SparseXML

Minimal XML Parser for Embedded Systems

SparseXML is a lightweight XML parser designed for resource-constrained embedded systems. It provides SAX-style event-driven parsing with minimal memory footprint (~1KB) and zero external dependencies.

Integration

Simply copy these 3 files to your project:

• sparsexml.h – Public API header
• sparsexml-priv.h – Private definitions
• sparsexml.c – Implementation

Then include sparsexml.h in your code. No build system or external dependencies required.

Features

• Minimal Memory: Fixed 1KB buffer, no dynamic allocation
• Event-Driven: SAX-style callbacks for tags, attributes, content
• Entity Processing: Standard XML, numeric, and HTML entities
• EXI Support: Schema-less EXI binary format parsing
• Embedded-Ready: Pure C, zero dependencies

Quick Start

#include "sparsexml.h"

unsigned char on_tag(char* name) { 
    printf("Tag: %s\n", name); 
    return SXMLExplorerContinue; 
}

unsigned char on_content(char* content) { 
    printf("Content: %s\n", content); 
    return SXMLExplorerContinue; 
}

int main() {
    SXMLExplorer* ex = sxml_make_explorer();
    sxml_register_func(ex, on_tag, on_content, NULL, NULL);
    sxml_enable_entity_processing(ex, 1);
    
    char xml[] = "<root>Hello &amp; World</root>";
    sxml_run_explorer(ex, xml);
    
    sxml_destroy_explorer(ex);
    return 0;
}

Building and Testing

make
./test-sparsexml
./examples/simple

Memory Requirements

• RAM: ~1KB for parsing buffer + minimal stack usage
• Flash: ~2KB for code (varies by compiler/architecture)

Supported XML Features

• ✅ Basic XML structure parsing
• ✅ XML comments (<!-- -->)
• ✅ CDATA sections (<![CDATA[]]>)
• ✅ Standard XML entities (<, >, &, ", ')
• ✅ Numeric character references (A, A)
• ✅ Extended HTML entities (©, ®, ™,  , etc.)
• ✅ XML namespaces (ns:tag format)
• ✅ Basic DOCTYPE parsing
• ✅ Buffer overflow protection
• ✅ Configurable entity processing

EXI Support

Parse W3C EXI binary files in schema-less mode:

// Parse EXI binary data
unsigned char result = sxml_run_explorer_exi(explorer, exi_data, exi_size);

• Compatible with exificient-generated EXI files
• Dynamic string table management
• Generic content classification

Configuration Options

sxml_enable_entity_processing(explorer, 1);      // Standard XML entities
sxml_enable_numeric_entities(explorer, 1);       // A format
sxml_enable_extended_entities(explorer, 1);      // © format
sxml_enable_namespace_processing(explorer, 1);   // ns:tag format

Use Cases

• Configuration file parsing on microcontrollers
• IoT sensor data processing
• Embedded web service responses
• Simple data exchange protocols

License

BSD 4-Clause License - see LICENSE file.