Usermode/Libraries/libc.so_src/heap.c

   1 /*\r
   2 AcessOS Basic LibC\r
   3 heap.c - Heap Manager\r
   4 */\r
   5 #include <acess/sys.h>\r
   6 #include <stdlib.h>\r
   7 #include <string.h>\r
   8 #include "lib.h"\r
   9 \r
  10 #if 0\r
  11 # define DEBUGS(s...)   _SysDebug(s)\r
  12 #else\r
  13 # define DEBUGS(s...)   do{}while(0)\r
  14 #endif\r
  15 \r
  16 // === Constants ===\r
  17 #define MAGIC   0xACE55051      //AcessOS1\r
  18 #define MAGIC_FREE      (~MAGIC)\r
  19 #define BLOCK_SIZE      16      //Minimum\r
  20 #define HEAP_INIT_SIZE  0x10000\r
  21 \r
  22 typedef unsigned int Uint;\r
  23 \r
  24 // === TYPES ===\r
  25 typedef struct {\r
  26         uint32_t        magic;\r
  27         size_t  size;\r
  28         char    data[];\r
  29 }       heap_head;\r
  30 typedef struct {\r
  31         heap_head       *header;\r
  32         uint32_t        magic;\r
  33 }       heap_foot;\r
  34 \r
  35 // === LOCAL VARIABLES ===\r
  36 static void     *_heap_start = NULL;\r
  37 static void     *_heap_end = NULL;\r
  38 \r
  39 // === PROTOTYPES ===\r
  40 EXPORT void     *malloc(size_t bytes);\r
  41 EXPORT void     *calloc(size_t bytes, size_t count);\r
  42 EXPORT void     free(void *mem);\r
  43 EXPORT void     *realloc(void *mem, size_t bytes);\r
  44 EXPORT void     *sbrk(int increment);\r
  45 LOCAL void      *extendHeap(int bytes);\r
  46 static void     *FindHeapBase();\r
  47 LOCAL uint      brk(uintptr_t newpos);\r
  48 \r
  49 //Code\r
  50 \r
  51 /**\r
  52  \fn EXPORT void *malloc(size_t bytes)\r
  53  \brief Allocates memory from the heap space\r
  54  \param bytes   Integer - Size of buffer to return\r
  55  \return Pointer to buffer\r
  56 */\r
  57 EXPORT void *malloc(size_t bytes)\r
  58 {\r
  59         size_t  bestSize;\r
  60         size_t  closestMatch = 0;\r
  61         void    *bestMatchAddr = 0;\r
  62         heap_head       *curBlock;\r
  63 \r
  64 //      _SysDebug("&_heap_start = %p, _heap_start = %p", &_heap_start, _heap_start);\r
  65         // Initialise Heap\r
  66         if(_heap_start == NULL)\r
  67         {\r
  68                 _heap_start = sbrk(0);\r
  69                 _heap_end = _heap_start;\r
  70                 extendHeap(HEAP_INIT_SIZE);\r
  71         }\r
  72         \r
  73         curBlock = _heap_start;\r
  74 //      _SysDebug("_heap_start = %p", _heap_start);\r
  75         \r
  76         bestSize = bytes + sizeof(heap_head) + sizeof(heap_foot) + BLOCK_SIZE - 1;\r
  77         bestSize = (bestSize/BLOCK_SIZE)*BLOCK_SIZE;    //Round up to block size\r
  78         \r
  79         while( (uintptr_t)curBlock < (uintptr_t)_heap_end)\r
  80         {\r
  81                 //_SysDebug(" malloc: curBlock = 0x%x, curBlock->magic = 0x%x\n", curBlock, curBlock->magic);\r
  82                 if(curBlock->magic == MAGIC_FREE)\r
  83                 {\r
  84                         if(curBlock->size == bestSize)\r
  85                                 break;\r
  86                         if(bestSize < curBlock->size && (curBlock->size < closestMatch || closestMatch == 0)) {\r
  87                                 closestMatch = curBlock->size;\r
  88                                 bestMatchAddr = curBlock;\r
  89                         }\r
  90                 }\r
  91                 else if(curBlock->magic != MAGIC)\r
  92                 {\r
  93                         //Corrupt Heap\r
  94                         _SysDebug("malloc: Corrupt Heap\n");\r
  95                         return NULL;\r
  96                 }\r
  97                 curBlock = (heap_head*)((uintptr_t)curBlock + curBlock->size);\r
  98         }\r
  99         \r
 100         if((uintptr_t)curBlock < (uintptr_t)_heap_start) {\r
 101                 _SysDebug("malloc: Heap underrun for some reason\n");\r
 102                 return NULL;\r
 103         }\r
 104         \r
 105         //Found a perfect match\r
 106         if((uintptr_t)curBlock < (uintptr_t)_heap_end) {\r
 107                 curBlock->magic = MAGIC;\r
 108                 return (void*)((uintptr_t)curBlock + sizeof(heap_head));\r
 109         }\r
 110         \r
 111         //Out of Heap Space\r
 112         if(!closestMatch) {\r
 113                 curBlock = extendHeap(bestSize);        //Allocate more\r
 114                 if(curBlock == NULL) {\r
 115                         _SysDebug("malloc: Out of Heap Space\n");\r
 116                         return NULL;\r
 117                 }\r
 118                 curBlock->magic = MAGIC;\r
 119                 DEBUGS("malloc(0x%x) = %p (extend) 0x%x", bytes, curBlock->data, bestSize);\r
 120                 return curBlock->data;\r
 121         }\r
 122         \r
 123         heap_head *besthead = (void*)bestMatchAddr;\r
 124         \r
 125         //Split Block?\r
 126         if(closestMatch - bestSize > BLOCK_SIZE) {\r
 127                 heap_foot       *foot;\r
 128                 curBlock = (heap_head*)bestMatchAddr;\r
 129                 curBlock->magic = MAGIC;\r
 130                 curBlock->size = bestSize;\r
 131                 foot = (heap_foot*)(bestMatchAddr + bestSize - sizeof(heap_foot));\r
 132                 foot->header = curBlock;\r
 133                 foot->magic = MAGIC;\r
 134 \r
 135                 curBlock = (heap_head*)(bestMatchAddr + bestSize);\r
 136                 curBlock->magic = MAGIC_FREE;\r
 137                 curBlock->size = closestMatch - bestSize;\r
 138                 \r
 139                 foot = (heap_foot*)(bestMatchAddr + closestMatch - sizeof(heap_foot));\r
 140                 foot->header = curBlock;\r
 141                 \r
 142                 besthead->magic = MAGIC;        //mark as used\r
 143                 DEBUGS("malloc(0x%x) = %p (split) 0x%x", bytes, besthead->data, bestSize);\r
 144                 return besthead->data;\r
 145         }\r
 146         \r
 147         //Don't Split the block\r
 148         besthead->magic = MAGIC;\r
 149         DEBUGS("malloc(0x%x) = %p (reuse) 0x%x", bytes, besthead->data, besthead->size);\r
 150         return besthead->data;\r
 151 }\r
 152 \r
 153 /**\r
 154  * \fn EXPORT void *calloc(size_t bytes, size_t count)\r
 155  * \brief Allocate and zero a block of memory\r
 156  * \param __nmemb       Number of memeber elements\r
 157  * \param __size        Size of one element\r
 158  */\r
 159 EXPORT void *calloc(size_t __nmemb, size_t __size)\r
 160 {\r
 161         void    *ret = malloc(__size*__nmemb);\r
 162         if(!ret)        return NULL;\r
 163         memset(ret, 0, __size*__nmemb);\r
 164         return ret;\r
 165 }\r
 166 \r
 167 /**\r
 168  \fn EXPORT void free(void *mem)\r
 169  \brief Free previously allocated memory\r
 170  \param mem     Pointer - Memory to free\r
 171 */\r
 172 EXPORT void free(void *mem)\r
 173 {\r
 174         heap_head       *head = (void*)((intptr_t)mem-sizeof(heap_head));\r
 175         \r
 176         // Sanity please!\r
 177         if(!mem)        return;\r
 178         \r
 179         if(head->magic != MAGIC)        //Valid Heap Address\r
 180                 return;\r
 181         \r
 182         head->magic = MAGIC_FREE;\r
 183         DEBUGS("free(%p) : 0x%x bytes", mem, head->size);\r
 184         \r
 185         //Unify Right\r
 186         if((intptr_t)head + head->size < (intptr_t)_heap_end)\r
 187         {\r
 188                 heap_head       *nextHead = (heap_head*)((intptr_t)head + head->size);\r
 189                 if(nextHead->magic == MAGIC_FREE) {     //Is the next block free\r
 190                         head->size += nextHead->size;   //Amalgamate\r
 191                         nextHead->magic = 0;    //For Security\r
 192                 }\r
 193         }\r
 194         //Unify Left\r
 195         if((intptr_t)head - sizeof(heap_foot) > (intptr_t)_heap_start)\r
 196         {\r
 197                 heap_head       *prevHead;\r
 198                 heap_foot       *prevFoot = (heap_foot *)((intptr_t)head - sizeof(heap_foot));\r
 199                 if(prevFoot->magic == MAGIC) {\r
 200                         prevHead = prevFoot->header;\r
 201                         if(prevHead->magic == MAGIC_FREE) {\r
 202                                 prevHead->size += head->size;   //Amalgamate\r
 203                                 head->magic = 0;        //For Security\r
 204                         }\r
 205                 }\r
 206         }\r
 207 }\r
 208 \r
 209 /**\r
 210  \fn EXPORT void *realloc(void *oldPos, size_t bytes)\r
 211  \brief Reallocate a block of memory\r
 212  \param bytes   Integer - Size of new buffer\r
 213  \param oldPos  Pointer - Old Buffer\r
 214  \return Pointer to new buffer\r
 215 */\r
 216 EXPORT void *realloc(void *oldPos, size_t bytes)\r
 217 {\r
 218         void *ret;\r
 219         heap_head       *head;\r
 220         \r
 221         if(oldPos == NULL) {\r
 222                 return malloc(bytes);\r
 223         }\r
 224         \r
 225         //Check for free space after block\r
 226         head = (heap_head*)((uintptr_t)oldPos-sizeof(heap_head));\r
 227         \r
 228         //Hack to used free's amagamating algorithym and malloc's splitting\r
 229         free(oldPos);\r
 230         \r
 231         //Allocate new memory\r
 232         ret = malloc(bytes);\r
 233         if(ret == NULL)\r
 234                 return NULL;\r
 235         \r
 236         //Copy Old Data\r
 237         if(ret != oldPos) {\r
 238                 memcpy(ret, oldPos, head->size-sizeof(heap_head)-sizeof(heap_foot));\r
 239         }\r
 240         \r
 241         //Return\r
 242         return ret;\r
 243 }\r
 244 \r
 245 /**\r
 246  * \fn LOCAL void *extendHeap(int bytes)\r
 247  * \brief Create a new block at the end of the heap area\r
 248  * \param bytes Integer - Size reqired\r
 249  * \return Pointer to last free block\r
 250  */\r
 251 \r
 252 LOCAL void *extendHeap(int bytes)\r
 253 {\r
 254         heap_head       *head = _heap_end;\r
 255         heap_foot       *foot;\r
 256         \r
 257         //Expand Memory Space  (Use foot as a temp pointer)\r
 258         foot = sbrk(bytes);\r
 259         if(foot == (void*)-1)\r
 260                 return NULL;\r
 261         \r
 262         //Create New Block\r
 263         // Header\r
 264         head->magic = MAGIC_FREE;       //Unallocated\r
 265         head->size = bytes;\r
 266         // Footer\r
 267         foot = _heap_end + bytes - sizeof(heap_foot);\r
 268         foot->header = head;\r
 269         foot->magic = MAGIC;\r
 270         \r
 271         //Combine with previous block if nessasary\r
 272         if(_heap_end != _heap_start && ((heap_foot*)((uintptr_t)_heap_end-sizeof(heap_foot)))->magic == MAGIC) {\r
 273                 heap_head       *tmpHead = ((heap_foot*)((uintptr_t)_heap_end-sizeof(heap_foot)))->header;\r
 274                 if(tmpHead->magic == MAGIC_FREE) {\r
 275                         tmpHead->size += bytes;\r
 276                         foot->header = tmpHead;\r
 277                         head = tmpHead;\r
 278                 }\r
 279         }\r
 280         \r
 281         _heap_end = (void*) ((uintptr_t)foot+sizeof(heap_foot));\r
 282         return head;\r
 283 }\r
 284 \r
 285 /**\r
 286  \fn EXPORT void *sbrk(int increment)\r
 287  \brief Increases the program's memory space\r
 288  \param count   Integer - Size of heap increase\r
 289  \return Pointer to start of new region\r
 290 */\r
 291 EXPORT void *sbrk(int increment)\r
 292 {\r
 293         static uintptr_t oldEnd = 0;\r
 294         static uintptr_t curEnd = 0;\r
 295 \r
 296         //_SysDebug("sbrk: (increment=%i)", increment);\r
 297 \r
 298         if (curEnd == 0) {\r
 299                 oldEnd = curEnd = (uintptr_t)FindHeapBase();\r
 300                 //_SysAllocate(curEnd); // Allocate the first page\r
 301         }\r
 302 \r
 303         //_SysDebug(" sbrk: oldEnd = 0x%x", oldEnd);\r
 304         if (increment == 0)     return (void *) curEnd;\r
 305 \r
 306         oldEnd = curEnd;\r
 307 \r
 308         // Single Page\r
 309         if( (curEnd & 0xFFF) && (curEnd & 0xFFF) + increment < 0x1000 )\r
 310         {\r
 311                 //if( curEnd & 0xFFF == 0 )\r
 312                 //{\r
 313                 //      if( !_SysAllocate(curEnd) )\r
 314                 //      {\r
 315                 //              _SysDebug("sbrk - Error allocating memory");\r
 316                 //              return (void*)-1;\r
 317                 //      }\r
 318                 //}\r
 319                 curEnd += increment;\r
 320                 //_SysDebug("sbrk: RETURN %p (single page, no alloc)", (void *) oldEnd);\r
 321                 return (void *)oldEnd;\r
 322         }\r
 323 \r
 324         increment -= curEnd & 0xFFF;\r
 325         curEnd += 0xFFF;        curEnd &= ~0xFFF;\r
 326         while( increment > 0 )\r
 327         {\r
 328                 if( !_SysAllocate(curEnd) )\r
 329                 {\r
 330                         // Error?\r
 331                         _SysDebug("sbrk - Error allocating memory");\r
 332                         return (void*)-1;\r
 333                 }\r
 334                 increment -= 0x1000;\r
 335                 curEnd += 0x1000;\r
 336         }\r
 337 \r
 338         //_SysDebug("sbrk: RETURN %p", (void *) oldEnd);\r
 339         return (void *) oldEnd;\r
 340 }\r
 341 \r
 342 /**\r
 343  * \fn EXPORT int IsHeap(void *ptr)\r
 344  */\r
 345 EXPORT int IsHeap(void *ptr)\r
 346 {\r
 347         #if 0\r
 348         heap_head       *head;\r
 349         heap_foot       *foot;\r
 350         #endif\r
 351         if( (uintptr_t)ptr < (uintptr_t)_heap_start )   return 0;\r
 352         if( (uintptr_t)ptr > (uintptr_t)_heap_end )     return 0;\r
 353         \r
 354         #if 0\r
 355         head = (void*)((Uint)ptr - 4);\r
 356         if( head->magic != MAGIC )      return 0;\r
 357         foot = (void*)( (Uint)ptr + head->size - sizeof(heap_foot) );\r
 358         if( foot->magic != MAGIC )      return 0;\r
 359         #endif\r
 360         return 1;\r
 361 }\r
 362 \r
 363 // === STATIC FUNCTIONS ===\r
 364 /**\r
 365  * Does the job of brk(0)\r
 366  */\r
 367 static void *FindHeapBase()\r
 368 {\r
 369         #if 0\r
 370         #define MAX             0xC0000000      // Address\r
 371         #define THRESHOLD       512     // Pages\r
 372         uint    addr;\r
 373         uint    stretch = 0;\r
 374         uint64_t        tmp;\r
 375         \r
 376         // Scan address space\r
 377         for(addr = 0;\r
 378                 addr < MAX;\r
 379                 addr += 0x1000\r
 380                 )\r
 381         {\r
 382                 tmp = _SysGetPhys(addr);\r
 383                 if( tmp != 0 ) {\r
 384                         stretch = 0;\r
 385                 } else {\r
 386                         stretch ++;\r
 387                         if(stretch > THRESHOLD)\r
 388                         {\r
 389                                 return (void*)( addr - stretch*0x1000 );\r
 390                         }\r
 391                 }\r
 392                 //__asm__ __volatile__ (\r
 393                 //      "push %%ebx;mov %%edx,%%ebx;int $0xAC;pop %%ebx"\r
 394                 //      ::"a"(256),"d"("%x"),"c"(addr));\r
 395         }\r
 396         \r
 397         return NULL;\r
 398         #else\r
 399         return (void*)0x00900000;\r
 400         #endif\r
 401 }\r
 402 \r
 403 LOCAL uint brk(uintptr_t newpos)\r
 404 {\r
 405         static uintptr_t        curpos;\r
 406         uint    pages;\r
 407         uint    ret = curpos;\r
 408          int    delta;\r
 409         \r
 410         _SysDebug("brk: (newpos=0x%x)", newpos);\r
 411         \r
 412         // Find initial position\r
 413         if(curpos == 0) curpos = (uintptr_t)FindHeapBase();\r
 414         \r
 415         // Get Current Position\r
 416         if(newpos == 0) return curpos;\r
 417         \r
 418         if(newpos < curpos)     return newpos;\r
 419         \r
 420         delta = newpos - curpos;\r
 421         _SysDebug(" brk: delta = 0x%x", delta);\r
 422         \r
 423         // Do we need to add pages\r
 424         if(curpos & 0xFFF && (curpos & 0xFFF) + delta < 0x1000)\r
 425                 return curpos += delta;\r
 426         \r
 427         // Page align current position\r
 428         if(curpos & 0xFFF)      delta -= 0x1000 - (curpos & 0xFFF);\r
 429         curpos = (curpos + 0xFFF) & ~0xFFF;\r
 430         \r
 431         // Allocate Pages\r
 432         pages = (delta + 0xFFF) >> 12;\r
 433         while(pages--)\r
 434         {\r
 435                 _SysAllocate(curpos);\r
 436                 curpos += 0x1000;\r
 437                 delta -= 0x1000;\r
 438         }\r
 439         \r
 440         // Bring the current position to exactly what we want\r
 441         curpos -= ((delta + 0xFFF) & ~0xFFF) - delta;\r
 442         \r
 443         return ret;     // Return old curpos\r
 444 }\r