Add fast timezone id validation function

commit_hash:a2c20ffc1acc83385a3195d76eb95818b3ad6a67

6 files changed, 29 insertions, 3 deletions

diff --git a/library/cpp/type_info/tz/is_valid_gen.h b/library/cpp/type_info/tz/is_valid_gen.h
new file mode 100644
index 00000000000..70f1029deff
--- /dev/null
+++ b/library/cpp/type_info/tz/is_valid_gen.h
@@ -0,0 +1,2 @@
+// this file is generated, do not edit
+return idx < 600 && idx != 586 && idx != 593;
diff --git a/library/cpp/type_info/tz/tz.cpp b/library/cpp/type_info/tz/tz.cpp
index b2c3fc9d7f0..409519dc976 100644
--- a/library/cpp/type_info/tz/tz.cpp
+++ b/library/cpp/type_info/tz/tz.cpp
@@ -5,7 +5,7 @@ namespace NTi {
 namespace {
 
 static constexpr std::initializer_list<const std::string_view> TimezonesInit = {
-#include "tz.gen"
+#include "tz_gen.h"
 };
 
 static constexpr TArrayRef<const std::string_view> Timezones(TimezonesInit);
diff --git a/library/cpp/type_info/tz/tz.h b/library/cpp/type_info/tz/tz.h
index b683269af29..51ccd15276a 100644
--- a/library/cpp/type_info/tz/tz.h
+++ b/library/cpp/type_info/tz/tz.h
@@ -6,4 +6,11 @@ namespace NTi {
 
 TArrayRef<const std::string_view> GetTimezones();
 
+inline bool IsValidTimezoneIndex(size_t idx) {
+    // this function is equivalent to:
+    // const auto zones = GetTimezones();
+    // return idx < zones.size() && !zones[idx].empty();
+    #include "is_valid_gen.h"
+}
+
 }
diff --git a/library/cpp/type_info/tz/tz.gen b/library/cpp/type_info/tz/tz_gen.h
index e71c9cc81e7..e71c9cc81e7 100644
--- a/library/cpp/type_info/tz/tz.gen
+++ b/library/cpp/type_info/tz/tz_gen.h
diff --git a/library/cpp/type_info/tz/tz_ut.cpp b/library/cpp/type_info/tz/tz_ut.cpp
index 65e8340cdc5..781c80fa226 100644
--- a/library/cpp/type_info/tz/tz_ut.cpp
+++ b/library/cpp/type_info/tz/tz_ut.cpp
@@ -13,4 +13,12 @@ Y_UNIT_TEST_SUITE(TTz) {
         UNIT_ASSERT(GetTimezones().size() > 0);
         UNIT_ASSERT_VALUES_EQUAL(GetTimezones()[0], "GMT");
     }
+
+    Y_UNIT_TEST(IsValidTimezoneIndex) {
+        auto timezones = GetTimezones();
+        for (size_t i = 0; i < timezones.size(); ++i) {
+            UNIT_ASSERT(IsValidTimezoneIndex(i) == !timezones[i].empty());
+        }
+        UNIT_ASSERT(!IsValidTimezoneIndex(timezones.size()));
+    }
 }
diff --git a/library/cpp/type_info/tz/update.py b/library/cpp/type_info/tz/update.py
index d1d0f71decf..f6ca4f1b904 100755
--- a/library/cpp/type_info/tz/update.py
+++ b/library/cpp/type_info/tz/update.py
@@ -5,12 +5,13 @@ import re
 
 def main():
     REGEXP = """^("(.+)",|"",//(.+))$"""
-    OUTPUT = "../tz.gen"
+    OUTPUT = "../tz_gen.h"
+    OUTPUT_VALID = "../is_valid_gen.h"
     INPUT = OUTPUT
     CONTRIB_ZONES = "../../../../../contrib/libs/cctz/tzdata/ya.make.resources"
     RES_PREFIX = "/cctz/tzdata/"
 
-    print("process %s into %s" % (INPUT, OUTPUT))
+    print("process %s into %s and %s" % (INPUT, OUTPUT, OUTPUT_VALID))
     with open(INPUT, "r") as inp:
         lines = inp.readlines()
 
@@ -43,15 +44,23 @@ def main():
             zones.append(zone)
 
     lines = []
+    idx = 0
+    pred = ""
     for zone in zones:
         if zone in scontrib:
             lines.append('"%s",\n' % zone)
         else:
             lines.append('"",//%s\n' % zone)
+            pred += " && idx != %s" % idx
+        idx += 1
 
     with open(OUTPUT, "w") as outp:
         outp.writelines(lines)
 
+    with open(OUTPUT_VALID, "w") as outp:
+        outp.write("// this file is generated, do not edit\n")
+        outp.write("return idx < %s%s;\n" % (len(zones), pred))
+
     print("saved %s zones" % len(zones))