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