From 48f121b6d429efa285505359663f4c2af6c84b83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ho=C5=99e=C5=88ovsk=C3=BD?=
 <martin.horenovsky@gmail.com>
Date: Mon, 22 Sep 2025 22:41:14 +0200
Subject: [PATCH] WIP

---
 .../IntrospectiveTests/ToString.tests.cpp     | 73 ++++++++++++++++++-
 1 file changed, 71 insertions(+), 2 deletions(-)

diff --git a/tests/SelfTest/IntrospectiveTests/ToString.tests.cpp b/tests/SelfTest/IntrospectiveTests/ToString.tests.cpp
index be639ce3..8593e0d5 100644
--- a/tests/SelfTest/IntrospectiveTests/ToString.tests.cpp
+++ b/tests/SelfTest/IntrospectiveTests/ToString.tests.cpp
@@ -6,11 +6,13 @@
 
 // SPDX-License-Identifier: BSL-1.0
 
+#include <catch2/benchmark/catch_benchmark.hpp>
+#include <catch2/catch_template_test_macros.hpp>
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
 #include <catch2/internal/catch_enum_values_registry.hpp>
 #include <catch2/matchers/catch_matchers_string.hpp>
 #include <catch2/matchers/catch_matchers_vector.hpp>
-#include <catch2/catch_test_macros.hpp>
-#include <catch2/catch_template_test_macros.hpp>
 
 #include <chrono>
 
@@ -139,3 +141,70 @@ TEST_CASE( "Exception thrown inside stringify does not fail the test", "[toStrin
     ThrowsOnStringification tos;
     CHECK( tos == tos );
 }
+
+namespace {
+    [[maybe_unused]]
+    std::string convertIntoString( Catch::StringRef string,
+                                   bool escapeInvisibles ) {
+        std::string ret;
+        // This is enough for the "don't escape invisibles" case, and a good
+        // lower bound on the "escape invisibles" case.
+        ret.reserve( string.size() + 2 );
+
+        if ( !escapeInvisibles ) {
+            ret += '"';
+            ret += string;
+            ret += '"';
+            return ret;
+        }
+
+        size_t last_start = 0;
+        auto write_to = [&]( size_t idx ) {
+            if ( last_start < idx ) {
+                //ret.append( string.data() + last_start, idx - last_start );
+                ret += string.substr( last_start, idx - last_start );
+            }
+            last_start = idx + 1;
+        };
+
+        ret += '"';
+        for ( size_t i = 0; i < string.size(); ++i ) {
+            const char c = string[i];
+            if (c == '\r' || c == '\n' || c == '\t' || c == '\f') {
+                write_to( i );
+                if ( c == '\r' ) { ret.append( "\\r" ); }
+                if ( c == '\n' ) { ret.append( "\\n" ); }
+                if ( c == '\t' ) { ret.append( "\\t" ); }
+                if ( c == '\f' ) { ret.append( "\\f" ); }
+            }
+        }
+        write_to( string.size() );
+        ret += '"';
+
+        return ret;
+    }
+}
+
+
+TEST_CASE( "string escaping benchmark", "[toString][!benchmark]" ) {
+    const auto input_length = GENERATE( as<size_t>{}, 10, 100, 10'000, 100'000 );
+    std::string test_input( input_length, 'a' );
+    BENCHMARK( "no-escape string, no-escaping, len=" +
+               std::to_string( input_length ) ) {
+        return Catch::Detail::convertIntoString( test_input, false );
+    };
+    BENCHMARK( "no-escape string, escaping, len=" +
+               std::to_string( input_length ) ) {
+        return Catch::Detail::convertIntoString( test_input, true );
+    };
+
+    std::string escape_input( input_length, '\r' );
+    BENCHMARK( "full escape string, no-escaping, len=" +
+               std::to_string( input_length ) ) {
+        return Catch::Detail::convertIntoString( escape_input, false );
+    };
+    BENCHMARK( "full escape string, escaping, len=" +
+               std::to_string( input_length ) ) {
+        return Catch::Detail::convertIntoString( escape_input, true );
+    };
+}