Add unit formatting

kernel/src/main.cpp

@@ -6,6 +6,7 @@
 #include "memory/Heap.h"
 #include "memory/MemoryManager.h"
 #include "video/TextConsole.h"
+#include <Units.h>
 
 Result<void> init()
 {
@@ -51,6 +52,14 @@ Result<void> init()
 
     TRY(destroy(mem));
 
+    char buffer[64];
+    to_dynamic_unit(MemoryManager::free(), buffer, sizeof(buffer));
+    Serial::printf("Free memory: %s\n", buffer);
+    to_dynamic_unit(MemoryManager::used(), buffer, sizeof(buffer));
+    Serial::printf("Used memory: %s\n", buffer);
+    to_dynamic_unit(MemoryManager::reserved(), buffer, sizeof(buffer));
+    Serial::printf("Reserved memory: %s\n", buffer);
+
     while (1)
     {
         while ((Timer::ticks_ms() - start) < 20) { CPU::wait_for_interrupt(); }

luna/CMakeLists.txt

@@ -2,6 +2,7 @@ set(FREESTANDING_SOURCES
     Format.cpp
     NumberParsing.cpp
     String.cpp
+    Units.cpp
 )
 
 set(SOURCES

luna/Format.cpp

@@ -467,4 +467,43 @@ Result<usize> cstyle_format(const char* format, callback_t callback, void* arg,
     }
 
     return state.count;
+}
+
+struct StringFormatInfo
+{
+    char* buffer;
+    size_t remaining;
+};
+
+Result<usize> vstring_format(char* buf, size_t max, const char* format, va_list ap)
+{
+    StringFormatInfo info = {.buffer = buf, .remaining = max - 1};
+
+    usize result = TRY(cstyle_format(
+        format,
+        [](char c, void* arg) -> Result<void> {
+            StringFormatInfo* info_arg = (StringFormatInfo*)arg;
+            if (!info_arg->remaining) return {};
+            *(info_arg->buffer) = c;
+            info_arg->buffer++;
+            info_arg->remaining--;
+            return {};
+        },
+        &info, ap));
+
+    *(info.buffer) = 0;
+
+    return result;
+}
+
+Result<usize> string_format(char* buf, size_t max, const char* format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+
+    usize result = TRY(vstring_format(buf, max, format, ap));
+
+    va_end(ap);
+
+    return result;
 }

luna/Format.h

@@ -5,4 +5,6 @@
 
 typedef Result<void> (*callback_t)(char, void*);
 
-Result<usize> cstyle_format(const char* format, callback_t callback, void* arg, va_list ap);
+Result<usize> cstyle_format(const char* format, callback_t callback, void* arg, va_list ap);
+Result<usize> vstring_format(char* buf, size_t max, const char* format, va_list ap);
+Result<usize> string_format(char* buf, size_t max, const char* format, ...);

luna/Units.cpp

@@ -0,0 +1,17 @@
+#include <Format.h>
+#include <Units.h>
+#include <limits.h>
+
+Result<usize> to_dynamic_unit(usize value, char* buffer, size_t max)
+{
+    if (value < 1024) { return string_format(buffer, max, "%u bytes", value); }
+
+    const char* unit_prefixes = "KMGTPE";
+    for (int i = 40; i >= 0 && value > (0xfffccccccccccccUL >> i); i -= 10)
+    {
+        value >>= 10;
+        unit_prefixes++;
+    }
+
+    return string_format(buffer, max, "%u.%u %ciB", value / 1024, (value % 1024) / 103, *unit_prefixes);
+}

luna/Units.h

@@ -0,0 +1,4 @@
+#pragma once
+#include <Result.h>
+
+Result<usize> to_dynamic_unit(usize value, char* buffer, usize max);