contrib/tzdata/ziguard.awk

   1 # Convert tzdata source into vanguard or rearguard form.
   2
   3 # Contributed by Paul Eggert.  This file is in the public domain.
   4
   5 # This is not a general-purpose converter; it is designed for current tzdata.
   6 #
   7 # When converting to vanguard form, the output can use negative SAVE
   8 # values.
   9 #
  10 # When converting to rearguard form, the output uses only nonnegative
  11 # SAVE values.  The idea is for the output data to simulate the behavior
  12 # of the input data as best it can within the constraints of the
  13 # rearguard format.
  14
  15 BEGIN {
  16   dataform_type["vanguard"] = 1
  17   dataform_type["main"] = 1
  18   dataform_type["rearguard"] = 1
  19
  20   # The command line should set DATAFORM.
  21   if (!dataform_type[DATAFORM]) exit 1
  22   vanguard = DATAFORM == "vanguard"
  23 }
  24
  25 /^Zone/ { zone = $2 }
  26
  27 DATAFORM != "main" {
  28   in_comment = /^#/
  29   uncomment = comment_out = 0
  30
  31   # If the line should differ due to Czechoslovakia using negative SAVE values,
  32   # uncomment the desired version and comment out the undesired one.
  33   if (zone == "Europe/Prague" && /1947 Feb 23/) {
  34     if (($(in_comment + 2) != "-") == vanguard) {
  35       uncomment = in_comment
  36     } else {
  37       comment_out = !in_comment
  38     }
  39   }
  40
  41   # If this line should differ due to Ireland using negative SAVE values,
  42   # uncomment the desired version and comment out the undesired one.
  43   Rule_Eire = /^#?Rule[\t ]+Eire[\t ]/
  44   Zone_Dublin_post_1968 \
  45     = (zone == "Europe/Dublin" && /^#?[\t ]+[01]:00[\t ]/ \
  46        && (!$(in_comment + 4) || 1968 < $(in_comment + 4)))
  47   if (Rule_Eire || Zone_Dublin_post_1968) {
  48     if ((Rule_Eire \
  49          || (Zone_Dublin_post_1968 && $(in_comment + 3) == "IST/GMT"))  \
  50         == vanguard) {
  51       uncomment = in_comment
  52     } else {
  53       comment_out = !in_comment
  54     }
  55   }
  56
  57   # If this line should differ due to Namibia using Rule SAVE suffixes,
  58   # uncomment the desired version and comment out the undesired one.
  59   Rule_Namibia = /^#?Rule[\t ]+Namibia[\t ]/
  60   Zone_using_Namibia_rule \
  61     = (zone == "Africa/Windhoek" \
  62        && ($(in_comment + 2) == "Namibia" \
  63            || (1994 <= $(in_comment + 4) && $(in_comment + 4) <= 2017) \
  64            || in_comment + 3 == NF))
  65   if (Rule_Namibia || Zone_using_Namibia_rule) {
  66       if ((Rule_Namibia \
  67            ? ($(in_comment + 9) ~ /^-/ \
  68               || ($(in_comment + 9) == 0 && $(in_comment + 10) == "CAT")) \
  69            : $(in_comment + 1) == "2:00" && $(in_comment + 2) == "Namibia") \
  70           == vanguard) {
  71       uncomment = in_comment
  72     } else {
  73       comment_out = !in_comment
  74     }
  75   }
  76
  77   if (uncomment) {
  78     sub(/^#/, "")
  79   }
  80   if (comment_out) {
  81     sub(/^/, "#")
  82   }
  83
  84   # In rearguard format, change the Japan rule line with "Sat>=8 25:00"
  85   # to "Sun>=9 1:00", to cater to zic before 2007 and to older Java.
  86   if (!vanguard && $1 == "Rule" && $7 == "Sat>=8" && $8 == "25:00") {
  87     sub(/Sat>=8/, "Sun>=9")
  88     sub(/25:00/, " 1:00")
  89   }
  90 }
  91
  92 # If a Link line is followed by a Zone line for the same data, comment
  93 # out the Link line.  This can happen if backzone overrides a Link
  94 # with a Zone.
  95 /^Link/ {
  96   linkline[$3] = NR
  97 }
  98 /^Zone/ {
  99   sub(/^Link/, "#Link", line[linkline[$2]])
 100 }
 101
 102 { line[NR] = $0 }
 103
 104 END {
 105   for (i = 1; i <= NR; i++)
 106     print line[i]
 107 }