Implementation:Google deepmind Mujoco XML Util Header

Knowledge Sources	Google_deepmind_Mujoco
Domains	Physics Simulation, XML Parsing, Schema Validation
Last Updated	2026-02-15 04:00 GMT

Overview

Declares XML utility classes and functions including mjXError for error reporting, mjXSchema for XML validation, mjMap for key-value mappings, and mjXUtil for attribute reading.

Description

xml_util.h provides the foundational types used across the XML parsing subsystem. It declares mjCopyError for safe error string copying, FirstChildElement/NextSiblingElement wrappers for TinyXML2 traversal, the mjXError exception class with formatted error messages, and the mjXSchema class for declarative XML schema validation with support for printing schemas as plain text or HTML. The mjMap struct provides simple string-to-int mappings for enum lookups, and mjXUtil is declared as a utility class with static methods for reading typed XML attributes.

Usage

Included by all XML parsing files (native reader, native writer, URDF parser, and xml.cc) as the shared utility foundation for XML operations.

Code Reference

Source Location

• Repository: Google_deepmind_Mujoco
• File: src/xml/xml_util.h
• Lines: 1-217

Key Functions

void mjCopyError(char* dst, const char* src, int maxlen);

XMLElement* FirstChildElement(XMLElement* e, const char* name = nullptr);
XMLElement* NextSiblingElement(XMLElement* e, const char* name = nullptr);

class [[nodiscard]] mjXError {
 public:
  mjXError(const tinyxml2::XMLElement* elem = 0,
           const char* msg = 0, const char* str = 0, int pos = 0);
  char message[1000];
};

class mjXSchema {
 public:
  mjXSchema(std::vector<const char*> schema[], unsigned nrow);
  std::string GetError();
  tinyxml2::XMLElement* Check(tinyxml2::XMLElement* elem, int level);
};

struct _mjMap { const char* key; int value; };
typedef struct _mjMap mjMap;

Import

#include "xml/xml_util.h"

I/O Contract

Inputs

Name	Type	Required	Description
elem	tinyxml2::XMLElement*	Yes	XML element to validate or read attributes from
schema	std::vector<const char*>[]	Yes (for mjXSchema)	Schema definition rows
nrow	unsigned	Yes (for mjXSchema)	Number of schema rows

Outputs

Name	Type	Description
std::string	std::string	Error message from schema validation
XMLElement*	XMLElement*	Validated element, or nullptr on validation failure

Related Pages

• Environment:Google_deepmind_Mujoco_C_Build_Environment