[util] Turn all Collapse / CollapseInPlace overloads into template functions to support arbitrary string types

2 files changed, 25 insertions, 5 deletions

diff --git a/util/string/strip.h b/util/string/strip.h
index 599fdd93ad..666300e0e7 100644
--- a/util/string/strip.h
+++ b/util/string/strip.h
@@ -246,12 +246,14 @@ std::enable_if_t<std::is_invocable_v<TWhitespaceFunc, typename TStringType::valu
     return CollapseImpl(from, to, maxLen, isWhitespace);
 }
 
-inline bool Collapse(const TString& from, TString& to, size_t maxLen = 0) {
-    return Collapse(from, to, IsAsciiSpace<typename TString::value_type>, maxLen);
+template <class TStringType>
+inline bool Collapse(const TStringType& from, TStringType& to, size_t maxLen = 0) {
+    return Collapse(from, to, IsAsciiSpace<typename TStringType::value_type>, maxLen);
 }
 
 /// Replaces several consequtive space symbols with one (processing is limited to maxLen bytes)
-inline TString& CollapseInPlace(TString& s, size_t maxLen = 0) {
+template <class TStringType>
+inline TStringType& CollapseInPlace(TStringType& s, size_t maxLen = 0) {
     Collapse(s, s, maxLen);
     return s;
 }
@@ -262,8 +264,9 @@ inline TStringType& CollapseInPlace(TStringType& s, TWhitespaceFunc isWhitespace
 }
 
 /// Replaces several consequtive space symbols with one (processing is limited to maxLen bytes)
-[[nodiscard]] inline TString Collapse(const TString& s, size_t maxLen = 0) {
-    TString ret;
+template <class TStringType>
+[[nodiscard]] inline TStringType Collapse(const TStringType& s, size_t maxLen = 0) {
+    TStringType ret;
     Collapse(s, ret, maxLen);
     return ret;
 }
diff --git a/util/string/strip_ut.cpp b/util/string/strip_ut.cpp
index 0b1687ffa7..283ab66fdf 100644
--- a/util/string/strip_ut.cpp
+++ b/util/string/strip_ut.cpp
@@ -139,6 +139,23 @@ Y_UNIT_TEST_SUITE(TStripStringTest) {
 #endif
     }
 
+    Y_UNIT_TEST(TestCollapseUtf16) {
+        TUtf16String s;
+        Collapse(UTF8ToWide<true>("  123    456  "), s);
+        UNIT_ASSERT(s == UTF8ToWide<true>(" 123 456 "));
+        Collapse(UTF8ToWide<true>("  123    456  "), s, 10);
+        UNIT_ASSERT(s == UTF8ToWide<true>(" 123 456  "));
+
+        s = UTF8ToWide<true>(" a b c ");
+        TUtf16String s2 = s;
+        CollapseInPlace(s2);
+
+        UNIT_ASSERT(s == s2);
+#ifndef TSTRING_IS_STD_STRING
+        UNIT_ASSERT(s.c_str() == s2.c_str()); // Collapse() does not change the string at all
+#endif
+    }
+
     Y_UNIT_TEST(TestCollapse) {
         TString s;
         Collapse(TString("  123    456  "), s);