Add tests and locale invariant string equal function in support of the 'extensible enum' guideline. (#197)

* Add locale invariant string equal function in support of the 'extensible enum' guideline.

* Resolve gcc narrowing warning.

* Fix case flipping table to go the correct direction 😳

* organize tests and add one test for invariant locale compare as exaple

* Add more test cases.

* Move to Details namespace.

sdk/core/azure-core/CMakeLists.txt

@@ -9,7 +9,7 @@ set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
 set(CURL_MIN_REQUIRED_VERSION 7.4)
-find_package(CURL ${CURL_MIN_REQUIRED_VERSION} CONFIG) 
+find_package(CURL ${CURL_MIN_REQUIRED_VERSION} CONFIG)
 if(NOT CURL_FOUND)
   find_package(CURL ${CURL_MIN_REQUIRED_VERSION} REQUIRED)
 endif()
@@ -18,14 +18,15 @@ add_library (
   ${TARGET_NAME}
   src/context.cpp
   src/credentials/credentials.cpp
+  src/http/curl/curl.cpp
   src/credentials/policy/policies.cpp
   src/http/policy.cpp
   src/http/request.cpp
   src/http/response.cpp
   src/http/body_stream.cpp
   src/http/url.cpp
-  src/http/curl/curl.cpp
   src/http/winhttp/win_http_transport.cpp
+  src/strings.cpp
   )
 
 target_include_directories (${TARGET_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/inc> $<INSTALL_INTERFACE:include/az_core>)

sdk/core/azure-core/inc/azure.hpp

@@ -3,12 +3,13 @@
 
 #pragma once
 
+#include <string>
 #include <internal/contract.hpp>
 
 #define AZURE_UNREFERENCED_PARAMETER(x) ((void) (x));
 
-namespace Azure { namespace Core {
+namespace Azure { namespace Core { namespace Details {
 
+bool LocaleInvariantCaseInsensitiveEqual(const std::string& lhs, const std::string& rhs) noexcept;
 
-
-}} // namespace Azure::Core
+}}} // namespace Azure::Core::Details

sdk/core/azure-core/src/strings.cpp

@@ -0,0 +1,81 @@
+#include <algorithm>
+#include <azure.hpp>
+
+namespace {
+// The locale invariant case table is generated with the following program
+// followed by clang-format.
+#if 0
+// generate with
+// cl /EHsc /W4 /WX .\casetable.cpp && .\casetable.exe
+#include <iterator>
+#include <numeric>
+#include <stdio.h>
+
+const int *PrintUpToLine(const int *first, const int *const last) {
+    if (first != last) {
+        printf("0x%02X,", *first);
+        for (ptrdiff_t idx = 1; ++first != last && idx < 8; ++idx) {
+            printf(" 0x%02X,", *first);
+        }
+
+        puts("");
+    }
+
+    return first;
+}
+
+int main() {
+    using namespace std;
+    int characters[256];
+    iota(begin(characters), end(characters), 0);
+    for (ptrdiff_t idx = 'a'; idx <= 'z'; ++idx) {
+        characters[idx] = idx - ('a' - 'A');
+    }
+
+    const int *first = begin(characters);
+    const auto last = first + size(characters);
+    printf("{");
+    while (first != last) {
+        first = PrintUpToLine(first, last);
+    }
+    printf("};");
+}
+
+#endif
+
+const unsigned char c_LocaleInvariantUppercaseTable[256] = {
+    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
+    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
+    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
+    0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+    0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
+    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
+    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
+    0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
+    0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
+    0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
+    0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
+    0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
+    0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
+};
+} // unnamed namespace
+
+namespace Azure { namespace Core { namespace Details {
+
+  bool LocaleInvariantCaseInsensitiveEqual(const std::string& lhs, const std::string& rhs) noexcept
+  {
+    return std::equal(
+        lhs.begin(),
+        lhs.end(),
+        rhs.begin(),
+        rhs.end(),
+        [](const char left, const char right) noexcept {
+          return c_LocaleInvariantUppercaseTable[static_cast<unsigned char>(left)]
+              == c_LocaleInvariantUppercaseTable[static_cast<unsigned char>(right)];
+        });
+  }
+
+}}} // namespace Azure::Core::Details

sdk/core/azure-core/test/CMakeLists.txt

@@ -13,7 +13,8 @@ add_executable (
      ${TARGET_NAME}
      main.cpp
      nullable.cpp
-     http.cpp)
+     http.cpp
+     string.cpp)
 
 target_link_libraries(${TARGET_NAME} PRIVATE azure-core)
 add_gtest(${TARGET_NAME})

sdk/core/azure-core/test/main.cpp

@@ -7,4 +7,4 @@ int main(int argc, char** argv)
 {
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
-}
+}

sdk/core/azure-core/test/string.cpp

@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+#include "gtest/gtest.h"
+#include <azure.hpp>
+#include <string>
+
+TEST(String, invariantCompare)
+{
+  using Azure::Core::Details::LocaleInvariantCaseInsensitiveEqual;
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("", ""));
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("a", "a"));
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("a", "A"));
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("aa", "AA"));
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("aA", "AA"));
+  EXPECT_TRUE(LocaleInvariantCaseInsensitiveEqual("abc", "ABC"));
+  EXPECT_FALSE(LocaleInvariantCaseInsensitiveEqual("", "a"));
+  EXPECT_FALSE(LocaleInvariantCaseInsensitiveEqual("a", ""));
+  EXPECT_FALSE(LocaleInvariantCaseInsensitiveEqual("a", "aA"));
+  EXPECT_FALSE(LocaleInvariantCaseInsensitiveEqual("abc", "abcd"));
+}