TIFF predictor 2 (ISO 32000-2 §7.4.4.4, Table 10) went through the
bit-level BitChunks/BitWriter path for every bit depth, re-reading the
previous output pixel through a new BitReader per pixel. Whole-byte
samples (8 and 16 bits per component) are now undone on byte slices,
each sample added to the same component of the pixel to its left,
wrapping at its width; 1-, 2- and 4-bit samples keep the bit-level path.
The output is byte-identical, including the dropped partial last row.
A page of 45 full-page 8-bit grey images so predicted (PDFBOX-1350)
renders in about 4 s instead of 23 s with the same pixels.
Vendored hayro-syntax patch 42.
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
Co-authored-by: mtlcl410 <chuanlin@niar.org.tw>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
- Pdf::new_with_password reads the table the last startxref names first: a wrong password is
refused through it, and the rebuilt table is taken only when it is encrypted exactly when
that table is.
- Tests: an encrypted file with a cut-off update needs its password; data after %%EOF holding
an object header reads as the document model reads it (both take its page).
- vendor/README.md lists the split tests.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
The renderer (hayro-syntax (44)) counted the sections its chain reached, and
a hybrid section's /XRefStm stream (ISO 32000-2 §7.5.8.4) counted as one, so
a hybrid update without /Prev was rebuilt by cos but not by the renderer. It
now asks what cos asks: whether the newest section names an earlier one
through /Prev. The /XRefStm stream belongs to the same update.
Tests: a synthetic hybrid fixture (pdfcraft-testkit), with and without
/Prev, in cos and render.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
An update whose cross-reference section has no /Prev (ISO 32000-2 §7.5.6,
§7.5.8.2) cuts the earlier revisions, and the page tree with them, off the
chain. The signed PDFBOX-2720 and PDFBOX-2942 files have this shape: the
document model found no page tree and the renderer showed 2 blank pages
found by scanning for page dictionaries.
When the chain reaches only the newest section, the file holds another
startxref and the catalog's /Pages can't be read, both readers now rebuild
the table from the file's objects, as for a damaged file:
- cos: the existing reconstruction (newest in-file definition wins), a
repair-log line saying why, and `Document::rebuilt_unlinked_update`.
- hayro-syntax (44): `root_xref` repairs the table before the page tree is
read; `Pdf::rebuilt_unlinked_update` says so.
- render: an open warning, and the lazy structure reader accepts such a
rebuilt file, so links, fields and bookmarks are read too.
A save rewrites the file in full (main's rule for reconstructed files).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
- hayro-syntax patch 44: a /MediaBox without area counts as missing, so
the page is sized, placed and clipped by the same Letter region and its
content is drawn (MuPDF and PDFium both draw it on 612 x 792).
- pdfcraft-model: Page::crop falls back to Letter for such a box too.
- vendor/README.md: the raw-crop summary names the Letter fallback.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
A page with no /MediaBox, its own or inherited, rendered as A4, while
PdfCraft's page model and inspector already sized it as US Letter and
other readers draw it at 612 x 792 pt (PDFBOX-4001-reduced.pdf).
ISO 32000-2 §7.7.3.3 Table 31 requires the box and gives no default;
follow the readers. `base_dimensions`' fallback for a visible region
without area uses the same Letter size, so a /MediaBox [0 0 0 0] page
is Letter too. Vendored hayro-syntax patch 44. The model test pins the
size it already gave.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
When a file's last incremental update stops after its cross-reference rows,
with no trailer or startxref, the last startxref in the file is the older
revision's. pdfcraft-cos finds no startxref in the last 4 KiB and rebuilds
from object headers (latest objects win); vendored hayro-syntax read the older
table, so the view showed the older revision (PDFBOX-3934: 12 pages, the model
13). ISO 32000-2 §7.5.6: a later section supersedes earlier ones; repair is
unspecified and PDFium, MuPDF, Poppler and qpdf take the latest objects.
hayro-syntax patch 43: when the last startxref is more than 4 KiB from the end
and N G obj headers follow it, Pdf::new_with_password rebuilds first; the older
table is read only when the rebuilt one has no page. Trailing data without
object headers and a startxref near the end read as before.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
A CCITTFaxDecode image whose /DecodeParms /Rows exceeds the image's
/Height (PDFBOX-771: /Rows 1084975104 on 2,592 columns) asked the decoder
for /Rows rows; the size check refused that, and every page drew blank.
The image is /Height rows (ISO 32000-2 Table 87), so the decoder is asked
for those; /Rows still counts for a stream decoded without an image's
height. pdfcraft-cos already decodes /Height rows; a test pins it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
A writer declared /Predictor 15 on an image and its soft mask without
applying it, so the inflated data is exactly /Height rows of the row length
with no filter-type byte before each (ISO 32000-2 §7.4.4.4 requires one per
PNG-predicted row). Read with the predictor, every row's first sample was
taken for a filter type, the image came out a row short and shifted, and the
page drew it in fragments; image export said its data was shorter than its
size. PDFium, MuPDF and Poppler read such data as the samples it is.
Only that exact length takes the new path, and only for the last Flate
filter of an image whose height is known; anything else is predicted as
before. The renderer (vendored hayro-syntax, patch 40) reports it with
warn!, like its other lenient filter decodes; pdfcraft-filters returns it as
tolerated damage (partial in tolerant decoding, an error in strict), through
the new decode_image_tolerant_within that pdfcraft-cos uses for images.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
The previous commit was made on main's newer head with the older tree, so
it undid #977 and other changes from main. This commit puts main's files
back: the PR changes only vendor/hayro-syntax/src/page.rs, vendor/README.md
and crates/render/src/text/tests.rs again.
Review: a page's own box without area now gives way to an inherited one
with area before the default (A4 for a media box, the media box for a crop
box); the test adds a page whose own /MediaBox [0 0 0 0] inherits a larger
box with text past A4.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
A /MediaBox without area ([0 0 0 0]) is read as a missing one (the
default page), and a /CropBox without area, or with none in common with
the media box, as a missing one (the media box, ISO 32000-2 §14.11.2,
Table 33). Kept, the page's visible region had no area: nothing was drawn
and no text was extracted.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
The empty password opens an EFOpen-only document as no password does,
and the credentials of one opened without the key open no other. An
embedded file may name its EFOpen filter in a /Crypt filter of its own,
with no /EFF; handlers older than crypt filters (V1, V2) don't qualify
(hayro-syntax patch 36 too). Saves without the key refuse what they
would have to encrypt: a removed /Encrypt, or an edited or added
embedded file. The password given after opening unlocks the embedded
files, unless one read as stored has been edited.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
A crypt filter whose /AuthEvent is /EFOpen needs its password only when
an embedded file is accessed (ISO 32000-2 7.6.6, Table 25). A document
whose strings and streams are in the clear (/StmF, /StrF /Identity) and
whose encrypting filters are all EFOpen ones, /EFF naming one, now opens
without a password in cos and in the renderer (hayro-syntax patch 36).
Without the password there is no file key: the embedded files' data is
held and saved as stored, and Document::embedded_files_locked and
reads_as_stored say so. Asking for such an attachment's bytes is an
error. A full save that would renumber data whose key mixes in the
object number (RC4, AES-128), or change the document's security, is
refused. The password still opens the document and its attachments.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
ISO 32000-2 7.3.8.2: Length "indicates how many bytes of the PDF file are
used for the stream's data". cos and hayro-syntax used /Length only when
`endstream` followed it, and otherwise searched for the keyword; with
none left in the file the stream was an error and its object null. A
producer that writes `endstrea` after every stream lost every font and
every page's content, and its pages drew blank with no warning. With no
`endstream` left, a /Length the file holds is now the stream's extent.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn
* M1: a crypt filter selected by reference is used
A stream can name its own crypt filter, and every part of that can be indirect. cos read only the
direct forms, and took anything else for no name, which is /Identity. So a stream selecting a filter
by reference was saved in the clear in a file meant to be encrypted, and in a file from elsewhere
its ciphertext was read as data. The /Encrypt dictionary's /StmF, /StrF, /EFF, /CFM, /Filter,
/EncryptMetadata and a filter's /Length had the same fault, and /StmF by reference left every
stream undecrypted. A stream's /Type and a signature dictionary's are read through references too.
transform now reads these from the document, so a full save encrypts before it renumbers: the
references in what it reads have to be the document's. Dropping a crypt filter that new protection
doesn't define comes before the walk, so what it copies out of a reference is encrypted too.
Loading can re-enter here, and LoadGuard ends a cycle, which reads as absent. A chain longer than
any decoder takes names no filter: its entries would be followed for every stream sharing it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M2: a stream with a crypt filter of its own is drawn
The renderer decrypted every stream with the document's filter and then failed on /Crypt as a filter
it couldn't decode, so a stream naming its own filter read as nothing, however it was spelled, and a
page whose content was such a stream stayed blank. It now uses the filter the stream names, /Identity
without one, and /Crypt is nothing further to decode (hayro-syntax patch 30).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: tests for a crypt filter's place among the others
A lone parameter dictionary is the first filter's, so /Crypt behind another filter has no name of
its own, and an array too short for /Crypt's entry stays as it is when the filter is dropped.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: encryption reads every legal form, and a full save keeps them
From a review of the crypt filter fix.
The renderer read a stream's own filter from the form /DecodeParms had to match the form of /Filter,
so [/Crypt] with a lone dictionary, an everyday spelling, read as /Identity and the page stayed
blank. Parameters are now taken in either form, which also gives [/FlateDecode] its predictor.
It also refused a V4 file without /StmF or /StrF, which are optional, and used a /CF entry named
/Identity, which is never one. A chain past what cos decodes names no filter there, so it names none
here either (hayro-syntax patch 30).
A full save lost what a direct /Encrypt refers to, and kept its references under the old numbers, so
nothing in the file read afterwards. /O or /U given by reference were decrypted and encrypted again
under a new number, so the file it wrote no longer opened. What /Encrypt and /ID refer to now stays
as stored. /ID by reference, which has to be direct, is read, and written direct.
A signature dictionary is known by a /ByteRange given by reference, and a null or dangling /Type or
/Subtype is an absent one. References to references are followed in Document::resolve, so /Name by
way of two no longer saves a stream in the clear. New protection drops every /Crypt in a chain.
An object stream's /DecodeParms can be given by reference.
Reading what decides how an object is treated can load more objects, each doing the same, which a
file could make a tree that doubles with every level once the cache lets go of it. What is loaded
for one of these no longer follows its own.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: what a read follows is bounded by a budget, and nothing shared is copied per stream
From a review of the fixes before this, all in them.
A flag that kept what is loaded for a selector from following its own stopped the fan-out, but a
legal file lost object stream members to it: read first through a selector, an object stream with
parameters by reference was kept undecoded, and a full save wrote nulls without saying so. A budget
replaces it: one read or write of an object, with all it loads on the way, follows up to 32
references, which is more than any object needs when all of it is by reference. Past that they
read as absent, so a file's ladder of selectors still stops, and nothing a real file holds is lost.
Finding out whether a dictionary is a signature's loaded objects for every dictionary of an object,
and a load that fails takes a scan of the file, so one read could hang. Only a dictionary with a
direct string /Contents is asked now, and the budget bounds those.
/ID written direct copied every entry, so a 1 MB file naming a large string thousands of times ran
out of memory: it is at most two strings now. Dropping a crypt filter copied a shared /DecodeParms or
/Filter into every stream, 1 GB from a 1 MB file: of what's shared only filter names and the
parameters decoders read are copied now, through Document::with_direct_parms.
The renderer skips /Crypt in a chain instead of copying the data for each entry.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: only an object itself follows references, and a failed scan is remembered
From a review of the budget.
Following a reference while walking deep inside an object added that depth again for each object
loaded, which overflowed a 2 MiB stack on a file under 10 KB and took the process with it, past any
catch_unwind. References are now followed for the object itself and never for what is nested in it.
A stream can't be nested, and a signature dictionary nested in another object reads as it says
directly, as it did before this PR. walk is back to following nothing.
A reference that fails to load scans the file, and nothing remembered that, so a 1 MB file took
minutes to save. What a scan didn't find is kept for the document: the file doesn't change.
Filter names copied out of a shared chain are bounded, since a name can be any length. /ID keeps each
entry in its place, or the key made from the first entry changes. direct_id's comment was on another
function.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: tests with no deadline a busy machine can reach
Wide margins on the two that time what they guard. A test of dictionaries nested in an object goes:
nothing nested follows a reference now, which the small-stack test covers.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: a crypt filter past what a read may follow is the document's own
Past the budget a reference reads as absent, and a crypt filter with no /Name is /Identity, so a stream
that selected one by reference had its ciphertext read as data. What can't be told takes the document's
filter, as a /Filter that can't be read does.
Found by CodeRabbit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: a read refused, not a budget full, is what leaves a crypt filter unknown
My last commit took a read that used up all it may follow for one that was refused, so an /Identity
stream read at exactly 32 follows was decrypted to garbage. Refused reads are counted now, and only
one on the way to this stream's /Name says anything about it.
Found by CodeRabbit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* M1: a save keeps the handler, the key and the permissions
Under every algorithm and by either kind of save, `/Encrypt`, `/ID`, the file key and the permissions
come back as they were. No test held that. `/ID` by reference is held through an incremental save
too, which leaves it as it was.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
* cos: encrypt an edited or added object whatever /Encrypt names
stored_as_is now also requires the object to be unedited, so an edit of
an object /Encrypt or /ID refers to, or a new object given a number they
name, is encrypted on both saves. encryption_members skips numbers with
no object behind them and streams, which those dictionaries never hold.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: FredApps <153173854+FredApps@users.noreply.github.com>
* A rebuilt xref finds an object whose header names another generation (#5580)
`poppler-85140-0.pdf` is 340 bytes with no cross-reference table, and the
header of its one page reads `3 18446744073709551616 obj` while the page tree
points at `3 0 R`. Before #427 the digits wrapped and 2^64 wrapped to exactly
0, so the header read as `3 0 obj` and the file opened by accident. Once an
overflowing integer became a real, the object was unreachable and the file
stopped opening at all, which `cargo xtask check` reports as a regression.
The generation is not really the point. `3 99999 obj` with the same page tree
is refused in exactly the same way on main -- the control for the new test
fails on that row first, with "page 1 does not exist" -- so this is a
mismatched generation in a rebuilt table, not an integer overflow. A table
rebuilt by scanning the file has no revision history to tell two generations of
an object apart, and a file that needs rebuilding references everything as
`N 0 R` whatever its headers say.
So, in the reconstruction path only:
- a generation number that cannot be read is taken as 0, the value such a
file's references use (`read_object_header`). A generation is at most
65,535 (ISO 32000-2 §7.5.4), so there is nothing to lose by it;
- every scanned object is also filed under generation 0, with `or_insert` so
a real `N 0 obj` is never displaced by the alias;
- the object is read back behind the same lenient header, since reading it
parses the header again and the strict identifier check rejected it
(`read_repaired_body`, gated on `repaired`).
Reading numbers anywhere else is unchanged, and a table read from the file's
own xref keeps the exact identifier match. The scan already files objects found
in object streams under generation 0, and cos's table parser already takes an
unreadable generation as 0, so this follows what the code does elsewhere.
The test covers generations 0, 99999 and 2^64 with no table and no `startxref`,
and asserts the page is found at its own size. Its fixture is built in the test
rather than taken from the corpus, so it holds without the pinned checkout.
* The generation-0 stand-in is one key, not a second object
Two consequences of filing a scanned object under generation 0 as well,
both from review.
`XRef::objects` walks the table's keys, so an object with a stand-in came out
once per key: a document whose page tree cannot be read is recovered by looking
for objects that are pages, and it reported the page twice. Enumeration now
yields one object per location, after the sort it already does. Both keys stay
for lookups; only this walk is deduplicated.
And `or_insert` never replaces, so a later `3 1 obj` moved the exact `3 1` key
to the later body while the `3 0` stand-in stayed on the earlier one -- `3 0 R`
and `3 1 R` would then read different objects. The scan now tracks which
generation-0 keys are stand-ins: a real `N 0 obj` takes the key and keeps it,
and a later header for the same number replaces a stand-in.
The tests check both through what comes out: page 2 must not exist for a
single-page file recovered without a page tree, and with two `3 1 obj` headers
the page comes back at the later body's 300x150 rather than the earlier
200x100.
* M2: the repair scan keeps its place on a non-header, and an object stream's first member is enumerated (#5580)
- read_object_header's lenient path works on a clone, so `42 3 0 obj` no longer costs the
header after the stray number (CodeRabbit, minor).
- XRef::objects deduplicates by location and object number: an object stream and its first
member share (offset, 0) and are two objects (CodeRabbit, minor).
- vendor/README.md: hayro-syntax patch (34) and its tests.
Both new tests fail with their fix reverted.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Brandon Thomas <echelon@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
They use std::thread and std::sync::mpsc, so they take the same gate, and
so does the helper only they use. The crate's test build doesn't compile
without std on main either, for reasons of its own; these add nothing to
that.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
`IndirectObject<f32>` read an object holding `6 0 R` as the number 6, so `/Decode [11 0 R 0]`, with
11 naming 6 and 6 holding 1, read as 6, and `/W` gave glyphs such widths. As anything but a number,
such an object was lost.
`XRef::get_with` is how every reference is read, to an object stored on its own or in an object
stream, so it now follows such objects in a loop, up to 32 references as `Document::resolve` does in
#5548. A loop takes no stack however long the chain, and a cycle runs out of references and reads as
a missing object, as a reference to nothing does: the image with such a `/Decode` isn't drawn, as
with `/Decode [99 0 R 0]`.
An object stream isn't reached that way: it has to be a stream stored as that object, and following
a reference to one stored inside another let a 1 KB file run out of stack. `XRef::objects` leaves
such objects out, or a page came out once more for each one holding a reference to it, and a comment
inside a reference counts as white space, as it does everywhere else.
Reading an object stream's index now counts against the 64 nested loads, and reads its dictionary
alone. That is older than this branch, which only made it slightly worse: a chain of object streams,
each with a member of the next for its `/N`, `/First` or `/Length`, recursed with no limit, holding a
copy of the chain at each, and aborted on 750 KB with an 8 MiB stack, or 250 KB with 2 MiB, in a test
build. Parsing the stream read `/Length` as well as `/N`, two ways to the next stream's index, and a
failed index isn't remembered, so the work doubled at each stream: 20 streams in a ring took 20 s on
`main`. ISO 32000-2 7.5.7 keeps an object stream's `/Length` out of object streams, so no legal file
has a `/Length` chain. Nothing forbids `/N` or `/First` by reference, though no writer I know of makes
such a chain. Past the limit it reads as missing unless a stream within 64 of it has been read.
`/W` and `/W2` with their list by reference are tested too.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
From a review of who reads a refusal.
The rule is to leave it out and say so, and it held on some paths only. An image whose JBIG2 mask is
refused no longer comes out opaque. The first image past the allowance reads as that and not as
corrupt. A page reports what it left out. The Office warning stopped blaming forms. Redaction refuses
the run, leaving the document as it was: removing a readable image whole would take what no mark
covers with it, unreported.
The 2 GiB an export holds is twice the document if that is more, so a large honest file loses nothing.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
One image has its own limit, about 6 s to 17 s, but nothing bounded a file of thousands of images
made to reach it: an operation took that long for each, and an image sharing /JBIG2Globals decodes
them again.
Image::decode_within (hayro-jbig2 patch 11) spends from what a run may still do, starting with its
page's pixels, and charge_reading charges reading a stream and its globals, 4 steps a byte, before
anything is parsed, so an image that fails has paid too. pdfcraft_filters::decode_jbig2_within takes
it, and ImageBudget in cos is that allowance: 2^34 steps, about 1,000 scanned pages, and 2^13 more for
each byte of the file, so a long scan is read whole. An image past it spends all that's left, and
later ones aren't read, globals included.
Optimize leaves such an image as it is and counts it in Report::images_refused. Image export leaves it
out, with the reason, and stops at 2 GiB of files held. Office export shares one allowance, leaves the
picture out and says the page was truncated. Redaction removes it whole, as any image it can't read.
Rendering gives a page's images 2^30 steps between them, inside the watchdog, and each page starts
afresh in Context::new as its other budgets do (hayro-syntax patch 31, hayro-interpret patch 73).
It's a thread-local, unbounded until a page sets it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
Two more ways a reference was lost in the same readers. A Pattern space read its family name twice,
which took the underlying space when that was a name or a reference, so an uncoloured pattern took
its components as RGB: [/Pattern /DeviceCMYK] drew a cyan as red, direct names included (patch 72).
Tuples of array items, which /Decode, /W and /W2 are read as, took a reference at their start for the
whole tuple. A tuple can't be given by reference, so it was lost and the array ended there: an image
with /Decode [7 0 R 0] wasn't drawn, and CID widths fell back to /DW. A tuple now reads its items
directly, and each follows its own reference (hayro-syntax patch 32).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
Each JBIG2 bitmap was bounded on its own, but a few kilobytes could still exhaust memory:
nothing bounded what a page's segments hold for later ones, or how far one segment could
multiply them. Measured on black-box streams, peak memory before and after:
- intermediate regions, 16 in 774 bytes: 514 MiB, now 98 MiB;
- an 8 MiB symbol exported 1,200 times, a 2,989-byte PDF: killed at 8 GiB, now 79 MB;
- dictionaries of zero-width symbols: 781 MB, now 72 MB;
- dictionaries retaining their coding contexts, 1.1 MB: 2.89 GB, now 71 MB;
- 65,535 references to one dictionary, 78 KB: about 17 GB, now 6 MB;
- a halftone grid of 16,384 cells a side, 98 bytes: 1.1 GB, now 2.4 MB;
- a pattern dictionary of 65,535 patterns, 48 bytes: 539 MB, now 15 MB, and it still draws;
- a custom Huffman table behind nested Flate, a 1,297-byte PDF: killed at 8 GiB, now 278 MB,
which is mostly the decoded stream;
- 11-byte segments behind nested Flate in a stream and its globals, a 4,765-byte PDF: 5 GB, now
602 MB, which is mostly the two decoded streams;
- an Indexed image whose page header claims 2^20 a side, a 743-byte PDF: aborted asking for
137 GB, now 23 MB;
- a chain of 4,000 /JBIG2Globals streams that are JBIG2 themselves, on a 2 MiB stack: overflowed
it and aborted, now 24 MB.
So PageState counts what it stores: regions, pattern and symbol dictionaries and Huffman
tables, with bitmap headers, retained contexts and a charge per item, up to 64 MiB, two square
bitmaps of 16,384 a side. A dictionary's new and exported symbols count against what is left as they are
made, not once it is stored. A segment may refer to at most 2^20 symbols, checked before any are
collected. A halftone grid has at most 2^25 cells. A pattern dictionary keeps at most 16 MiB of
shifted copies, which only speed up drawing, and none that wouldn't fit what the page has left. A custom Huffman table has at most 2^16 lines, and a
stream with its globals at most 2^20 segments and 2^22 references, checked as they are read. A
page past the bounds on a bitmap is refused when the stream is opened, since callers size their
output from its header before the page bitmap is made. And in hayro-syntax, a /JBIG2Globals
stream that is itself JBIG2 isn't decoded: globals are raw segments, so it reads as globals that
can't be decoded.
An image past a bound isn't drawn, as with the other caps, and the rest of the page is. This
bounds memory, not time: decoding work has no total yet.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AmsdeUCdTaD72jkDw2pJKY
The vendored hayro-syntax ran PNG predictors through the bit-level
BitChunks/BitWriter machinery TIFF predictors need, although PNG filters are
defined on bytes (ISO 32000-2 §7.4.4.4, PNG specification §9). A 993 x 936
RGB image took about 63 ms to unfilter whatever its row filters; undone on
byte slices it takes about 3 ms (Up) to 16 ms (Paeth) in a release build.
It also fixes a row that ends part-way through a pixel (three 4-bit samples
at an odd width): the bit-level path dropped its last byte, each later row
started a byte early and the picture came out sheared.
TIFF predictor 2 keeps the old path. Vendored hayro-syntax patch 29.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SqmHYx8FiWM5PcsoiErgp9
Review is right that `Stack::push` always returned `Some(())`, so `overflowed`
never became true and the whole-instruction discard was dead code.
Making it live breaks the page. `an_operator_with_hundreds_of_operands_does_
not_end_the_content` (#4260) puts 300 stray operands before `0 1 0 rg` and
asserts the `rg` still reads its own three: with the discard alive the fill
stays the previous red, measured as `left: [255, 0, 0]` against
`right: [0, 255, 0]`.
The ring buffer already gives the right answer. It keeps the newest operands,
which are the ones nearest the operator -- its own -- and no operator takes
anywhere near 256 of them: `scn` takes one per colourant and ISO 32000 allows a
DeviceN space 32. So the strays fall off the back and the operator is applied to
its own operands, which is what Acrobat and Chromium do. Dropping the
instruction would lose content that is there to be read.
The dead branch and the flag are gone, `push` no longer returns a result it
cannot produce, and a test pins what the buffer does: the strays are `1` and the
operator's own operand is `0`, so the two answers differ. Keeping the oldest
operands instead fails it at 256 strays.
A malformed token ended the content stream where it stood, so the renderer,
text extraction, Find and search-based redaction all lost the rest of the
page -- while the edit reader, MuPDF and pdftotext read it (#3565, #3568). A
redaction that cannot see the text below the bad token cannot remove it,
which is the part that matters.
Each malformed shape is stepped over instead: an unterminated string, a
number that is only a sign or a dot, a name with a bad hex escape, an
unbalanced dictionary or array. Content after an inline image whose data
holds `EI` is still read, under a bounded lookahead.
Rebased onto main, 1,898 commits on: the tokenizer is still
vendor/hayro-syntax/src/content/mod.rs and applied as it was, and render's
raster.rs is split, so the two tests went to render/raster/tests.rs.
Main took hayro-syntax patches 26 and 27 (xref streams), so the patch
that keeps up to 256 operands per instruction moves to 28 in
vendor/README.md and in every comment that cites it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0175FWj4xFhMhSH3UpMU8DSC
ISO 32000-2 §8.6.6.5: "DeviceN colour spaces (PDF 1.3) may contain an
arbitrary number of colour components", and scn takes one operand per
component. The content parser (vendored hayro-syntax) held ten operands
per instruction; pushing the eleventh failed, and the failure ended the
whole content stream. A twelve-ink background fill therefore drew
nothing, and nothing after it was drawn either: a blank page, no error.
hayro-syntax patch (26): an instruction keeps up to 256 operands (enough
for the largest DeviceN space the interpreter reads, 255 inks, plus a
pattern name). Past that the oldest are dropped, in order, rather than
the stream ending: operators already read the operands nearest to them,
so this is how stray operands are treated below the cap too.
hayro-interpret patch (55): a Separation or DeviceN tint transform that
can't be read no longer makes the colour space unreadable (its paints
were drawn in DeviceGray from the first tint, white for a full tint);
it keeps the space, and like a transform that fails when evaluated it
paints that colour in the alternate space's initial colour. Those
fallbacks, and a cs/CS colour space that can't be read, were silent:
they are reported once per content stream as
InterpreterWarning::ColorFallback, which pdfcraft-render records as
RenderWarning::ColourFallback and pdfcraft-cli render prints.
Tests, each seen failing with its fix reverted: the report's twelve-ink
page paints black and draws what follows; a four-ink control; 300 stray
operands before rg still draw; a calculator tint transform that pops
too much, and an unknown function type, fall back with one warning and
the rest of the page drawn; hayro-syntax keeps all twelve scn operands
and, past the cap, the latest 256 in order (fails without the reorder).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0175FWj4xFhMhSH3UpMU8DSC
* fix(render): bound xref streams, JBIG2 referred-to counts, saved graphics states and /W2 runs
Input bounds and crash fixes in the vendored hayro crates, ported from
the snapshot craft-libs carries (storytold/craft-libs#176, #239, #241):
- hayro-syntax: an xref stream subsection must be backed by its decoded
data. All-zero /W widths and a count longer than the data are refused
before any entry is inserted; a tiny stream with a large /Size or
/Index count inserted that many entries.
- hayro-syntax: a subsection running past object number u32::MAX is
refused; start + i overflowed.
- hayro-syntax: the xref stream type field is read big-endian at its
full /W[0] width, and /W[0] over 8 bytes is refused like /W[1].
- hayro-jbig2: the long-form referred-to segment count is capped at
u16::MAX before its retention bytes are read; the 29-bit count went
straight to Vec::with_capacity (about 2 GiB) and aborted the process.
- hayro-interpret: at most 4096 saved graphics states holding at most
64 MiB together. A q past either limit is counted but not copied, and
its Q still removes the clips added since.
- hayro-interpret: a /W2 run whose first CID is past MAX_CID stops there,
as /W does; a first CID of 4294967295 discarded the whole /W2 table.
Each patch is marked in the source, has a regression test in its crate,
and is listed in vendor/README.md.
* fix(render): a binary usecmap counts against the CMap nesting limit; /W2 checks the CID first
- hayro-cmap: a binary CMap's usecmap passed its own depth to the nested
parse, so a self-referencing binary CMap recursed until the stack
overflowed. It now counts like a text usecmap (ledger hayro-cmap 2).
- hayro-interpret: the /W2 first-CID check runs before the run's metrics
are read, so an incomplete run past MAX_CID no longer discards the rest
of the table (ledger 52).
* fix(render): refuse xref-stream object numbers past i32::MAX
ObjectIdentifier stores an i32; a number between i32::MAX and u32::MAX
was cast to a negative object number (ledger hayro-syntax 26).
bflatastic
KenM76andClaude Opus 5.5
Hamza
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