EntityExpander.expand located the next '&', '<', and ';' with String.firstIndex
over graphemes, so every literal byte of a run was decoded into a grapheme just
to look for a one-byte marker. All three markers are ASCII, so a UTF-8 index is
a valid string index: scan over raw.utf8 instead, and the found index still
subscripts the string directly (the marker byte is never a continuation byte,
so its index lands on a scalar and grapheme boundary).
The decoded text is unchanged, including runs where the marker follows
multibyte UTF-8: a precomposed letter, a combining sequence, or an astral
character all leave the marker on a grapheme boundary.
Measured parse ~5.5% faster on the 20k-item generated corpus via a same-state
A/B (6.5x to ~6.1x slower than libxml2). Verified by EntityDecodeBulkTests
(extended with four multibyte-boundary cases), the W3C XML conformance corpora,
the Xalan XSLT gold-output corpus, the full suite, and the WASM build.
EntityExpander.expand rebuilt every reference-bearing text run one character at
a time: result.append(character) per character, with a per-character charge
against the amplification budget. A text node holding a single & was copied
grapheme by grapheme, which is the bulk of the per-text-node cost in a document
whose content uses entities.
Scan to the next '&' or '<' and append the literal run in one operation,
charging the budget by the run length. The decoded text, the CDATA-verbatim
shielding, and the billion-laughs budget enforcement are unchanged: the same
overrun throws at the same input, since charging a run of length L against
budget B fails exactly when L > B, the same condition the per-character guard
enforced.
Also return early from recordReferenceContentFindings when there are no DTD
content models (the common no-DTD case): it otherwise scanned each text run for
'&' and rendered the enclosing element's qualified name before the model lookup
that would fail anyway.
Measured parse ~5% faster on the 20k-item generated corpus via a same-state A/B
(9.06x to ~8.5x slower than libxml2). Verified by the W3C XML conformance
corpora, the new EntityDecodeBulkTests six-case decode differential, the full
suite, the Xalan XSLT gold-output corpus, and the WASM build, with an
adversarial equivalence review of the rewrite.
The eduni sections run with exact classified baselines. Fixes: 3.3.3
CDATA attribute-value normalization (literal whitespace to space before
reference decoding; char-ref whitespace survives; tokenized collapse on
SPACE only); production-68 lenient undeclared entities in content and
attribute values (validity finding, reference kept literal, nothing
fetched); errata E15 (references/comments/PIs/whitespace in EMPTY,
char-ref whitespace as data in element content, double-escape shape
included); errata E2 duplicate enumeration tokens; errata E14
declarations completed inside PE replacements (VC: Proper
Declaration/PE Nesting); NCName ID values; namespace declarations
subject to the every-attribute-declared rule. Reader validity machinery
split to EventReaderValidity for caps.
Closes#127
A general entity whose replacement text contains markup (directly or
transitively) is reparsed as content at the reference (4.4.2 Included):
the replacement is WFC-validated, cycle-checked, and budgeted, then
pushed back into the reader stream, so its elements become elements in
the tree and the pull-event stream rather than escaped character data.
Character references in internal entity literals now expand at
declaration time for general entities too (4.4.5), making char-ref
markup splice and the Appendix D double escape render as a literal
ampersand; the reference-time WFC validates remaining references
instead of re-expanding. Text-only entities keep the coalescing
single-pass path. Sun valid is 28/28.
Closes#133
Implement the replacement-text constraint at the point of reference: when a
general entity is included, its replacement (character references expanded
as at declaration time) must reparse as balanced content in isolation, via a
new EntityReplacementGrammar mini-parser. This rejects a bare or incomplete
reference ('&', '	' unterminated), tags spanning the entity boundary
('</foo><foo>'), a raw '<' or incomplete reference inside an embedded
attribute value, '<' followed by a non-name character, and a reserved-target
PI in the replacement, exactly the suite's semantics, including that an
UNREFERENCED entity may carry any value and that only the first declaration
of a name binds. Attribute-list defaults must reference already-declared
internal (not external/unparsed/forward-declared) entities with a
non-recursive chain. A CDATA section inside replacement text now shields its
content from reference expansion, fixing the last valid-side case.
W3C xmltest final standing: valid/sa 119/119, not-wf/sa 180/186, with the
six remaining deviations all deliberate and documented in the baseline:
internal-subset conditional/CDATA sections (063, 107) and parameter-entity
references (160-162) are features this package supports, and 141 expects the
1998 suite's name-character classes where this package implements XML 1.0
Fifth Edition's. Zero false positives across all 846 tests at every step.
Closes#120
Character references now require lowercase 'x' for hex and a referenced code
point inside the XML Char production (rejecting �, , ,
surrogates, and X). The reserved 'xml' processing-instruction target
(any case) is legal only as the declaration at the document's very first
bytes: whitespace or a comment before <?xml ...?>, a declaration inside
content or after the root, and case variants like <?XML?> are all rejected.
Comments and PI data are checked for the XML Char production like content.
not-wf/sa: 109/186 rejected (from 93); valid/sa unchanged at 118/119; all
846 suite tests green, baseline rebased to the exact 77 remaining (the
internal-subset grammar and entity replacement-text classes on #120).
Part of #120, #105
The whole-buffer ISO-2022-JP, GB18030, and EUC-TW decoders index the input
ArraySlice directly instead of materializing an Array first (one avoidable
O(n) allocation per decode each); declaredEncoding's subsequence scan uses
elementsEqual instead of allocating an Array per candidate offset. Document
the two analysis-flagged bounds: entity expansion is doubly bounded (the
character budget caps output; the visiting set caps recursion depth at the
number of declared entities), and the RELAX NG derivative engine carries no
memoization by design (the simplifying constructors keep real grammars
small; adversarial nested-choice grammars can grow the residual, so treat
untrusted schemas accordingly). Behavior unchanged, all suites green.
Closes#118
Add opt-in DTD processing behind Limits(allowDoctype:), off by default. When on,
DoctypeScanner reads the <!DOCTYPE> internal subset and honors internal
<!ENTITY name "value"> general entities, which EntityDecoder expands recursively
in text and attribute values.
Safety is mandatory and reimplemented from the Expat amplification-accounting
model (no upstream code copied):
- only entity-expanded characters count against a shared budget
(Limits.maxEntityExpansion); overflow raises amplificationLimitExceeded, which
defeats billion-laughs.
- a visiting set detects recursive entities (recursiveEntity).
- undeclared references raise undefinedEntity.
- external entities are never stored or loaded, so XXE stays closed.
The default still rejects <!DOCTYPE>. 8 DTD tests (incl. billion-laughs and the
external-entity refusal); 49 total.
Replace the notImplemented stub with a real parser built on a pull-based,
streaming event core that never requires the whole document in memory.
- Parsing.EventReader: pulls characters through a source closure with a bounded
lookahead buffer and emits one Parsing.Event at a time, holding only an
open-element stack. Drives chunked/streamed input.
- Parsing.Parser: builds a Model.Node tree iteratively over the event core
(explicit stack, no recursion).
- Reader: streaming character cursor (closure-backed, bounded buffer) replacing
the previous whole-string Array.
- EntityDecoder: the five predefined entities and decimal/hex char references.
- Handles elements, attributes, text, comments, CDATA, processing instructions,
and an XML declaration in the prolog. Rejects <!DOCTYPE> by default (no
DTD/XXE/entity-expansion exposure).
- Top-level API: parse(_:), parse(pulling:), events(_:), events(pulling:).
- 21 tests including event-stream and chunked-source coverage.
