Add missing common files

src/common.h

@@ -0,0 +1,75 @@
+// MIT License
+//
+// Copyright (c) 2022 Marc Ransome
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef FLOG_COMMON_H
+#define FLOG_COMMON_H
+
+/*! \file common.h
+ *
+ *  Constants, helper functions, and error handling types for common operations.
+ */
+
+#define PROGRAM_NAME "flog"
+#define PROGRAM_VERSION "1.4.0"
+
+/*! \brief An enumerated type representing error conditions. */
+typedef enum FlogErrorData {
+    FLOG_ERROR_NONE,
+    FLOG_ERROR_ALLOC,
+    FLOG_ERROR_APPEND,
+    FLOG_ERROR_LVL,
+    FLOG_ERROR_MSG,
+    FLOG_ERROR_OPTS,
+    FLOG_ERROR_SUBSYS,
+} FlogError;
+
+/*! \brief Print usage information to stdout stream. */
+void flog_usage(void);
+
+/*! \brief Print version string to stdout stream. */
+void flog_version(void);
+
+/*! \brief Return a string representation of an error condition.
+ *
+ * \param[in] error A \c FlogError enumeration variant
+ *
+ * \return A pointer to a null-terminated string describing the error condition
+ */
+const char * flog_get_error_string(FlogError error);
+
+/*! \brief Print a formatted error message representation of the error condition.
+ *
+ * \param[in] error A \c FlogError enumeration variant representing the error condition
+ *
+ * \return void
+ */
+void flog_print_error(FlogError error);
+
+/*! \brief Print a formatted error message string.
+ *
+ * \param[out] error A null-terminated string describing the error condition.
+ *
+ * \return void
+ */
+void flog_print_error_string(const char *error);
+
+#endif //FLOG_COMMON_H