private void LoadPage(int pageNum)
{
PdfDictionary targetPage = pageRefs[pageNum];
if (targetPage != null)
{
return;
}
//if we go here, we have to split PdfPages that contains pageNum
int parentIndex = FindPageParent(pageNum);
PdfPages parent = parents[parentIndex];
PdfArray kids = parent.GetKids();
if (kids == null)
{
throw new PdfException(PdfException.InvalidPageStructure1).SetMessageParams(pageNum + 1);
}
int kidsCount = parent.GetCount();
// we should handle separated pages, it means every PdfArray kids must contain either PdfPage or PdfPages,
// mix of PdfPage and PdfPages not allowed.
bool findPdfPages = false;
// NOTE optimization? when we already found needed index
for (int i = 0; i < kids.Size(); i++)
{
PdfDictionary page = kids.GetAsDictionary(i);
if (page == null)
{
// null values not allowed in pages tree.
throw new PdfException(PdfException.InvalidPageStructure1).SetMessageParams(pageNum + 1);
}
PdfObject pageKids = page.Get(PdfName.Kids);
if (pageKids != null)
{
if (pageKids.IsArray())
{
findPdfPages = true;
}
else
{
// kids must be of type array
throw new PdfException(PdfException.InvalidPageStructure1).SetMessageParams(pageNum + 1);
}
}
}
if (findPdfPages)
{
// handle mix of PdfPage and PdfPages.
// handle count property!
IList <PdfPages> newParents = new List <PdfPages>(kids.Size());
PdfPages lastPdfPages = null;
for (int i = 0; i < kids.Size() && kidsCount > 0; i++)
{
PdfDictionary pdfPagesObject = kids.GetAsDictionary(i);
if (pdfPagesObject.GetAsArray(PdfName.Kids) == null)
{
// pdfPagesObject is PdfPage
if (lastPdfPages == null)
{
// possible if only first kid is PdfPage
lastPdfPages = new PdfPages(parent.GetFrom(), document, parent);
kids.Set(i, lastPdfPages.GetPdfObject());
newParents.Add(lastPdfPages);
}
else
{
// Only remove from kids if we did not replace the entry with new PdfPages
kids.Remove(i);
i--;
}
// decrement count first so that page is not counted twice when moved to lastPdfPages
parent.DecrementCount();
lastPdfPages.AddPage(pdfPagesObject);
kidsCount--;
}
else
{
// pdfPagesObject is PdfPages
int from = lastPdfPages == null?parent.GetFrom() : lastPdfPages.GetFrom() + lastPdfPages.GetCount();
lastPdfPages = new PdfPages(from, kidsCount, pdfPagesObject, parent);
newParents.Add(lastPdfPages);
kidsCount -= lastPdfPages.GetCount();
}
}
parents.JRemoveAt(parentIndex);
for (int i = newParents.Count - 1; i >= 0; i--)
{
parents.Add(parentIndex, newParents[i]);
}
// recursive call, to load needed pageRef.
// NOTE optimization? add to loadPage startParentIndex.
LoadPage(pageNum);
}
else
{
int from = parent.GetFrom();
// Possible exception in case kids.getSize() < parent.getCount().
// In any case parent.getCount() has higher priority.
// NOTE optimization? when we already found needed index
for (int i = 0; i < parent.GetCount(); i++)
{
pageRefs[from + i] = kids.GetAsDictionary(i);
}
}
}