genesys: Implement image data source that mimics current reading from USB

backend/genesys_image_buffer.cc

@@ -83,3 +83,113 @@ void ImageBuffer::get_data(std::size_t size, std::uint8_t* out_data)
         copy_buffer();
     } while(out_data < out_data_end);
 }
+
+void FakeBufferModel::push_step(std::size_t buffer_size, std::size_t row_bytes)
+{
+    sizes_.push_back(buffer_size);
+    available_sizes_.push_back(0);
+    row_bytes_.push_back(row_bytes);
+}
+
+std::size_t FakeBufferModel::available_space() const
+{
+    if (sizes_.empty())
+        throw SaneException("Model has not been setup");
+    return sizes_.front() - available_sizes_.front();
+}
+
+void FakeBufferModel::simulate_read(std::size_t size)
+{
+    if (sizes_.empty()) {
+        throw SaneException("Model has not been setup");
+    }
+    if (available_space() < size) {
+        throw SaneException("Attempted to simulate read of too much memory");
+    }
+
+    available_sizes_.front() += size;
+
+    for (unsigned i = 1; i < sizes_.size(); ++i) {
+        auto avail_src = available_sizes_[i - 1];
+        auto avail_dst = sizes_[i] - available_sizes_[i];
+
+        auto avail = (std::min(avail_src, avail_dst) / row_bytes_[i]) * row_bytes_[i];
+        available_sizes_[i - 1] -= avail;
+        available_sizes_[i] += avail;
+    }
+    available_sizes_.back() = 0;
+}
+
+ImageBufferGenesysUsb::ImageBufferGenesysUsb(std::size_t total_size,
+                                             const FakeBufferModel& buffer_model,
+                                             ProducerCallback producer) :
+    remaining_size_{total_size},
+    buffer_model_{buffer_model},
+    producer_{producer}
+{}
+
+void ImageBufferGenesysUsb::get_data(std::size_t size, std::uint8_t* out_data)
+{
+    const std::uint8_t* out_data_end = out_data + size;
+
+    auto copy_buffer = [&]()
+    {
+        std::size_t bytes_copy = std::min<std::size_t>(out_data_end - out_data, available());
+        std::memcpy(out_data, buffer_.data() + buffer_offset_, bytes_copy);
+        out_data += bytes_copy;
+        buffer_offset_ += bytes_copy;
+    };
+
+    // first, read remaining data from buffer
+    if (available() > 0) {
+        copy_buffer();
+    }
+
+    if (out_data == out_data_end) {
+        return;
+    }
+
+    // now the buffer is empty and there's more data to be read
+    do {
+        if (remaining_size_ == 0)
+            return; // BUG: the caller should correctly handle the read amount
+
+        auto bytes_to_read = get_read_size();
+        buffer_offset_ = 0;
+        buffer_end_ = bytes_to_read;
+        buffer_.resize(bytes_to_read);
+
+        producer_(bytes_to_read, buffer_.data());
+
+        if (remaining_size_ < bytes_to_read) {
+            remaining_size_ = 0;
+        } else {
+            remaining_size_ -= bytes_to_read;
+        }
+
+        copy_buffer();
+    } while(out_data < out_data_end);
+}
+
+std::size_t ImageBufferGenesysUsb::get_read_size()
+{
+    std::size_t size = buffer_model_.available_space();
+
+    // never read an odd number. exception: last read
+    // the chip internal counter does not count half words.
+    size &= ~1;
+
+    // Some setups need the reads to be multiples of 256 bytes
+    size &= ~0xff;
+
+    if (remaining_size_ < size) {
+        size = remaining_size_;
+        /*round up to a multiple of 256 bytes */
+        size += (size & 0xff) ? 0x100 : 0x00;
+        size &= ~0xff;
+    }
+
+    buffer_model_.simulate_read(size);
+
+    return size;
+}

backend/genesys_image_buffer.h

@@ -104,4 +104,53 @@ private:
     std::vector<std::uint8_t> buffer_;
 };
 
+class FakeBufferModel
+{
+public:
+    FakeBufferModel() {}
+
+    void push_step(std::size_t buffer_size, std::size_t row_bytes);
+
+    std::size_t available_space() const;
+
+    void simulate_read(std::size_t size);
+
+private:
+    std::vector<std::size_t> sizes_;
+    std::vector<std::size_t> available_sizes_;
+    std::vector<std::size_t> row_bytes_;
+};
+
+// This class is similar to ImageBuffer, but preserves historical peculiarities of buffer handling
+// in the backend to preserve exact behavior
+class ImageBufferGenesysUsb
+{
+public:
+    using ProducerCallback = std::function<void(std::size_t size, std::uint8_t* out_data)>;
+
+    ImageBufferGenesysUsb() {}
+    ImageBufferGenesysUsb(std::size_t total_size, const FakeBufferModel& buffer_model,
+                          ProducerCallback producer);
+
+    std::size_t remaining_size() const { return remaining_size_; }
+
+    std::size_t available() const { return buffer_end_ - buffer_offset_; }
+
+    void get_data(std::size_t size, std::uint8_t* out_data);
+
+private:
+
+    std::size_t get_read_size();
+
+    std::size_t remaining_size_ = 0;
+
+    std::size_t buffer_offset_ = 0;
+    std::size_t buffer_end_ = 0;
+    std::vector<std::uint8_t> buffer_;
+
+    FakeBufferModel buffer_model_;
+
+    ProducerCallback producer_;
+};
+
 #endif // BACKEND_GENESYS_IMAGE_BUFFER_H

backend/genesys_image_pipeline.cc

@@ -69,6 +69,21 @@ void ImagePipelineNodeBufferedCallableSource::get_next_row_data(std::uint8_t* ou
     curr_row_++;
 }
 
+
+ImagePipelineNodeBufferedGenesysUsb::ImagePipelineNodeBufferedGenesysUsb(
+        std::size_t width, std::size_t height, PixelFormat format, std::size_t total_size,
+        const FakeBufferModel& buffer_model, ProducerCallback producer) :
+    width_{width},
+    height_{height},
+    format_{format},
+    buffer_{total_size, buffer_model, producer}
+{}
+
+void ImagePipelineNodeBufferedGenesysUsb::get_next_row_data(std::uint8_t* out_data)
+{
+    buffer_.get_data(get_row_bytes(), out_data);
+}
+
 ImagePipelineNodeArraySource::ImagePipelineNodeArraySource(std::size_t width, std::size_t height,
                                                            PixelFormat format,
                                                            std::vector<std::uint8_t> data) :

backend/genesys_image_pipeline.h

@@ -127,6 +127,33 @@ private:
     ImageBuffer buffer_;
 };
 
+class ImagePipelineNodeBufferedGenesysUsb : public ImagePipelineNode
+{
+public:
+    using ProducerCallback = std::function<void(std::size_t size, std::uint8_t* out_data)>;
+
+    ImagePipelineNodeBufferedGenesysUsb(std::size_t width, std::size_t height,
+                                        PixelFormat format, std::size_t total_size,
+                                        const FakeBufferModel& buffer_model,
+                                        ProducerCallback producer);
+
+    std::size_t get_width() const override { return width_; }
+    std::size_t get_height() const override { return height_; }
+    PixelFormat get_format() const override { return format_; }
+
+    void get_next_row_data(std::uint8_t* out_data) override;
+
+    std::size_t buffer_available() const { return buffer_.available(); }
+
+private:
+    ProducerCallback producer_;
+    std::size_t width_ = 0;
+    std::size_t height_ = 0;
+    PixelFormat format_ = PixelFormat::UNKNOWN;
+
+    ImageBufferGenesysUsb buffer_;
+};
+
 // A pipeline node that produces data from the given array.
 class ImagePipelineNodeArraySource : public ImagePipelineNode
 {

testsuite/backend/genesys/tests_image_pipeline.cc

@@ -30,6 +30,43 @@
 
 #include <numeric>
 
+void test_image_buffer_genesys_usb()
+{
+    std::vector<std::size_t> requests;
+
+    auto on_read_usb = [&](std::size_t x, std::uint8_t* data)
+    {
+        (void) data;
+        requests.push_back(x);
+    };
+
+    FakeBufferModel model;
+    model.push_step(453120, 1);
+    model.push_step(56640, 3540);
+    ImageBufferGenesysUsb buffer{1086780, model, on_read_usb};
+
+    std::vector<std::uint8_t> dummy;
+    dummy.resize(1086780);
+
+    buffer.get_data(453120, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+    buffer.get_data(56640, dummy.data());
+
+    std::vector<std::size_t> expected = {
+        453120, 56576, 56576, 56576, 56832, 56576, 56576, 56576, 56832, 56576, 56576, 56576, 11008
+    };
+    ASSERT_EQ(requests, expected);
+}
+
 void test_node_buffered_callable_source()
 {
     using Data = std::vector<std::uint8_t>;
@@ -294,6 +331,7 @@ void test_node_pixel_shift_lines()
 
 void test_image_pipeline()
 {
+    test_image_buffer_genesys_usb();
     test_node_buffered_callable_source();
     test_node_format_convert();
     test_node_desegment_1_line();