json.cpp is a lightweight JSON parsing and serialization library specifically designed for classic C++. Unlike modern alternatives, json.cpp stands out for its exceptional performance speed and simplicity. This library is inspired by the need for a more efficient solution compared to libraries like nlohmann/json. Here’s why json.cpp is the superior choice:

• Lightning-Fast Compilation: json.cpp compiles approximately 10x faster than nlohmann's library. For instance, processing a simple parse operation with nlohmann would take at least 1200 ms. In contrast, json.cpp achieves compilation in about 120 ms, largely due to minimal overhead from dependencies on traditional C++ Standard Library components such as <string>, <map>, and <vector>.

• Minimalistic Code Size: With only 233 lines in json.h and 1,303 lines in json.cpp, json.cpp is 10x smaller than the nlohmann equivalent, which has over 24,766 lines. This reduction makes json.cpp easier to customize and understand, allowing developers to reason about its behavior efficiently to ensure it fits their specific production needs.

• Enhanced Test Suite Compliance: json.cpp achieves superior conformance with the JSONTestSuite, passing all tests comprehensively. Conversely, nlohmann’s library does not fully comply with the suite's standards, ensuring json.cpp remains robust and reliable.

Key Features of json.cpp

To make full use of json.cpp, you will need:

1. json.h
2. json.cpp
3. Google’s double-conversion library

The integration with the double-conversion library allows for highly accurate serialization of 32-bit floating-point numbers, crucial for applications like HTTP servers that handle embeddings. This feature minimizes inaccuracies experienced with other JSON libraries, ensuring that floats retain their precision when serialized.

Sample Usage

Here’s a simple example showcasing how to utilize json.cpp:

#include "json.h"

int main() {
    Json jsonData;
    jsonData.setFloatValue(0.289f);
    std::string jsonString = jsonData.toString();
    std::cout << jsonString; // Outputs accurate float representation
}

With a focus on speed and simplicity, json.cpp is the ideal choice for C++ developers seeking an efficient yet straightforward JSON handling library.