Repo created

libs/coding/csv_reader.cpp

@@ -0,0 +1,163 @@
+#include "coding/csv_reader.hpp"
+
+#include "base/logging.hpp"
+#include "base/string_utils.hpp"
+
+namespace coding
+{
+CSVReader::CSVReader(std::unique_ptr<ReaderInterface> reader, bool hasHeader, char delimiter)
+  : m_reader(std::move(reader))
+  , m_hasHeader(hasHeader)
+  , m_delimiter(delimiter)
+{
+  if (!HasHeader())
+    return;
+
+  auto const row = ReadRow();
+  if (row)
+    m_header = *row;
+}
+
+CSVReader::CSVReader(std::string const & filename, bool hasHeader, char delimiter)
+  : CSVReader(std::make_unique<DefaultReader>(filename), hasHeader, delimiter)
+{}
+
+CSVReader::CSVReader(std::istream & stream, bool hasHeader, char delimiter)
+  : CSVReader(std::make_unique<IstreamWrapper>(stream), hasHeader, delimiter)
+{}
+
+CSVReader::CSVReader(Reader const & reader, bool hasHeader, char delimiter)
+  : CSVReader(std::make_unique<ReaderWrapper>(reader), hasHeader, delimiter)
+{}
+
+bool CSVReader::HasHeader() const
+{
+  return m_hasHeader;
+}
+
+char CSVReader::GetDelimiter() const
+{
+  return m_delimiter;
+}
+
+CSVReader::Row const & CSVReader::GetHeader() const
+{
+  return m_header;
+}
+
+CSVReader::Rows CSVReader::ReadAll()
+{
+  Rows file;
+  ForEachRow([&](auto const & row) { file.emplace_back(row); });
+  return file;
+}
+
+std::optional<CSVReader::Row> CSVReader::ReadRow()
+{
+  auto const line = m_reader->ReadLine();
+  if (!line)
+    return {};
+
+  Row row;
+  strings::ParseCSVRow(*line, m_delimiter, row);
+  ++m_currentLine;
+  return row;
+}
+
+size_t CSVReader::GetCurrentLineNumber() const
+{
+  return m_currentLine;
+}
+
+CSVReader::IstreamWrapper::IstreamWrapper(std::istream & stream) : m_stream(stream) {}
+
+std::optional<std::string> CSVReader::IstreamWrapper::ReadLine()
+{
+  std::string line;
+  return std::getline(m_stream, line) ? line : std::optional<std::string>();
+}
+
+CSVReader::ReaderWrapper::ReaderWrapper(Reader const & reader) : m_reader(reader) {}
+
+std::optional<std::string> CSVReader::ReaderWrapper::ReadLine()
+{
+  std::vector<char> line;
+  char ch = '\0';
+  while (m_pos < m_reader.Size() && ch != '\n')
+  {
+    m_reader.Read(m_pos, &ch, sizeof(ch));
+    line.emplace_back(ch);
+    ++m_pos;
+  }
+
+  if (line.empty())
+    return {};
+
+  auto end = std::end(line);
+  if (line.back() == '\n')
+    --end;
+
+  return std::string(std::begin(line), end);
+}
+
+CSVReader::DefaultReader::DefaultReader(std::string const & filename) : m_stream(filename)
+{
+  if (!m_stream)
+    LOG(LERROR, ("Can't open file ", filename));
+
+  m_stream.exceptions(std::ios::badbit);
+}
+
+std::optional<std::string> CSVReader::DefaultReader::ReadLine()
+{
+  return IstreamWrapper(m_stream).ReadLine();
+}
+
+CSVRunner::Iterator::Iterator(CSVReader & reader, bool isEnd) : m_reader(reader)
+{
+  if (!isEnd)
+    m_current = m_reader.ReadRow();
+}
+
+CSVRunner::Iterator::Iterator(Iterator const & other) : m_reader(other.m_reader), m_current(other.m_current) {}
+
+CSVRunner::Iterator & CSVRunner::Iterator::operator++()
+{
+  m_current = m_reader.ReadRow();
+  return *this;
+}
+
+CSVRunner::Iterator CSVRunner::Iterator::operator++(int)
+{
+  Iterator tmp(*this);
+  operator++();
+  return tmp;
+}
+
+bool CSVRunner::Iterator::operator==(Iterator const & other) const
+{
+  return &m_reader == &other.m_reader && static_cast<bool>(m_current) == static_cast<bool>(other.m_current);
+}
+
+bool CSVRunner::Iterator::operator!=(Iterator const & other) const
+{
+  return !(*this == other);
+}
+
+CSVReader::Row & CSVRunner::Iterator::operator*()
+{
+  return *m_current;
+}
+
+CSVRunner::CSVRunner(CSVReader && reader) : m_reader(std::move(reader)) {}
+
+CSVRunner::Iterator CSVRunner::begin()
+{
+  return Iterator(m_reader);
+}
+
+CSVRunner::Iterator CSVRunner::end()
+{
+  return Iterator(m_reader, true /* isEnd */);
+}
+}  // namespace coding