ICU-22696 Add uhash support for std::string_view.

icu4c/source/common/uhash.cpp

@@ -12,6 +12,8 @@
 ******************************************************************************
 */
 
+#include <string_view>
+
 #include "uhash.h"
 #include "unicode/ustring.h"
 #include "cstring.h"
@@ -944,6 +946,12 @@ uhash_hashIChars(const UHashTok key) {
     return s == nullptr ? 0 : ustr_hashICharsN(s, static_cast<int32_t>(uprv_strlen(s)));
 }
 
+U_CAPI int32_t U_EXPORT2
+uhash_hashIStringView(const UHashTok key) {
+    const std::string_view* s = static_cast<std::string_view*>(key.pointer);
+    return s == nullptr ? 0 : ustr_hashICharsN(s->data(), static_cast<int32_t>(s->size()));
+}
+
 U_CAPI UBool U_EXPORT2
 uhash_equals(const UHashtable* hash1, const UHashtable* hash2){
     int32_t count1, count2, pos, i;
@@ -1051,6 +1059,29 @@ uhash_compareIChars(const UHashTok key1, const UHashTok key2) {
     return (UBool)(*p1 == *p2);
 }
 
+U_CAPI UBool U_EXPORT2
+uhash_compareIStringView(const UHashTok key1, const UHashTok key2) {
+    const std::string_view* p1 = static_cast<std::string_view*>(key1.pointer);
+    const std::string_view* p2 = static_cast<std::string_view*>(key2.pointer);
+    if (p1 == p2) {
+        return true;
+    }
+    if (p1 == nullptr || p2 == nullptr) {
+        return false;
+    }
+    const std::string_view& v1 = *p1;
+    const std::string_view& v2 = *p2;
+    if (v1.size() != v2.size()) {
+        return false;
+    }
+    for (size_t i = 0; i < v1.size(); ++i) {
+        if (uprv_tolower(v1[i]) != uprv_tolower(v2[i])) {
+            return false;
+        }
+    }
+    return true;
+}
+
 /********************************************************************
  * PUBLIC int32_t Support Functions
  ********************************************************************/

icu4c/source/common/uhash.h

@@ -694,6 +694,15 @@ uhash_hashChars(const UHashTok key);
 U_CAPI int32_t U_EXPORT2
 uhash_hashIChars(const UHashTok key);
 
+/**
+ * Generate a case-insensitive hash code for a std::string_view.
+ * Use together with uhash_compareIStringView.
+ * @param key A pointer to the std::string_view to hash.
+ * @return A hash code for the key.
+ */
+U_CAPI int32_t U_EXPORT2
+uhash_hashIStringView(const UHashTok key);
+
 /**
  * Comparator for null-terminated UChar* strings.  Use together with
  * uhash_hashUChars.
@@ -724,6 +733,16 @@ uhash_compareChars(const UHashTok key1, const UHashTok key2);
 U_CAPI UBool U_EXPORT2
 uhash_compareIChars(const UHashTok key1, const UHashTok key2);
 
+/**
+ * Case-insensitive comparator for std::string_view.
+ * Use together with uhash_hashIStringView.
+ * @param key1 A pointer to the std::string_view for comparison
+ * @param key2 A pointer to the std::string_view for comparison
+ * @return true if key1 and key2 are equal, return false otherwise.
+ */
+U_CAPI UBool U_EXPORT2
+uhash_compareIStringView(const UHashTok key1, const UHashTok key2);
+
 /********************************************************************
  * UnicodeString Support Functions
  ********************************************************************/

icu4c/source/common/unicode/urename.h

@@ -991,6 +991,7 @@
 #define uhash_compareCaselessUnicodeString U_ICU_ENTRY_POINT_RENAME(uhash_compareCaselessUnicodeString)
 #define uhash_compareChars U_ICU_ENTRY_POINT_RENAME(uhash_compareChars)
 #define uhash_compareIChars U_ICU_ENTRY_POINT_RENAME(uhash_compareIChars)
+#define uhash_compareIStringView U_ICU_ENTRY_POINT_RENAME(uhash_compareIStringView)
 #define uhash_compareLong U_ICU_ENTRY_POINT_RENAME(uhash_compareLong)
 #define uhash_compareScriptSet U_ICU_ENTRY_POINT_RENAME(uhash_compareScriptSet)
 #define uhash_compareUChars U_ICU_ENTRY_POINT_RENAME(uhash_compareUChars)
@@ -1008,6 +1009,7 @@
 #define uhash_hashCaselessUnicodeString U_ICU_ENTRY_POINT_RENAME(uhash_hashCaselessUnicodeString)
 #define uhash_hashChars U_ICU_ENTRY_POINT_RENAME(uhash_hashChars)
 #define uhash_hashIChars U_ICU_ENTRY_POINT_RENAME(uhash_hashIChars)
+#define uhash_hashIStringView U_ICU_ENTRY_POINT_RENAME(uhash_hashIStringView)
 #define uhash_hashLong U_ICU_ENTRY_POINT_RENAME(uhash_hashLong)
 #define uhash_hashScriptSet U_ICU_ENTRY_POINT_RENAME(uhash_hashScriptSet)
 #define uhash_hashUChars U_ICU_ENTRY_POINT_RENAME(uhash_hashUChars)

icu4c/source/test/intltest/itutil.cpp

@@ -46,6 +46,7 @@ extern IntlTest *createPluralMapTest();
 #if !UCONFIG_NO_FORMATTING
 extern IntlTest *createStaticUnicodeSetsTest();
 #endif
+static IntlTest *createUHashTest();
 
 void IntlTestUtilities::runIndexedTest( int32_t index, UBool exec, const char* &name, char* par )
 {
@@ -80,6 +81,7 @@ void IntlTestUtilities::runIndexedTest( int32_t index, UBool exec, const char* &
 #endif
     TESTCASE_AUTO_CLASS(LocaleBuilderTest);
     TESTCASE_AUTO_CREATE_CLASS(LocaleMatcherTest);
+    TESTCASE_AUTO_CREATE_CLASS(UHashTest);
     TESTCASE_AUTO_END;
 }
 
@@ -905,3 +907,45 @@ void EnumSetTest::TestEnumSet() {
     assertFalse(WHERE, flags.get(THING2));
     assertFalse(WHERE, flags.get(THING3));
 }
+
+/** UHashTest **/
+#include "uhash.h"
+#include <string_view>
+
+class UHashTest : public IntlTest {
+public:
+    UHashTest() = default;
+    virtual void runIndexedTest(int32_t index, UBool exec, const char*& name, char* par = nullptr) override;
+    void TestStringView();
+};
+
+static IntlTest* createUHashTest() {
+    return new UHashTest();
+}
+
+void UHashTest::runIndexedTest(int32_t index, UBool exec, const char*& name, char*  /*par*/) {
+    TESTCASE_AUTO_BEGIN;
+    TESTCASE_AUTO(TestStringView);
+    TESTCASE_AUTO_END;
+}
+
+void UHashTest::TestStringView() {
+    IcuTestErrorCode status(*this, "TestStringView");
+    LocalUHashtablePointer table(
+        uhash_open(uhash_hashIStringView, uhash_compareIStringView, nullptr, status));
+    if (status.errIfFailureAndReset("uhash_open") ||
+        !assertTrue("uhash_open", table.isValid())) {
+        return;
+    }
+
+    std::string_view key("aaa");
+    std::string_view value("bbb");
+
+    uhash_put(table.getAlias(), &key, &value, status);
+    if (status.errIfFailureAndReset("uhash_put")) return;
+
+    std::string_view lookup("AAA");
+
+    auto* result = static_cast<std::string_view*>(uhash_get(table.getAlias(), &lookup));
+    assertTrue("uhash_get", result == &value);
+}