summaryrefslogtreecommitdiff
path: root/backend/genesys/row_buffer.h
diff options
context:
space:
mode:
Diffstat (limited to 'backend/genesys/row_buffer.h')
-rw-r--r--backend/genesys/row_buffer.h214
1 files changed, 214 insertions, 0 deletions
diff --git a/backend/genesys/row_buffer.h b/backend/genesys/row_buffer.h
new file mode 100644
index 0000000..e1a0c82
--- /dev/null
+++ b/backend/genesys/row_buffer.h
@@ -0,0 +1,214 @@
+/* sane - Scanner Access Now Easy.
+
+ Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>
+
+ This file is part of the SANE package.
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ MA 02111-1307, USA.
+
+ As a special exception, the authors of SANE give permission for
+ additional uses of the libraries contained in this release of SANE.
+
+ The exception is that, if you link a SANE library with other files
+ to produce an executable, this does not by itself cause the
+ resulting executable to be covered by the GNU General Public
+ License. Your use of that executable is in no way restricted on
+ account of linking the SANE library code into it.
+
+ This exception does not, however, invalidate any other reasons why
+ the executable file might be covered by the GNU General Public
+ License.
+
+ If you submit changes to SANE to the maintainers to be included in
+ a subsequent release, you agree by submitting the changes that
+ those changes may be distributed with this exception intact.
+
+ If you write modifications of your own for SANE, it is your choice
+ whether to permit this exception to apply to your modifications.
+ If you do not wish that, delete this exception notice.
+*/
+
+#ifndef BACKEND_GENESYS_LINE_BUFFER_H
+#define BACKEND_GENESYS_LINE_BUFFER_H
+
+#include "error.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <cstddef>
+#include <vector>
+
+namespace genesys {
+
+class RowBuffer
+{
+public:
+ RowBuffer(std::size_t line_bytes) : row_bytes_{line_bytes} {}
+ RowBuffer(const RowBuffer&) = default;
+ RowBuffer& operator=(const RowBuffer&) = default;
+ ~RowBuffer() = default;
+
+ const std::uint8_t* get_row_ptr(std::size_t y) const
+ {
+ if (y >= height()) {
+ throw SaneException("y %zu is out of range", y);
+ }
+ return data_.data() + row_bytes_ * get_row_index(y);
+ }
+
+ std::uint8_t* get_row_ptr(std::size_t y)
+ {
+ if (y >= height()) {
+ throw SaneException("y %zu is out of range", y);
+ }
+ return data_.data() + row_bytes_ * get_row_index(y);
+ }
+
+ const std::uint8_t* get_front_row_ptr() const { return get_row_ptr(0); }
+ std::uint8_t* get_front_row_ptr() { return get_row_ptr(0); }
+ const std::uint8_t* get_back_row_ptr() const { return get_row_ptr(height() - 1); }
+ std::uint8_t* get_back_row_ptr() { return get_row_ptr(height() - 1); }
+
+ bool empty() const { return is_linear_ && first_ == last_; }
+
+ bool full()
+ {
+ if (is_linear_) {
+ return last_ == buffer_end_;
+ }
+ return first_ == last_;
+ }
+
+ bool is_linear() const { return is_linear_; }
+
+ void linearize()
+ {
+ if (!is_linear_) {
+ std::rotate(data_.begin(), data_.begin() + row_bytes_ * first_, data_.end());
+ last_ = height();
+ first_ = 0;
+ is_linear_ = true;
+ }
+ }
+
+ void pop_front()
+ {
+ if (empty()) {
+ throw SaneException("Trying to pop out of empty() line buffer");
+ }
+
+ first_++;
+ if (first_ == last_) {
+ first_ = 0;
+ last_ = 0;
+ is_linear_ = true;
+ } else if (first_ == buffer_end_) {
+ first_ = 0;
+ is_linear_ = true;
+ }
+ }
+
+ void push_front()
+ {
+ if (height() + 1 >= height_capacity()) {
+ ensure_capacity(std::max<std::size_t>(1, height() * 2));
+ }
+
+ if (first_ == 0) {
+ is_linear_ = false;
+ first_ = buffer_end_;
+ }
+ first_--;
+ }
+
+ void pop_back()
+ {
+ if (empty()) {
+ throw SaneException("Trying to pop out of empty() line buffer");
+ }
+ if (last_ == 0) {
+ last_ = buffer_end_;
+ is_linear_ = true;
+ }
+ last_--;
+ if (first_ == last_) {
+ first_ = 0;
+ last_ = 0;
+ is_linear_ = true;
+ }
+ }
+
+ void push_back()
+ {
+ if (height() + 1 >= height_capacity()) {
+ ensure_capacity(std::max<std::size_t>(1, height() * 2));
+ }
+
+ if (last_ == buffer_end_) {
+ is_linear_ = false;
+ last_ = 0;
+ }
+ last_++;
+ }
+
+ std::size_t row_bytes() const { return row_bytes_; }
+
+ std::size_t height() const
+ {
+ if (!is_linear_) {
+ return last_ + buffer_end_ - first_;
+ }
+ return last_ - first_;
+ }
+
+ std::size_t height_capacity() const { return buffer_end_; }
+
+ void clear()
+ {
+ first_ = 0;
+ last_ = 0;
+ }
+
+private:
+ std::size_t get_row_index(std::size_t index) const
+ {
+ if (index >= buffer_end_ - first_) {
+ return index - (buffer_end_ - first_);
+ }
+ return index + first_;
+ }
+
+ void ensure_capacity(std::size_t capacity)
+ {
+ if (capacity < height_capacity())
+ return;
+ linearize();
+ data_.resize(capacity * row_bytes_);
+ buffer_end_ = capacity;
+ }
+
+private:
+ std::size_t row_bytes_ = 0;
+ std::size_t first_ = 0;
+ std::size_t last_ = 0;
+ std::size_t buffer_end_ = 0;
+ bool is_linear_ = true;
+ std::vector<std::uint8_t> data_;
+};
+
+} // namespace genesys
+
+#endif // BACKEND_GENESYS_LINE_BUFFER_H