename = ""
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if (startdef) {
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i = zonedef[startdef]
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if (i) {
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do
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output_line[i - 1] = ""
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while (output_line[i++] ~ /^[-+0-9]/);
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}
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}
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zonedef[zonename] = nout + 1
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# Save the line for later output.
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line = field[1]
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for (i = 2; i <= n; i++)
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line = line " " field[i]
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output_line[nout++] = line
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}
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function output_saved_lines(i)
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{
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for (i = 0; i < nout; i++)
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if (output_line[i])
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print output_line[i]
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}
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BEGIN {
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print "# This zic input file is in the public domain."
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}
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/^[[:space:]]*[^#[:space:]]/ {
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process_input_line($0)
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}
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END {
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output_saved_lines()
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}
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