Userspace: Add u8sum

This program caluculates the sum of bytes in file mod 256

userspace/CMakeLists.txt

@@ -10,6 +10,7 @@ set(USERSPACE_PROJECTS
 	ls
 	Shell
 	test
+	u8sum
 	yes
 )
 

userspace/u8sum/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(u8sum CXX)
+
+set(SOURCES
+	main.cpp
+)
+
+add_executable(u8sum ${SOURCES})
+target_compile_options(u8sum PUBLIC -O2 -g)
+target_link_libraries(u8sum PUBLIC libc)
+
+add_custom_target(u8sum-install
+	COMMAND cp ${CMAKE_CURRENT_BINARY_DIR}/u8sum ${BANAN_BIN}/
+	DEPENDS u8sum
+)

userspace/u8sum/main.cpp

@@ -0,0 +1,29 @@
+#include <fcntl.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+	for (int i = 1; i < argc; i++)
+	{
+		FILE* fp = fopen(argv[i], "r");
+		if (fp == nullptr)
+		{
+			perror("nullptr");
+			continue;
+		}
+
+		uint8_t sum = 0;
+
+		uint8_t buffer[1024];
+		while (size_t ret = fread(buffer, 1, sizeof(buffer), fp))
+			for (int j = 0; j < ret; j++)
+				sum += buffer[j];
+
+		if (ferror(fp))
+			perror("fread");
+		else
+			printf("%s: %02x\n", argv[i], sum);
+
+		fclose(fp);
+	}
+}