test new format

tty_protocol_writer.cpp

@@ -0,0 +1,128 @@
+#include "tty_protocol_writer.h"
+
+#include <stdexcept>
+#include <utility>
+
+#ifdef _WIN32
+
+TtyProtocolWriter::TtyProtocolWriter(std::string path) : path_(std::move(path)) {
+    throw std::runtime_error("tty output is supported only on Linux/POSIX");
+}
+
+TtyProtocolWriter::~TtyProtocolWriter() = default;
+
+TtyProtocolWriter::TtyProtocolWriter(TtyProtocolWriter&& other) noexcept = default;
+
+TtyProtocolWriter& TtyProtocolWriter::operator=(TtyProtocolWriter&& other) noexcept = default;
+
+void TtyProtocolWriter::emit_packet_start() const {}
+
+void TtyProtocolWriter::emit_step(uint16_t index, int16_t ch1_avg, int16_t ch2_avg) const {
+    (void) index;
+    (void) ch1_avg;
+    (void) ch2_avg;
+}
+
+const std::string& TtyProtocolWriter::path() const {
+    return path_;
+}
+
+void TtyProtocolWriter::write_frame(uint16_t word0, uint16_t word1, uint16_t word2, uint16_t word3) const {
+    (void) word0;
+    (void) word1;
+    (void) word2;
+    (void) word3;
+}
+
+void TtyProtocolWriter::close_fd() noexcept {}
+
+#else
+
+#include <cerrno>
+#include <cstring>
+#include <fcntl.h>
+#include <sstream>
+#include <sys/types.h>
+#include <unistd.h>
+
+namespace {
+
+std::string io_error(const std::string& action, const std::string& path) {
+    std::ostringstream out;
+    out << action << " '" << path << "': " << std::strerror(errno);
+    return out.str();
+}
+
+} // namespace
+
+TtyProtocolWriter::TtyProtocolWriter(std::string path) : path_(std::move(path)) {
+    fd_ = ::open(path_.c_str(), O_WRONLY | O_NOCTTY);
+    if (fd_ < 0) {
+        throw std::runtime_error(io_error("Cannot open tty output", path_));
+    }
+}
+
+TtyProtocolWriter::~TtyProtocolWriter() {
+    close_fd();
+}
+
+TtyProtocolWriter::TtyProtocolWriter(TtyProtocolWriter&& other) noexcept
+    : path_(std::move(other.path_)),
+      fd_(other.fd_) {
+    other.fd_ = -1;
+}
+
+TtyProtocolWriter& TtyProtocolWriter::operator=(TtyProtocolWriter&& other) noexcept {
+    if (this != &other) {
+        close_fd();
+        path_ = std::move(other.path_);
+        fd_ = other.fd_;
+        other.fd_ = -1;
+    }
+    return *this;
+}
+
+void TtyProtocolWriter::emit_packet_start() const {
+    write_frame(0x000A, 0xFFFF, 0xFFFF, 0xFFFF);
+}
+
+void TtyProtocolWriter::emit_step(uint16_t index, int16_t ch1_avg, int16_t ch2_avg) const {
+    write_frame(0x000A,
+                index,
+                static_cast<uint16_t>(ch1_avg),
+                static_cast<uint16_t>(ch2_avg));
+}
+
+const std::string& TtyProtocolWriter::path() const {
+    return path_;
+}
+
+void TtyProtocolWriter::write_frame(uint16_t word0, uint16_t word1, uint16_t word2, uint16_t word3) const {
+    const uint16_t frame[4] = {word0, word1, word2, word3};
+    const std::uint8_t* bytes = reinterpret_cast<const std::uint8_t*>(frame);
+    std::size_t remaining = sizeof(frame);
+
+    while (remaining != 0U) {
+        const ssize_t written = ::write(fd_, bytes, remaining);
+        if (written < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+            throw std::runtime_error(io_error("Cannot write tty frame to", path_));
+        }
+        if (written == 0) {
+            throw std::runtime_error("tty write returned 0 bytes for '" + path_ + "'");
+        }
+        bytes += static_cast<std::size_t>(written);
+        remaining -= static_cast<std::size_t>(written);
+    }
+}
+
+void TtyProtocolWriter::close_fd() noexcept {
+    if (fd_ >= 0) {
+        ::close(fd_);
+        fd_ = -1;
+    }
+}
+
+#endif