3 files changed, 187 insertions, 0 deletions
diff --git a/kernel/io/logger/base.cxx b/kernel/io/logger/base.cxx
new file mode 100644
index 0000000..bb1e3c4
--- /dev/null
+++ b/kernel/io/logger/base.cxx
@@ -0,0 +1,11 @@
+#include <io/logger/base.ipp>
+
+#if defined (__x86_64__)
+#include <amd64/io/com1.h>
+
+namespace hos::io
+{
+    template class logger<com_logger>;
+}
+
+#endif
diff --git a/kernel/io/logger/base.h b/kernel/io/logger/base.h
new file mode 100644
index 0000000..7aa9e2d
--- /dev/null
+++ b/kernel/io/logger/base.h
@@ -0,0 +1,31 @@
+#ifndef HOS_IO_BASE_H
+#define HOS_IO_BASE_H
+
+namespace hos::io
+{
+    enum log_level
+    {
+        DEBUG,
+        INFO,
+        WARN,
+        ERROR,
+        FATAL
+    };
+
+    /// Ah, the glorious CRTP...
+    template <typename concrete_logger>
+    class logger
+    {
+    public:
+        logger  (enum log_level level);
+
+        void            set_level   (enum log_level level);
+        void            write       (enum log_level level, const char *message, ...);
+    protected:
+        char            buffer[512];
+    private:
+        enum log_level  level;
+    };
+}
+
+#endif
diff --git a/kernel/io/logger/base.ipp b/kernel/io/logger/base.ipp
new file mode 100644
index 0000000..b48a132
--- /dev/null
+++ b/kernel/io/logger/base.ipp
@@ -0,0 +1,145 @@
+#ifndef HOS_IO_BASE_IMPL
+#define HOS_IO_BASE_IMPL
+
+#include <io/logger/base.h>
+#include <utils.h>
+
+#include <stdarg.h>
+
+namespace hos::io
+{
+    template <typename concrete_logger>
+    logger<concrete_logger>::logger (enum log_level level)
+    {
+        this->set_level(level);
+    }
+
+    template <typename concrete_logger>
+    void logger<concrete_logger>::set_level (enum log_level level)
+    {
+        this->level = level;
+    }
+
+    template <typename concrete_logger>
+    void logger<concrete_logger>::write (enum log_level level, const char *message, ...)
+    {
+        if (level < this->level)
+        {
+            return;
+        }
+
+        char *bufferptr = this->buffer;
+        memset(bufferptr, 0, sizeof(this->buffer));
+
+        const char *logtypes[] = {
+            "DEBUG: ",
+            "INFO: ",
+            "WARN: ",
+            "ERROR: ",
+            "FATAL: "
+        };
+
+        int len = 0;
+        switch (level)
+        {
+            case log_level::DEBUG: {
+                len = strlen(logtypes[0]);
+
+                memcpy(bufferptr, logtypes[0], len);
+                bufferptr += len;
+                break;
+                                   }
+            case log_level::INFO: {
+                len = strlen(logtypes[1]);
+
+                memcpy(bufferptr, logtypes[1], len);
+                bufferptr += len;
+                break;
+                                  }
+            case log_level::WARN: {
+                len = strlen(logtypes[2]);
+
+                memcpy(bufferptr, logtypes[2], len);
+                bufferptr += len;
+                break;
+                                  }
+            case log_level::ERROR: {
+                len = strlen(logtypes[3]);
+
+                memcpy(bufferptr, logtypes[3], len);
+                bufferptr += len;
+                break;
+                                   }
+            case log_level::FATAL: {
+                len = strlen(logtypes[4]);
+
+                memcpy(bufferptr, logtypes[4], len);
+                bufferptr += len;
+                break;
+                                   }
+        }
+
+        len = strlen(message);
+        if (bufferptr + len >= this->buffer + 510) {
+            const char failed[] = "LOGGER: Message longer than display buffer.";
+            memcpy(bufferptr, failed, strlen(failed));
+            static_cast<concrete_logger*>(this)->flush();
+        }
+
+        va_list args;
+        va_start(args, message);
+
+        char temp_buffer[this->buffer + 510 - bufferptr];
+        char *tempptr = temp_buffer;
+        memset(tempptr, 0, sizeof(temp_buffer));
+
+        char next;
+        while ((next = *message++) != 0)
+        {
+            if (next == '%')
+            {
+                next = *message++;
+                switch (next)
+                {
+                    case 'c': {
+                        char c = va_arg(args, int);
+
+                        if (!((tempptr + 1) - temp_buffer > (long int) sizeof(temp_buffer)))
+                        {
+                            memcpy(tempptr, &c, 1);
+                            tempptr++;
+                        }
+
+                        break;
+                              }
+                    case 's': {
+                        char *string = va_arg(args, char *);
+                        
+                        len = strlen(string);
+                        if (!((tempptr + len) - temp_buffer > (long int) sizeof(temp_buffer)))
+                        {
+                            memcpy(tempptr, string, len);
+                            tempptr += len;    
+                        }
+
+                        break;
+                              }
+                }
+            } else {
+                memcpy(tempptr, &next, 1);
+                tempptr++;
+            }
+        }
+
+        va_end(args);
+
+        len = strlen(temp_buffer); 
+        memcpy(bufferptr, temp_buffer, len);
+        bufferptr += len;
+
+        memcpy(bufferptr, "\n", 1);
+        static_cast<concrete_logger*>(this)->flush();
+    } 
+}
+
+#endif