Benchmark: ArrayBuffer - MeasureThat.net

Script Preparation code:

var str = "aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7aa34a5b6c5acb67acb5acb678acb6ac4b5a6c7b5a4c3b45a67c8b76a54cb34a5c6b7";

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 _base64ToArrayBufferFaster(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] = lookup[binary_string[i]];
    }
    return bytes.buffer;
}

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
_base64ToArrayBufferFaster(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:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.75 Safari/537.36

Browser/OS: Chrome 55 on Linux

View result in a separate tab

Test name	Executions per second
Cached decode	4673.2 Ops/sec
Simple decode	146800.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark definition and individual test cases.

**Benchmark Definition**

The benchmark is testing the performance of two functions: `_base64ToArrayBufferFaster` and `_base64ToArrayBuffer`. Both functions take a base64-encoded string as input and return an ArrayBuffer.

```json
{
    "Name": "ArrayBuffer",
    "Description": null,
    "Script Preparation Code": "...",
    ...
}
```

The script preparation code sets up some variables:

* `str`: a long, base64-encoded string.
* `chars`: a string containing all the characters used in the base64 encoding (A-Z, a-z, 0-9, +).
* A lookup table (`lookup`) is created to map each character to its index in the `chars` string.

**Individual Test Cases**

There are two test cases:

1. **Cached decode**: The benchmark definition uses `_base64ToArrayBufferFaster(str);`. This function appears to be optimized for performance, as it uses a lookup table to quickly find the indices of the characters in the input string.
2. **Simple decode**: The benchmark definition uses `_base64ToArrayBuffer(str);`. This function is less optimized than the cached version and simply converts each character to its corresponding index in the `chars` string.

**Pros and Cons**

* **Cached decode**:
	+ Pros: faster execution time, as it uses a lookup table for optimal performance.
	+ Cons: more complex implementation, which may increase maintenance costs.
* **Simple decode**:
	+ Pros: simpler implementation, easier to understand and maintain.
	+ Cons: slower execution time due to the lack of optimization.

**Other Considerations**

* The benchmark is using `window.atob` to convert the base64-encoded string to a binary string. This function is part of the Web API and provides a convenient way to perform base64 decoding.
* The test cases are measuring the performance of the functions in different browsers (Chrome 55). This allows users to compare the performance of each function across different platforms.

**Alternatives**

If you wanted to create similar benchmarks for other base64 encoding algorithms or approaches, you could consider using:

1. **Other Web API functions**: Instead of `window.atob`, you could use other functions like `btoa` (binary-safe atob) or `atob` with a custom implementation.
2. **Native libraries**: You could use native libraries like libbase64 or base64-js to perform base64 encoding and decoding.
3. **Third-party libraries**: There are many third-party libraries available that provide optimized base64 encoding and decoding implementations.

Note that each alternative has its own pros and cons, which would need to be carefully considered when creating a benchmark.

Related benchmarks:

ArrayBuffer (version: 0)

Comparing performance of: Cached decode vs Simple decode

Created: 8 years ago by: Guest

Jump to the latest result

Cached decode

Simple decode

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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