format bytes prettily in free_printer

src/arch/x86/kmain.cpp

@@ -3,6 +3,7 @@
 //
 #include <cstddef>
 
+#include "BytesFormatter.hpp"
 #include "LockGuard.hpp"
 #include "MemFs.hpp"
 #include "MountTable.hpp"
@@ -72,19 +73,19 @@ void freeprinter() {
         String buf;
         buf += "=====\n";
         buf += "Free mem: ";
-        buf += get_free() * 1024;
+        buf += BytesFormatter::formatStr(get_free() * 1024);
         buf += "\n";
         GlobalTtyManager.all_tty_putstr(buf.c_str());
         buf = "";
 
         buf += "Heap allocated: ";
-        buf += get_heap_allocated();
+        buf += BytesFormatter::formatStr(get_heap_allocated());
         buf += "\n";
         GlobalTtyManager.all_tty_putstr(buf.c_str());
         buf = "";
 
         buf += "Heap used: ";
-        buf += get_heap_used();
+        buf += BytesFormatter::formatStr(get_heap_used());
         buf += "\n";
         buf += "=====\n";
         GlobalTtyManager.all_tty_putstr(buf.c_str());

src/arch/x86/syscalls.cpp

@@ -28,7 +28,7 @@ void setup_syscalls() {
     union {
         STAR star;
         uint64_t bytes;
-    } newstar{};
+    } __attribute__((__packed__)) newstar{};
 
     newstar.star.ret_cs_ss = (GDTSEL(gdt_data_user) - 8) | 0x3;
     assert(newstar.star.ret_cs_ss + 8 == (GDTSEL(gdt_data_user) | 0x3));

src/kernel/BytesFormatter.cpp

@@ -0,0 +1,45 @@
+//
+// Created by Stepan Usatiuk on 22.03.2024.
+//
+
+#include "BytesFormatter.hpp"
+
+static void print2dec(String &out, uint64_t what) {
+    uint64_t after_dot = what % 100;
+    what /= 100;
+    out += what;
+    out += ".";
+    out += after_dot;
+}
+
+BytesFormatter::BytesFormat BytesFormatter::format(unsigned long long int bytes) {
+    String outNum;
+
+    if (bytes > 1024ULL * 1024 * 1024 * 1024) {
+        print2dec(outNum, bytes / (1024ULL * 1024ULL * 1024ULL * 10ULL));
+        return {std::move(outNum), "TiB"};
+    }
+    if (bytes > 1024ULL * 1024 * 1024) {
+        print2dec(outNum, bytes / (1024ULL * 1024ULL * 10ULL));
+        return {std::move(outNum), "GiB"};
+    }
+    if (bytes > 1024ULL * 1024) {
+        print2dec(outNum, bytes / (1024ULL * 10ULL));
+        return {std::move(outNum), "MiB"};
+    }
+    if (bytes > 1024ULL) {
+        print2dec(outNum, bytes / (10ULL));
+        return {std::move(outNum), "KiB"};
+    }
+    outNum += bytes;
+    return {std::move(outNum), "Bytes"};
+}
+
+String BytesFormatter::formatStr(unsigned long long int bytes) {
+    auto fmt = format(bytes);
+    String out;
+    out += fmt.number;
+    out += " ";
+    out += fmt.prefix;
+    return out;
+}

src/kernel/BytesFormatter.hpp

@@ -0,0 +1,31 @@
+//
+// Created by Stepan Usatiuk on 22.03.2024.
+//
+
+#ifndef OS2_BYTESFORMATTER_HPP
+#define OS2_BYTESFORMATTER_HPP
+
+#include "String.hpp"
+
+/// Utility class to format byte values according to their magnitude
+class BytesFormatter {
+public:
+    /// Structure for returning the processed byte value
+    struct BytesFormat {
+        String number;///< Number part of the value
+        String prefix;///< Unit of measure
+    };
+
+    /// Formats the bytes in BytesFormat format
+    /// \param bytes Number of bytes
+    /// \return      BytesFormat value
+    static BytesFormat format(unsigned long long bytes);
+
+    /// Formats the bytes into a string
+    /// \param bytes Number of bytes
+    /// \return      String, consisting of the scaled number and the unit of measure separated by a space
+    static String formatStr(unsigned long long bytes);
+};
+
+
+#endif//OS2_BYTESFORMATTER_HPP

src/kernel/CMakeLists.txt

@@ -1,6 +1,18 @@
 target_include_directories(kernel.elf PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
 
-target_sources(kernel.elf PRIVATE mutex.cpp cppsupport.cpp Spinlock.cpp LockGuard.cpp rand.cpp VMA.cpp asserts.cpp TtyManager.cpp Tty.cpp cv.cpp)
+target_sources(kernel.elf PRIVATE
+        mutex.cpp
+        cppsupport.cpp
+        Spinlock.cpp
+        LockGuard.cpp
+        rand.cpp
+        VMA.cpp
+        asserts.cpp
+        TtyManager.cpp
+        Tty.cpp
+        cv.cpp
+        BytesFormatter.cpp
+)
 
 add_subdirectory(templates)
 add_subdirectory(vfs)