Elamur Groupantsmathlib-http-codecs
The groupant beside tools/mathlib/src/http.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | partial | invariant-and-cost |
| descriptant | present | descriptant |
| invariant | partial | invariant-and-cost |
| tests | bounded checks | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
byte_length | byte_length | partial source derived model | byte_length |
escape_idempotence | escape_idempotence | partial source derived model | escape_idempotence |
era_boundary | era_boundary | partial source derived model | era_boundary |
calendar_projection_scope | calendar_projection_scope | partial source derived model | calendar_projection_scope |
Model text
descriptant
mathlib-http-codecs
hex emits two lowercase digits per byte; encode emits unreserved ASCII or uppercase %HH per byte; civil maps bounded signed day offsets by Euclidean Gregorian eras.
Epoch 2026-10-31
Prospective model retained before changes. Existing production bytes are preserved; additions are bounded inline tests. Nine source groupants expose ingestion and routing boundaries; typed children bind exact source bytes and reuse their parent syntax projection. Native tests run twice per profile; behavior mutants run as compiled source changes and exact bytes are restored before positive checks.
Important retained observation: network-looking helpers are not all pure (DNS inside github_host and books build); selection deliberately excludes those effects. Mixed-format manifest order is not deterministic, and error paths do not imply rollback.
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
approximant
Forward relation
hex emits two lowercase digits per byte; encode emits unreserved ASCII or uppercase %HH per byte; civil maps bounded signed day offsets by Euclidean Gregorian eras.
Model observations include returns, retained state and ordered partial effects; on external failures the successful-prefix relation replaces a total-function claim.
catalog
behavior_complement
Subject: mathlib-http-codecs, source SHA-256 3df63f2ba1d7bcdb4f0bf02fa7c7a1f0feb5817d22f7409456945ccf6a57aa32; finite transition observation.
Canonical encode output never contains literal space, slash or non-ASCII; hex contains only lowercase ASCII hexadecimal characters.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
reverse_reconstruction
Subject: mathlib-http-codecs, source SHA-256 3df63f2ba1d7bcdb4f0bf02fa7c7a1f0feb5817d22f7409456945ccf6a57aa32; finite transition observation.
hex decode and canonical percent decode uniquely recover bytes on their image. Civil inverse determines day number only for valid Gregorian triples in the bounded nonoverflowing domain; utc_now formatting loses subsecond precision.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
byte_length
Subject: mathlib-http-codecs, source SHA-256 3df63f2ba1d7bcdb4f0bf02fa7c7a1f0feb5817d22f7409456945ccf6a57aa32; finite transition observation.
UTF-8 é has two encoded bytes and output %C3%A9 length six; counting code points would give a wrong cost/output-length model.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
escape_idempotence
Subject: mathlib-http-codecs, source SHA-256 3df63f2ba1d7bcdb4f0bf02fa7c7a1f0feb5817d22f7409456945ccf6a57aa32; finite transition observation.
encode is not idempotent: encoding %2F gives %252F. It is a value encoder, not a normalizer of already-escaped URLs.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
era_boundary
Subject: mathlib-http-codecs, source SHA-256 3df63f2ba1d7bcdb4f0bf02fa7c7a1f0feb5817d22f7409456945ccf6a57aa32; finite transition observation.
civil(-1)=1969-12-31 and civil(11017)=2000-03-01; leap handling follows century/400-year terms. Fixtures constrain boundaries, not all i64 arithmetic.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
calendar_projection_scope
civil's output is a date triple; utc_now computes days=secs/86400 and rem=secs%86400, then appends whole-second clock fields. Different subsecond instants share output; civil itself has no clock or filesystem effects. Extreme i64 offsets can overflow before era decomposition and are outside the stated domain.
Subject and source identity: manifest.json. Domain: scoped forward/invariant; relation is source-derived and partial. Evidence: tests.md distinguishes actual checks from unexecuted effect paths; finite fixtures do not prove all inputs.
tests
Bounded evidence
Selected actual source checks:
- mathlib::http::tests::encodes_and_dates
- mathlib::http::wave33::byte_codecs_and_civil_boundaries
These checks are file-level evidence; fragment branches not reached by these names remain source-derived.
External wave33 mathlib receipt retains native-commands.json, numeric statuses, raw debug/release logs, sorted exact outcomes, mutation logs and original/restored hashes. Seventeen named checks pass twice per profile; six production behavior mutants reject in both profiles, with restored positives. Source syntax is regenerated twice after formatting and compared byte-for-byte. Structural validation tests bindings, not Rust semantics.
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
invariant-and-cost
Invariant and cost
Invariant
Hex output length=2n. Encoded output length=n+2k for k non-unreserved bytes. Empty input maps empty for both codecs.
Cost
O(input bytes) codecs; civil fixed arithmetic work, subject to nonoverflowing signed offsets.
Domain and gaps
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/tools/mathlib/src/http.rs.groupant/codecs.groupant/