mm.c

winNT技术操作系统,国外开放的原代码和LIUX一样

/*
 * GLX Hardware Device Driver common code
 * Copyright (C) 1999 Wittawat Yamwong
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * WITTAWAT YAMWONG, OR ANY OTHER CONTRIBUTORS BE LIABLE FOR ANY CLAIM, 
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include "mm.h"


void
mmDumpMemInfo(const memHeap_t *heap)
{
   const TMemBlock *p;

   fprintf(stderr, "Memory heap %p:\n", (void *)heap);
   if (heap == 0) {
      fprintf(stderr, "  heap == 0\n");
   } else {
      p = (TMemBlock *)heap;
      while (p) {
	 fprintf(stderr, "  Offset:%08x, Size:%08x, %c%c\n",p->ofs,p->size,
		 p->free ? '.':'U',
		 p->reserved ? 'R':'.');
	 p = p->next;
      }
   }
   fprintf(stderr, "End of memory blocks\n");
}

memHeap_t *
mmInit(int ofs, int size)
{
   PMemBlock blocks;
  
   if (size <= 0) {
      return NULL;
   }
   blocks = (TMemBlock *) _mesa_calloc(sizeof(TMemBlock));
   if (blocks) {
      blocks->ofs = ofs;
      blocks->size = size;
      blocks->free = 1;
      return (memHeap_t *)blocks;
   }
   else {
      return NULL;
   }
}


static TMemBlock *
SliceBlock(TMemBlock *p, 
           int startofs, int size, 
           int reserved, int alignment)
{
   TMemBlock *newblock;

   /* break left */
   if (startofs > p->ofs) {
      newblock = (TMemBlock*) _mesa_calloc(sizeof(TMemBlock));
      if (!newblock)
	 return NULL;
      newblock->ofs = startofs;
      newblock->size = p->size - (startofs - p->ofs);
      newblock->free = 1;
      newblock->next = p->next;
      p->size -= newblock->size;
      p->next = newblock;
      p = newblock;
   }

   /* break right */
   if (size < p->size) {
      newblock = (TMemBlock*) _mesa_calloc(sizeof(TMemBlock));
      if (!newblock)
	 return NULL;
      newblock->ofs = startofs + size;
      newblock->size = p->size - size;
      newblock->free = 1;
      newblock->next = p->next;
      p->size = size;
      p->next = newblock;
   }

   /* p = middle block */
   p->align = alignment;
   p->free = 0;
   p->reserved = reserved;
   return p;
}


PMemBlock
mmAllocMem(memHeap_t *heap, int size, int align2, int startSearch)
{
   int mask,startofs,endofs;
   TMemBlock *p;

   if (!heap || align2 < 0 || size <= 0)
      return NULL;
   mask = (1 << align2)-1;
   startofs = 0;
   p = (TMemBlock *)heap;
   while (p) {
      if ((p)->free) {
	 startofs = (p->ofs + mask) & ~mask;
	 if ( startofs < startSearch ) {
	    startofs = startSearch;
	 }
	 endofs = startofs+size;
	 if (endofs <= (p->ofs+p->size))
	    break;
      }
      p = p->next;
   }
   if (!p)
      return NULL;
   p = SliceBlock(p,startofs,size,0,mask+1);
   p->heap = heap;
   return p;
}


PMemBlock
mmFindBlock(memHeap_t *heap, int start)
{
   TMemBlock *p = (TMemBlock *)heap;

   while (p) {
      if (p->ofs == start && p->free) 
	 return p;

      p = p->next;
   }

   return NULL;
}


static INLINE int
Join2Blocks(TMemBlock *p)
{
   /* XXX there should be some assertions here */
   if (p->free && p->next && p->next->free) {
      TMemBlock *q = p->next;
      p->size += q->size;
      p->next = q->next;
      _mesa_free(q);
      return 1;
   }
   return 0;
}

int
mmFreeMem(PMemBlock b)
{
   TMemBlock *p,*prev;

   if (!b)
      return 0;
   if (!b->heap) {
      fprintf(stderr, "no heap\n");
      return -1;
   }
   p = b->heap;
   prev = NULL;
   while (p && p != b) {
      prev = p;
      p = p->next;
   }
   if (!p || p->free || p->reserved) {
      if (!p)
	 fprintf(stderr, "block not found in heap\n");
      else if (p->free)
	 fprintf(stderr, "block already free\n");
      else
	 fprintf(stderr, "block is reserved\n");
      return -1;
   }
   p->free = 1;
   Join2Blocks(p);
   if (prev)
      Join2Blocks(prev);
   return 0;
}


void
mmDestroy(memHeap_t *heap)
{
   TMemBlock *p;

   if (!heap)
      return;

   p = (TMemBlock *) heap;
   while (p) {
      TMemBlock *next = p->next;
      _mesa_free(p);
      p = next;
   }
}