[nostalgia/core/gba][ox/std] Move heap manager from NostalgiaCore to OxStd

deps/ox/src/ox/std/heapmgr.cpp

@@ -0,0 +1,143 @@
+/*
+ * Copyright 2016 - 2020 gtalent2@gmail.com
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include "assert.hpp"
+#include "bit.hpp"
+#include "heapmgr.hpp"
+
+namespace ox::heapmgr {
+
+static struct HeapSegment *volatile g_heapBegin = nullptr;
+static struct HeapSegment *volatile g_heapEnd = nullptr;
+static struct HeapSegment *volatile heapIdx = nullptr;
+
+static constexpr std::size_t alignedSize(std::size_t sz) {
+	return sz + (sz & 7);
+}
+
+template<typename T>
+static constexpr std::size_t alignedSize(T = {}) {
+	return alignedSize(sizeof(T));
+}
+
+void HeapSegment::init(std::size_t maxSize = ox::bit_cast<std::size_t>(g_heapEnd)) {
+	this->size = maxSize - ox::bit_cast<std::size_t>(this);
+	this->inUse = false;
+}
+
+template<typename T>
+T *HeapSegment::data() {
+	return ox::bit_cast<T*>(ox::bit_cast<uint8_t*>(this) + alignedSize(this));
+}
+
+template<typename T = uint8_t>
+T *HeapSegment::end() {
+	const auto size = alignedSize(this) + alignedSize(this->size);
+	auto e = ox::bit_cast<uintptr_t>(ox::bit_cast<uint8_t*>(this) + size);
+	return ox::bit_cast<T*>(e);
+}
+
+
+void initHeap(char *heapBegin, char *heapEnd) {
+	g_heapBegin = ox::bit_cast<HeapSegment*>(heapBegin);
+	g_heapEnd = ox::bit_cast<HeapSegment*>(heapEnd);
+	heapIdx = g_heapBegin;
+	heapIdx->size = ox::bit_cast<std::size_t>(heapEnd) - ox::bit_cast<std::size_t>(heapIdx);
+	heapIdx->inUse = false;
+}
+
+struct SegmentPair {
+	HeapSegment *anteSegment = nullptr;
+	HeapSegment *segment = nullptr;
+};
+
+static SegmentPair findSegmentOf(void *ptr) {
+	HeapSegment *prev = nullptr;
+	for (auto seg = g_heapBegin; seg < g_heapEnd;) {
+		if (seg->data<void>() == ptr) {
+			return {prev, seg};
+		}
+		prev = seg;
+		seg = seg->end<HeapSegment>();
+	}
+	return {};
+}
+
+static HeapSegment *findSegmentFor(std::size_t sz) {
+	for (auto s = g_heapBegin; s <= g_heapEnd; s = s->end<HeapSegment>()) {
+		if (s->size >= sz && !s->inUse) {
+			return s;
+		}
+	}
+	oxPanic(OxError(1), "malloc: could not find segment");
+	return nullptr;
+}
+
+[[nodiscard]] void *malloc(std::size_t allocSize) {
+	const auto targetSize = alignedSize(sizeof(HeapSegment)) + alignedSize(allocSize);
+	auto seg = findSegmentFor(targetSize);
+	if (seg == nullptr) {
+		return nullptr;
+	}
+	const auto bytesRemaining = seg->size - targetSize;
+	seg->size = targetSize;
+	seg->inUse = true;
+	seg->end<HeapSegment>()->init(bytesRemaining);
+	return seg->data<void>();
+}
+
+void free(void *ptr) {
+	auto p = findSegmentOf(ptr);
+	if (p.anteSegment) {
+		p.anteSegment->size += p.segment->size;
+	} else if (p.segment) {
+		p.segment->inUse = false;
+	} else {
+		oxPanic(OxError(1), "Bad heap free");
+	}
+}
+
+}
+
+#ifndef OX_USE_STDLIB
+
+using namespace ox;
+
+void *operator new(std::size_t allocSize) {
+	return heapmgr::malloc(allocSize);
+}
+
+void *operator new[](std::size_t allocSize) {
+	return heapmgr::malloc(allocSize);
+}
+
+void operator delete(void *ptr) {
+	heapmgr::free(ptr);
+}
+
+void operator delete[](void *ptr) {
+	heapmgr::free(ptr);
+}
+
+void operator delete(void *ptr, unsigned) {
+	heapmgr::free(ptr);
+}
+
+void operator delete[](void *ptr, unsigned) {
+	heapmgr::free(ptr);
+}
+
+void operator delete(void *ptr, unsigned long int) {
+	heapmgr::free(ptr);
+}
+
+void operator delete[](void *ptr, unsigned long int) {
+	heapmgr::free(ptr);
+}
+
+#endif