From f4c112b59fcee233ba33b0308c2db9d6e49f3a9f Mon Sep 17 00:00:00 2001
From: Alex Zolotarev <alex@maps.me>
Date: Thu, 31 Mar 2016 09:51:32 +0300
Subject: [PATCH] strings::NormalizeDigits for full-width unicode numbers.

---
 base/base_tests/string_utils_test.cpp | 13 +++++++++++++
 base/string_utils.cpp                 | 15 +++++++++++++++
 base/string_utils.hpp                 |  3 +++
 3 files changed, 31 insertions(+)

diff --git a/base/base_tests/string_utils_test.cpp b/base/base_tests/string_utils_test.cpp
index 55b256bacf..05c269d29c 100644
--- a/base/base_tests/string_utils_test.cpp
+++ b/base/base_tests/string_utils_test.cpp
@@ -612,3 +612,16 @@ UNIT_TEST(EditDistance)
   testUniStringEditDistance("ll", "l1", 1);
   testUniStringEditDistance("\u0132ij", "\u0133IJ", 3);
 }
+
+UNIT_TEST(NormalizeDigits)
+{
+  auto const nd = [](string str) -> string
+  {
+    strings::NormalizeDigits(str);
+    return str;
+  };
+  TEST_EQUAL(nd(""), "", ());
+  TEST_EQUAL(nd("z12345／／"), "z12345／／", ());
+  TEST_EQUAL(nd("a０１9２ "), "a0192 ", ());
+  TEST_EQUAL(nd("３４５６７８９"), "3456789", ());
+}
diff --git a/base/string_utils.cpp b/base/string_utils.cpp
index e9f2aa1d39..6e643d18f2 100644
--- a/base/string_utils.cpp
+++ b/base/string_utils.cpp
@@ -113,6 +113,21 @@ UniString Normalize(UniString const & s)
   return result;
 }
 
+void NormalizeDigits(string & utf8)
+{
+  for (size_t i = 0; i + 2 < utf8.size(); ++i)
+  {
+    if (utf8[i] == '\xEF' && utf8[i + 1] == '\xBC')
+    {
+      char const n = utf8[i + 2];
+      if (n < '\x90' || n > '\x99')
+        continue;
+      utf8[i] = n - 0x90 + '0';
+      utf8.erase(i + 1, 2);
+    }
+  }
+}
+
 namespace
 {
   char ascii_to_lower(char in)
diff --git a/base/string_utils.hpp b/base/string_utils.hpp
index 4d006a0d08..a7a6a4290d 100644
--- a/base/string_utils.hpp
+++ b/base/string_utils.hpp
@@ -43,6 +43,9 @@ UniString MakeLowerCase(UniString const & s);
 void NormalizeInplace(UniString & s);
 UniString Normalize(UniString const & s);
 
+/// Replaces "full width" unicode digits with ascii ones.
+void NormalizeDigits(string & utf8);
+
 /// Counts number of start symbols in string s (that is not lower and not normalized) that maches
 /// to lower and normalized string low_s. If s doen't starts with low_s then returns 0; otherwise
 /// returns number of start symbols in s that equivalent to lowStr