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102 lines
3.7 KiB
C++
102 lines
3.7 KiB
C++
#include <qpdf/QPDFPageLabelDocumentHelper.hh>
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#include <qpdf/QTC.hh>
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QPDFPageLabelDocumentHelper::QPDFPageLabelDocumentHelper(QPDF& qpdf) :
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QPDFDocumentHelper(qpdf),
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m(new Members())
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{
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QPDFObjectHandle root = qpdf.getRoot();
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if (root.hasKey("/PageLabels")) {
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m->labels =
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std::make_shared<QPDFNumberTreeObjectHelper>(root.getKey("/PageLabels"), this->qpdf);
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}
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}
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bool
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QPDFPageLabelDocumentHelper::hasPageLabels()
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{
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return nullptr != m->labels;
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}
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QPDFObjectHandle
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QPDFPageLabelDocumentHelper::getLabelForPage(long long page_idx)
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{
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QPDFObjectHandle result(QPDFObjectHandle::newNull());
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if (!hasPageLabels()) {
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return result;
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}
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QPDFNumberTreeObjectHelper::numtree_number offset = 0;
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QPDFObjectHandle label;
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if (!m->labels->findObjectAtOrBelow(page_idx, label, offset)) {
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return result;
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}
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if (!label.isDictionary()) {
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return result;
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}
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QPDFObjectHandle S = label.getKey("/S"); // type (D, R, r, A, a)
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QPDFObjectHandle P = label.getKey("/P"); // prefix
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QPDFObjectHandle St = label.getKey("/St"); // starting number
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long long start = 1;
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if (St.isInteger()) {
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start = St.getIntValue();
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}
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QIntC::range_check(start, offset);
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start += offset;
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result = QPDFObjectHandle::newDictionary();
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result.replaceKey("/S", S);
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result.replaceKey("/P", P);
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result.replaceKey("/St", QPDFObjectHandle::newInteger(start));
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return result;
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}
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void
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QPDFPageLabelDocumentHelper::getLabelsForPageRange(
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long long start_idx,
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long long end_idx,
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long long new_start_idx,
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std::vector<QPDFObjectHandle>& new_labels)
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{
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// Start off with a suitable label for the first page. For every remaining page, if that page
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// has an explicit entry, copy it. Otherwise, let the subsequent page just sequence from the
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// prior entry. If there is no entry for the first page, fabricate one that would match how the
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// page would look in a new file in which it also didn't have an explicit label.
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QPDFObjectHandle label = getLabelForPage(start_idx);
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if (label.isNull()) {
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label = QPDFObjectHandle::newDictionary();
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label.replaceKey("/St", QPDFObjectHandle::newInteger(1 + new_start_idx));
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}
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// See if the new label is redundant based on the previous entry in the vector. If so, don't add
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// it.
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size_t size = new_labels.size();
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bool skip_first = false;
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if (size >= 2) {
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QPDFObjectHandle last = new_labels.at(size - 1);
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QPDFObjectHandle last_idx = new_labels.at(size - 2);
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if (last_idx.isInteger() && last.isDictionary() &&
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(label.getKey("/S").unparse() == last.getKey("/S").unparse()) &&
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(label.getKey("/P").unparse() == last.getKey("/P").unparse()) &&
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label.getKey("/St").isInteger() && last.getKey("/St").isInteger()) {
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long long int st_delta =
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label.getKey("/St").getIntValue() - last.getKey("/St").getIntValue();
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long long int idx_delta = new_start_idx - last_idx.getIntValue();
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if (st_delta == idx_delta) {
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QTC::TC("qpdf", "QPDFPageLabelDocumentHelper skip first");
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skip_first = true;
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}
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}
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}
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if (!skip_first) {
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new_labels.push_back(QPDFObjectHandle::newInteger(new_start_idx));
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new_labels.push_back(label);
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}
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long long int idx_offset = new_start_idx - start_idx;
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for (long long i = start_idx + 1; i <= end_idx; ++i) {
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if (m->labels->hasIndex(i) && (label = getLabelForPage(i)).isDictionary()) {
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new_labels.push_back(QPDFObjectHandle::newInteger(i + idx_offset));
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new_labels.push_back(label);
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}
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}
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}
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