Strings

String representation, System::String utilities, StringBuilder, and encoding.

The String Type: std::string

In sharp-runtime, C# string maps directly to std::string. There is no custom String object type. std::string is UTF-8 by convention, though the library does not enforce encoding — it relies on the content passed by the caller.

In SharpRuntimeHelper.hpp, a type alias is provided for porting convenience:

namespace SharpRuntime {
    using String = std::string;  // C# string → std::string
}

System::String — Static Utility Class

include/System/String.hpp | src/System/String.cpp

System::String is a deleted-constructor static class — it cannot be instantiated. It provides static helper methods that mirror commonly-used C# string instance methods.

Status: Partial — only a useful subset is implemented.

Method	Description	Status
`Split(string, char)`	Splits by a single character delimiter; returns `vector<string>`	Implemented
`IsEmpty(string)`	True if string is empty	Implemented
`IsNullOrEmpty(string)`	True if string is empty (null not possible in C++, same as IsEmpty)	Implemented
`StartsWith(string, string)`	True if string starts with prefix	Implemented
`Format(string, intcs)`	Formats with one integer argument	Implemented
`Format(string, string)`	Formats with one string argument	Implemented
`ToString(intcs, int, char)`	Zero-pads integer to given width	Implemented

using namespace System;

auto parts = String::Split("a,b,c", ',');   // {"a", "b", "c"}
bool empty = String::IsNullOrEmpty("");      // true
bool sw    = String::StartsWith("hello", "hel"); // true
std::string fmt = String::Format("{0} items", 5); // "5 items"

ℹ Note on C# string methods

C# string has many instance methods (ToLower(), Trim(), Contains(), etc.) that are NOT in System::String. For these, use std::string methods directly: s.find(), s.substr(), etc., or the C++20/23 standard library.

System::Text::StringBuilder

include/System/Text/StringBuilder.hpp | src/System/Text/StringBuilder.cpp

A mutable string buffer for efficient string construction. Backed by an internal std::string.

Status: Partial

System::Text::StringBuilder sb;
sb.Append("Hello");
sb.Append(", ");
sb.Append("World");
std::string result = sb.ToString();  // "Hello, World"
sb.Clear();

// Insert, Remove, Replace are also implemented
sb.Append("abcdef");
sb.Insert(2, "XY");    // "abXYcdef"
sb.Remove(0, 2);       // "XYcdef"
sb.Replace("cd", "ZZ"); // "XYZZef"

String Comparison

include/System/StringComparison.hpp | include/System/StringComparer.hpp

Headers for StringComparison enum (OrdinalIgnoreCase, CurrentCulture, etc.) and StringComparer class exist as compatibility types.

Needs verification

The extent to which StringComparer comparison modes are fully implemented needs verification from the source headers.

Encoding

include/System/Text/Encoding.hpp

Abstract encoding base class with static accessors for common encodings:

Encoding::UTF8 → UTF8Encoding
Encoding::ASCII → ASCIIEncoding
Encoding::Latin1 → Latin1Encoding
Encoding::Unicode → UnicodeEncoding (UTF-16)
Encoding::UTF32 → UTF32Encoding

Character Type

C# char (UTF-16, 16-bit) maps to SharpRuntime::charcs = char16_t. In practice, most string operations in the library use std::string (byte strings) rather than std::u16string.

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