Bitmap: Introduce new malloc-aware initialization functions

Lets us call resize(new_size) instead of initialize(realloc(location, new_size), new_size)

kernel/src/memory/UserVM.cpp

@@ -33,18 +33,15 @@ Result<bool> UserVM::try_expand(usize size)
 {
     if (m_bitmap.size_in_bytes() == MAX_VM_SIZE) { return false; }
 
-    usize new_size = m_bitmap.size_in_bytes() + size;
+    const usize old_size = m_bitmap.size_in_bytes();
+    usize new_size = old_size + size;
 
     if (new_size > MAX_VM_SIZE) new_size = MAX_VM_SIZE;
 
-    usize old_size = m_bitmap.size_in_bytes();
+    m_bitmap.resize(new_size);
-
-    void* const base = TRY(krealloc(m_bitmap.location(), new_size));
-
-    m_bitmap.initialize(base, new_size);
     m_bitmap.clear_region(old_size * 8, (new_size - old_size) * 8, false);
 
-    kdbgln("user vm expanded to base=%p, size=%zu", base, new_size);
+    kdbgln("user vm expanded to base=%p, size=%zu", m_bitmap.location(), new_size);
 
     return true;
 }
@@ -110,5 +107,5 @@ Result<void> UserVM::free_several_pages(u64 address, usize count)
 UserVM::~UserVM()
 {
     kdbgln("user vm destroyed: base=%p, size=%zu", m_bitmap.location(), m_bitmap.size_in_bytes());
-    kfree(m_bitmap.location());
+    m_bitmap.deallocate();
 }

luna/include/luna/Bitmap.h

@@ -8,9 +8,15 @@ class Bitmap
     Bitmap();
     Bitmap(void* location, usize size_in_bytes);
 
+    // Naive initialization functions.
     void initialize(void* location, usize size_in_bytes);
     void* move(void* new_location, usize new_location_size_in_bytes);
 
+    // Dynamic memory initialization functions.
+    Result<void> allocate(usize size_in_bytes);
+    Result<void*> resize(usize new_size_in_bytes);
+    Result<void> deallocate();
+
     void set(usize index, bool value);
     bool get(usize index) const;
 

luna/src/Bitmap.cpp

@@ -1,6 +1,7 @@
 #include <luna/Bitmap.h>
 #include <luna/CString.h>
 #include <luna/Check.h>
+#include <luna/Heap.h>
 
 Bitmap::Bitmap()
 {
@@ -16,6 +17,24 @@ void Bitmap::initialize(void* location, usize size_in_bytes)
     m_size_in_bytes = size_in_bytes;
 }
 
+Result<void> Bitmap::allocate(usize size_in_bytes)
+{
+    initialize(TRY(malloc_impl(size_in_bytes)), size_in_bytes);
+    return {};
+}
+
+Result<void*> Bitmap::resize(usize new_size_in_bytes)
+{
+    m_location = (u8*)TRY(realloc_impl(m_location, new_size_in_bytes));
+    m_size_in_bytes = new_size_in_bytes;
+    return (void*)m_location;
+}
+
+Result<void> Bitmap::deallocate()
+{
+    return free_impl(m_location);
+}
+
 void* Bitmap::move(void* new_location, usize new_location_size_in_bytes)
 {
     expect(initialized(), "Bitmap was never initialized");
@@ -24,7 +43,7 @@ void* Bitmap::move(void* new_location, usize new_location_size_in_bytes)
     else
         memcpy(new_location, m_location, new_location_size_in_bytes);
 
-    void* old_location = (void*)m_location;
+    void* const old_location = (void*)m_location;
 
     m_location = (u8*)new_location;
     m_size_in_bytes = new_location_size_in_bytes;
@@ -36,8 +55,8 @@ void Bitmap::set(usize index, bool value)
 {
     expect(initialized(), "Bitmap was never initialized");
     expect(index < size(), "Bitmap access out of range");
-    u64 byte_index = index / 8;
+    const u64 byte_index = index / 8;
-    u8 bit_mask = (u8)(0b10000000 >> (index % 8));
+    const u8 bit_mask = (u8)(0b10000000 >> (index % 8));
     m_location[byte_index] &= (u8)(~bit_mask);
     if (value) { m_location[byte_index] |= bit_mask; }
 }
@@ -46,8 +65,8 @@ bool Bitmap::get(usize index) const
 {
     expect(initialized(), "Bitmap was never initialized");
     expect(index < size(), "Bitmap access out of range");
-    usize byte_index = index / 8;
+    const usize byte_index = index / 8;
-    u8 bit_mask = (u8)(0b10000000 >> (index % 8));
+    const u8 bit_mask = (u8)(0b10000000 >> (index % 8));
     return (m_location[byte_index] & bit_mask) > 0;
 }
 
@@ -73,7 +92,7 @@ void Bitmap::clear_region(usize start, usize bits, bool value)
     }
 
     // Clear out the rest in bytes.
-    usize bytes = bits / 8;
+    const usize bytes = bits / 8;
 
     memset(&m_location[start / 8], value_byte(value), bytes);
     start += bytes * 8;
@@ -163,7 +182,7 @@ Option<usize> Bitmap::find_region(bool value, usize count, usize begin) const
 
 Option<usize> Bitmap::find_and_toggle_region(bool value, usize count, usize begin)
 {
-    usize index = TRY(find_region(value, count, begin));
+    const usize index = TRY(find_region(value, count, begin));
     clear_region(index, count, !value);
     return index;
 }
@@ -184,7 +203,7 @@ bool Bitmap::match_region(usize start, usize bits, bool value)
     }
 
     // Match the rest in bytes.
-    usize bytes = bits / 8;
+    const usize bytes = bits / 8;
     const u8 byte_that_contains_only_value = value_byte(value);
 
     for (usize i = start; i < start + bytes; i += 8)