sipha 3.0.0

PEG parser, syntax trees, and code generation
Documentation 
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use super::error::{BadGraphKind, ParseError};
use super::frames::SnapEntry;
#[cfg(not(feature = "std"))]
use alloc::vec::Vec;
#[cfg(feature = "std")]
use std::vec::Vec;

#[inline]
pub(super) fn flag_is_set(flags: &[u64], flag_id: u16) -> bool {
    let w = (flag_id >> 6) as usize;
    w < flags.len() && (flags[w] >> (flag_id & 63)) & 1 != 0
}

#[inline]
pub(super) fn restore_snapshot(
    flags: &mut [u64],
    snaps: &mut Vec<SnapEntry>,
    mark: u32,
) -> Result<(), ParseError> {
    let mark = mark as usize;
    if mark > snaps.len() {
        return Err(ParseError::BadGraph(BadGraphKind::SnapshotMarkOutOfRange {
            mark: u32::try_from(mark).unwrap_or(u32::MAX),
        }));
    }
    for entry in snaps[mark..].iter().rev() {
        if (entry.word as usize) < flags.len() {
            flags[entry.word as usize] = entry.val;
        }
    }
    snaps.truncate(mark);
    Ok(())
}