added sys/log module and setup function

src/main.c

@@ -1,6 +1,19 @@
+#include <sys/log.h>
 #include <yacc/parser.tab.h>
 
+#define LOG_LEVEL LOG_LEVEL_DEBUG
+
+void setup(void)
+{
+    log_init();
+    DEBUG("starting gemstone...");
+
+    DEBUG("finished starting up gemstone...");
+}
+
 int main() {
+    setup();
+
     yyparse();
     return 0;
 }

src/sys/log.c

@@ -0,0 +1,110 @@
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/log.h>
+
+static struct Logger_t {
+    FILE** streams;
+    size_t stream_count;
+} GlobalLogger;
+
+void log_init(void)
+{
+    log_register_stream(LOG_DEFAULT_STREAM);
+}
+
+void log_register_stream(FILE* restrict stream)
+{
+    if (GlobalLogger.stream_count == 0)
+    {
+        GlobalLogger.streams = (FILE**) malloc(sizeof(FILE*));
+        GlobalLogger.stream_count = 1;
+
+        if (GlobalLogger.streams == NULL)
+        {
+            PANIC("failed to allocate stream buffer");
+        }   
+    }
+    else
+    {
+        GlobalLogger.stream_count++;
+        size_t bytes = GlobalLogger.stream_count * sizeof(FILE*);
+        GlobalLogger.streams = (FILE**) realloc(GlobalLogger.streams, bytes);
+
+        if (GlobalLogger.streams == NULL)
+        {
+            PANIC("failed to reallocate stream buffer");
+        }
+    }
+
+    GlobalLogger.streams[GlobalLogger.stream_count - 1] = stream;
+}
+
+static void vflogf(
+    FILE* restrict stream,
+    const char* restrict level,
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    va_list args)
+{
+    fprintf(stream, "%s in %s() at %s:%lu: ", level, func, file, line);
+    vfprintf(stream, format, args);
+}
+
+void __logf(
+    const char* restrict level,
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...)
+{
+    va_list args;
+    va_start(args, format);
+
+    for (size_t i = 0; i < GlobalLogger.stream_count; i++)
+    {
+        FILE* stream = GlobalLogger.streams[i];
+
+        vflogf(stream, level, file, line, func, format, args);
+    }
+
+    va_end(args);
+}
+
+void __panicf(
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...)
+{
+    va_list args;
+    va_start(args, format);
+
+    vflogf(stderr, LOG_STRING_PANIC, file, line, func, format, args);
+
+    va_end(args);
+
+    exit(EXIT_FAILURE);
+}
+
+void __fatalf(
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...)
+{
+    va_list args;
+    va_start(args, format);
+
+    vflogf(stderr, LOG_STRING_FATAL, file, line, func, format, args);
+
+    va_end(args);
+
+    abort();
+}

src/sys/log.h

@@ -0,0 +1,81 @@
+#ifndef _SYS_ERR_H_
+#define _SYS_ERR_H_
+
+#include <stdio.h>
+#include <sys/cdefs.h>
+
+#define LOG_DEFAULT_STREAM stderr
+
+#define LOG_LEVEL_ERROR         3
+#define LOG_LEVEL_WARNING       2
+#define LOG_LEVEL_INFORMATION   1
+#define LOG_LEVEL_DEBUG         0
+
+#define LOG_LEVEL LOG_LEVEL_DEBUG
+
+#define LOG_MAX_BACKTRACE_FRAMES 64
+
+#define LOG_STRING_PANIC       "Critical"
+#define LOG_STRING_FATAL       "Fatal"
+#define LOG_STRING_ERROR       "Error"
+#define LOG_STRING_WARNING     "Warning"
+#define LOG_STRING_INFORMATION "Information"
+#define LOG_STRING_DEBUG       "Debug"
+
+/**
+ * @brief Panic is used in cases where the process is in an unrecoverable state.
+ *        This macro will print debug information to stderr and call abort() to
+ *        performa a ungracefull exit. No clean up possible.
+ */
+#define PANIC(format, ...) __panicf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
+
+/**
+ * @brief Panic is used in cases where the process is in an invalid or undefined state.
+ *        This macro will print debug information to stderr and call exit() to
+ *        initiate a gracefull exit, giving the process the opportunity to clean up.
+ */
+#define FATAL(format, ...) __fatalf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
+
+/*
+Standard log macros. These will not terminate the application.
+Can be turned off by setting LOG_LEVEL. All logs which have smaller log numbers
+will not print.
+*/
+#define ERROR(format, ...) __LOG(LOG_STRING_ERROR, LOG_LEVEL_ERROR, format"\n", ##__VA_ARGS__)
+#define WARN(format, ...) __LOG(LOG_STRING_WARNING, LOG_LEVEL_WARNING, format"\n", ##__VA_ARGS__)
+#define INFO(format, ...) __LOG(LOG_STRING_INFORMATION, LOG_LEVEL_INFORMATION, format"\n", ##__VA_ARGS__)
+#define DEBUG(format, ...) __LOG(LOG_STRING_DEBUG, LOG_LEVEL_DEBUG, format"\n", ##__VA_ARGS__)
+
+#define __LOG(level, priority, format, ...) \
+    do { \
+        if (LOG_LEVEL <= priority) \
+            __logf(level, __FILE_NAME__, __LINE__, __func__, format, ##__VA_ARGS__); \
+    } while(0)
+
+void __logf(
+    const char* restrict level,
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...);
+
+void __panicf(
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...);
+
+void __fatalf(
+    const char* restrict file,
+    const unsigned long line,
+    const char* restrict func,
+    const char* restrict format,
+    ...);
+
+void log_init(void);
+
+void log_register_stream(FILE* restrict stream);
+
+#endif /* _SYS_ERR_H_ */