Initial commit

.gitignore

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+# Compiled object files
+*.o
+
+# Generated objects (source, executables, tarballs, etc.)
+
+# Vim swap files
+.*.swp
+
+# Autotools objects
+.deps
+.dirstamp
+.libs
+ar-lib
+autom4te.cache
+m4
+compile
+config.*
+configure
+depcomp
+install-sh
+libtool
+ltmain.sh
+missing
+Makefile
+Makefile.in
+*.la
+*.lo
+*.m4
+stamp-h1
+tap-driver.sh
+test-driver
+*.log
+*.trs
+*.pc
+
+# Build directory
+/build/

LICENSE

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+MIT License
+
+Copyright (c) 2021 Nirenjan Krishnan
+
+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.

README.md

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+Pinelog - a lightweight logging API
+===================================
+
+Pinelog is a lightweight logging API for C programs that's designed to be
+included in your program source code. Parameters for Pinelog are configured at
+build time by means of preprocessor flags.

pinelog.c

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+/*
+ * Pinelog lightweight logging library
+ *
+ * Copyright (C) 2021 Nirenjan Krishnan (nirenjan@nirenjan.org)
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <time.h>
+#include <errno.h>
+
+#include "pinelog.h"
+
+/**********************************************************************
+ * Global variables
+ *********************************************************************/
+
+/** Stream buffer */
+static FILE *output_stream = NULL;
+
+/** Default logging level */
+static int log_level = LOG_LVL_ERROR;
+
+/* Initialize defaults */
+void log_init_defaults(void)
+{
+    output_stream = stdout;
+    log_level = LOG_LVL_ERROR;
+}
+
+int log_set_output_stream(FILE *stream)
+{
+    if (stream == NULL) {
+        return EINVAL;
+    }
+
+    /* If current output stream is not stdout or stderr, then close it */
+    if (output_stream != stdout && output_stream != stderr) {
+        fclose(output_stream);
+    }
+
+    setlinebuf(stream);
+    output_stream = stream;
+    return 0;
+}
+
+int log_set_output_file(const char *file)
+{
+    FILE *stream;
+    if (file == NULL) {
+        return EINVAL;
+    }
+
+    errno = 0;
+    stream = fopen(file, "w");
+    if (stream == NULL) {
+        return errno;
+    }
+
+    return log_set_output_stream(stream);
+}
+
+int log_get_level(void)
+{
+    return log_level;
+}
+
+int log_set_level(int level)
+{
+    if (level < LOG_LVL_NONE || level > LOG_LVL_TRACE) {
+        return EINVAL;
+    }
+
+    log_level = level;
+    return 0;
+}
+
+/**********************************************************************
+ * Configure logging parameters
+ *********************************************************************/
+#ifndef PINELOG_SHOW_DATE
+#define PINELOG_SHOW_DATE 0
+#endif
+
+#ifndef PINELOG_SHOW_LEVEL
+#define PINELOG_SHOW_LEVEL 0
+#endif
+
+#ifndef PINELOG_SHOW_BACKTRACE
+#define PINELOG_SHOW_BACKTRACE 0
+#endif
+
+/**********************************************************************
+ * Configure level strings
+ *********************************************************************/
+#ifndef PINELOG_FATAL
+#define PINELOG_FATAL "FATAL"
+#endif
+
+#ifndef PINELOG_ERROR
+#define PINELOG_ERROR "ERROR"
+#endif
+
+#ifndef PINELOG_WARNING
+#define PINELOG_WARNING "WARNING"
+#endif
+
+#ifndef PINELOG_INFO
+#define PINELOG_INFO "INFO"
+#endif
+
+#ifndef PINELOG_DEBUG
+#define PINELOG_DEBUG "DEBUG"
+#endif
+
+#ifndef PINELOG_TRACE
+#define PINELOG_TRACE "TRACE"
+#endif
+
+/**********************************************************************
+ * Log the message to the output stream
+ *********************************************************************/
+void log_message(int level, const char *file, int line, const char *fmt, ...)
+{
+    va_list ap;
+
+    /* Don't log anything if the level is not severe enough */
+    if (level > log_level || level < 0) {
+        return;
+    }
+
+    /* Cap the log level */
+    if (level > LOG_LVL_TRACE) {
+        level = LOG_LVL_TRACE;
+    }
+
+    /* Validate and set output stream */
+    if (output_stream == NULL) {
+        output_stream = stdout;
+    }
+
+    #if PINELOG_SHOW_DATE
+    do {
+        time_t t;
+        struct tm *tmp;
+        char date_string[20];
+        t = time(NULL);
+        tmp = localtime(&t);
+        strftime(date_string, sizeof(date_string), "%F %T ", tmp);
+        fputs(date_string, out_stream);
+    } while (0);
+    #endif
+
+    #if PINELOG_SHOW_LEVEL
+    do {
+        static const char *level_strings[] = {
+            PINELOG_FATAL,
+            PINELOG_ERROR,
+            PINELOG_WARNING,
+            PINELOG_INFO,
+            PINELOG_DEBUG,
+            PINELOG_TRACE,
+        };
+
+        fputs(level_strings[level], out_stream);
+        fputs(": ", out_stream);
+    } while (0)
+    #endif
+
+    #if PINELOG_SHOW_BACKTRACE
+        fprintf(out_stream, "%s:%d ", file, line);
+    #endif
+
+    va_start(ap, fmt);
+    vfprintf(output_stream, fmt, ap);
+    va_end(ap);
+}

pinelog.h

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+/*
+ * Pinelog lightweight logging library
+ *
+ * Copyright (C) 2021 Nirenjan Krishnan (nirenjan@nirenjan.org)
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/**
+ * @file logging.h
+ * @brief Logging utility library
+ *
+ * This file contains the prototypes for the pinelog logging library
+ * used by any programs that need to log messages.
+ *
+ * @author Nirenjan Krishnan (nirenjan@nirenjan.org)
+ */
+#ifndef LOGGING_H
+#define LOGGING_H
+
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Logging levels
+ *
+ * The log levels indicate the lowest severity level that will actually be
+ * logged to the logging framework.
+ */
+enum {
+    /** No messages will be logged */
+    LOG_LVL_NONE = -1,
+
+    /** Only fatal messages will be logged */
+    LOG_LVL_FATAL,
+
+    /** Error messages. This is the default log level */
+    LOG_LVL_ERROR,
+
+    /** Warning messages */
+    LOG_LVL_WARNING,
+
+    /** Informational messages */
+    LOG_LVL_INFO,
+
+    /** Debug messages */
+    LOG_LVL_DEBUG,
+
+    /** Trace messages */
+    LOG_LVL_TRACE,
+};
+
+/**
+ * @brief Initialize the logging library and set the defaults
+ */
+void log_init_defaults(void);
+
+/**
+ * @brief Set the output stream. Must be a FILE pointer.
+ *
+ * @param[in]   stream  Pointer to the output stream
+ *
+ * @returns 0 on success, EINVAL if the pointer is not valid.
+ */
+int log_set_output_stream(FILE *stream);
+
+/**
+ * @brief Set the output file.
+ *
+ * @param[in]   file    Filename to write to
+ *
+ * @returns 0 on success, EINVAL if the filename pointer is not valid, other
+ * error if the file could not be opened for writing.
+ */
+int log_set_output_file(const char *file);
+
+/**
+ * @brief Set the logging level
+ *
+ * @param[in]   level   Level to filter
+ *
+ * @returns 0 on success, EINVAL if the level is not valid
+ */
+int log_set_level(int level);
+
+/**
+ * @brief Get the logging level
+ *
+ * @returns the configured logging level
+ */
+int log_get_level(void);
+
+/**
+ * @brief Log a message to the logger
+ *
+ * This is the actual function that logs the message. The application should
+ * never need to call this directly, but instead, should always use the
+ * \code LOG_* macros.
+ *
+ * @param[in]   level   Level to log the message at
+ * @param[in]   fmt     Format string
+ *
+ * @returns None
+ */
+void log_message(int level, const char *file, int line, const char *fmt, ...);
+
+#define LOG_FATAL(fmt, ...) do { \
+    if (LOG_LVL_FATAL <= log_get_level()) { \
+        log_message(LOG_LVL_FATAL, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+    exit(1); \
+} while (0)
+
+#define LOG_ERROR(fmt, ...) do { \
+    if (LOG_LVL_ERROR <= log_get_level()) { \
+        log_message(LOG_LVL_ERROR, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+} while (0)
+
+#define LOG_WARN(fmt, ...) do { \
+    if (LOG_LVL_WARNING <= log_get_level()) { \
+        log_message(LOG_LVL_WARNING, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+} while(0)
+
+#define LOG_INFO(fmt, ...) do { \
+    if (LOG_LVL_INFO <= log_get_level()) { \
+        log_message(LOG_LVL_INFO, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+} while(0)
+
+#define LOG_DEBUG(fmt, ...) do { \
+    if (LOG_LVL_DEBUG <= log_get_level()) { \
+        log_message(LOG_LVL_DEBUG, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+} while(0)
+
+#define LOG_TRACE(fmt, ...) do { \
+    if (LOG_LVL_TRACE <= log_get_level()) { \
+        log_message(LOG_LVL_TRACE, __FILE__, __LINE__, fmt, ##__VA_ARGS__); \
+    } \
+} while(0)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // !defined LOGGING_H