From e0db637423ab6ea210d4c7e003f4884470f3ae69 Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Mon, 27 Feb 2023 15:07:33 +0000
Subject: [PATCH] validate the number of entries in xref subsections
Fixes #47.
---
pdf.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/pdf.c b/pdf.c
index 5fea322..4077373 100644
--- a/pdf.c
+++ b/pdf.c
@@ -977,6 +977,21 @@ act_xrstment(const HParseResult *p, void *u)
return H_MAKE(XREntry, xr);
}
+/*
+ * Validate that the declared number of entries in a cross-reference
+ * subsection matches the number that was actually parsed.
+ *
+ * p = ((nat nat) (xrent ...))
+ */
+bool
+validate_xrsub(HParseResult *p, void *u)
+{
+ uint64_t n = H_FIELD_UINT(0, 1);
+ HCountedArray *seq = H_FIELD_SEQ(1);
+
+ return (seq->used == n);
+}
+
#define act_xrefs h_act_last
/*
@@ -2477,7 +2492,7 @@ init_parser(struct Env *aux)
xreol,
VIOL(SEQ(h_many1(wchar)), "Nonconformant WS at end of xref entry (severity=1)")))));
H_RULE(xrhead, SEQ(nat, IGN(sp), nat, nl));
- H_RULE(xrsub, SEQ(xrhead, h_many(xrent)));
+ H_VRULE(xrsub, SEQ(xrhead, h_many(xrent)));
H_ARULE(xrefs, SEQ(KW("xref"), nl, h_many(xrsub)));
/* cross-reference streams */
--
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