gosax

gosax is a Go library for XML SAX (Simple API for XML) parsing, supporting read-only functionality. This library is designed for efficient and memory-conscious XML parsing, drawing inspiration from various sources to provide a performant parser.

Features

• Read-only SAX parsing: Stream and process XML documents without loading the entire document into memory.
• Efficient parsing: Utilizes techniques inspired by quick-xml and pkg/json for high performance.
• SWAR (SIMD Within A Register): Optimizations for fast text processing, inspired by memchr.
• Compatibility with encoding/xml: Includes utility functions to bridge gosax types with encoding/xml types, facilitating easy integration with existing code that uses the standard library.

Benchmark

goos: darwin
goarch: arm64
pkg: github.com/orisano/gosax
BenchmarkReader_Event-12    	       5	 211845800 ns/op	1103.30 MB/s	 2097606 B/op	       6 allocs/op

Installation

To install gosax, use go get:

go get github.com/orisano/gosax

Usage

Here is a basic example of how to use gosax to parse an XML document:

package main

import (
	"fmt"
	"log"
	"strings"

	"github.com/orisano/gosax"
)

func main() {
	xmlData := `<root><element>Value</element></root>`
	reader := strings.NewReader(xmlData)

	r := gosax.NewReader(reader)
	for {
		e, err := r.Event()
		if err != nil {
			log.Fatal(err)
		}
		if e.Type() == gosax.EventEOF {
			break
		}
		fmt.Println(string(e.Bytes))
	}
	// Output:
	// <root>
	// <element>
	// Value
	// </element>
	// </root>
}

Bridging with encoding/xml

gosax provides utility functions to convert its types to encoding/xml types:

This allows for easy integration with existing code that uses the standard library's XML package.

Important Note for encoding/xml Users:

When migrating from encoding/xml to gosax, be aware that there is a significant difference in how self-closing tags are handled. To achieve behavior similar to encoding/xml, you must set gosax.Reader.EmitSelfClosingTag to true. This ensures that self-closing tags are properly recognized and handled as distinct events.

import (
    "encoding/xml"
    "github.com/orisano/gosax"
)

// ... 

event, _ := r.Event()
if event.Type() == gosax.EventStart {
    startElement, err := gosax.StartElement(event.Bytes)
    // Now you can use startElement as an xml.StartElement
    // ...
}

License

This library is licensed under the terms specified in the LICENSE file.

Acknowledgements

gosax is inspired by the following projects and resources:

• Dave Cheney's GopherCon SG 2023 Talk
• quick-xml
• memchr (SWAR part)

Contributing

Contributions are welcome! Please fork the repository and submit pull requests.

Contact

For any questions or feedback, feel free to open an issue on the GitHub repository.