Crate gds21

Gds21 Integrated Circuit Layout Parser & Writer

GDSII is the IC industry’s de facto standard for storing and sharing layout data. Gds21 is a library for reading and creating GDSII data, similar to and largely inspired by libraries such as gdstk and its predecessor gdspy. Gds21 differs in being designed primarily as an interface layer to GDSII for the larger Layout21 library. Reading and generating GDSII-format data are primary goals; offering ease-of-use functionality for more elaborate manipulations of GDS data is not. (Although these manipulations can be performed on Gds21’s data structures). Gds21 accordingly stores layout data on GDSII’s terms, using GDSII’s idioms and naming conventions.

Layout data is represented in three primary forms:

• A short tree with three layers:
  • The root is a GdsLibrary, which primarily consists of a set of cells (GdsStructs), and secondarily a set of metadata. Each GdsLibrary is a universe unto itself, in that it has no mechanisms for comprehending layout cells or data defined outside itself. On-disk each GdsLibrary is typically paired one-to-one with a .gds file.
  • Libraries consist of cell definitions AKA GdsStructs, which define each layout cell (or module, or “struct” in GDSII terms).
  • Cells consist of GdsElements, an enumeration which includes individual polygons (GdsBoundary), instances of other layout cells (GdsStructRef), text (GdsTextElem), and a few other geometric elements.
• For storage on disk, the GdsLibrary tree is flattened to a series of GdsRecords. These records indicate the beginning, end, and content of each tree-node. Detailed descriptions of these records comprise the majority of the GDSII spec.
• Records are stored on-disk in binary form as detailed in the GDSII spec. Each includes a record-type header, datatype, length field, and optional additional content. These raw-bytes are never stored by Gds21, only generated and consumed on their way into and out of Read and Write objects (typically Files).

Alternate Serialization

Each element in Gds21’s GdsLibrary tree is serde-serializable. Gds21 includes dependencies for serializing and de-serializing to and from JSON, YAML, and TOML formats. Note these text-based representations will generally be substantially larger than binary GDSII data.

Usage

Loading a GdsLibrary from disk:

let lib = GdsLibrary::load("sample.gds")?;

Creating a new and empty GdsLibrary, and adding a GdsStruct cell-definition:

use gds21::{GdsLibrary, GdsStruct, GdsUnits};
let mut lib = GdsLibrary::new("mylib");
lib.structs.push(GdsStruct::new("mycell"));

Saving a GdsLibrary to disk:

lib.save("mylib.gds");

Converting a GdsLibrary to JSON, YAML, or TOML:

let lib = gds21::GdsLibrary::new("mylib");
let json = serde_json::to_string(&lib);
let yaml = serde_yaml::to_string(&lib);
let toml = toml::to_string(&lib);

Structs

GdsArrayRef	Gds Array Reference
GdsBoundary	Gds Boundary Element
GdsBox	Gds Box Element
GdsDateTimes	Gds Modification Dates & Times
GdsElemFlags	Gds Element Flags
GdsFloat64	GDSII’s Home-Grown Floating-Point Format
GdsLayerSpec	Gds Layer Spec
GdsLibrary	Gds Library
GdsNode	Gds Node Element
GdsPath	Gds Path Element
GdsPlex	Gds Plex
GdsPresentation	Gds Text-Presentation Flags
GdsProperty	Gds Property
GdsStrans	Gds Translation Settings
GdsStruct	Gds Struct (Cell) Definition
GdsStructRef	Gds Struct Reference (Cell Instance)
GdsTextElem	Gds Text Element
GdsUnits	Gds Library Units
Unsupported	Placeholder for Unsupported (But Spec-Valid) Features

Enums

GdsContext	Enumeration of each context in which a record can be parsed, primarily for error reporting
GdsDataType	Gds DataType Enumeration
GdsElement	Gds Element Enumeration
GdsError	Gds Error Enumeration
GdsFormatType	Gds Mask-Format Enumeration
GdsRecord	Gds Record Enumeration
GdsRecordType	Gds Record Types

Traits

ToRecords

Trait for conversion of GdsElements and similar tree-elements to sequences of GdsRecords.