From fe9d9e38367ad7b577eae6e09b5881e1d7e5aa2a Mon Sep 17 00:00:00 2001
From: Greg Bowne <gbowne144@gmail.com>
Date: Wed, 14 Feb 2024 16:21:16 -0800
Subject: [PATCH] fixing issues from PR

---
 main.c | 99 +++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 56 insertions(+), 43 deletions(-)

diff --git a/main.c b/main.c
index 98e406f..62c293e 100644
--- a/main.c
+++ b/main.c
@@ -68,7 +68,7 @@ struct block *find_first(size_t s)
 struct block *fragment_block(struct block *in, size_t s)
 {
 	// Calculate the size of the new block, including the block header
-	size_t newBlockSize = ALIGN16(s) + BLOCK_SIZE;
+	size_t newBlockSize = s + BLOCK_SIZE;
 
 	// Check if the current block can be split
 	if (in->size <= newBlockSize)
@@ -107,8 +107,9 @@ struct block *find_best_fit(size_t s)
 	while (current)
 	{
 		if (current->free && current->size >= s)
+	{
+			if (best_fit && current->size < best_fit->size) // Check for NULL before comparison
 		{
-			if (!best_fit || current->size < best_fit->size)
 			{
 				best_fit = current;
 			}
@@ -116,6 +117,7 @@ struct block *find_best_fit(size_t s)
 		current = current->next;
 	}
 	return best_fit;
+	}
 }
 
 /// Will find or allocate a memory block.
@@ -199,51 +201,62 @@ void *realloc(void *ptr, size_t new_size)
 /// @note If all data after the provided memory is free, it will reduce the heap size.
 void my_custom_free(void *ptr)
 {
-	if (!ptr)
-	{
-		return;
-	}
+    if (!ptr)
+    {
+        return;
+    }
 
-	struct block *b = (struct block *)((char *)ptr - BLOCK_SIZE);
-	if (b->free)
-	{
-		fprintf(stderr, "Double free detected at block %p.\n", ptr);
-		abort(); // Terminate the program immediately due to serious error
-	}
+    struct block *b = (struct block *)((char *)ptr - BLOCK_SIZE);
+    if (b->free)
+    {
+        fprintf(stderr, "Double free detected at block %p.\n", ptr);
+        abort(); // Terminate the program immediately due to serious error
+    }
 
-	b->free = 1;
+    b->free =  1;
 
-	// Coalesce free blocks
-	while (b->prev && b->prev->free)
-	{
-		// Merge with previous block
-		b->prev->size += BLOCK_SIZE + b->size;
-		b->prev->next = b->next;
-		b = b->prev;
-	}
-	while (b->next && b->next->free)
-	{
-		// Merge with next block
-		b->size += BLOCK_SIZE + b->next->size;
-		b->next = b->next->next;
-	}
+    // Coalesce free blocks
+    while (b->prev && b->prev->free)
+    {
+        // Merge with previous block
+        b->prev->size += BLOCK_SIZE + b->size;
+        b->prev->next = b->next;
+        b = b->prev;
+    }
 
-	// Check if we can shrink the heap
-	if (b == last)
-	{
-		// Update 'last' to the previous block or NULL if there's no previous block
-		last = b->prev;
-		if (last)
-		{
-			last->next = NULL;
-		}
-		else
-		{
-			first = NULL;
-		}
-		// Reduce the program break to release the memory
-		sbrk(0 - (b->size + BLOCK_SIZE));
-	}
+    // If there is a next block and it's free, merge with it
+    if (b->next && b->next->free)
+    {
+        b->size += BLOCK_SIZE + b->next->size;
+        b->next = b->next->next;
+        if (b->next)
+        {
+            b->next->prev = b;
+        }
+    }
+
+    // After merging, update the 'last' pointer if necessary
+    if (!b->next)
+    {
+        last = b;
+    }
+
+    // Check if we can shrink the heap
+    if (b == last)
+    {
+        // Update 'last' to the previous block or NULL if there's no previous block
+        last = b->prev;
+        if (last)
+        {
+            last->next = NULL;
+        }
+        else
+        {
+            first = NULL;
+        }
+        // Reduce the program break to release the memory
+        sbrk(0 - (b->size + BLOCK_SIZE));
+    }
 }
 
 int main()