# Current Data File Format

®ina; data files are saved in an optionally compressed &xml; format. If a data file is compressed, it can be piped through `gunzip` to recover the plain text &xml;.

This reference chapter documents the various &xml; elements that form a ®ina; data file and how they are used. The top-level element for a modern (third-generation) data file is &xml-regina;.

®ina;'s file format has gone through a few major changes over the years:

- The third-generation format was introduced in ®ina; 7.0, and is the format described here. It is an &xml;-based format whose root element is &xml-regina;.

- The second-generation format was used by ®ina; versions 3.0–6.0.1, and is described in full detail in the archived documentation from ®ina; 6.0.1. This is also an &xml;-based format, but whose root element is &xml-reginadata;. ®ina; can transparently read second-generation data files, and it can also write to them on request.

- The first-generation format was a binary format used by ®ina; 2.4 and earlier, and was discontinued in mid-2002. ®ina; can no longer read or write to it at all.

Regarding international characters: As of ®ina; version &utf8intro;, all &xml; data is encoded using &utf8; (which includes plain &ascii; as a subset). In versions 4.4 and earlier, data was encoded in &latin1; without declaring this explicitly in the &xml; header; ®ina; is aware of this, and treats all older data files as &latin1; when they are loaded.

&data-abeliangroup; &data-angles; &data-anon; &data-anonref; &data-attachment; &data-code; &data-compact-surface; &data-component; &data-components; &data-compressingdisc; &data-connected; &data-connections; &data-container; &data-crossings; &data-euler-surface; &data-filtercomb; &data-filterprop; &data-filtertrivial; &data-fundgroup; &data-group; &data-H1; &data-H1Bdry; &data-H1Rel; &data-H2; &data-haken; &data-handlebody; &data-hypersurface; &data-hypersurfaces; &data-irreducible; &data-link; &data-node; &data-oneeff; &data-orbl-surface; &data-realbdry-surface; &data-regina; &data-reln; &data-script; &data-simplex; &data-snappeadata; &data-spanstrict; &data-spantaut; &data-spatiallink; &data-splitsfce; &data-struct; &data-surface; &data-surfaces; &data-tag; &data-textdata; &data-threesphere; &data-tri; &data-twosided; &data-txi; &data-var; &data-zeroeff;

## Deprecated and Removed Elements

The following &xml; elements were used in older ®ina; data files, but are no longer part of the current file format.

Those elements that are marked as deprecated can still be read by the current version of ®ina;, but will not be written when a data file is saved.

Those elements that are marked as removed can no longer be read or written. If ®ina; attempts to read an old data file containing removed element(s), those removed elements will be silently ignored.

&data-allowstrict; &data-allowtaut; &data-angleparams; &data-compact-filter; &data-euler-filter; &data-filter; &data-filter-combination; &data-filter-properties; &data-flags; &data-line; &data-op; &data-orbl-filter; &data-packet; &data-packet-dim2triangulation; &data-packet-dim3triangulation; &data-packet-dim4triangulation; &data-packet-triangulation; &data-packet-anglestructurelist; &data-packet-container; &data-packet-link; &data-packet-normalhypersurfacelist; &data-packet-normalsurfacelist; &data-packet-pdf; &data-packet-script; &data-packet-snappea; &data-packet-surfacefilter; &data-packet-text; &data-params; &data-pent; &data-pentachora; &data-pdf; &data-realbdry-filter; &data-reginadata; &data-simplices; &data-snappea; &data-solidtorus; &data-tet; &data-tetrahedra; &data-text; &data-threeball; &data-triangle; &data-triangles; &data-turaevviro;