Shrink the logger

* Move _write function to the log.c
* Change the way to setup the logger
* Update the readme
* Add terminal commands

project/Core/Src/log.c

@@ -1,7 +1,7 @@
 /**
  * @file log.c
  * @brief Logger implementation
- * @author Lorenz C.
+ * @author Lorenz C. && Speetjens S.
  */
 
 #include <stdarg.h>
@@ -10,71 +10,33 @@
 #include "stm32f7xx_hal.h"
 #include "log.h"
 
-/**
- * @brief Entry in the tag list containing the tag and the log level
- */
-typedef struct {
-    const char* tag;
-    log_level_t level;
-} tag_entry_t;
-
-static tag_entry_t tag_entries[LOGGER_MAX_TAG_ENTRIES];
-static size_t tag_entries_count = 0;
-static const char* TAG = "logger";
-
-
-void logger_set_log_level(const char* tag, log_level_t level) {
-    // Check if the tag is already in the list
-    for (int i = 0; i < tag_entries_count; i++) {
-        if (tag_entries[i].tag == tag) {
-            tag_entries[i].level = level;
-            return;
-        }
-    }
-
-    // The tag is not in the list yet, so add it
-    if (tag_entries_count < LOGGER_MAX_TAG_ENTRIES) {
-        tag_entries[tag_entries_count].tag = tag;
-        tag_entries[tag_entries_count].level = level;
-        tag_entries_count++;
-    } else {
-        LOG_WARN(TAG, "Could not add tag %s to list: List is full. Try increasing LOGGER_MAX_TAG_ENTRIES", tag);
-    }
-}
-
-log_level_t logger_get_log_level(const char* tag) {
-    log_level_t level = LOGGER_MIN_LOG_LEVEL;
-
-    // Try to find the tag in the list
-    for (int i = 0; i < tag_entries_count; i++) {
-        if (tag_entries[i].tag == tag) {
-            level = tag_entries[i].level;
-            break;
-        }
-    }
-
-    return level;
-}
+extern UART_HandleTypeDef huart1;
 
 /**
  * @brief Get the current timestamp to be used in the logger
  *
  * @return The current timestamp in milliseconds since boot
  */
-uint32_t logger_get_timestamp(void) {
-    return HAL_GetTick();
+
+int _write(int file, char *data, int len) {
+    HAL_StatusTypeDef status;
+
+    switch (file) {
+        case STDOUT_FILENO:
+        case STDERR_FILENO:
+            status = HAL_UART_Transmit(&huart1, (uint8_t*)data, len, HAL_MAX_DELAY);
+            if (status != HAL_OK) {
+                errno = EIO;
+                return -1;
+            }
+            break;
+        default:
+            errno = EBADF;
+            return -1;
+    }
+    return len;
 }
 
-/**
- * @brief Write a log message to the console
- * For now, this is just a wrapper around printf.
- *
- * @param[in] format The format string (see printf)
- * @param[in] ...
- */
-void logger_write(const char* format, ...) {
-    va_list args;
-    va_start(args, format);
-    vprintf(format, args);
-    va_end(args);
-}
+uint32_t logger_get_timestamp(void) {
+    return HAL_GetTick();
+}