feat(linux): added fls() on Linux

components/linux/CMakeLists.txt

@@ -3,10 +3,14 @@ if(NOT "${target}" STREQUAL "linux")
     return()
 endif()
 
+set(includes "include")
 if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin")
     list(APPEND srcs getrandom.c assert_func.c)
+else()
+    list(APPEND srcs fls.c)
+    list(APPEND includes "linux_include")
 endif()
 
-idf_component_register(INCLUDE_DIRS include
+idf_component_register(INCLUDE_DIRS ${includes}
                        REQUIRED_IDF_TARGETS linux
                        SRCS ${srcs})

components/linux/fls.c

@@ -0,0 +1,18 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-4-Clause-UC
+ *
+ * SPDX-FileContributor: 2024 Espressif Systems (Shanghai) CO LTD
+ */
+
+#include "strings.h"
+
+int fls(unsigned int mask)
+{
+    if (mask == 0) {
+        return (0);
+    }
+
+    return (sizeof(mask) << 3) - __builtin_clz(mask);
+}

components/linux/linux_include/strings.h

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * This is a helper include for fls(), which is present in the ESP-IDF toolchains and MacOS, but not on Linux.
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int fls(unsigned int value);
+
+#ifdef __cplusplus
+}
+#endif
+
+#include_next <strings.h>

components/linux/test_apps/.build-test-rules.yml

@@ -0,0 +1,6 @@
+# Documentation: .gitlab/ci/README.md#manifest-file-to-control-the-buildtest-apps
+
+components/linux/test_apps/linux_test:
+  enable:
+    - if: IDF_TARGET in ["linux"]
+      reason: Test app is specifically for the linux target

components/linux/test_apps/linux_test/CMakeLists.txt

@@ -0,0 +1,9 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+set(COMPONENTS main)
+project(linux_test)

components/linux/test_apps/linux_test/README.md

@@ -0,0 +1,2 @@
+| Supported Targets | Linux |
+| ----------------- | ----- |

components/linux/test_apps/linux_test/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(SRCS "linux_test.c"
+                    INCLUDE_DIRS "."
+                    PRIV_REQUIRES unity)

components/linux/test_apps/linux_test/main/linux_test.c

@@ -0,0 +1,51 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "unity.h"
+#include "unity_test_runner.h"
+#include "unity_test_utils_memory.h"
+#include "esp_log.h"
+#include <strings.h>
+
+static const char* TAG = "event_test_app";
+
+void setUp(void)
+{
+    // If heap tracing is enabled in kconfig, leak trace the test
+    unity_utils_set_leak_level(0);
+    unity_utils_record_free_mem();
+}
+
+void tearDown(void)
+{
+    unity_utils_evaluate_leaks();
+}
+
+TEST_CASE("fls(0) = 0", "[fls]")
+{
+    TEST_ASSERT_EQUAL(0, fls(0));
+}
+
+TEST_CASE("fls(1) = 1", "[fls]")
+{
+    TEST_ASSERT_EQUAL(1, fls(1));
+}
+
+TEST_CASE("fls(0xF000) = 16", "[fls]")
+{
+    TEST_ASSERT_EQUAL(16, fls(0xF000));
+}
+
+TEST_CASE("fls(0x80000000) = 32", "[fls]")
+{
+    TEST_ASSERT_EQUAL(32, fls(0x80000000));
+}
+
+void app_main(void)
+{
+    ESP_LOGI(TAG, "Running linux test app");
+    unity_run_menu();
+}

components/linux/test_apps/linux_test/pytest_linux_test.py

@@ -0,0 +1,12 @@
+# SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import pytest
+from pytest_embedded_idf.dut import IdfDut
+
+
+@pytest.mark.linux
+@pytest.mark.host_test
+def test_linux_component(dut: IdfDut) -> None:
+    dut.expect_exact('Press ENTER to see the list of tests.')
+    dut.write('![ignore]')
+    dut.expect(r'\d{1} Tests 0 Failures 0 Ignored', timeout=10)

components/linux/test_apps/linux_test/sdkconfig.defaults

@@ -0,0 +1 @@
+CONFIG_IDF_TARGET="linux"

tools/ci/check_copyright_config.yaml

@@ -104,6 +104,13 @@ ethernet_component:
     - Apache-2.0
     - MIT           # To allow contributed drivers
 
+linux_component:
+  include:
+    - 'components/linux/fls.c'
+  allowed_licenses:
+    - Apache-2.0
+    - BSD-4-Clause-UC
+
 systemview:
   include:
     - 'components/app_trace/sys_view'