Supported encodings: Iconvex vs GNU libiconv 1.19

Machine-generated from GNU libiconv 1.19's six fixed-codec definition files. test/codec_parity_test.exs independently parses byte-exact upstream snapshots and requires exact set and alias parity.

Parity result

• Iconvex core fixed codecs: 112/112.
• iconvex_extras fixed codecs: 86/86.
• GNU-compatible Iconvex surface: 112 core + 86 extras = 198/198.
• GNU fixed-codec union: 198/198.
• Common fixed codecs: 198.
• GNU-only fixed codecs: 0.
• Iconvex-only fixed codecs: 0.
• GNU source spellings/aliases resolved by Iconvex: 758. Core owns 416; extras adds 342.
• Additional audited specification/ICU aliases: 30.
• Total resolved fixed-codec spellings: 788.
• Default GNU build iconv -l: 112/112, all supported by Iconvex.

Ecosystem context

This matrix deliberately measures GNU's fixed-codec namespace, not every Iconvex package. The full Iconvex ecosystem owns 2,105 canonical byte-stream codecs across ten runtime packages. See the repository-level ICONVEX_CODEC_PACKAGE_INDEX.csv for the generated codec-to-package map and ICONVEX_FULL_STACK_SUPPORT.md for the complete side-by-side list. GNU parity remains the exact 198/198 Core + Extras union.

Packed transport surface

Packing is orthogonal to the GNU codec registry. Iconvex.Packed can pack the one-unit-per-octet output of any built-in or external codec at every width from 1 through 8 bits, in exact MSB-first or byte-backed LSB-first order. It is not counted as a second character encoding because the Unicode mapping is unchanged; the transport preserves its exact unit width and meaningful bit length.

The leaf packages publish explicit packed profiles without inflating the byte-codec total: Telecom has 53 profiles (3, 5, 6, and 7 bits), Standards has 5, Bibliographic has 2, and Retro has 57 spanning 6 through 12 bits. iconvex_unicode exposes RFC 4042 UTF-9 and UTF-18 as native 9- and 18-bit Elixir bitstrings plus explicitly endian-tagged byte transports.

SUPPORTED_NAME_INVENTORY.csv is generated from the compiled core registry. The parity suite requires its 446 normalized names and canonical targets to be an exact runtime snapshot; research consumes this file directly.

GNU union means all fixed codecs implemented across encodings.def, encodings_extra.def, encodings_aix.def, encodings_dos.def, encodings_osf1.def, and encodings_zos.def. Default iconv -l exposes the 112 core codecs on this build; extra/platform definitions raise the source union to 198. The iconvex package intentionally contains exactly the GNU default set. Adding the separate iconvex_extras package exposes the complete union on every BEAM platform. A dash means that codec is intentionally owned by the other package.

Locale/ABI adapters

GNU also accepts CHAR and WCHAR_T through encodings_local.def. These are environment/ABI adapters, not fixed codecs, and GNU omits them from iconv -l. CHAR delegates to process locale encoding. WCHAR_T delegates to platform C wchar_t width/endian/layout. Iconvex intentionally excludes both: pure BEAM conversion has no libc locale or C wchar_t ABI. Use explicit fixed names such as UTF-8, UCS-4-INTERNAL, UTF-16LE, or UTF-32LE.

Complete fixed-codec list