testing and benchmarking functions of opencv

- Benchmark measurement tool added
- Tested a bunch of function
	- TODO: See why some function don't give stack memory back!

esp32/examples/esp_opencv_tests/main/system.cpp

@@ -0,0 +1,58 @@
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <esp_spiffs.h>
+#include <esp_log.h>
+
+#include "system.hpp"
+
+
+#define TAG "SYSTEM"
+
+
+esp_err_t init_spiffs() {
+    ESP_LOGI("spiffs_init", "Initializing SPIFFS");
+
+    esp_vfs_spiffs_conf_t conf = {
+            .base_path = "/spiffs",
+            .partition_label = NULL,
+            .max_files = 10,
+            .format_if_mount_failed = false
+    };
+
+    // Use settings defined above to initialize and mount SPIFFS filesystem.
+    // Note: esp_vfs_spiffs_register is an all-in-one convenience function.
+    esp_err_t ret = esp_vfs_spiffs_register(&conf);
+
+    if (ret != ESP_OK) {
+        if (ret == ESP_FAIL) {
+            ESP_LOGE("spiffs_init", "Failed to mount or format filesystem");
+        } else if (ret == ESP_ERR_NOT_FOUND) {
+            ESP_LOGE("spiffs_init", "Failed to find SPIFFS partition");
+        } else {
+            ESP_LOGE("spiffs_init", "Failed to initialize SPIFFS (%s)", esp_err_to_name(ret));
+        }
+        return ret;
+    }
+
+    size_t total = 0, used = 0;
+    ret = esp_spiffs_info(NULL, &total, &used);
+    if (ret != ESP_OK) {
+        ESP_LOGE("spiffs_init", "Failed to get SPIFFS partition information (%s)", esp_err_to_name(ret));
+    } else {
+        ESP_LOGI("spiffs_init", "Partition size: total: %d, used: %d", total, used);
+    }
+    return ESP_OK;
+}
+
+void wait_msec(uint16_t v) {
+    vTaskDelay(v / portTICK_PERIOD_MS);
+}
+
+void wait_sec(uint16_t v) {
+    vTaskDelay(v * 1000 / portTICK_PERIOD_MS);
+}
+
+void disp_mem_infos() {
+    ESP_LOGI(TAG, "task stack left: %d Bytes", uxTaskGetStackHighWaterMark(NULL));
+    ESP_LOGI(TAG, "heap left: %d Bytes", esp_get_free_heap_size());
+}