Add a nonstd::camel_case util function

microsoft · Jul 10, 2024 · 39f319e · 39f319e
1 parent 8294adf
commit 39f319e
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diff --git a/include/ccf/ds/nonstd.h b/include/ccf/ds/nonstd.h
@@ -6,11 +6,15 @@
 #include <array>
 #include <cctype>
 #include <filesystem>
+#include <regex>
 #include <string>
 #include <string_view>
 #include <type_traits>
 #include <vector>
 
+#define FMT_HEADER_ONLY
+#include <fmt/format.h>
+
 /**
  * This file defines various type traits and utils that are not available in the
  * standard library. Some are added in future versions of the standard library,
@@ -288,4 +292,32 @@ namespace ccf::nonstd
 
     return resolved.lexically_normal().string();
   }
+
+  static inline std::string camel_case(
+    std::string s,
+    // Should the first character be upper-cased?
+    bool camel_first = true,
+    // Regex fragment to identify which characters should be upper-cased, by
+    // matching a separator preceding them. Default is to match any
+    // non-alphanumeric character
+    const std::string& separator_regex = "[^[:alnum:]]")
+  {
+    // Replacement is always a 1-character string
+    std::string replacement(1, '\0');
+
+    std::string prefix_matcher =
+      camel_first ? fmt::format("(^|{})", separator_regex) : separator_regex;
+    std::regex re(prefix_matcher + "[a-z]");
+    std::smatch match;
+
+    while (std::regex_search(s, match, re))
+    {
+      // Replacement is the upper-casing of the final character from the match
+      replacement[0] = std::toupper(match.str()[match.length() - 1]);
+
+      s = s.replace(match.position(), match.length(), replacement);
+    }
+
+    return s;
+  }
 }
diff --git a/src/ds/test/nonstd.cpp b/src/ds/test/nonstd.cpp
@@ -319,4 +319,65 @@ TEST_CASE("envvars" * doctest::test_suite("nonstd"))
       fmt::format("/{}/{}", test_value1, test_value2) ==
       ccf::nonstd::expand_envvars_in_path("/$TEST_ENV_VAR1/$TEST_ENV_VAR2"));
   }
+}
+
+TEST_CASE("camel_case" * doctest::test_suite("nonstd"))
+{
+  {
+    INFO("Default separator");
+    REQUIRE(ccf::nonstd::camel_case("") == "");
+    REQUIRE(ccf::nonstd::camel_case("abc") == "Abc");
+    REQUIRE(ccf::nonstd::camel_case("abc", false) == "abc");
+
+    REQUIRE(ccf::nonstd::camel_case("hello world") == "HelloWorld");
+    REQUIRE(ccf::nonstd::camel_case("hello world", false) == "helloWorld");
+
+    REQUIRE(
+      ccf::nonstd::camel_case(
+        "camel-with.many/many!many_many,many|many$separators") ==
+      "CamelWithManyManyManyManyManyManySeparators");
+    REQUIRE(
+      ccf::nonstd::camel_case(
+        "camel-with.many/many!many_many,many|many$separators", false) ==
+      "camelWithManyManyManyManyManyManySeparators");
+
+    REQUIRE(
+      ccf::nonstd::camel_case("1handling2of3.numbers") ==
+      "1handling2of3Numbers");
+    REQUIRE(
+      ccf::nonstd::camel_case("1handling2of3.numbers", false) ==
+      "1handling2of3Numbers");
+
+    REQUIRE(
+      ccf::nonstd::camel_case(
+        "camel_With-Existing_mixed-casing_Is-1Perhaps_2Surprising") ==
+      "Camel_With-ExistingMixedCasing_Is-1Perhaps_2Surprising");
+    REQUIRE(
+      ccf::nonstd::camel_case(
+        "camel_With-Existing_mixed-casing_Is-1Perhaps_2Surprising", false) ==
+      "camel_With-ExistingMixedCasing_Is-1Perhaps_2Surprising");
+  }
+  {
+    INFO("Custom separators");
+    REQUIRE(ccf::nonstd::camel_case("hello world", true, "_") == "Hello world");
+    REQUIRE(
+      ccf::nonstd::camel_case("hello world", false, "_") == "hello world");
+
+    REQUIRE(ccf::nonstd::camel_case("hello_world", true, "_") == "HelloWorld");
+    REQUIRE(ccf::nonstd::camel_case("hello_world", false, "_") == "helloWorld");
+
+    REQUIRE(
+      ccf::nonstd::camel_case("what-about-/mixed/separators", true, "-") ==
+      "WhatAbout-/mixed/separators");
+    REQUIRE(
+      ccf::nonstd::camel_case("what-about-/mixed/separators", false, "-") ==
+      "whatAbout-/mixed/separators");
+
+    REQUIRE(
+      ccf::nonstd::camel_case("what-about-/mixed/separators", true, "/") ==
+      "What-about-MixedSeparators");
+    REQUIRE(
+      ccf::nonstd::camel_case("what-about-/mixed/separators", false, "/") ==
+      "what-about-MixedSeparators");
+  }
 }