1 files changed, 123 insertions, 0 deletions

diff --git a/src/z_bmalloc.c b/src/z_bmalloc.c
new file mode 100644
index 0000000..b415381
--- /dev/null
+++ b/src/z_bmalloc.c
@@ -0,0 +1,123 @@
+/* Emacs style mode select   -*- C++ -*-
+ *-----------------------------------------------------------------------------
+ *
+ *
+ *  PrBoom: a Doom port merged with LxDoom and LSDLDoom
+ *  based on BOOM, a modified and improved DOOM engine
+ *  Copyright (C) 1999 by
+ *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
+ *  Copyright (C) 1999-2000 by
+ *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
+ *  Copyright 2005, 2006 by
+ *  Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
+ *
+ *  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 2
+ *  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, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ *  02111-1307, USA.
+ *
+ * DESCRIPTION:
+ * This is designed to be a fast allocator for small, regularly used block sizes
+ *-----------------------------------------------------------------------------
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "doomtype.h"
+#include "z_zone.h"
+#include "z_bmalloc.h"
+#include "lprintf.h"
+
+typedef struct bmalpool_s {
+  struct bmalpool_s *nextpool;
+  size_t             blocks;
+  byte               used[0];
+} bmalpool_t;
+
+inline static void* getelem(bmalpool_t *p, size_t size, size_t n)
+{
+  return (((byte*)p) + sizeof(bmalpool_t) + sizeof(byte)*(p->blocks) + size*n);
+}
+
+inline static PUREFUNC int iselem(const bmalpool_t *pool, size_t size, const void* p)
+{
+  // CPhipps - need portable # of bytes between pointers
+  int dif = (const char*)p - (const char*)pool;
+
+  dif -= sizeof(bmalpool_t);
+  dif -= pool->blocks;
+  if (dif<0) return -1;
+  dif /= size;
+  return (((size_t)dif >= pool->blocks) ? -1 : dif);
+}
+
+enum { unused_block = 0, used_block = 1};
+
+void* Z_BMalloc(struct block_memory_alloc_s *pzone)
+{
+  register bmalpool_t **pool = (bmalpool_t **)&(pzone->firstpool);
+  while (*pool != NULL) {
+    byte *p = memchr((*pool)->used, unused_block, (*pool)->blocks); // Scan for unused marker
+    if (p) {
+      int n = p - (*pool)->used;
+#ifdef SIMPLECHECKS
+      if ((n<0) || ((size_t)n>=(*pool)->blocks))
+  I_Error("Z_BMalloc: memchr returned pointer outside of array");
+#endif
+      (*pool)->used[n] = used_block;
+      return getelem(*pool, pzone->size, n);
+    } else
+      pool = &((*pool)->nextpool);
+  }
+  {
+    // Nothing available, must allocate a new pool
+    bmalpool_t *newpool;
+
+    // CPhipps: Allocate new memory, initialised to 0
+
+    *pool = newpool = Z_Calloc(sizeof(*newpool) + (sizeof(byte) + pzone->size)*(pzone->perpool),
+             1,  pzone->tag, NULL);
+    newpool->nextpool = NULL; // NULL = (void*)0 so this is redundant
+
+    // Return element 0 from this pool to satisfy the request
+    newpool->used[0] = used_block;
+    newpool->blocks = pzone->perpool;
+    return getelem(newpool, pzone->size, 0);
+  }
+}
+
+void Z_BFree(struct block_memory_alloc_s *pzone, void* p)
+{
+  register bmalpool_t **pool = (bmalpool_t**)&(pzone->firstpool);
+
+  while (*pool != NULL) {
+    int n = iselem(*pool, pzone->size, p);
+    if (n >= 0) {
+#ifdef SIMPLECHECKS
+      if ((*pool)->used[n] == unused_block)
+  I_Error("Z_BFree: Refree in zone %s", pzone->desc);
+#endif
+      (*pool)->used[n] = unused_block;
+      if (memchr(((*pool)->used), used_block, (*pool)->blocks) == NULL) {
+  // Block is all unused, can be freed
+  bmalpool_t *oldpool = *pool;
+  *pool = (*pool)->nextpool;
+  Z_Free(oldpool);
+      }
+      return;
+    } else pool = &((*pool)->nextpool);
+  }
+  I_Error("Z_BFree: Free not in zone %s", pzone->desc);
+}