acadrust 0.6.7

A pure Rust library for reading and writing CAD files in DXF format (ASCII and Binary) and DWG format (Binary).
Documentation 
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//! Objects anchored to another Arch entity.
//!
//! A door, window, opening, or window corner stores an
//! `AEC_ANCHOR_OPENINGBASE_TO_WALL` (or another anchor) whose associative
//! dependency points at the host wall. Arch deletes those anchored
//! entities when the wall is removed.

use crate::entities::{EntityType, ExtendedEntityData};
use crate::objects::{AssociativeData, ObjectType};
use crate::types::Handle;
use crate::CadDocument;

/// Arch entities whose anchor depends on `host`.
pub fn entities_anchored_to(document: &CadDocument, host: Handle) -> Vec<Handle> {
    let mut anchored = Vec::new();
    for object in document.objects.values() {
        let ObjectType::Associative(value) = object else {
            continue;
        };
        let Some(dependent_on) = dependency_target(&value.data) else {
            continue;
        };
        if dependent_on != host {
            continue;
        }
        let Some(entity) = owning_entity(document, value.owner) else {
            continue;
        };
        if entity == host || anchored.contains(&entity) || !is_architecture_entity(document, entity)
        {
            continue;
        }
        anchored.push(entity);
    }
    for object in document.objects.values() {
        let ObjectType::Arch(value) = object else {
            continue;
        };
        if !value.dxf_name.contains("ANCHOR") || value.dxf_name.contains("DISP_REP") {
            continue;
        }
        if !anchor_points_at(value, host) {
            continue;
        }
        let Some(entity) = owning_entity(document, value.handle) else {
            continue;
        };
        if entity == host || anchored.contains(&entity) || !is_architecture_entity(document, entity)
        {
            continue;
        }
        anchored.push(entity);
    }
    anchored
}

fn anchor_points_at(object: &crate::classes::arch::ArchObject, host: Handle) -> bool {
    use crate::io::dwg::dwg_stream_readers::bit_reader::DwgBitReader;
    use crate::io::dwg::dwg_version::DwgVersion;
    use crate::io::dwg::DwgReferenceType;
    use crate::types::DxfVersion;
    let Some(raw) = object.raw_dwg_data.as_deref() else {
        return false;
    };
    if object.raw_dwg_handle_bits <= 8 {
        return false;
    }
    let total_bits = raw.len() as i64 * 8;
    let start = total_bits - object.raw_dwg_handle_bits;
    if start < 0 || start >= total_bits {
        return false;
    }
    let mut reader = DwgBitReader::from_shared(
        std::sync::Arc::<[u8]>::from(raw),
        DwgVersion::AC24,
        object.raw_dwg_version.unwrap_or(DxfVersion::AC1032),
    );
    reader.set_position_in_bits(start);
    let mut reference_type = DwgReferenceType::Undefined;
    for _ in 0..8 {
        if reader.position_in_bits() + 8 > total_bits {
            break;
        }
        let reference = reader.read_handle_reference(object.handle.value(), &mut reference_type);
        if reference == host.value() {
            return true;
        }
        if reference == 0 {
            break;
        }
    }
    false
}

/// Non-graphical objects whose owner chain ends at `root`.
pub fn objects_owned_by(document: &CadDocument, root: Handle) -> Vec<Handle> {
    document
        .objects
        .keys()
        .copied()
        .filter(|handle| owned_by(document, *handle, root))
        .collect()
}

fn dependency_target(data: &AssociativeData) -> Option<Handle> {
    match data {
        AssociativeData::Dependency(value) => Some(value.dependent_on),
        AssociativeData::GeomDependency(value) => Some(value.dependency.dependent_on),
        _ => None,
    }
}

fn owning_entity(document: &CadDocument, mut handle: Handle) -> Option<Handle> {
    for _ in 0..24 {
        if document.get_entity(handle).is_some() {
            return Some(handle);
        }
        let owner = document.object_owner(handle)?;
        if owner.is_null() || owner == handle {
            return None;
        }
        handle = owner;
    }
    None
}

fn owned_by(document: &CadDocument, mut handle: Handle, root: Handle) -> bool {
    for _ in 0..24 {
        let Some(owner) = document.object_owner(handle) else {
            return false;
        };
        if owner == root {
            return true;
        }
        if owner.is_null() || owner == handle {
            return false;
        }
        handle = owner;
    }
    false
}

pub(crate) fn is_architecture_entity(document: &CadDocument, handle: Handle) -> bool {
    matches!(
        document.get_entity(handle),
        Some(EntityType::Extended(entity))
            if matches!(entity.data, ExtendedEntityData::Arch(_))
    )
}