TString

TString is a custom C++ string implementation designed for efficient memory management by utilizing a buffer size that is always the closest power of two to the actual string size. This approach optimizes memory usage and provides dynamic growth. The library also includes a TStringConst class, which can be used for compile-time string operations, fully leveraging C++20's constexpr capabilities.

Features

• Dynamic Buffer Management: Allocates memory with buffer sizes that are powers of two, ensuring efficient memory management and reducing reallocations.
• String Operations: Provides common string operations, including concatenation, substring extraction, finding substrings, splitting, and appending.
• Move Semantics: Implements both copy and move constructors to efficiently manage resources during object transfers.
• Compile-time String Support: TStringConst allows compile-time operations for strings using constexpr in C++20.
• Utility Methods: Includes utility methods such as clear(), empty(), split(), and hash support.
• User-defined Literals: Supports the ""_T user-defined literal for easy creation of TString instances.
• Custom Reserve: Allows pre-allocation of memory to improve efficiency for operations involving large or frequent modifications.
• Benchmarking Support: Includes a benchmark suite comparing TString to std::string in various scenarios.

Getting Started

Prerequisites

• C++20 compatible compiler
• Microsoft Visual Studio, GCC, or Clang
• xmake build system

Installation

To use TString, clone the repository and include TString.hpp in your project:

# Clone the repository
git clone https://github.com/yourusername/TString.git

Include TString.hpp in your code:

#include "include/TString.hpp"

You can also add TString as a package through xmake by adding the TabNahida/repo-xmake repository:

add_repositories("tab-repo https://github.com/TabNahida/repo-xmake.git")
add_requires("tstring")

Then, include it in your target:

target("example")
    set_kind("binary")
    add_files("src/*.cpp")
    add_packages("tstring")

Example Usage

#include "TString.hpp"
#include <iostream>

int main() {
    TString myStr = "Hello, ";
    myStr.append("World!");
    std::cout << myStr << std::endl;  // Output: Hello, World!

    TString subStr = myStr.substr(0, 5);
    std::cout << subStr << std::endl;  // Output: Hello

    size_t found = myStr.find("World");
    if (found != TString::npos) {
        std::cout << "Found 'World' at position: " << found << std::endl;
    }

    TString combinedStr = myStr + " Again!";
    std::cout << combinedStr << std::endl;  // Output: Hello, World! Again!

    return 0;
}

Build with xmake

This project uses xmake to simplify the build process. To build and run tests, use the following commands:

1. Make sure xmake is installed.
2. Navigate to the project root directory.
3. Run the following commands:

# Configure the project
xmake f -c

# Build the project
xmake

# Run the built target
xmake run Test

Here is the xmake.lua configuration file used for the project:

add_languages("cxx20")

target("tstring")
    set_kind("static")
    add_files("src/TString.cpp")
    add_headerfiles("include/TString.hpp")
    add_includedirs("include")
target_end()

target("MainTest")
    set_kind("binary")
    add_files("src/main.cpp")
    add_deps("tstring")
    add_includedirs("include")
target_end()

target("BenchMark")
    set_kind("binary")
    add_files("src/benchmark.cpp")
    add_deps("tstring")
    add_includedirs("include")
target_end()

Features in Detail

• Dynamic Buffer Growth: The buffer dynamically grows by powers of two, reducing the frequency of memory allocations during string operations.
• Move Semantics: The implementation includes move constructors and assignment operators, allowing efficient transfers of resources without unnecessary copies.
• Compile-time Strings: TStringConst is designed to provide compile-time constant string operations using constexpr, enabling compile-time validation and manipulation.
• Custom Reserve Functionality: The reserve function allows pre-allocating buffer space to prevent frequent reallocations when working with large strings or repeated appending operations.
• Hash Support: TString can be used in hash containers like std::unordered_set and std::unordered_map by leveraging the std::hash specialization.

Benchmark Results

TString has been benchmarked against std::string across various common operations. The benchmark tests include construction, copy, append, substring, and find operations with both short and long strings. Below is a summary of some of the benchmark results:

Operation	TString (ms)	std::string (ms)
Construction (short string)	91	245
Construction (long string)	173	871
Copy (short string)	66	156
Append (single char)	14	19
Clear	76	109
Find (short string)	11	30
Find (long string)	8	14
Substring (short string)	71	67
Substring (long string)	73	165

Note: The benchmarks were run with default settings on an Intel Core Ultra 5 125H processor with 32GB LPDDR5X 7467MHz memory. The results may vary depending on hardware and compiler optimizations. For some operations, such as finding a substring in very long strings, TString and std::string may show different performance characteristics due to the algorithms and optimizations used.

Directory Structure

TString/
├── include/
│   └── TString.hpp
├── src/
│   └── main.cpp
├── xmake.lua
└── README.md

Contributing

Contributions are welcome! If you have ideas for improving TString, feel free to open an issue or submit a pull request.

License

This project is licensed under the MIT License.