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get_builtin_rules

libmagic_rs::builtin_rules

Function get_builtin_rules 

Source 
pub fn get_builtin_rules() -> Vec<MagicRule>
Expand description

Returns a copy of the built-in magic rules.

This function provides access to the magic rules compiled at build time from src/builtin_rules.magic. The rules are stored in a LazyLock static, so initialization only happens on the first call.

§Rules Included

The built-in rules include high-confidence file type detection for:

  • Executable formats: ELF (32/64-bit, LSB/MSB), PE/DOS executables
  • Archive formats: ZIP, TAR (POSIX), GZIP
  • Image formats: JPEG/JFIF, PNG, GIF (87a/89a), BMP
  • Document formats: PDF

§Performance

The rules are lazily initialized using LazyLock, meaning:

  • First call performs one-time initialization
  • Subsequent calls are very fast (just cloning the Vec)
  • Safe to call from multiple threads (initialization is synchronized)

§Returns

A cloned Vec<MagicRule> containing all built-in magic rules. Each caller gets an independent copy that can be modified without affecting other callers.

§Examples

use libmagic_rs::builtin_rules::get_builtin_rules;

let rules = get_builtin_rules();
println!("Built-in rules count: {}", rules.len());

// Rules can be used directly with the evaluator
// or combined with custom rules

§See Also