Implementation:Google deepmind Mujoco Filetype Detection

Knowledge Sources	MuJoCo
Domains	Model_IO, File_Handling
Last Updated	2026-02-15 06:00 GMT

Overview

Concrete pattern for detecting MuJoCo model file formats from the compile sample utility.

Description

The filetype function in MuJoCo's compile sample extracts the file extension, converts it to lowercase, and maps it to an integer type code. It handles the special case of no extension (type NONE) and unknown extensions (type UNKNOWN).

Usage

Use when implementing model conversion tools that need to distinguish between XML, MJB, and TXT file formats.

Code Reference

Source Location

• Repository: mujoco
• File: sample/compile.cc
• Lines: 72-103

Signature

// Pattern: local helper function
static int filetype(const char* filename);
// Returns: typeXML (1), typeMJB (2), typeTXT (3), typeUNKNOWN (0), typeNONE (4)

Import

// Not a library function - pattern from sample/compile.cc
#include <cctype>   // tolower
#include <cstring>  // strlen, strcpy

I/O Contract

Inputs

Name	Type	Required	Description
filename	const char*	Yes	File path to analyze

Outputs

Name	Type	Description
return	int	Type code: typeXML=1, typeMJB=2, typeTXT=3, typeUNKNOWN=0, typeNONE=4

Usage Examples

// Determine input and output formats
int input_type = filetype(argv[1]);
int output_type = argc > 2 ? filetype(argv[2]) : typeNONE;

if (input_type == typeXML) {
    m = mj_loadXML(argv[1], NULL, error, 1000);
} else if (input_type == typeMJB) {
    m = mj_loadModel(argv[1], NULL);
}

Related Pages

Implements Principle

• Principle:Google_deepmind_Mujoco_Model_Format_Detection