Benchmark: ArrayBuffer - MeasureThat.net

Script Preparation code:

var str = "aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7";

var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

// Use a lookup table to find the index.
var lookup = new Uint8Array(256);
for (var i = 0; i < chars.length; i++) {
  lookup[chars.charCodeAt(i)] = i;
}

function decode(base64) {
    var bufferLength = base64.length * 0.75,
    len = base64.length, i, p = 0,
    encoded1, encoded2, encoded3, encoded4;

    if (base64[base64.length - 1] === "=") {
      bufferLength--;
      if (base64[base64.length - 2] === "=") {
        bufferLength--;
      }
    }

    var arraybuffer = new ArrayBuffer(bufferLength),
    bytes = new Uint8Array(arraybuffer);

    for (i = 0; i < len; i+=4) {
      encoded1 = lookup[base64.charCodeAt(i)];
      encoded2 = lookup[base64.charCodeAt(i+1)];
      encoded3 = lookup[base64.charCodeAt(i+2)];
      encoded4 = lookup[base64.charCodeAt(i+3)];

      bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
      bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
      bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
    }

    return arraybuffer;
  };

function _base64ToArrayBuffer(base64) {
    var binary_string =  window.atob(base64);
    var len = binary_string.length;
    var bytes = new Uint8Array( len );
    for (var i = 0; i < len; i++)        {
        bytes[i] = binary_string.charCodeAt(i);
    }
    return bytes.buffer;
}

Tests:

Cached decode
decode(str);
Simple decode
_base64ToArrayBuffer(str);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Cached decode
Simple decode

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explain what's being tested on MeasureThat.net.

**Benchmark Definition Json**

The provided JSON represents a benchmark for testing the performance of two functions: `decode` and `_base64ToArrayBuffer`. The `decode` function is responsible for decoding a base64-encoded string, while `_base64ToArrayBuffer` simply converts a base64-encoded string to an array buffer.

**Options Compared**

There are two options being compared:

1. **Simple Decode**: This option uses the `_base64ToArrayBuffer` function, which is implemented using the `atob()` method in modern browsers.
2. **Cached Decode**: This option uses a custom implementation of the `decode` function, which appears to be a cached version of the original `decode` function.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Simple Decode**:
	* Pros: This approach is simple and easy to implement.
	* Cons: It relies on the browser's built-in `atob()` method, which might not be as efficient as a custom implementation.
2. **Cached Decode**:
	* Pros: This approach can potentially be faster due to the caching mechanism, but it also requires more code and complexity.
	* Cons: If the caching is not done correctly, it could lead to performance issues or even crashes.

**Library and Purpose**

The `atob()` method is a built-in function in modern browsers that converts a base64-encoded string to a binary string. It's used in the `_base64ToArrayBuffer` function to perform the conversion.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in this benchmark, except for the use of `atob()` which is a built-in method in modern browsers.

**Other Considerations**

When dealing with browser-specific code like this, it's essential to consider factors such as:

* Browser support: Make sure the benchmark works across different browsers and versions.
* Performance overhead: Consider any additional performance overhead due to things like caching or DOM manipulation.
* Code complexity: Balance simplicity with performance.

**Alternatives**

If you're looking for alternative approaches to measure base64 decoding performance, here are a few options:

1. **Use a dedicated library**: There are libraries like `base64-js` that provide optimized implementations of base64 decoding algorithms.
2. **Implement a custom algorithm**: You could implement your own base64 decoding algorithm using native code or WebAssembly (WASM) for better performance.
3. **Use an existing benchmark**: MeasureThat.net itself is just one example of a benchmarking platform; you can explore other options like Benchmark.js, jsperf, or even Google's V8 benchmark.

In summary, the benchmark on MeasureThat.net compares two approaches to base64 decoding: using the `_base64ToArrayBuffer` function and implementing a cached version of the `decode` function. While there are pros and cons to each approach, using a custom implementation with caching can potentially lead to better performance.

Related benchmarks:

ArrayBuffer (version: 0)

Comparing performance of: Cached decode vs Simple decode

Created: 9 years ago by: Guest

Jump to the latest result

Cached decode

Simple decode

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):