From c2c3c2d96e6296b439e901c89d868185cdc82960 Mon Sep 17 00:00:00 2001
From: VegOwOtenks <vegowotenks@jossco.de>
Date: Tue, 1 Oct 2024 21:37:05 +0200
Subject: [PATCH] Implemented Scratchpad_ReserveAligned and refactored
 internally

---
 src/Scratchpad/Scratchpad.c | 69 +++++++++++++++++++++++++++----------
 src/Scratchpad/Scratchpad.h |  1 +
 2 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/src/Scratchpad/Scratchpad.c b/src/Scratchpad/Scratchpad.c
index 488e854..b905d59 100644
--- a/src/Scratchpad/Scratchpad.c
+++ b/src/Scratchpad/Scratchpad.c
@@ -30,6 +30,32 @@ static void* _Scratchpad_ReserveHere(Scratchpad* pad, size_t size)
 	return scratch_buffer;
 }
 
+static int _Scratchpad_CreateEmbedded(Scratchpad* pad, size_t size)
+{
+	Scratchpad* new = Allocator_Allocate(pad->allocator, sizeof(*pad));
+	if (new != NULL) {
+		// Copy current pad in the *next pointer
+		memcpy(new, pad, sizeof(*pad));
+
+		// Calculate new capacity
+		size_t new_capacity = size > pad->capacity ?
+			pad->capacity * (size / pad->capacity + 1)
+			: pad->capacity;
+
+		// Initialize new pad
+		if (Scratchpad_Create(pad, new_capacity, pad->allocator)) {
+			Allocator_Free(pad->allocator, new, sizeof(*new));
+			return EXIT_FAILURE;
+		} else {
+			pad->next = new;
+		}
+	} else {
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}
+
 void* Scratchpad_Reserve(Scratchpad* pad, size_t size)
 {
 	if (pad == NULL) return NULL;
@@ -42,29 +68,36 @@ void* Scratchpad_Reserve(Scratchpad* pad, size_t size)
 	}
 
 	if (reserve == NULL) {
-		Scratchpad* new = Allocator_Allocate(pad->allocator, sizeof(*pad));
-		if (new != NULL) {
-			// Copy current pad in the *next pointer
-			memcpy(new, pad, sizeof(*pad));
-
-			// Calculate new capacity
-			size_t new_capacity = size > pad->capacity ?
-				pad->capacity * (size / pad->capacity + 1)
-				: pad->capacity;
-
-			// Initialize new pad
-			if (Scratchpad_Create(pad, new_capacity, pad->allocator)) {
-				Allocator_Free(pad->allocator, new, sizeof(*new));
-			} else {
-				reserve = Scratchpad_Reserve(pad, size);
-				pad->next = new;
-			}
-		}
+		if (_Scratchpad_CreateEmbedded(pad, size)) return NULL;
+		reserve = _Scratchpad_ReserveHere(pad, size);
 	}
 
 	return reserve;
 }
 
+void* Scratchpad_ReserveAligned(Scratchpad* pad, size_t amount, size_t alignment)
+{
+	if (pad == NULL) return NULL;
+
+	if (alignment == 1) return Scratchpad_Reserve(pad, amount);
+
+	Scratchpad* root = pad;
+	do {
+		uintptr_t pointer_value     = (uintptr_t) pad->memory;
+		uintptr_t alignment_padding = alignment - (pointer_value % alignment);
+		void* memory = _Scratchpad_ReserveHere(pad, alignment_padding + amount);
+		if (memory != NULL) return memory;
+
+		pad = pad->next;
+
+	} while (pad != NULL);
+
+	
+	if (_Scratchpad_CreateEmbedded(root, amount)) return NULL;
+
+	return _Scratchpad_ReserveHere(root, amount);
+}
+
 int Scratchpad_Reclaim(Scratchpad* pad, void* pointer, size_t length)
 {
 	if (pad == NULL) return EDESTADDRREQ;
diff --git a/src/Scratchpad/Scratchpad.h b/src/Scratchpad/Scratchpad.h
index 132b557..0ef9d4d 100644
--- a/src/Scratchpad/Scratchpad.h
+++ b/src/Scratchpad/Scratchpad.h
@@ -21,6 +21,7 @@ typedef struct Scratchpad_s {
 int Scratchpad_Create(Scratchpad* target, size_t capacity, allocator_t* allocator);
 
 void* Scratchpad_Reserve(Scratchpad* pad, size_t size);
+void* Scratchpad_ReserveAligned(Scratchpad* pad, size_t amount, size_t alignment);
 int Scratchpad_Reclaim(Scratchpad* pad, void* pointer, size_t length);
 void Scratchpad_Reset(Scratchpad* pad);