From 24c7c4e7df4798f9bded80e1cadcc82d0d5b626e Mon Sep 17 00:00:00 2001
From: TuDatTr <tran.tuan-dat@mailbox.org>
Date: Sun, 24 Jan 2021 19:40:08 +0100
Subject: [PATCH] Added remove_free()

---
 Makefile |   3 +-
 mm.c     | 147 ++++++++++++++++++++++++++++++++++++++++---------------
 2 files changed, 109 insertions(+), 41 deletions(-)

diff --git a/Makefile b/Makefile
index a8a9e6f..701bc21 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,8 @@
 # Students' Makefile for the Malloc Lab
 #
 CC = gcc
-CFLAGS = -Wall -O2 -m32 -g03 -pg
+# CFLAGS = -Wall -O2 -m32 -g03 -pg
+CFLAGS = -Wall -O0 -m32 -g03 -pg
 
 OBJS = mdriver.o mm.o memlib.o fsecs.o fcyc.o clock.o ftimer.o
 
diff --git a/mm.c b/mm.c
index 13567ca..053645e 100644
--- a/mm.c
+++ b/mm.c
@@ -104,16 +104,64 @@ team_t team = {
 
 #define PUT_PTR(p, ptr) (*(unsigned int *)(p) = (unsigned int)(ptr))
 
-#define PRV_FREE(bp) ((char *)(bp))
-#define NXT_FREE(bp) ((char *)(bp) + WSIZE)
+#define PRV_PTR(ptr) ((char *)(ptr))
+#define NXT_PTR(ptr) ((char *)(ptr) + WSIZE)
+
+#define PRV_BLK(ptr) (*(char **)(ptr))
+#define NXT_BLK(ptr) (*(char **)(NXT_PTR(ptr)))
 
 ////////////////////////////////////////////////////////////////////////////////
-////////////////////////////////// STATIC VARS /////////////////////////////////
+////////////////////////////////// GLOBAL VARS /////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
-const size_t LISTSIZE = 11;
+#define LISTSIZE 20
 static char* heap_listp;
 char* seg_list[LISTSIZE];
 
+static void insert_node(void *ptr, size_t size) {
+  int list = 0;
+  void *search_ptr = ptr;
+  void *insert_ptr = NULL;
+    
+  // Select segregated list 
+  while ((list < LISTSIZE - 1) && (size > 1)) {
+    size >>= 1;
+    list++;
+  }
+    
+  // Keep size ascending order and search
+  search_ptr = seg_list[list];
+  while ((search_ptr != NULL) && (size > GET_SIZE(HDRP(search_ptr)))) {
+    insert_ptr = search_ptr;
+    search_ptr = PRV_BLK(search_ptr);
+  }
+    
+  // Set predecessor and successor 
+  if (search_ptr != NULL) {
+    if (insert_ptr != NULL) {
+      PUT_PTR(PRV_PTR(ptr), search_ptr);
+      PUT_PTR(NXT_PTR(search_ptr), ptr);
+      PUT_PTR(NXT_PTR(ptr), insert_ptr);
+      PUT_PTR(PRV_PTR(insert_ptr), ptr);
+    } else {
+      PUT_PTR(PRV_PTR(ptr), search_ptr);
+      PUT_PTR(NXT_PTR(search_ptr), ptr);
+      PUT_PTR(NXT_PTR(ptr), NULL);
+      seg_list[list] = ptr;
+    }
+  } else {
+    if (insert_ptr != NULL) {
+      PUT_PTR(PRV_PTR(ptr), NULL);
+      PUT_PTR(NXT_PTR(ptr), insert_ptr);
+      PUT_PTR(PRV_PTR(insert_ptr), ptr);
+    } else {
+      PUT_PTR(PRV_PTR(ptr), NULL);
+      PUT_PTR(NXT_PTR(ptr), NULL);
+      seg_list[list] = ptr;
+    }
+  }
+    
+  return;
+}
 ////////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////// HELPER PREDEF //////////////////////////////// 
 ////////////////////////////////////////////////////////////////////////////////
@@ -125,53 +173,67 @@ static void* find_fit(size_t asize);
 static void* coalesce(void *bp);
 /* Page 831, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
 static void* extend_heap(size_t words);
-/* Page 831, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
-
+static void add_free(void* bp, size_t asize);
 ////////////////////////////////////////////////////////////////////////////////
 /////////////////////////////// HELPER FUNCTIONS /////////////////////////////// 
 ////////////////////////////////////////////////////////////////////////////////
-static void place(void *bp, size_t asize)
-{
-  size_t csize = GET_SIZE(HDRP(bp));
-
-  if (asize <= (2*(1 << (LISTSIZE-1)))) {
-    PUT(HDRP(bp), PACK(csize, 1));
-    PUT(FTRP(bp), PACK(csize, 1));
-  } else {
-    // Sonderfall 10
-  }
-
-  if ((csize - asize) >= (2*DSIZE)) {
-    PUT(HDRP(bp), PACK(asize, 1));
-    PUT(FTRP(bp), PACK(asize, 1));
-    bp = NEXT_BLKP(bp);
-    PUT(HDRP(bp), PACK(csize-asize, 0));
-    PUT(FTRP(bp), PACK(csize-asize, 0));
-  }
-  else {
-  }
+static void add_free(void* bp, size_t asize) {
+  insert_node(bp, asize);
 }
-
 static int getSzClass(size_t asize) {
   for (size_t i = 0; i < LISTSIZE; ++i) {
     if (asize == (1 << i)) {
       return i;
     }
   }
-  return LISTSIZE;
+  return LISTSIZE-1;
+}
+
+static void remove_free(void* bp) {
+  int szClass = getSzClass(GET_SIZE(HDRP(bp)));
+
+  if (PRV_BLK(bp) == NULL && NXT_BLK(bp) == NULL) {
+    seg_list[szClass] = NULL;
+  } else if (PRV_BLK(bp) != NULL && NXT_BLK(bp) == NULL) {
+    PUT_PTR(PRV_PTR(PRV_BLK(bp)), NULL);
+    seg_list[szClass] = PRV_BLK(bp);
+  } else if (PRV_BLK(bp) == NULL && NXT_BLK(bp) != NULL) {
+    PUT_PTR(PRV_PTR(NXT_BLK(bp)), NULL);
+  } if (PRV_BLK(bp) != NULL && NXT_BLK(bp) != NULL) { 
+    PUT_PTR(NXT_PTR(PRV_BLK(bp)), NXT_BLK(bp));
+    PUT_PTR(PRV_PTR(NXT_BLK(bp)), PRV_BLK(bp));
+  }
+}
+
+static void place(void *bp, size_t asize)
+{
+  size_t csize = GET_SIZE(HDRP(bp));
+
+  remove_free(bp);
+
+  PUT(HDRP(bp), PACK(csize, 1));
+  PUT(FTRP(bp), PACK(csize, 1));
+  if (asize <= (2*(1 << (LISTSIZE-1)))) {
+    return;
+  } else {
+    bp = NEXT_BLKP(bp);
+    PUT(HDRP(bp), PACK(csize-asize, 0));
+    PUT(FTRP(bp), PACK(csize-asize, 0));
+    add_free(bp, csize-asize);
+  }
 }
 
 static void* best_fit(void* ptr, size_t asize) {
   unsigned long left_over = GET_SIZE(ptr) - asize;
   void* bestfit = ptr;
-  int best_left_over = GET_SIZE(ptr) - asize);
-  while (NXT_FREE(ptr) != NULL) {
-    left_over = GET_SIZE(ptr) - asize);
+  unsigned long best_left_over = GET_SIZE(ptr) - asize;
+  while (NXT_PTR(ptr) != NULL) {
+    left_over = GET_SIZE(ptr) - asize;
     if(left_over<best_left_over){
       best_left_over = left_over;
       bestfit=ptr;
     }  
-    ptr = NXT_FREE(ptr);
+    ptr = NXT_BLK(ptr);
   }
   return bestfit;
 }
@@ -184,8 +246,8 @@ static void* find_fit(size_t asize)
     return NULL;
   } else {
     if (szClass != LISTSIZE -1) {
-    while (NXT_FREE(classPtr) != NULL) {
-      classPtr = NXT_FREE(classPtr);
+    while (NXT_PTR(classPtr) != NULL) {
+      classPtr = NXT_BLK(classPtr);
     }
     return classPtr;
     } else {
@@ -203,21 +265,31 @@ static void *coalesce(void *bp) {
   if (prev_alloc && next_alloc) {                /* Case 1 */
     return bp;
   } else if (prev_alloc && !next_alloc) {        /* Case 2 */
+    remove_free(bp);
+    remove_free(NEXT_BLKP(bp));
     size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
     PUT(HDRP(bp),PACK(size,0));
     PUT(FTRP(bp),PACK(size,0));
   } else if (!prev_alloc && next_alloc) {        /* Case 3 */
+    remove_free(bp);
+    remove_free(PREV_BLKP(bp));
     size += GET_SIZE(HDRP(PREV_BLKP(bp)));
     PUT(FTRP(bp), PACK(size, 0));
     PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
     bp = PREV_BLKP(bp);
   } else {                                       /* Case 4 */
+    remove_free(bp);
+    remove_free(PREV_BLKP(bp));
+    remove_free(NEXT_BLKP(bp));
     size += GET_SIZE(HDRP(PREV_BLKP(bp))) +
       GET_SIZE(FTRP(NEXT_BLKP(bp)));
     PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
     PUT(FTRP(NEXT_BLKP(bp)), PACK(size, 0));
     bp = PREV_BLKP(bp);
   }
+
+  add_free(bp, size);
+  
   return bp;
 }
 
@@ -227,10 +299,6 @@ static void *extend_heap(size_t words)
   char *bp;
   size_t size;
 
-  if (words == 0) {
-    return NULL;
-  }
-
   /* Allocate an even number of words to maintain alignment */
   size = (words % 2) ? (words+1) * WSIZE : words * WSIZE;
   if ((long)(bp = mem_sbrk(size)) == -1)
@@ -241,8 +309,7 @@ static void *extend_heap(size_t words)
   PUT(FTRP(bp), PACK(size,0)); /* Free block footer */
   PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); /* New epilogue header */
 
-  PUT_PTR(PRV_FREE(bp), 0);
-  PUT_PTR(NXT_FREE(bp), 0);
+  add_free(bp, size);
 
   /* Coalesce if the previous block was free */
   return coalesce(bp);