initial commit

lib/uuid-console/src/shell_stream.cpp

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+/*
+ * uuid-console - Microcontroller console shell
+ * Copyright 2019  Simon Arlott
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <uuid/console.h>
+
+#include <Arduino.h>
+
+namespace uuid {
+
+namespace console {
+
+int Shell::available() {
+    if (mode_ == Mode::BLOCKING) {
+        auto * blocking_data = reinterpret_cast<Shell::BlockingData *>(mode_data_.get());
+
+        if (!available_char()) {
+            return 0;
+        }
+
+        if (blocking_data->consume_line_feed_) {
+            const int input = peek_one_char();
+
+            if (input >= 0) {
+                const unsigned char c = input;
+
+                blocking_data->consume_line_feed_ = false;
+
+                if (previous_ == '\x0D' && c == '\x0A') {
+                    // Consume the first LF following a CR
+                    read_one_char();
+                    previous_ = c;
+                    return available();
+                }
+            } else {
+                // The underlying stream has not implemented peek,
+                // so the next read() could return -1 if LF is
+                // filtered out.
+            }
+        }
+
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+int Shell::read() {
+    if (mode_ == Mode::BLOCKING) {
+        auto *    blocking_data = reinterpret_cast<Shell::BlockingData *>(mode_data_.get());
+        const int input         = read_one_char();
+
+        if (input >= 0) {
+            const unsigned char c = input;
+
+            if (blocking_data->consume_line_feed_) {
+                blocking_data->consume_line_feed_ = false;
+
+                if (previous_ == '\x0D' && c == '\x0A') {
+                    // Consume the first LF following a CR
+                    previous_ = c;
+                    return read();
+                }
+            }
+
+            // Track read characters so that a final CR means we ignore the next LF
+            previous_ = c;
+        }
+
+        return input;
+    } else {
+        return -1;
+    }
+}
+
+int Shell::peek() {
+    if (mode_ == Mode::BLOCKING) {
+        auto *    blocking_data = reinterpret_cast<Shell::BlockingData *>(mode_data_.get());
+        const int input         = peek_one_char();
+
+        if (blocking_data->consume_line_feed_) {
+            if (input >= 0) {
+                const unsigned char c = input;
+
+                blocking_data->consume_line_feed_ = false;
+
+                if (previous_ == '\x0D' && c == '\x0A') {
+                    // Consume the first LF following a CR
+                    read_one_char();
+                    previous_ = c;
+                    return peek();
+                }
+            }
+        }
+
+        return input;
+    } else {
+        return -1;
+    }
+}
+
+void Shell::flush() {
+    // This is a pure virtual function in Arduino's Stream class, which
+    // makes no sense because that class is for input and this is an
+    // output function. Later versions move it to Print as an empty
+    // virtual function so this is here for backward compatibility.
+}
+
+} // namespace console
+
+} // namespace uuid