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This comment expands all tabs using an 8-character tab-width. You should ignore this commit when using git blame or use git blame -w. In the early days, I used to use tabs where possible for indentation, since emacs did this automatically. In recent years, I have switched to only using spaces, which means qpdf source code has been a mixture of spaces and tabs. I have avoided cleaning this up because of not wanting gratuitous whitespaces change to cloud the output of git blame, but I changed my mind after discussing with users who view qpdf source code in editors/IDEs that have other tab widths by default and in light of the fact that I am planning to start applying automatic code formatting soon.
126 lines
3.4 KiB
C++
126 lines
3.4 KiB
C++
#include <qpdf/Pl_TIFFPredictor.hh>
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#include <qpdf/QTC.hh>
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#include <qpdf/BitStream.hh>
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#include <qpdf/BitWriter.hh>
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#include <qpdf/QUtil.hh>
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#include <stdexcept>
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#include <vector>
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#include <string.h>
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#include <limits.h>
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Pl_TIFFPredictor::Pl_TIFFPredictor(char const* identifier, Pipeline* next,
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action_e action, 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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pos(0)
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{
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if (samples_per_pixel < 1)
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{
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throw std::runtime_error(
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"TIFFPredictor created with invalid samples_per_pixel");
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}
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if ((bits_per_sample < 1) ||
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(bits_per_sample > (8 * (sizeof(unsigned long long)))))
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{
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throw std::runtime_error(
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"TIFFPredictor created with invalid bits_per_sample");
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}
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unsigned long long bpr =
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((columns * bits_per_sample * samples_per_pixel) + 7) / 8;
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if ((bpr == 0) || (bpr > (UINT_MAX - 1)))
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{
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throw std::runtime_error(
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"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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this->cur_row = make_array_pointer_holder<unsigned char>(
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this->bytes_per_row);
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memset(this->cur_row.get(), 0, this->bytes_per_row);
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}
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Pl_TIFFPredictor::~Pl_TIFFPredictor()
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{
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}
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void
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Pl_TIFFPredictor::write(unsigned char* data, size_t len)
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{
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size_t left = this->bytes_per_row - this->pos;
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size_t offset = 0;
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while (len >= left)
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{
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// finish off current row
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memcpy(this->cur_row.get() + this->pos, data + offset, left);
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offset += left;
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len -= left;
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processRow();
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// Prepare for next row
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memset(this->cur_row.get(), 0, this->bytes_per_row);
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left = this->bytes_per_row;
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this->pos = 0;
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}
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if (len)
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{
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memcpy(this->cur_row.get() + this->pos, data + offset, len);
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}
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this->pos += len;
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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",
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(action == a_decode ? 0 : 1));
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BitWriter bw(this->getNext());
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BitStream in(this->cur_row.get(), this->bytes_per_row);
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std::vector<long long> prev;
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for (unsigned int i = 0; i < this->samples_per_pixel; ++i)
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{
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long long sample = in.getBitsSigned(this->bits_per_sample);
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bw.writeBitsSigned(sample, this->bits_per_sample);
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prev.push_back(sample);
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}
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for (unsigned int col = 1; col < this->columns; ++col)
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{
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for (unsigned int i = 0; i < this->samples_per_pixel; ++i)
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{
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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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{
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new_sample -= prev[i];
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prev[i] = sample;
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}
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else
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{
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new_sample += prev[i];
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prev[i] = 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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}
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void
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Pl_TIFFPredictor::finish()
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{
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if (this->pos)
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{
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// write partial row
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processRow();
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}
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this->pos = 0;
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memset(this->cur_row.get(), 0, this->bytes_per_row);
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getNext()->finish();
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}
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