LibC: Simplify malloc size classes

Problem:
- `size_classes` is a C-style array which makes it difficult to use in
  algorithms.
- `all_of` algorithm is re-written for the specific implementation.

Solution:
- Change `size_classes` to be an `Array`.
- Directly use the generic `all_of` algorithm instead of
  reimplementing.

3 files changed, 12 insertions, 18 deletions

diff --git a/Userland/DevTools/UserspaceEmulator/MallocTracer.cpp b/Userland/DevTools/UserspaceEmulator/MallocTracer.cpp
index 4f00c21c52..501d17c9af 100644
--- a/Userland/DevTools/UserspaceEmulator/MallocTracer.cpp
+++ b/Userland/DevTools/UserspaceEmulator/MallocTracer.cpp
@@ -68,7 +68,7 @@ void MallocTracer::target_did_malloc(Badge<Emulator>, FlatPtr address, size_t si
             }));
         auto& malloc_data = *mmap_region.malloc_metadata();
 
-        bool is_chunked_block = malloc_data.chunk_size <= size_classes[num_size_classes - 1];
+        bool is_chunked_block = malloc_data.chunk_size <= size_classes[size_classes.size() - 1];
         if (is_chunked_block)
             malloc_data.mallocations.resize((ChunkedBlock::block_size - sizeof(ChunkedBlock)) / malloc_data.chunk_size);
         else
@@ -92,7 +92,7 @@ ALWAYS_INLINE Mallocation* MallocRegionMetadata::mallocation_for_address(FlatPtr
 
 ALWAYS_INLINE Optional<size_t> MallocRegionMetadata::chunk_index_for_address(FlatPtr address) const
 {
-    bool is_chunked_block = chunk_size <= size_classes[num_size_classes - 1];
+    bool is_chunked_block = chunk_size <= size_classes[size_classes.size() - 1];
     if (!is_chunked_block) {
         // This is a BigAllocationBlock
         return 0;
diff --git a/Userland/Libraries/LibC/malloc.cpp b/Userland/Libraries/LibC/malloc.cpp
index 43519cf296..1da5b43ad9 100644
--- a/Userland/Libraries/LibC/malloc.cpp
+++ b/Userland/Libraries/LibC/malloc.cpp
@@ -102,12 +102,12 @@ struct BigAllocator {
 // are run. Similarly, we can not allow global destructors to destruct
 // them. We could have used AK::NeverDestoyed to prevent the latter,
 // but it would have not helped with the former.
-static u8 g_allocators_storage[sizeof(Allocator) * num_size_classes];
+static u8 g_allocators_storage[sizeof(Allocator) * size_classes.size()];
 static u8 g_big_allocators_storage[sizeof(BigAllocator)];
 
-static inline Allocator (&allocators())[num_size_classes]
+static inline Allocator (&allocators())[size_classes.size()]
 {
-    return reinterpret_cast<Allocator(&)[num_size_classes]>(g_allocators_storage);
+    return reinterpret_cast<Allocator(&)[size_classes.size()]>(g_allocators_storage);
 }
 
 static inline BigAllocator (&big_allocators())[1]
@@ -442,7 +442,7 @@ void __malloc_init()
     if (secure_getenv("LIBC_PROFILE_MALLOC"))
         s_profiling = true;
 
-    for (size_t i = 0; i < num_size_classes; ++i) {
+    for (size_t i = 0; i < size_classes.size(); ++i) {
         new (&allocators()[i]) Allocator();
         allocators()[i].size = size_classes[i];
     }
diff --git a/Userland/Libraries/LibC/mallocdefs.h b/Userland/Libraries/LibC/mallocdefs.h
index ebf90eeaef..4237219260 100644
--- a/Userland/Libraries/LibC/mallocdefs.h
+++ b/Userland/Libraries/LibC/mallocdefs.h
@@ -6,6 +6,8 @@
 
 #pragma once
 
+#include <AK/AllOf.h>
+#include <AK/Array.h>
 #include <AK/InlineLinkedList.h>
 #include <AK/Types.h>
 
@@ -14,18 +16,10 @@
 #define MALLOC_SCRUB_BYTE 0xdc
 #define FREE_SCRUB_BYTE 0xed
 
-static constexpr unsigned short size_classes[] = { 8, 16, 32, 64, 128, 256, 504, 1016, 2032, 4088, 8184, 16376, 32752, 0 };
-static constexpr size_t num_size_classes = (sizeof(size_classes) / sizeof(unsigned short)) - 1;
-
-consteval bool check_size_classes_alignment()
-{
-    for (size_t i = 0; i < num_size_classes; i++) {
-        if ((size_classes[i] % 8) != 0)
-            return false;
-    }
-    return true;
-}
-static_assert(check_size_classes_alignment());
+static constexpr Array<unsigned short, 13> size_classes { 8, 16, 32, 64, 128, 256, 504, 1016, 2032, 4088, 8184, 16376, 32752 };
+static constexpr auto malloc_alignment = 8;
+static_assert(all_of(size_classes.begin(), size_classes.end(),
+    [](const auto val) { return val % malloc_alignment == 0; }));
 
 struct CommonHeader {
     size_t m_magic;