Crate lazy_static_include

Lazy Static Include

This crate provides lazy_static_include_bytes and lazy_static_include_str macros to replace include_bytes and include_str macros.

Why should we do that? Because the original include_bytes and include_str macros bring extra data from files into the compiled executable binary file, the time for compiling surges.

High compilation time is detrimental to software development. lazy_static_include_bytes and lazy_static_include_str macros can help you lazy load data from files when you are not using the release profile. In other words, if you are using include_bytes and include_str macros, and you think your compilation time is too high to wait, you can choose to use lazy_static_include_bytes and lazy_static_include_str macros.

lazy_static_include_bytes and lazy_static_include_str macros include data from files into the compiled executable binary file only when you are using the release profile. Be careful when you distribute your program.

The paths used for lazy_static_include_bytes and lazy_static_include_str are relative to CARGO_MANIFEST_DIR.

Examples

#[macro_use] extern crate lazy_static_include;

lazy_static_include_str! {
    /// doc
    TEST => "data/test.txt",
    /// doc
    pub TEST2 => "data/test-2.txt",
}

assert_eq!("This is just a test text.", TEST);
assert_eq!("Some text...", TEST2);

#[macro_use] extern crate lazy_static_include;

lazy_static_include_bytes! {
    /// doc
    TEST => "data/test.txt",
    /// doc
    pub TEST2 => "data/test-2.txt",
}

assert_eq!("This is just a test text.".as_bytes(), TEST);
assert_eq!("Some text...".as_bytes(), TEST2);

You should notice that the value created from lazy_static_include_bytes and lazy_static_include_str macros isn't equal to &'static [u8] or &'static str when you are not using the release profile. If you want to get an exact &'static [u8] or &'static str reference, you can dereference the value or just use the as_ref method.

#[macro_use] extern crate lazy_static_include;

lazy_static_include_bytes! {
    /// doc
    TEST => "data/test.txt",
}

#[cfg(debug_assertions)]
let data: &'static [u8] = *TEST;

#[cfg(not(debug_assertions))]
let data: &'static [u8] = TEST;

let data: &'static [u8] = TEST.as_ref();

Include Array

There is a special macro lazy_static_include_array which can include arrays from files. The array is fixed sized and can be one of these following types: bool, char, usize, u8, u16, u32, u64, u128, isize, i8, i16, i32, i64, i128, f32, f64, &'static str.

Also, the lazy_static_include_array macro includes data from files into the compiled executable binary file only when you are using the release profile. Be careful when you distribute your program.

The paths used for lazy_static_include_array are relative to CARGO_MANIFEST_DIR.

#[macro_use] extern crate lazy_static_include;

lazy_static_include_array! {
    /// doc
    TEST: [u64; 5] => "data/u64_array.txt",
    /// doc
    pub TEST2: [&'static str; 3] => "data/string_array.txt"
}

assert_eq!(123, TEST[0]);
assert_eq!(456, TEST[1]);
assert_eq!(789, TEST[2]);
assert_eq!(1000, TEST[3]);
assert_eq!(500000000000u64, TEST[4]);

assert_eq!("Hi", TEST2[0]);
assert_eq!("Hello", TEST2[1]);
assert_eq!("哈囉", TEST2[2]);

Benchmark

Using static mechanisms makes your program faster. See my benchmark result below (AMD Ryzen 9 3900X 12-Core Processor 12C/24T 3.90GHz, ran on 2020/07/02):

test include_array_lazy_static   ... bench:          45 ns/iter (+/- 3)
test include_array_native_static ... bench:          45 ns/iter (+/- 3)
test include_array_no_static     ... bench:      20,959 ns/iter (+/- 295)
test include_bytes_lazy_static   ... bench:         754 ns/iter (+/- 7)
test include_bytes_native_static ... bench:         755 ns/iter (+/- 11)
test include_bytes_no_static     ... bench:       4,560 ns/iter (+/- 179)
test include_str_lazy_static     ... bench:         753 ns/iter (+/- 10)
test include_str_native_static   ... bench:         755 ns/iter (+/- 7)
test include_str_no_static       ... bench:       4,830 ns/iter (+/- 198)

When using the release profile, the performance of lazy_static_include_* is very close to include_* (in fast, they are the same). That means you don't need to worry about the overhead, but just enjoy the faster compilation time.

You can run the benchmark program by executing,

cargo bench

Macros

lazy_static_include_array	Includes a file containing a rust array.
lazy_static_include_bytes	Includes a file as a reference to a byte array (&'static [u8]).
lazy_static_include_str	Includes a utf8-encoded file as a string slice (&'static str).