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EPS: delegate binary preview header, sections, and ASCII85 to craft-eps

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This commit is contained in:
Dylan M. Taylor
2026-11-14 01:28:35 +00:00
parent e4035a75db
commit cb5b06672f
4 changed files with 22 additions and 136 deletions
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Cargo.lock
Generated
+14 -1
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@@ -978,6 +978,11 @@ dependencies = [
"ruzstd",
]
[[package]]
name = "craft-codepage"
version = "0.1.0"
source = "git+https://github.com/storytold/craft-libs?rev=6d620e971e820b517b11a99cad040ebac670e1e2#6d620e971e820b517b11a99cad040ebac670e1e2"
[[package]]
name = "craft-docpath"
version = "0.1.0"
@@ -986,13 +991,20 @@ source = "git+https://github.com/storytold/craft-libs?rev=9be9a63782298ab59cd9b7
[[package]]
name = "craft-dxf"
version = "0.1.0"
source = "git+https://github.com/storytold/craft-libs?rev=119415f46f601e20b9bc6b1b4d6979ceda86d88e#119415f46f601e20b9bc6b1b4d6979ceda86d88e"
source = "git+https://github.com/storytold/craft-libs?rev=6d620e971e820b517b11a99cad040ebac670e1e2#6d620e971e820b517b11a99cad040ebac670e1e2"
dependencies = [
"craft-codepage",
"encoding_rs",
"kurbo 0.13.1",
"log",
"thiserror 2.0.21",
]
[[package]]
name = "craft-eps"
version = "0.1.0"
source = "git+https://github.com/storytold/craft-libs?rev=6d620e971e820b517b11a99cad040ebac670e1e2#6d620e971e820b517b11a99cad040ebac670e1e2"
[[package]]
name = "craft-fonts-build"
version = "0.1.0"
@@ -6548,6 +6560,7 @@ dependencies = [
name = "vectorcraft-eps"
version = "0.24.1"
dependencies = [
"craft-eps",
"craft-pdf",
"encoding_rs",
"fax",
crates/eps/Cargo.toml
+1
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@@ -9,6 +9,7 @@ description = "VectorCraft Encapsulated PostScript: a hand-written EPS writer (P
workspace = true
[dependencies]
craft-eps = { workspace = true }
vectorcraft-geom = { workspace = true }
vectorcraft-color = { workspace = true }
vectorcraft-doc = { workspace = true }
crates/eps/src/lib.rs
+5 -46
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@@ -352,64 +352,23 @@ fn read_data(ps: &[u8], name: &str) -> Option<Vec<u8>> {
None
}
/// The magic number of an EPS file with a binary header (a preview).
const DOS_MAGIC: [u8; 4] = [0xC5, 0xD0, 0xD3, 0xC6];
/// The binary header's size.
const DOS_HEADER: usize = 30;
pub use craft_eps::{DOS_HEADER, DOS_MAGIC, Sections, is_eps};
/// `ps` behind a binary header, followed by the TIFF preview `tiff`.
fn dos_eps(ps: &[u8], tiff: &[u8]) -> Result<Vec<u8>, String> {
let big = || "the file is too large for an EPS preview header (4 GB): choose no preview".to_string();
let ps_len = u32::try_from(ps.len()).map_err(|_| big())?;
let tiff_at = u32::try_from(DOS_HEADER + ps.len()).map_err(|_| big())?;
let tiff_len = u32::try_from(tiff.len()).map_err(|_| big())?;
tiff_at.checked_add(tiff_len).ok_or_else(big)?;
let mut out = Vec::with_capacity(DOS_HEADER + ps.len() + tiff.len());
out.extend(DOS_MAGIC);
out.extend((DOS_HEADER as u32).to_le_bytes());
out.extend(ps_len.to_le_bytes());
// No metafile preview.
out.extend(0u32.to_le_bytes());
out.extend(0u32.to_le_bytes());
out.extend(tiff_at.to_le_bytes());
out.extend(tiff_len.to_le_bytes());
// No checksum.
out.extend(0xFFFFu16.to_le_bytes());
out.extend(ps);
out.extend(tiff);
Ok(out)
craft_eps::wrap(ps, Some(tiff), None).map_err(|e| e.to_string())
}
/// The sections of an EPS file: its PostScript and its TIFF preview (binary header), or the whole
/// file as PostScript. `None` when a binary header points outside the file.
pub fn sections(bytes: &[u8]) -> Option<(&[u8], Option<&[u8]>)> {
if !bytes.starts_with(&DOS_MAGIC) {
return Some((bytes, None));
}
let word = |at: usize| bytes.get(at..at + 4).and_then(|b| <[u8; 4]>::try_from(b).ok()).map(|b| u32::from_le_bytes(b) as usize);
let part = |at: usize| {
let (start, len) = (word(at)?, word(at + 4)?);
bytes.get(start..start.checked_add(len)?)
};
let ps = part(4)?;
let tiff = match word(24) {
Some(0) | None => None,
Some(_) => Some(part(20)?),
};
Some((ps, tiff))
let s = craft_eps::sections(bytes).ok()?;
Some((s.postscript, s.tiff))
}
/// The Windows metafile preview behind an EPS file's binary header, if it has one.
pub fn metafile_preview(bytes: &[u8]) -> Option<&[u8]> {
if !bytes.starts_with(&DOS_MAGIC) {
return None;
}
let word = |at: usize| bytes.get(at..at + 4).and_then(|b| <[u8; 4]>::try_from(b).ok()).map(|b| u32::from_le_bytes(b) as usize);
let (start, len) = (word(12)?, word(16)?);
if start == 0 || len == 0 {
return None;
}
bytes.get(start..start.checked_add(len)?)
craft_eps::sections(bytes).ok()?.metafile
}
/// The native document an EPS file written by [`export`] carries, if any.
crates/eps/src/ps.rs
+2 -89
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@@ -180,54 +180,7 @@ pub(crate) fn clip_op(rule: FillRule) -> &'static str {
/// `bytes` in ASCII85 with its `~>` end, in lines of about [`LINE`] characters, none starting
/// with `%` (DSC readers would take it for a comment).
pub(crate) fn ascii85(bytes: &[u8]) -> String {
let mut raw = String::with_capacity(bytes.len() * 5 / 4 + 8);
let (chunks, rest) = bytes.as_chunks::<4>();
for c in chunks {
let v = u32::from_be_bytes(*c);
if v == 0 {
raw.push('z');
} else {
push85(&mut raw, v, 5);
}
}
if !rest.is_empty() {
let mut c = [0u8; 4];
for (d, s) in c.iter_mut().zip(rest) {
*d = *s;
}
push85(&mut raw, u32::from_be_bytes(c), rest.len() + 1);
}
raw.push_str("~>");
let mut out = String::with_capacity(raw.len() + raw.len() / LINE + 2);
if raw.starts_with('%') {
// Whitespace is ignored by readers, and keeps the first line from starting with `%`.
out.push(' ');
}
let mut col = 0;
for ch in raw.chars() {
if col >= LINE && ch != '%' {
out.push('\n');
col = 0;
}
out.push(ch);
col += 1;
}
out.push('\n');
out
}
/// The first `n` base-85 digits of `v`.
fn push85(s: &mut String, mut v: u32, n: usize) {
let mut d = [0u8; 5];
for slot in d.iter_mut().rev() {
*slot = (v % 85) as u8 + b'!';
v /= 85;
}
for b in d.iter().take(n) {
s.push(char::from(*b));
}
}
pub(crate) use craft_eps::ascii85::encode as ascii85;
/// Most bytes [`ascii85_decode`] makes: what one filter or data section may hold.
pub(crate) const MAX_ASCII85: usize = 1 << 28;
@@ -241,47 +194,7 @@ pub(crate) fn ascii85_decode(text: &str) -> Option<Vec<u8>> {
/// [`ascii85_decode`] of at most `max` bytes: `z` is four bytes for one, so the length of the
/// text doesn't bound what it becomes (#1715).
pub(crate) fn ascii85_decode_within(text: &str, max: usize) -> Option<Vec<u8>> {
let mut out = Vec::with_capacity((text.len() / 5 * 4).min(max));
let mut group = [0u8; 5];
let mut n = 0;
let mut chars = text.bytes().filter(|b| !b.is_ascii_whitespace()).peekable();
while let Some(b) = chars.next() {
if out.len() > max {
return None;
}
match b {
b'~' => {
if chars.next() != Some(b'>') {
return None;
}
if n == 1 {
return None;
}
if n > 1 {
let padded: Vec<u8> = group.iter().take(n).copied().chain(std::iter::repeat(b'u')).take(5).collect();
let v = value85(&padded)?;
out.extend(v.to_be_bytes().iter().take(n - 1));
}
return (out.len() <= max).then_some(out);
}
b'z' if n == 0 => out.extend([0; 4]),
b'!'..=b'u' => {
*group.get_mut(n)? = b;
n += 1;
if n == 5 {
out.extend(value85(&group)?.to_be_bytes());
n = 0;
}
}
_ => return None,
}
}
None
}
/// The value of five base-85 digits; `None` past `u32::MAX`.
fn value85(digits: &[u8]) -> Option<u32> {
digits.iter().try_fold(0u32, |acc, d| acc.checked_mul(85)?.checked_add(u32::from(d.checked_sub(b'!')?)))
craft_eps::ascii85::decode(text.as_bytes(), max)
}
/// Run-length encoding (PackBits: what PostScript's `RunLengthDecode` reads), shared with TIFF.