StringUtil: Add Ellipsise()

src/common-tests/CMakeLists.txt

@@ -3,6 +3,7 @@ add_executable(common-tests
   file_system_tests.cpp
   path_tests.cpp
   rectangle_tests.cpp
+  string_tests.cpp
 )
 
 target_link_libraries(common-tests PRIVATE common gtest gtest_main)

src/common-tests/common-tests.vcxproj

@@ -7,6 +7,7 @@
     <ClCompile Include="file_system_tests.cpp" />
     <ClCompile Include="path_tests.cpp" />
     <ClCompile Include="rectangle_tests.cpp" />
+    <ClCompile Include="string_tests.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\dep\googletest\googletest.vcxproj">

src/common-tests/common-tests.vcxproj.filters

@@ -6,5 +6,6 @@
     <ClCompile Include="bitutils_tests.cpp" />
     <ClCompile Include="file_system_tests.cpp" />
     <ClCompile Include="path_tests.cpp" />
+    <ClCompile Include="string_tests.cpp" />
   </ItemGroup>
 </Project>

src/common-tests/string_tests.cpp

@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2019-2023 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
+
+#include "common/string_util.h"
+#include <gtest/gtest.h>
+
+TEST(StringUtil, Ellipsise)
+{
+  ASSERT_EQ(StringUtil::Ellipsise("HelloWorld", 6, "..."), "Hel...");
+  ASSERT_EQ(StringUtil::Ellipsise("HelloWorld", 7, ".."), "Hello..");
+  ASSERT_EQ(StringUtil::Ellipsise("HelloWorld", 20, ".."), "HelloWorld");
+  ASSERT_EQ(StringUtil::Ellipsise("", 20, "..."), "");
+  ASSERT_EQ(StringUtil::Ellipsise("Hello", 10, "..."), "Hello");
+}
+
+TEST(StringUtil, EllipsiseInPlace)
+{
+  std::string s;
+  s = "HelloWorld";
+  StringUtil::EllipsiseInPlace(s, 6, "...");
+  ASSERT_EQ(s, "Hel...");
+  s = "HelloWorld";
+  StringUtil::EllipsiseInPlace(s, 7, "..");
+  ASSERT_EQ(s, "Hello..");
+  s = "HelloWorld";
+  StringUtil::EllipsiseInPlace(s, 20, "..");
+  ASSERT_EQ(s, "HelloWorld");
+  s = "";
+  StringUtil::EllipsiseInPlace(s, 20, "...");
+  ASSERT_EQ(s, "");
+  s = "Hello";
+  StringUtil::EllipsiseInPlace(s, 10, "...");
+  ASSERT_EQ(s, "Hello");
+}

src/common/string_util.cpp

@@ -1,7 +1,9 @@
-// SPDX-FileCopyrightText: 2019-2022 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-FileCopyrightText: 2019-2023 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
 
+#include "assert.h"
 #include "string_util.h"
+
 #include <cctype>
 #include <codecvt>
 #include <cstdio>
@@ -395,6 +397,47 @@ invalid:
   return 1;
 }
 
+std::string StringUtil::Ellipsise(const std::string_view& str, u32 max_length, const char* ellipsis /*= "..."*/)
+{
+  std::string ret;
+  ret.reserve(max_length);
+
+  const u32 str_length = static_cast<u32>(str.length());
+  const u32 ellipsis_len = static_cast<u32>(std::strlen(ellipsis));
+  DebugAssert(ellipsis_len > 0 && ellipsis_len <= max_length);
+
+  if (str_length > max_length)
+  {
+    const u32 copy_size = std::min(str_length, max_length - ellipsis_len);
+    if (copy_size > 0)
+      ret.append(str.data(), copy_size);
+    if (copy_size != str_length)
+      ret.append(ellipsis);
+  }
+  else
+  {
+    ret.append(str);
+  }
+
+  return ret;
+}
+
+void StringUtil::EllipsiseInPlace(std::string& str, u32 max_length, const char* ellipsis /*= "..."*/)
+{
+  const u32 str_length = static_cast<u32>(str.length());
+  const u32 ellipsis_len = static_cast<u32>(std::strlen(ellipsis));
+  DebugAssert(ellipsis_len > 0 && ellipsis_len <= max_length);
+
+  if (str_length > max_length)
+  {
+    const u32 keep_size = std::min(static_cast<u32>(str.length()), max_length - ellipsis_len);
+    if (keep_size != str_length)
+      str.erase(keep_size);
+
+    str.append(ellipsis);
+  }
+}
+
 size_t StringUtil::DecodeUTF8(const std::string_view& str, size_t offset, char32_t* ch)
 {
   return DecodeUTF8(str.data() + offset, str.length() - offset, ch);

src/common/string_util.h

@@ -271,6 +271,10 @@ size_t DecodeUTF8(const void* bytes, size_t length, char32_t* ch);
 size_t DecodeUTF8(const std::string_view& str, size_t offset, char32_t* ch);
 size_t DecodeUTF8(const std::string& str, size_t offset, char32_t* ch);
 
+// Replaces the end of a string with ellipsis if it exceeds the specified length.
+std::string Ellipsise(const std::string_view& str, u32 max_length, const char* ellipsis = "...");
+void EllipsiseInPlace(std::string& str, u32 max_length, const char* ellipsis = "...");
+
 /// Strided memcpy/memcmp.
 ALWAYS_INLINE static void StrideMemCpy(void* dst, std::size_t dst_stride, const void* src, std::size_t src_stride,
                                        std::size_t copy_size, std::size_t count)