Port Mortem / Repo pool

Recommended Repo Pool

This is a recommendation, not a requirement.

Pick one from here, or bring your own public repo, no pre-approval needed. A bring-your-own repo just needs to be at least 1,000 source lines (and under ~8,000), OSS-licensed, and not already ported to your target language. A test suite is optional but recommended. This list is a curated starting point of small, pure-logic libraries across the eight tracks.

Before you commit to a repo, check its license. If it has a test suite, confirm it runs on a clean clone. Tests are optional here, but passing the original suite unmodified is the ideal to aim for, not a requirement. Line counts below are rough estimates, not measured, so verify with cloc or tokei. Each track's suggested range is on its track card; the sweet spot is the Standard band (~2k–8k lines), and smaller Sprint repos are welcome too.

A C → Rust 10

Repository	Port	~LOC	Size	License	What it does
DaveGamble/cJSON	C → Rust,Zig	2000-3000	Standard (2k–8k)	MIT	ANSI-C JSON parser/printer
lammertb/libcrc	C → Rust,Zig	2000-3500	Standard (2k–8k)	MIT	CRC16/32/64, CRC-CCITT, NMEA checksums
ludocode/mpack	C → Rust,Zig	6000-8000	Standard (2k–8k)	MIT	MessagePack encoder/decoder (tree parser + writer)
clwi/CWPack	C → Rust	1000-1500	Sprint (500–2k)	MIT	ANSI-C no-alloc MessagePack encoder/decoder
codeplea/tinyexpr	C → Rust,Zig	600-900	Sprint (500–2k)	zlib	Recursive-descent math expression evaluator
jserv/MathEX	C → Rust,Zig	600-1000	Sprint (500–2k)	MIT	String math-expression evaluator w/ vars & funcs
phoboslab/qoi	C → Rust,Zig	600	Sprint (500–2k)	MIT	Quite OK Image lossless codec (single header)
benhoyt/inih	C → Rust,Zig	300-500	Under 500	BSD-3-Clause	Minimal embeddable INI parser
victoroliv2/quite-ok-image-format	C → Rust	400-700	Under 500	check license	from-scratch C99 QOI reference
zserge/jsmn	C → Rust,Zig	~200	Under 500	MIT	Minimal JSON tokenizer (embedded)

B Zig → Rust 18

Repository	Port	~LOC	Size	License	What it does
frmdstryr/zig-datetime	Zig → Rust	1800-2000	Standard (2k–8k)	MIT	datetime/calendar arithmetic + formatting
kubkon/zig-yaml	Zig → Rust	5000-8000	Standard (2k–8k)	MIT	YAML 1.2 parser, untyped + typed mapping
mattyhall/tomlz	Zig → Rust	1500-2500	Standard (2k–8k)	MIT	well-tested TOML v1.0.0 parser/serializer
pblischak/zprob	Zig → Rust	2000-4000	Standard (2k–8k)	LGPL-3.0	RNG distribution sampling + mass/density fns
sam701/zig-toml	Zig → Rust	2000-2500	Standard (2k–8k)	MIT	LL TOML v1.1 parser into Zig structs
tiehuis/zig-regex	Zig → Rust	3000	Standard (2k–8k)	MIT	regex engine: NFA compile + Pike/backtracking VM
euantorano/ip.zig	Zig → Rust	500-900	Sprint (500–2k)	BSD-3-Clause	IPv4/IPv6 address types and utilities
matthewtolman/zig_csv	Zig → Rust	1500-2500	Sprint (500–2k)	MIT	CSV writer + map/column/zero-alloc/stream parsers
ziglibs/s2s	Zig → Rust	500-800	Sprint (500–2k)	MIT	runtime binary serialize/deserialize for Zig types
beho/zig-csv	Zig → Rust	300-600	Under 500	MIT	non-allocating CSV tokenizer with iterator API
daneelsan/brainfuckz	Zig → Rust	300-600	Under 500	MIT	Brainfuck interpreter/CLI
dantecatalfamo/brainfuck-zig	Zig → Rust	150-300	Under 500	MIT	embeddable Brainfuck interpreter
deatil/zig-md2	Zig → Rust	200-350	Under 500	Apache-2.0	MD2 hash
deatil/zig-md4	Zig → Rust	200-350	Under 500	Apache-2.0	MD4 hash
gernest/base32	Zig → Rust	300-500	Under 500	MIT	base32 encode/decode (std/hex/Crockford)
SasLuca/zig-nanoid	Zig → Rust	200-400	Under 500	MIT	tiny URL-friendly unique ID generator
Vexu/zuri	Zig → Rust	300-500	Under 500	MIT	URI parser
notCalle/parzig	Zig → Rust	unknown	unknown	check license	Parser-combinator library for Zig

C TypeScript → Go 6

Repository	Port	~LOC	Size	License	What it does
harrisiirak/cron-parser	TypeScript → Go	Standard (est)	Standard (2k–8k)	MIT	cron expression parser/iterator with timezone
GoogleChromeLabs/jsbi	TypeScript → Go,Rust	1892	Sprint (500–2k)	Apache-2.0	pure-JS ECMAScript BigInt implementation
thachnn/semver-ts	TypeScript → Go	1500-2500	Sprint (500–2k)	ISC (verify)	SemVer parser/comparator in TS
alexewerlof/micromustache	TypeScript → Go	<400	Under 500	MIT	fast small variable-interpolation Mustache subset
gregoranders/ts-csv	TypeScript → Go	200-500	Under 500	check license	simple RFC-style CSV parser
ka-weihe/fastest-levenshtein	TypeScript → Go	100-150	Under 500	MIT	Fastest Levenshtein (Myers bit-parallel)

D Python → Rust 17

Repository	Port	~LOC	Size	License	What it does
jquast/wcwidth	Python → Rust	5000-8000	Standard (2k–8k)	MIT	POSIX wcwidth/wcswidth terminal char-width
kiorky/croniter	Python → Rust	1500-2500	Standard (2k–8k)	MIT	parse cron expr and iterate datetimes
life4/textdistance	Python → Rust	2000-3500	Standard (2k–8k)	MIT	30+ string-distance algorithms, common interface
mdomke/schwifty	Python → Rust	2000-4000	Standard (2k–8k)	check license	IBAN parsing/validation and BIC handling
SethMMorton/natsort	Python → Rust	2000-3000	Standard (2k–8k)	MIT	natural (human) sort ordering of strings
byroot/pysrt	Python → Rust	700-1200	Sprint (500–2k)	GPL-3.0-only	SubRip (.srt) subtitle parser/manipulator
erikrose/parsimonious	Python → Rust	1500-2500	Sprint (500–2k)	MIT	Fast pure-Python PEG parser
jpvanhal/inflection	Python → Rust	500-1000	Sprint (500–2k)	MIT	pluralize/singularize/camelize/underscore English
oubiwann/metaphone	Python → Rust	500-900	Sprint (500–2k)	check license	Metaphone and Double Metaphone encoders
python-parsy/parsy	Python → Rust	<800	Sprint (500–2k)	MIT	monadic parser-combinator library, stdlib-only
rbarrois/python-semanticversion	Python → Rust	1000-1800	Sprint (500–2k)	BSD-2-Clause	SemVer 2.0.0 parse/compare + npm-style specs
scrapinghub/price-parser	Python → Rust	500-1000	Sprint (500–2k)	BSD-3-Clause	extract price + currency from raw text
itsrainingmani/py-ulid	Python → Rust	200-400	Under 500	MIT	ULID generation/parsing (Crockford base32)
Lilykos/pyphonetics	Python → Rust	400-800	Under 500	check license	Soundex/Metaphone/RefinedSoundex/Lein/MRA phonetics
suminb/base62	Python → Rust	150-250	Under 500	BSD	base62 URL-safe encode/decode incl. bytes
toastdriven/pylev	Python → Rust	150-300	Under 500	BSD (New)	Pure-Python Levenshtein distance
zopefoundation/roman	Python → Rust	<300	Under 500	ZPL (verify)	integer<->Roman numeral converter

E Go → Rust 24

Repository	Port	~LOC	Size	License	What it does
BurntSushi/toml	Go → Rust	3000-4500	Standard (2k–8k)	MIT	Reflection-based TOML decoder/encoder (v1.0.0)
dustin/go-humanize	Go → Rust	2000-3000	Standard (2k–8k)	MIT	human-friendly formatting: bytes/SI/commas/ordinals/times
gobwas/glob	Go → Rust	2000-3000	Standard (2k–8k)	MIT	Compile-once glob matcher (lexer->compiler->matcher)
gocarina/gocsv	Go → Rust	2000-3000	Standard (2k–8k)	MIT	CSV <-> struct (de)serialization
gookit/ini	Go → Rust	2000-3500	Standard (2k–8k)	MIT	INI config mgmt, multi-file load, ENV parsing
gorhill/cronexpr	Go → Rust	1500-2500	Standard (2k–8k)	GPL-3.0 OR Apache-2.0	cron expression parser + next-time computation
leekchan/accounting	Go → Rust	2000-3000	Standard (2k–8k)	MIT	money/number formatting with precision + separators
martinlindhe/unit	Go → Rust	3000-4000	Standard (2k–8k)	MIT	physical unit conversions (length/mass/temp/energy/speed)
robfig/cron	Go → Rust	2000-3000	Standard (2k–8k)	MIT	cron spec parser + job scheduler
araddon/dateparse	Go → Rust	1500-2000	Sprint (500–2k)	MIT	permissive date-string parsing via state machine
gosimple/slug	Go → Rust	400-800	Sprint (500–2k)	MPL-2.0	URL-friendly slugify w/ transliteration
jacoelho/banking	Go → Rust	1000-2000	Sprint (500–2k)	check license	IBAN validate/generate + SEPA (ISO 3166-1)
martinlindhe/subtitles	Go → Rust	800-1500	Sprint (500–2k)	check license	subtitle library/CLI (.srt/.vtt/.ssa)
Masterminds/semver	Go → Rust	1500-2500	Sprint (500–2k)	MIT	Parse/compare/sort/constraint-check SemVer
mmcloughlin/geohash	Go → Rust	800-1500	Sprint (500–2k)	MIT	string + integer geohash encode/decode/neighbor
oklog/ulid	Go → Rust	1000-1500	Sprint (500–2k)	Apache-2.0	ULID generation/parsing
spaolacci/murmur3	Go → Rust	1000-2500	Sprint (500–2k)	BSD-3-Clause	MurmurHash3 32/64/128-bit
almerlucke/go-iban	Go → Rust	300-700	Under 500	check license	IBAN validation
itchyny/base58-go	Go → Rust	200-400	Under 500	MIT (verify)	base58 library + CLI (Flickr/Ripple/Bitcoin)
mr-tron/base58	Go → Rust	200-500	Under 500	MIT	fast base58 encode/decode
stefanovazzocell/bencode	Go → Rust	400-800	Under 500	MIT	fast secure bencode parser/encoder, no deps
vaughan0/go-ini	Go → Rust	100-200	Under 500	MIT	Line-by-line INI parser
zeebo/bencode	Go → Rust	500-900	Under 500	MIT (verify)	struct-tag-based bencode encode/decode
sergi/go-diff	Go → Rust	8000-12000	Over 8k	MIT + Apache-2.0	diff-match-patch: diff, fuzzy match, patch apply

F JavaScript → Go / Rust 11

Repository	Port	~LOC	Size	License	What it does
micromatch/picomatch	JavaScript → Go,Rust	2000-2500	Standard (2k–8k)	MIT	zero-dep bash-style glob matcher
MikeMcl/bignumber.js	JavaScript → Go,Rust	2520	Standard (2k–8k)	MIT	arbitrary-precision decimal + non-decimal arithmetic
MikeMcl/decimal.js	JavaScript → Go,Rust	4035	Standard (2k–8k)	MIT	arbitrary-precision Decimal type
tnfe/bbo	JavaScript → Go,Rust	2000-4000	Standard (2k–8k)	MIT (verify)	Zero-dependency JS utility library
bgrins/TinyColor	JavaScript → Go,Rust	1187	Sprint (500–2k)	MIT	color parse/manipulate/convert (hex/rgb/hsl/hsv)
janl/mustache.js	JavaScript → Go,Rust	764	Sprint (500–2k)	MIT	logic-less Mustache templates (scanner/parser/render)
ljharb/qs	JavaScript → Go,Rust	900-1100	Sprint (500–2k)	BSD-3-Clause	query-string parser/serializer with nesting
omichelsen/compare-versions	JavaScript → Go,Rust	200-400	Under 500	MIT	Semver-ish version comparison, zero deps
sindresorhus/slugify	JavaScript → Go,Rust	300-700	Under 500	MIT	slugify a string with transliteration + counter
visionmedia/bytes.js	JavaScript → Go,Rust	<500	Under 500	MIT	human-readable byte-size format/parse
Yomguithereal/mnemonist	JavaScript → Go,Rust	6000-9000	Over 8k	MIT	~50 classic/exotic data structures

G C → Zig 17

Repository	Port	~LOC	Size	License	What it does
cktan/tomlc99	C → Zig	2400-2700	Standard (2k–8k)	MIT	small TOML v1.0 parser in C99
DaveGamble/cJSON	C → Rust,Zig	2000-3000	Standard (2k–8k)	MIT	ANSI-C JSON parser/printer
kgabis/parson	C → Zig	2500-2700	Standard (2k–8k)	MIT	lightweight C89 JSON parser/serializer, two files
lammertb/libcrc	C → Rust,Zig	2000-3500	Standard (2k–8k)	MIT	CRC16/32/64, CRC-CCITT, NMEA checksums
ludocode/mpack	C → Rust,Zig	6000-8000	Standard (2k–8k)	MIT	MessagePack encoder/decoder (tree parser + writer)
antirez/sds	C → Zig	1400	Sprint (500–2k)	BSD-2-Clause	binary-safe dynamic strings (Redis SDS)
cesanta/mjson	C → Zig	1200-1500	Sprint (500–2k)	MIT	no-alloc JSON parser/emitter + JSON-RPC state machine
codeplea/tinyexpr	C → Rust,Zig	600-900	Sprint (500–2k)	zlib	Recursive-descent math expression evaluator
cofyc/argparse	C → Zig	520	Sprint (500–2k)	MIT	command-line argument parser (bool/int/str/subcmd)
getdnsapi/yxml	C → Zig	1240	Sprint (500–2k)	MIT	small non-validating stream XML parser (FSM)
jserv/MathEX	C → Rust,Zig	600-1000	Sprint (500–2k)	MIT	String math-expression evaluator w/ vars & funcs
JuliaStrings/utf8proc	C → Zig	782 core + big table	Sprint (500–2k)	MIT	UTF-8 Unicode processing (NF, case-fold, graphemes)
kokke/tiny-regex-c	C → Zig	550	Sprint (500–2k)	Unlicense (PD)	tiny regex engine, no malloc/recursion
phoboslab/qoi	C → Rust,Zig	600	Sprint (500–2k)	MIT	Quite OK Image lossless codec (single header)
skeeto/pdjson	C → Zig	1030	Sprint (500–2k)	Unlicense (PD)	streaming/pull JSON parser, full UTF-8 + surrogates
benhoyt/inih	C → Rust,Zig	300-500	Under 500	BSD-3-Clause	Minimal embeddable INI parser
zserge/jsmn	C → Rust,Zig	~200	Under 500	MIT	Minimal JSON tokenizer (embedded)

H Open pair (X → Y) 19

Repository	Port	~LOC	Size	License	What it does
harrisiirak/cron-parser	TypeScript → Go	Standard (est)	Standard (2k–8k)	MIT	cron expression parser/iterator with timezone
java-diff-utils/java-diff-utils	Java → Rust,Go	2500-4000	Standard (2k–8k)	Apache-2.0	diff/patch: Myers diff, patch apply, unified-diff parse
micromatch/picomatch	JavaScript → Go,Rust	2000-2500	Standard (2k–8k)	MIT	zero-dep bash-style glob matcher
MikeMcl/bignumber.js	JavaScript → Go,Rust	2520	Standard (2k–8k)	MIT	arbitrary-precision decimal + non-decimal arithmetic
MikeMcl/decimal.js	JavaScript → Go,Rust	4035	Standard (2k–8k)	MIT	arbitrary-precision Decimal type
olbrich/ruby-units	Ruby → Rust,Go	2000-3000	Standard (2k–8k)	MIT	units-of-measure: parse/convert/arithmetic
0xd34df00d/hsqoi	Haskell → Rust	500-1000	Sprint (500–2k)	check license	Haskell QOI codec
bgrins/TinyColor	JavaScript → Go,Rust	1187	Sprint (500–2k)	MIT	color parse/manipulate/convert (hex/rgb/hsl/hsv)
canton7/sem_version	Ruby → Rust	300-600	Sprint (500–2k)	MIT (verify)	SemVer 2.0.0 parse/validate/compare
GoogleChromeLabs/jsbi	TypeScript → Go,Rust	1892	Sprint (500–2k)	Apache-2.0	pure-JS ECMAScript BigInt implementation
HoldOffHunger/roman-numerals	PHP → Go	500-1500	Sprint (500–2k)	check license	Roman numerals extended (to trillions)
janl/mustache.js	JavaScript → Go,Rust	764	Sprint (500–2k)	MIT	logic-less Mustache templates (scanner/parser/render)
janlelis/paint	Ruby → Rust,Go	500-800	Sprint (500–2k)	MIT	terminal ANSI colorization (truecolor/256/16)
ljharb/qs	JavaScript → Go,Rust	900-1100	Sprint (500–2k)	BSD-3-Clause	query-string parser/serializer with nesting
yougov/fuzzy	Python → Rust	500-1000	Sprint (500–2k)	check license	fast phonetics (Soundex/NYSIIS/Double Metaphone, Cython/C)
jlindsey/semantic	Ruby → Rust	200-400	Under 500	MIT	SemVer parse/compare class
machinateur/roman-numerals	PHP → Go	<300	Under 500	check license	Roman numeral converter (PHP)
visionmedia/bytes.js	JavaScript → Go,Rust	<500	Under 500	MIT	human-readable byte-size format/parse
Yomguithereal/mnemonist	JavaScript → Go,Rust	6000-9000	Over 8k	MIT	~50 classic/exotic data structures

104 repositories across 8 tracks. Again: use one of these or bring your own.