// Copyright (C) 2016 Symtern Project Contributors
//
// Licensed under the Apache License, Version 2.0 <LICENSE-Apache
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. This file may not be copied, modified, or
// distributed except according to those terms.
//! Symtern benchmarks using short random strings as inputs.
#![feature(test)]
extern crate test;
extern crate rand;
extern crate symtern;
#[macro_use] extern crate lazy_static;

use rand::Rng;
use test::Bencher;
use symtern::prelude::*;
use symtern::Pool;
use symtern::adaptors::Inline;

const TEST_STRING_CHARS: [char; 26] = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'];

lazy_static! {
    static ref TEST_STRINGS_2: Vec<String> = generate_strings(400_000, 2);
    static ref TEST_STRINGS_3: Vec<String> = generate_strings(400_000, 3);
    static ref TEST_STRINGS_4: Vec<String> = generate_strings(400_000, 4);
    static ref TEST_STRINGS_5: Vec<String> = generate_strings(400_000, 5);
    static ref TEST_STRINGS_6: Vec<String> = generate_strings(400_000, 6);
    static ref TEST_STRINGS_7: Vec<String> = generate_strings(400_000, 7);
    static ref TEST_STRINGS_8: Vec<String> = generate_strings(100_000, 8);

    static ref TEST_STRINGS_16: Vec<String> = generate_strings(100_000, 16);
    static ref TEST_STRINGS_32: Vec<String> = generate_strings(100_000, 32);
}

fn generate_string(dest: &mut String, length: usize, chars: &[char]) {
    dest.clear();
    let mut rng = rand::thread_rng();
    for _ in 0..length {
        dest.push(chars[rng.gen::<usize>() % chars.len()]);
    }
}

fn generate_strings(n: usize, length: usize) -> Vec<String> {
    let mut out = Vec::new();
    let mut s = String::with_capacity(length);
    for _ in 0..n {
        generate_string(&mut s, length, &TEST_STRING_CHARS);
        out.push(s.clone());
    }
    out
}

macro_rules! bench_intern_fn {
    ($name: ident, $new: expr, $strings_set: ident, $len: expr) => {
        #[bench]
        #[allow(unused_mut)]
        fn $name(b: &mut Bencher) {
            let mut strings = $strings_set.clone();
            let mut pool = $new;
            b.iter(|| pool.intern(&strings.pop().expect("ran out of test strings")[..]));
            b.bytes = ($strings_set.len() - strings.len()) as u64 * $len ;
        }
    };
}

macro_rules! bench_resolve_fn {
    ($name: ident, $new: expr, $strings_set: ident) => {
        #[bench]
        fn $name(b: &mut Bencher) {
            let mut pool = $new;
            let strings = &$strings_set;
            let mut symbols = strings.iter().map(|s| pool.intern(&s[..]).expect("failed to intern string")).collect::<Vec<_>>();
            b.iter(|| pool.resolve(symbols.pop().expect("ran out of test symbols")).expect("resolution failure"));
        }
    };
    ($name: ident, $new: expr, $strings_set: ident, resolve_ref) => {
        #[bench]
        #[allow(unused_mut)]
        fn $name(b: &mut Bencher) {
            let mut pool = $new;
            let strings = &$strings_set;
            let mut symbols = strings.iter().map(|s| pool.intern(&s[..]).expect("failed to intern string")).collect::<Vec<_>>();
            b.iter(|| { let sym = symbols.pop().expect("ran out of test symbols");
                        pool.resolve(&sym).expect("resolution failure"); });
        }
    }
}

bench_intern_fn!(intern_basic_4 , Pool::<str,u64>::new()  , TEST_STRINGS_4, 4);
bench_intern_fn!(intern_basic_8 , Pool::<str,u64>::new()  , TEST_STRINGS_8, 8);
bench_intern_fn!(intern_basic_16, Pool::<str,u64>::new()  , TEST_STRINGS_16, 16);
bench_intern_fn!(intern_basic_32, Pool::<str,u64>::new()  , TEST_STRINGS_16, 32);

bench_intern_fn!(intern_short_2 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_2, 2);
bench_intern_fn!(intern_short_3 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_3, 3);
bench_intern_fn!(intern_short_4 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_4, 4);
bench_intern_fn!(intern_short_5 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_5, 5);
bench_intern_fn!(intern_short_6 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_6, 6);
bench_intern_fn!(intern_short_7 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_7, 7);
bench_intern_fn!(intern_short_8 , Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_8, 8);
bench_intern_fn!(intern_short_16, Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_16, 16);
bench_intern_fn!(intern_short_32, Inline::<Pool<str,u64>>::new()      , TEST_STRINGS_16, 32);

bench_resolve_fn!(resolve_basic_4 , Pool::<str,u64>::new(), TEST_STRINGS_4);
bench_resolve_fn!(resolve_basic_8 , Pool::<str,u64>::new(), TEST_STRINGS_8);
bench_resolve_fn!(resolve_basic_16, Pool::<str,u64>::new(), TEST_STRINGS_16);
bench_resolve_fn!(resolve_basic_32, Pool::<str,u64>::new(), TEST_STRINGS_32);

bench_resolve_fn!(resolve_short_4 , Inline::<Pool<str,u64>>::new()    , TEST_STRINGS_4, resolve_ref);
bench_resolve_fn!(resolve_short_8 , Inline::<Pool<str,u64>>::new()    , TEST_STRINGS_8, resolve_ref);
bench_resolve_fn!(resolve_short_16, Inline::<Pool<str,u64>>::new()    , TEST_STRINGS_16, resolve_ref);
bench_resolve_fn!(resolve_short_32, Inline::<Pool<str,u64>>::new()    , TEST_STRINGS_32, resolve_ref);