Added core for segregated list

mm.c

@@ -34,6 +34,7 @@ team_t team = {
   /* Second member's email address (leave blank if none) */
   "tuan-dat.tran@stud.uni-due.de"
 };
+
 ////////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////// STRUCTURE //////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
@@ -43,7 +44,7 @@ team_t team = {
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 // HEADER      | SIZE                                                                                       | A|
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
-// BODY        | ALLOCED MEMORY                                                                                |
+// BP->        | ALLOCED MEMORY                                                                                |
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 // FOOTER      | SIZE                                                                                       | A|
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
@@ -53,11 +54,11 @@ team_t team = {
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 // HEADER      | SIZE                                                                                       | A|
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
-//             | PTR TO PREV FREE BLK                                                                          |
+// BP->        | PTR TO PREV FREE BLK                                                                          |
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 //             | PTR TO NEXT FREE BLK                                                                          |
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
-// BODY        | UNALLOC MEMORY                                                                                |
+//             | UNALLOC MEMORY                                                                                |
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 // FOOTER      | SIZE                                                                                       | A|
 //             +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
@@ -80,6 +81,7 @@ team_t team = {
 #define CHUNKSIZE (1<<12) /* Extend heap by this amount (bytes) */
 
 #define MAX(x, y) ((x) > (y)? (x) : (y))
+#define MIN(x, y) ((x) < (y)? (x) : (y))
 
 /* Pack a size and allocated bit into a word */
 #define PACK(size, alloc) ((size) | (alloc))
@@ -100,12 +102,17 @@ team_t team = {
 #define NEXT_BLKP(bp) ((char *)(bp) + GET_SIZE(((char *)(bp) - WSIZE)))
 #define PREV_BLKP(bp) ((char *)(bp) - GET_SIZE(((char *)(bp) - DSIZE)))
 
+#define PUT_PTR(p, ptr) (*(unsigned int *)(p) = (unsigned int)(ptr))
+
+#define PRV_FREE(bp) ((char *)(bp))
+#define NXT_FREE(bp) ((char *)(bp) + WSIZE)
+
 ////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////// STATIC VARS /////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
-const size_t LIST_SIZE = 100;
+const size_t LISTSIZE = 11;
 static char* heap_listp;
-static char* seg_list[LIST_SIZE];
+char* seg_list[LISTSIZE];
 
 ////////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////// HELPER PREDEF //////////////////////////////// 
@@ -138,23 +145,42 @@ static void place(void *bp, size_t asize)
     PUT(FTRP(bp), PACK(csize, 1));
   }
 }
-static void* first_fit(size_t asize) {
-  /* First fit search */
-  void *bp;
 
-  for (bp = heap_listp; GET_SIZE(HDRP(bp)) > 0; bp = NEXT_BLKP(bp)) {
+static int getSzClass(size_t asize) {
-    if (!GET_ALLOC(HDRP(bp)) && (asize <= GET_SIZE(HDRP(bp)))) {
+  for (size_t i = 0; i < LISTSIZE; ++i) {
-      return bp;
+    if (asize == (1 << i)) {
+      return i;
     }
   }
-  return NULL; /* No fit */
+  return LISTSIZE;
-
 }
 
+static void* best_fit(void* ptr, size_t asize) {
+  unsigned long left_over = GET_SIZE(ptr) - asize;
+  int c = 0;
+  while (NXT_FREE(ptr) != NULL) {
+    left_over = (MIN(left_over, GET_SIZE(ptr) - asize));
+    ptr = NXT_FREE(ptr);
+  }
+  return NULL;
+}
 /* Page 856, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
 static void* find_fit(size_t asize)
 {
-  return first_fit(asize);
+  int szClass  = getSzClass(asize);
+  void* classPtr = seg_list[szClass];
+  if (classPtr == NULL) {
+    return NULL;
+  } else {
+    if (szClass != LISTSIZE -1) {
+    while (NXT_FREE(classPtr) != NULL) {
+      classPtr = NXT_FREE(classPtr);
+    }
+    return classPtr;
+    } else {
+      return best_fit(classPtr, asize);
+    }
+  }
 }
 
 /* Page 833, Pearson R. Bryant – D. O’Hallaron. Computer Systems: A Programmer’s Perspective.3rd Edition, Pearson, 2003. */
@@ -190,6 +216,10 @@ 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)
@@ -200,6 +230,9 @@ 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);
+
   /* Coalesce if the previous block was free */
   return coalesce(bp);
 }
@@ -213,9 +246,11 @@ static void *extend_heap(size_t words)
  */
 int mm_init(void)
 {
-  for (size_t i = 0; i < LIST_SIZE; ++i) {
+  // init seg_list
+  for (size_t i = 0; i < LISTSIZE; ++i) {
     seg_list[i] = NULL;
   }
+
   /* Create the initial empty heap */
   if ((heap_listp = mem_sbrk(4*WSIZE)) == (void *)-1)
     return -1;
@@ -250,7 +285,7 @@ void *mm_malloc(size_t size)
   if (size <= DSIZE)
     asize = 2*DSIZE;
   else
-    asize = DSIZE * ((size + (DSIZE) + (DSIZE-1)) / DSIZE);
+    asize = ALIGN(size+DSIZE);
 
   /* Search the free list for a fit */
   if ((bp = find_fit(asize)) != NULL) {
@@ -275,6 +310,7 @@ void mm_free(void *ptr)
   size_t size = GET_SIZE(HDRP(ptr));
   PUT(HDRP(ptr), PACK(size, 0));
   PUT(FTRP(ptr), PACK(size, 0));
+
   coalesce(ptr);
 }