Diff: utility/mempool.cpp

Revision:

0:e3fb1267e3c3

Child:

19:e416943f7119

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/utility/mempool.cpp	Wed Dec 21 16:58:10 2016 +0100
@@ -0,0 +1,171 @@
+/*
+ mempool.cpp - sleek implementation of a memory pool
+ Copyright (c) 2013 Norbert Truchsess <norbert.truchsess@t-online.de>
+ All rights reserved.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "mempool.h"
+#include <string.h>
+
+#define POOLOFFSET 1
+
+struct memblock MemoryPool::blocks[MEMPOOL_NUM_MEMBLOCKS+1];
+
+void
+MemoryPool::init()
+{
+  memset(&blocks[0], 0, sizeof(blocks));
+  blocks[POOLSTART].begin = MEMPOOL_STARTADDRESS;
+  blocks[POOLSTART].size = 0;
+  blocks[POOLSTART].nextblock = NOBLOCK;
+}
+
+memhandle
+MemoryPool::allocBlock(memaddress size)
+{
+  memblock* best = NULL;
+  memhandle cur = POOLSTART;
+  memblock* block = &blocks[POOLSTART];
+  memaddress bestsize = MEMPOOL_SIZE + 1;
+
+  do
+    {
+      memhandle next = block->nextblock;
+      memaddress freesize = ( next == NOBLOCK ? blocks[POOLSTART].begin + MEMPOOL_SIZE : blocks[next].begin) - block->begin - block->size;
+      if (freesize == size)
+        {
+          best = &blocks[cur];
+          goto found;
+        }
+      if (freesize > size && freesize < bestsize)
+        {
+          bestsize = freesize;
+          best = &blocks[cur];
+        }
+      if (next == NOBLOCK)
+        {
+          if (best)
+            goto found;
+          else
+            goto collect;
+        }
+      block = &blocks[next];
+      cur = next;
+    }
+  while (true);
+
+  collect:
+    {
+      cur = POOLSTART;
+      block = &blocks[POOLSTART];
+      memhandle next;
+      while ((next = block->nextblock) != NOBLOCK)
+        {
+          memaddress dest = block->begin + block->size;
+          memblock* nextblock = &blocks[next];
+          memaddress* src = &nextblock->begin;
+          if (dest != *src)
+            {
+#ifdef MEMPOOL_MEMBLOCK_MV
+              MEMPOOL_MEMBLOCK_MV(dest,*src,nextblock->size);
+#endif
+              *src = dest;
+            }
+          block = nextblock;
+        }
+      if (blocks[POOLSTART].begin + MEMPOOL_SIZE - block->begin - block->size >= size)
+        best = block;
+      else
+        goto notfound;
+    }
+
+  found:
+    {
+      block = &blocks[POOLOFFSET];
+      for (cur = POOLOFFSET; cur < MEMPOOL_NUM_MEMBLOCKS + POOLOFFSET; cur++)
+        {
+          if (block->size)
+            {
+              block++;
+              continue;
+            }
+          memaddress address = best->begin + best->size;
+#ifdef MEMBLOCK_ALLOC
+          MEMBLOCK_ALLOC(address,size);
+#endif
+          block->begin = address;
+          block->size = size;
+          block->nextblock = best->nextblock;
+          best->nextblock = cur;
+          return cur;
+        }
+    }
+
+  notfound: return NOBLOCK;
+}
+
+void
+MemoryPool::freeBlock(memhandle handle)
+{
+  if (handle == NOBLOCK)
+    return;
+  memblock *b = &blocks[POOLSTART];
+
+  do
+    {
+      memhandle next = b->nextblock;
+      if (next == handle)
+        {
+          memblock *f = &blocks[next];
+#ifdef MEMBLOCK_FREE
+          MEMBLOCK_FREE(f->begin,f->size);
+#endif
+          b->nextblock = f->nextblock;
+          f->size = 0;
+          f->nextblock = NOBLOCK;
+          return;
+        }
+      if (next == NOBLOCK)
+        return;
+      b = &blocks[next];
+      #if defined(ESP8266)
+//        yield();
+      #endif
+    }
+  while (true);
+}
+
+void
+MemoryPool::resizeBlock(memhandle handle, memaddress position)
+{
+  memblock * block = &blocks[handle];
+  block->begin += position;
+  block->size -= position;
+}
+
+void
+MemoryPool::resizeBlock(memhandle handle, memaddress position, memaddress size)
+{
+  memblock * block = &blocks[handle];
+  block->begin += position;
+  block->size = size;
+}
+
+memaddress
+MemoryPool::blockSize(memhandle handle)
+{
+  return blocks[handle].size;
+}