1 files changed, 35 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/pplib/ppxref.h b/source/luametatex/source/libraries/pplib/ppxref.h
new file mode 100644
index 000000000..fbb83bece
--- /dev/null
+++ b/source/luametatex/source/libraries/pplib/ppxref.h
@@ -0,0 +1,35 @@
+
+#ifndef PP_XREF_H
+#define PP_XREF_H
+
+/*
+What we call xref is actually "xref section" in PDF spec and what we call section is "xref subsection".
+Our ppxref is a list of sections, sorted by xrefsection->first and xrefsection->last bounds. Every section
+keeps a list of ppref *refs, enumerated from xrefsection->first to xrefsection->last. To find a reference
+by number we make a binary search over sections bounds, then jump to the proper ppref *ref.
+*/
+
+typedef struct {
+  ppuint first;     // first reference number in section
+  ppuint last;      // last reference number in section
+  ppref *refs;      // references list
+} ppxsec;
+
+struct ppxref {
+  ppxsec *sects;    // subsections list
+  size_t size;      // actual sections size
+  size_t space;     // available sections space
+  ppobj trailer;    // trailer dict or stream
+  ppuint count;     // count of references in all sections
+  ppxref *prev;     // previous xref
+  ppdoc *pdf;       // parent pdf to access entries in linearized docs
+  size_t offset;    // file offset of xref
+  //ppcrypt *crypt;   // per xref encryption state?
+};
+
+ppxref * ppxref_create (ppdoc *pdf, size_t initsize, size_t xrefoffset);
+ppxsec * ppxref_push_section (ppxref *xref, ppheap *heap);
+int ppxref_sort (ppxref *xref);
+ppref * ppxref_find_local (ppxref *xref, ppuint refnumber);
+
+#endif
+\ No newline at end of file