patterns 0.3.2

no_std, no alloc pattern scan library using simd
Documentation 
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mod common;
use std::{collections::HashMap, panic::catch_unwind};

use common::*;
use patterns::*;

#[track_caller]
fn all_alignments(pattern: &str, data: &[u8], matches: &[usize]) -> bool {
    let location = std::panic::Location::caller();
    let parsed = pattern.parse::<Pattern>().unwrap();

    let run = |data: &[u8]| -> Vec<Result<Vec<usize>, String>> {
        (0..=63)
            .map(|i| {
                with_misaligned(data, i, |data| {
                    // hide panic backtraces
                    let hook = std::panic::take_hook();
                    std::panic::set_hook(Box::new(|_| {}));

                    let ret =
                        catch_unwind(|| parsed.matches(data).collect::<Vec<_>>()).map_err(|msg| {
                            msg.downcast::<String>()
                                .map(|s| *s)
                                .or_else(|msg| msg.downcast::<&str>().map(|s| s.to_string()))
                                .unwrap_or_else(|_| "other panic".to_owned())
                        });

                    std::panic::set_hook(hook);
                    ret
                })
            })
            .collect()
    };

    let results = run(data);

    if results
        .iter()
        .all(|result| result.as_ref().is_ok_and(|r| r == matches))
    {
        return true;
    }

    eprintln!();

    eprintln!("[{location}] TEST FAILED");
    eprintln!("[{location}] pattern = {pattern:?}");
    if data.len() < 16 {
        eprintln!(
            "[{location}] data    = [{}]",
            data.iter()
                .map(|i| format!("{:02x}", i))
                .collect::<Vec<_>>()
                .join(" ")
        );
    }
    eprintln!("[{location}] matches = {matches:x?}");

    // key: result, value: alignments
    let mut hm: HashMap<Result<&[usize], &String>, Vec<usize>> = HashMap::new();
    for (i, r) in results.iter().enumerate() {
        match r {
            Ok(r) => hm.entry(Ok(r)).or_default().push(i),
            Err(msg) => hm.entry(Err(msg)).or_default().push(i),
        };
    }

    // trivial case -- result is the same for all alignments
    if hm.len() == 1 {
        match &results[0] {
            Ok(r) => eprintln!("[{location}] result = {:x?}", r),
            Err(msg) => eprintln!("[{location}] result = panic {:?}", msg),
        }
        return false;
    }

    hm.remove(&Ok(matches));
    // hm.remove(&Ok(&[]));

    if (1..=10).contains(&hm.len()) {
        let mut aligns = ['.'; 64];
        let mut tmp = hm.iter().collect::<Vec<_>>();
        tmp.sort_by_key(|(_, v)| *v);
        for (i, (_, v)) in tmp.iter().enumerate() {
            for &a in *v {
                aligns[a] = char::from_digit(i as u32, 10).unwrap();
            }
        }
        eprintln!(
            "[{location}] offset   ({})",
            results
                .iter()
                .enumerate()
                .map(|(i, _)| char::from_digit(i as u32 / 10, 10).unwrap())
                .collect::<String>()
        );
        eprintln!(
            "[{location}]          ({})",
            results
                .iter()
                .enumerate()
                .map(|(i, _)| char::from_digit(i as u32 % 10, 10).unwrap())
                .collect::<String>()
        );
        eprintln!(
            "[{location}] result[] ({})",
            aligns.iter().collect::<String>()
        );
        for (i, (k, _)) in tmp.iter().enumerate() {
            match k {
                Ok(r) => eprintln!("[{location}] result[{i}] = {r:x?}"),
                Err(msg) => eprintln!("[{location}] result[{i}] = panic: {msg:?}"),
            }
        }
    } else {
        let mut tmp = hm.iter().collect::<Vec<_>>();
        tmp.sort_by_key(|(_, v)| *v);
        for (result, alignments) in tmp {
            eprintln!(
                "[{location}] aligns {}",
                (0..63)
                    .map(|i| if alignments.contains(&i) { "#" } else { "." })
                    .collect::<Vec<_>>()
                    .join("")
            );
            eprintln!("[{location}] result = {result:x?}");
        }
    }
    eprintln!();

    false
}

#[test]
fn basic() {
    let mut ok = true;
    ok &= all_alignments("42", &[0x42], &[0]);
    ok &= all_alignments("24", &[0x42], &[]);
    ok &= all_alignments("42", &[0x42, 0x42], &[0, 1]);
    assert!(ok);
}

#[test]
fn leading_wildcard() {
    let mut ok = true;
    ok &= all_alignments("? 42", &[0x42], &[]);
    ok &= all_alignments("? 42", &[0x42, 0x22], &[]);
    ok &= all_alignments("? 42", &[0x22, 0x42], &[0]);
    assert!(ok);
}

#[test]
fn trailing_wildcard() {
    let mut ok = true;
    ok &= all_alignments("42 ?", &[0x42], &[]);
    ok &= all_alignments("42 ?", &[0x42, 0x22], &[0]);
    assert!(ok);
}

#[test]
fn trailing_zero() {
    let mut ok = true;
    ok &= all_alignments("00", &[0x42], &[]);
    ok &= all_alignments("42 00", &[0x42], &[]);
    ok &= all_alignments("00", &[0x00], &[0]);
    ok &= all_alignments("42 00", &[0x42, 0x00], &[0]);
    assert!(ok);
}

#[test]
fn xxh3_data_test() {
    assert_eq!(
        xxh3_data(16).as_slice(),
        &[199, 123, 58, 187, 111, 135, 172, 217, 243, 107, 74, 26, 68, 247, 139, 243]
    );
}

#[test]
fn overlap() {
    let mut ok = true;
    let data = &[0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd];
    ok &= all_alignments("ab ?? ?? cd", data, &[0, 2]);
    ok &= all_alignments("ab ?? ??", data, &[0, 2]);
    ok &= all_alignments("?? ?? cd", data, &[1, 3]);
    assert!(ok);
}

#[test]
fn repeat_across_buffer() {
    let mut ok = true;
    let mut data = [0_u8; 64];
    data[0] = 1;
    data[1] = 1;
    ok &= all_alignments("01", &data, &[0, 1]);
    assert!(ok);
}

#[test]
fn small() {
    let mut ok = true;
    //    00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
    // 0x c7 7b 3a bb 6f 87 ac d9 f3 6b 4a 1a 44 f7 8b f3
    // 1x 3e 69 48 79 79 85 51 1c d0 36 c6 a9 c6 b3 1c 1d
    // 2x 93 47 f2 9a a4 16 00 1e c2 8f 1f 5e 73 70 05 06
    // 3x 4c 14 53 22 e9 63 61 c2 f8 c0 12 6b 89 b4 fa fc
    let data = xxh3_data(64);
    ok &= all_alignments("c7 7b", &data, &[0]);
    ok &= all_alignments("c7 7b ?", &data, &[0]);
    ok &= all_alignments("? c7 7b", &data, &[]);
    ok &= all_alignments("f3", &data, &[0x08, 0x0F]);
    ok &= all_alignments("f3 ? 4a", &data, &[0x08]);
    ok &= all_alignments("f3 ? 69", &data, &[0x0F]);
    ok &= all_alignments("c2", &data, &[0x28, 0x37]);
    ok &= all_alignments("c2 ? ? 5e", &data, &[0x28]);
    ok &= all_alignments("c2 ? ? 12", &data, &[0x37]);
    ok &= all_alignments("14 53 22 e9 63", &data, &[0x31]);

    // uneven tail
    ok &= all_alignments("c2", &data[..=0x37], &[0x28, 0x37]);
    ok &= all_alignments("14 53 22 e9 63", &data[..=0x37], &[0x31]);

    // double
    let data2 = data.repeat(2);
    ok &= all_alignments("c7 7b", &data2, &[0, 64]);
    ok &= all_alignments("c7 7b ?", &data2, &[0, 64]);
    ok &= all_alignments("? c7 7b", &data2, &[63]);
    ok &= all_alignments("f3", &data2, &[0x08, 0x0F, 0x48, 0x4F]);
    ok &= all_alignments("f3 ? 4a", &data2, &[0x08, 0x48]);
    ok &= all_alignments("f3 ? 69", &data2, &[0x0F, 0x4F]);
    ok &= all_alignments("c2", &data2, &[0x28, 0x37, 0x68, 0x77]);
    ok &= all_alignments("c2 ? ? 5e", &data2, &[0x28, 0x68]);
    ok &= all_alignments("c2 ? ? 12", &data2, &[0x37, 0x77]);
    ok &= all_alignments("14 53 22 e9 63", &data2, &[0x31, 0x71]);

    // across block boundary
    ok &= all_alignments("fa fc c7", &data2, &[0x3E]);
    ok &= all_alignments("fc c7 7b", &data2, &[0x3F]);
    ok &= all_alignments("fc ?? 7b", &data2, &[0x3F]);

    // uneven tail
    ok &= all_alignments("c2", &data2[..=0x77], &[0x28, 0x37, 0x68, 0x77]);
    ok &= all_alignments("14 53 22 e9 63", &data2[..=0x77], &[0x31, 0x71]);

    // wildcard beyond the end, 2nd iterator call
    ok &= all_alignments("6b ?? ?? ?? ?? ??", &data2, &[0x09, 0x3B, 0x49]);
    assert!(ok);
}

#[test]
fn medium() {
    let mut ok = true;
    let data = xxh3_data(256);
    // c7 7b 3a bb 6f 87 ac d9 f3 6b 4a 1a 44 f7 8b f3
    // 3e 69 48 79 79 85 51 1c d0 36 c6 a9 c6 b3 1c 1d
    // 93 47 f2 9a a4 16 00 1e c2 8f 1f 5e 73 70 05 06
    // 4c 14 53 22 e9 63 61 c2 f8 c0 12 6b 89 b4 fa fc
    // 6c 21 67 3f 75 92 6a 82 07 ac a3 37 bc 38 e9 8c
    // a5 39 d2 ef 8a 0c 4d 7c d5 70 24 b4 a6 06 1d 82
    // a9 48 a2 a5 d1 12 54 f0 5e 92 75 e4 75 f7 fd f6
    // f2 58 95 64 7d 5e ee b9 cb 87 78 89 3d 73 c3 50
    // 9b 3f a9 34 a5 38 6f ad cc 24 10 47 83 77 a5 cc
    // a7 a9 44 76 4b 57 0c 4a 07 f6 80 e9 21 72 35 f5
    // ac 5b 0e 60 2e a9 fb 55 2b fa ed 4b ec c3 18 62
    // a4 9d fb 52 e1 90 45 fe e3 90 4f d2 fc 7b 02 bc
    // 40 89 6e 4e 66 fe 67 4b 8e 09 cb 44 03 83 4f 0a
    // 67 df 82 f4 0e a2 f2 f2 45 e5 27 b3 6e e5 31 82
    // d8 40 5f e6 f9 7d cc 6f 7d 30 4a 80 db 66 6c b3
    // 85 67 0c a2 5c 6d 82 e0 35 d9 ee 0d 66 ec 03 3f
    ok &= all_alignments("34", &data, &[0x83]);
    ok &= all_alignments("34 a5", &data, &[0x83]);
    ok &= all_alignments("34 a5 38", &data, &[0x83]);
    assert!(ok);
}