mirror of https://github.com/qpdf/qpdf.git
115 lines
3.4 KiB
C++
115 lines
3.4 KiB
C++
#include <qpdf/Pl_TIFFPredictor.hh>
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#include <qpdf/BitStream.hh>
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#include <qpdf/BitWriter.hh>
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#include <qpdf/QTC.hh>
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#include <climits>
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#include <stdexcept>
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Pl_TIFFPredictor::Pl_TIFFPredictor(
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char const* identifier,
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Pipeline* next,
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action_e action,
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unsigned int columns,
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unsigned int samples_per_pixel,
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unsigned int bits_per_sample) :
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Pipeline(identifier, next),
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action(action),
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columns(columns),
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samples_per_pixel(samples_per_pixel),
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bits_per_sample(bits_per_sample),
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p_next(getNext())
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{
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if (samples_per_pixel < 1) {
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throw std::runtime_error("TIFFPredictor created with invalid samples_per_pixel");
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}
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if ((bits_per_sample < 1) || (bits_per_sample > (8 * (sizeof(unsigned long long))))) {
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throw std::runtime_error("TIFFPredictor created with invalid bits_per_sample");
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}
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unsigned long long bpr = ((columns * bits_per_sample * samples_per_pixel) + 7) / 8;
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if ((bpr == 0) || (bpr > (UINT_MAX - 1))) {
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throw std::runtime_error("TIFFPredictor created with invalid columns value");
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}
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this->bytes_per_row = bpr & UINT_MAX;
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}
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void
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Pl_TIFFPredictor::write(unsigned char const* data, size_t len)
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{
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auto end = data + len;
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auto row_end = data + (bytes_per_row - cur_row.size());
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while (row_end <= end) {
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// finish off current row
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cur_row.insert(cur_row.end(), data, row_end);
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data = row_end;
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row_end += bytes_per_row;
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processRow();
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// Prepare for next row
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cur_row.clear();
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}
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cur_row.insert(cur_row.end(), data, end);
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}
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void
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Pl_TIFFPredictor::processRow()
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{
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QTC::TC("libtests", "Pl_TIFFPredictor processRow", (action == a_decode ? 0 : 1));
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previous.assign(samples_per_pixel, 0);
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if (bits_per_sample != 8) {
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BitWriter bw(p_next);
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BitStream in(cur_row.data(), cur_row.size());
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for (unsigned int col = 0; col < this->columns; ++col) {
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for (auto& prev: previous) {
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long long sample = in.getBitsSigned(this->bits_per_sample);
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long long new_sample = sample;
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if (action == a_encode) {
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new_sample -= prev;
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prev = sample;
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} else {
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new_sample += prev;
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prev = new_sample;
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}
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bw.writeBitsSigned(new_sample, this->bits_per_sample);
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}
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}
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bw.flush();
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} else {
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out.clear();
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auto next = cur_row.begin();
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auto cr_end = cur_row.end();
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auto pr_end = previous.end();
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while (next != cr_end) {
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for (auto prev = previous.begin(); prev != pr_end && next != cr_end; ++prev, ++next) {
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long long sample = *next;
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long long new_sample = sample;
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if (action == a_encode) {
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new_sample -= *prev;
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*prev = sample;
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} else {
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new_sample += *prev;
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*prev = new_sample;
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}
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out.push_back(static_cast<unsigned char>(255U & new_sample));
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}
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}
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p_next->write(out.data(), out.size());
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}
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}
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void
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Pl_TIFFPredictor::finish()
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{
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if (!cur_row.empty()) {
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// write partial row
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cur_row.insert(cur_row.end(), bytes_per_row - cur_row.size(), 0);
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processRow();
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}
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cur_row.clear();
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p_next->finish();
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}
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