added drivers

app/drivers/utils/ulog/ulog.c

@@ -0,0 +1,154 @@
+/**
+MIT License
+
+Copyright (c) 2019 R. Dunbar Poor <rdpoor@gmail.com>
+
+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.
+*/
+
+/**
+ * \file ulog.c
+ *
+ * \brief uLog: lightweight logging for embedded systems
+ *
+ * See ulog.h for sparse documentation.
+ */
+
+#include "ulog.h"
+
+#ifdef ULOG_ENABLED // whole file...
+
+// #include <stdio.h>
+#include "printf.h"
+#include <string.h>
+#include <stdarg.h>
+
+// =============================================================================
+// types and definitions
+
+typedef struct
+{
+    ulog_function_t fn;
+    ulog_level_t threshold;
+} subscriber_t;
+
+// =============================================================================
+// local storage
+
+static subscriber_t s_subscribers[ULOG_MAX_SUBSCRIBERS];
+static char s_message[ULOG_MAX_MESSAGE_LENGTH];
+
+// =============================================================================
+// user-visible code
+
+void ulog_init()
+{
+    memset(s_subscribers, 0, sizeof(s_subscribers));
+}
+
+// search the s_subscribers table to install or update fn
+ulog_err_t ulog_subscribe(ulog_function_t fn, ulog_level_t threshold)
+{
+    int available_slot = -1;
+    int i;
+    for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++)
+    {
+        if (s_subscribers[i].fn == fn)
+        {
+            // already subscribed: update threshold and return immediately.
+            s_subscribers[i].threshold = threshold;
+            return ULOG_ERR_NONE;
+        }
+        else if (s_subscribers[i].fn == NULL)
+        {
+            // found a free slot
+            available_slot = i;
+        }
+    }
+    // fn is not yet a subscriber.  assign if possible.
+    if (available_slot == -1)
+    {
+        return ULOG_ERR_SUBSCRIBERS_EXCEEDED;
+    }
+    s_subscribers[available_slot].fn = fn;
+    s_subscribers[available_slot].threshold = threshold;
+    return ULOG_ERR_NONE;
+}
+
+// search the s_subscribers table to remove
+ulog_err_t ulog_unsubscribe(ulog_function_t fn)
+{
+    int i;
+    for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++)
+    {
+        if (s_subscribers[i].fn == fn)
+        {
+            s_subscribers[i].fn = NULL; // mark as empty
+            return ULOG_ERR_NONE;
+        }
+    }
+    return ULOG_ERR_NOT_SUBSCRIBED;
+}
+
+const char *ulog_level_name(ulog_level_t severity)
+{
+    switch (severity)
+    {
+    case ULOG_TRACE_LEVEL:
+        return "TRACE";
+    case ULOG_DEBUG_LEVEL:
+        return "DEBUG";
+    case ULOG_INFO_LEVEL:
+        return "INFO";
+    case ULOG_WARNING_LEVEL:
+        return "WARNING";
+    case ULOG_ERROR_LEVEL:
+        return "ERROR";
+    case ULOG_CRITICAL_LEVEL:
+        return "CRITICAL";
+    case ULOG_ALWAYS_LEVEL:
+        return "ALWAYS";
+    default:
+        return "UNKNOWN";
+    }
+}
+
+void ulog_message(ulog_level_t severity, const char *fmt, ...)
+{
+    va_list ap;
+    int i;
+    va_start(ap, fmt);
+    vsnprintf(s_message, ULOG_MAX_MESSAGE_LENGTH, fmt, ap);
+    va_end(ap);
+
+    for (i = 0; i < ULOG_MAX_SUBSCRIBERS; i++)
+    {
+        if (s_subscribers[i].fn != NULL)
+        {
+            if (severity >= s_subscribers[i].threshold)
+            {
+                s_subscribers[i].fn(severity, s_message);
+            }
+        }
+    }
+}
+
+// =============================================================================
+// private code
+
+#endif // #ifdef ULOG_ENABLED