X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=blobdiff_plain;f=geekos%2Fsrc%2Flwip%2Fcore%2Fmem.c;fp=geekos%2Fsrc%2Flwip%2Fcore%2Fmem.c;h=9783c5d6e0621d0a745b2aaedf2a4d5966c981a1;hp=0000000000000000000000000000000000000000;hb=ddc16b0737cf58f7aa90a69c6652cdf4090aec51;hpb=626595465a2c6987606a6bc697df65130ad8c2d3

diff --git a/geekos/src/lwip/core/mem.c b/geekos/src/lwip/core/mem.c
new file mode 100644
index 0000000..9783c5d
--- /dev/null
+++ b/geekos/src/lwip/core/mem.c
@@ -0,0 +1,577 @@
+/**
+ * @file
+ * Dynamic memory manager
+ *
+ * This is a lightweight replacement for the standard C library malloc().
+ *
+ * If you want to use the standard C library malloc() instead, define
+ * MEM_LIBC_MALLOC to 1 in your lwipopts.h
+ *
+ * To let mem_malloc() use pools (prevents fragmentation and is much faster than
+ * a heap but might waste some memory), define MEM_USE_POOLS to 1, define
+ * MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list
+ * of pools like this (more pools can be added between _START and _END):
+ *
+ * Define three pools with sizes 256, 512, and 1512 bytes
+ * LWIP_MALLOC_MEMPOOL_START
+ * LWIP_MALLOC_MEMPOOL(20, 256)
+ * LWIP_MALLOC_MEMPOOL(10, 512)
+ * LWIP_MALLOC_MEMPOOL(5, 1512)
+ * LWIP_MALLOC_MEMPOOL_END
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *         Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/sys.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+#if MEM_USE_POOLS
+/* lwIP head implemented with different sized pools */
+
+/**
+ * This structure is used to save the pool one element came from.
+ */
+struct mem_helper
+{
+   memp_t poolnr;
+};
+
+/**
+ * Allocate memory: determine the smallest pool that is big enough
+ * to contain an element of 'size' and get an element from that pool.
+ *
+ * @param size the size in bytes of the memory needed
+ * @return a pointer to the allocated memory or NULL if the pool is empty
+ */
+void *
+mem_malloc(mem_size_t size)
+{
+  struct mem_helper *element;
+  memp_t poolnr;
+
+  for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr++) {
+    /* is this pool big enough to hold an element of the required size
+       plus a struct mem_helper that saves the pool this element came from? */
+    if ((size + sizeof(struct mem_helper)) <= memp_sizes[poolnr]) {
+      break;
+    }
+  }
+  if (poolnr > MEMP_POOL_LAST) {
+    LWIP_ASSERT("mem_malloc(): no pool is that big!", 0);
+    return NULL;
+  }
+  element = (struct mem_helper*)memp_malloc(poolnr);
+  if (element == NULL) {
+    /* No need to DEBUGF or ASSERT: This error is already
+       taken care of in memp.c */
+    /** @todo: we could try a bigger pool if this one is empty! */
+    return NULL;
+  }
+
+  /* save the pool number this element came from */
+  element->poolnr = poolnr;
+  /* and return a pointer to the memory directly after the struct mem_helper */
+  element++;
+
+  return element;
+}
+
+/**
+ * Free memory previously allocated by mem_malloc. Loads the pool number
+ * and calls memp_free with that pool number to put the element back into
+ * its pool
+ *
+ * @param rmem the memory element to free
+ */
+void
+mem_free(void *rmem)
+{
+  struct mem_helper *hmem = (struct mem_helper*)rmem;
+
+  LWIP_ASSERT("rmem != NULL", (rmem != NULL));
+  LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem)));
+
+  /* get the original struct mem_helper */
+  hmem--;
+
+  LWIP_ASSERT("hmem != NULL", (hmem != NULL));
+  LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem)));
+  LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX));
+
+  /* and put it in the pool we saved earlier */
+  memp_free(hmem->poolnr, hmem);
+}
+
+#else /* MEM_USE_POOLS */
+/* lwIP replacement for your libc malloc() */
+
+/**
+ * The heap is made up as a list of structs of this type.
+ * This does not have to be aligned since for getting its size,
+ * we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes.
+ */
+struct mem {
+  /** index (-> ram[next]) of the next struct */
+  mem_size_t next;
+  /** index (-> ram[next]) of the next struct */
+  mem_size_t prev;
+  /** 1: this area is used; 0: this area is unused */
+  u8_t used;
+};
+
+/** All allocated blocks will be MIN_SIZE bytes big, at least!
+ * MIN_SIZE can be overridden to suit your needs. Smaller values save space,
+ * larger values could prevent too small blocks to fragment the RAM too much. */
+#ifndef MIN_SIZE
+#define MIN_SIZE             12
+#endif /* MIN_SIZE */
+/* some alignment macros: we define them here for better source code layout */
+#define MIN_SIZE_ALIGNED     LWIP_MEM_ALIGN_SIZE(MIN_SIZE)
+#define SIZEOF_STRUCT_MEM    LWIP_MEM_ALIGN_SIZE(sizeof(struct mem))
+#define MEM_SIZE_ALIGNED     LWIP_MEM_ALIGN_SIZE(MEM_SIZE)
+
+/** the heap. we need one struct mem at the end and some room for alignment */
+static u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT];
+/** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */
+static u8_t *ram;
+/** the last entry, always unused! */
+static struct mem *ram_end;
+/** pointer to the lowest free block, this is used for faster search */
+static struct mem *lfree;
+/** concurrent access protection */
+static sys_sem_t mem_sem;
+
+/**
+ * "Plug holes" by combining adjacent empty struct mems.
+ * After this function is through, there should not exist
+ * one empty struct mem pointing to another empty struct mem.
+ *
+ * @param mem this points to a struct mem which just has been freed
+ * @internal this function is only called by mem_free() and mem_realloc()
+ *
+ * This assumes access to the heap is protected by the calling function
+ * already.
+ */
+static void
+plug_holes(struct mem *mem)
+{
+  struct mem *nmem;
+  struct mem *pmem;
+
+  LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram);
+  LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end);
+  LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0);
+
+  /* plug hole forward */
+  LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", mem->next <= MEM_SIZE_ALIGNED);
+
+  nmem = (struct mem *)&ram[mem->next];
+  if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) {
+    /* if mem->next is unused and not end of ram, combine mem and mem->next */
+    if (lfree == nmem) {
+      lfree = mem;
+    }
+    mem->next = nmem->next;
+    ((struct mem *)&ram[nmem->next])->prev = (u8_t *)mem - ram;
+  }
+
+  /* plug hole backward */
+  pmem = (struct mem *)&ram[mem->prev];
+  if (pmem != mem && pmem->used == 0) {
+    /* if mem->prev is unused, combine mem and mem->prev */
+    if (lfree == mem) {
+      lfree = pmem;
+    }
+    pmem->next = mem->next;
+    ((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram;
+  }
+}
+
+/**
+ * Zero the heap and initialize start, end and lowest-free
+ */
+void
+mem_init(void)
+{
+  struct mem *mem;
+
+  LWIP_ASSERT("Sanity check alignment",
+    (SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT-1)) == 0);
+
+  /* align the heap */
+  ram = LWIP_MEM_ALIGN(ram_heap);
+  /* initialize the start of the heap */
+  mem = (struct mem *)ram;
+  mem->next = MEM_SIZE_ALIGNED;
+  mem->prev = 0;
+  mem->used = 0;
+  /* initialize the end of the heap */
+  ram_end = (struct mem *)&ram[MEM_SIZE_ALIGNED];
+  ram_end->used = 1;
+  ram_end->next = MEM_SIZE_ALIGNED;
+  ram_end->prev = MEM_SIZE_ALIGNED;
+
+  mem_sem = sys_sem_new(1);
+
+  /* initialize the lowest-free pointer to the start of the heap */
+  lfree = (struct mem *)ram;
+
+#if MEM_STATS
+  lwip_stats.mem.avail = MEM_SIZE_ALIGNED;
+#endif /* MEM_STATS */
+}
+
+/**
+ * Put a struct mem back on the heap
+ *
+ * @param rmem is the data portion of a struct mem as returned by a previous
+ *             call to mem_malloc()
+ */
+void
+mem_free(void *rmem)
+{
+  struct mem *mem;
+
+  if (rmem == NULL) {
+    LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | 2, ("mem_free(p == NULL) was called.\n"));
+    return;
+  }
+  LWIP_ASSERT("mem_free: sanity check alignment", (((mem_ptr_t)rmem) & (MEM_ALIGNMENT-1)) == 0);
+
+  /* protect the heap from concurrent access */
+  sys_arch_sem_wait(mem_sem, 0);
+
+  LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
+    (u8_t *)rmem < (u8_t *)ram_end);
+
+  if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
+    LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n"));
+#if MEM_STATS
+    ++lwip_stats.mem.err;
+#endif /* MEM_STATS */
+    sys_sem_signal(mem_sem);
+    return;
+  }
+  /* Get the corresponding struct mem ... */
+  mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
+  /* ... which has to be in a used state ... */
+  LWIP_ASSERT("mem_free: mem->used", mem->used);
+  /* ... and is now unused. */
+  mem->used = 0;
+
+  if (mem < lfree) {
+    /* the newly freed struct is now the lowest */
+    lfree = mem;
+  }
+
+#if MEM_STATS
+  lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram);
+#endif /* MEM_STATS */
+
+  /* finally, see if prev or next are free also */
+  plug_holes(mem);
+  sys_sem_signal(mem_sem);
+}
+
+/**
+ * In contrast to its name, mem_realloc can only shrink memory, not expand it.
+ * Since the only use (for now) is in pbuf_realloc (which also can only shrink),
+ * this shouldn't be a problem!
+ *
+ * @param rmem pointer to memory allocated by mem_malloc the is to be shrinked
+ * @param newsize required size after shrinking (needs to be smaller than or
+ *                equal to the previous size)
+ * @return for compatibility reasons: is always == rmem, at the moment
+ */
+void *
+mem_realloc(void *rmem, mem_size_t newsize)
+{
+  mem_size_t size;
+  mem_size_t ptr, ptr2;
+  struct mem *mem, *mem2;
+
+  /* Expand the size of the allocated memory region so that we can
+     adjust for alignment. */
+  newsize = LWIP_MEM_ALIGN_SIZE(newsize);
+
+  if(newsize < MIN_SIZE_ALIGNED) {
+    /* every data block must be at least MIN_SIZE_ALIGNED long */
+    newsize = MIN_SIZE_ALIGNED;
+  }
+
+  if (newsize > MEM_SIZE_ALIGNED) {
+    return NULL;
+  }
+
+  LWIP_ASSERT("mem_realloc: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
+   (u8_t *)rmem < (u8_t *)ram_end);
+
+  if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
+    LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n"));
+    return rmem;
+  }
+  /* Get the corresponding struct mem ... */
+  mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
+  /* ... and its offset pointer */
+  ptr = (u8_t *)mem - ram;
+
+  size = mem->next - ptr - SIZEOF_STRUCT_MEM;
+  LWIP_ASSERT("mem_realloc can only shrink memory", newsize <= size);
+  if (newsize > size) {
+    /* not supported */
+    return NULL;
+  }
+  if (newsize == size) {
+    /* No change in size, simply return */
+    return rmem;
+  }
+
+  /* protect the heap from concurrent access */
+  sys_arch_sem_wait(mem_sem, 0);
+
+#if MEM_STATS
+  lwip_stats.mem.used -= (size - newsize);
+#endif /* MEM_STATS */
+
+  mem2 = (struct mem *)&ram[mem->next];
+  if(mem2->used == 0) {
+    /* The next struct is unused, we can simply move it at little */
+    mem_size_t next;
+    /* remember the old next pointer */
+    next = mem2->next;
+    /* create new struct mem which is moved directly after the shrinked mem */
+    ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
+    if (lfree == mem2) {
+      lfree = (struct mem *)&ram[ptr2];
+    }
+    mem2 = (struct mem *)&ram[ptr2];
+    mem2->used = 0;
+    /* restore the next pointer */
+    mem2->next = next;
+    /* link it back to mem */
+    mem2->prev = ptr;
+    /* link mem to it */
+    mem->next = ptr2;
+    /* last thing to restore linked list: as we have moved mem2,
+     * let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not
+     * the end of the heap */
+    if (mem2->next != MEM_SIZE_ALIGNED) {
+      ((struct mem *)&ram[mem2->next])->prev = ptr2;
+    }
+    /* no need to plug holes, we've already done that */
+  } else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) {
+    /* Next struct is used but there's room for another struct mem with
+     * at least MIN_SIZE_ALIGNED of data.
+     * Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem
+     * ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED').
+     * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty
+     *       region that couldn't hold data, but when mem->next gets freed,
+     *       the 2 regions would be combined, resulting in more free memory */
+    ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
+    mem2 = (struct mem *)&ram[ptr2];
+    if (mem2 < lfree) {
+      lfree = mem2;
+    }
+    mem2->used = 0;
+    mem2->next = mem->next;
+    mem2->prev = ptr;
+    mem->next = ptr2;
+    if (mem2->next != MEM_SIZE_ALIGNED) {
+      ((struct mem *)&ram[mem2->next])->prev = ptr2;
+    }
+    /* the original mem->next is used, so no need to plug holes! */
+  }
+  /* else {
+    next struct mem is used but size between mem and mem2 is not big enough
+    to create another struct mem
+    -> don't do anyhting. 
+    -> the remaining space stays unused since it is too small
+  } */
+  sys_sem_signal(mem_sem);
+  return rmem;
+}
+
+/**
+ * Adam's mem_malloc() plus solution for bug #17922
+ * Allocate a block of memory with a minimum of 'size' bytes.
+ *
+ * @param size is the minimum size of the requested block in bytes.
+ * @return pointer to allocated memory or NULL if no free memory was found.
+ *
+ * Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT).
+ */
+void *
+mem_malloc(mem_size_t size)
+{
+  mem_size_t ptr, ptr2;
+  struct mem *mem, *mem2;
+
+  if (size == 0) {
+    return NULL;
+  }
+
+  /* Expand the size of the allocated memory region so that we can
+     adjust for alignment. */
+  size = LWIP_MEM_ALIGN_SIZE(size);
+
+  if(size < MIN_SIZE_ALIGNED) {
+    /* every data block must be at least MIN_SIZE_ALIGNED long */
+    size = MIN_SIZE_ALIGNED;
+  }
+
+  if (size > MEM_SIZE_ALIGNED) {
+    return NULL;
+  }
+
+  /* protect the heap from concurrent access */
+  sys_arch_sem_wait(mem_sem, 0);
+
+  /* Scan through the heap searching for a free block that is big enough,
+   * beginning with the lowest free block.
+   */
+  for (ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE_ALIGNED - size;
+       ptr = ((struct mem *)&ram[ptr])->next) {
+    mem = (struct mem *)&ram[ptr];
+
+    if ((!mem->used) &&
+        (mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) {
+      /* mem is not used and at least perfect fit is possible:
+       * mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */
+
+      if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) {
+        /* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing
+         * at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem')
+         * -> split large block, create empty remainder,
+         * remainder must be large enough to contain MIN_SIZE_ALIGNED data: if
+         * mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size,
+         * struct mem would fit in but no data between mem2 and mem2->next
+         * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty
+         *       region that couldn't hold data, but when mem->next gets freed,
+         *       the 2 regions would be combined, resulting in more free memory
+         */
+        ptr2 = ptr + SIZEOF_STRUCT_MEM + size;
+        /* create mem2 struct */
+        mem2 = (struct mem *)&ram[ptr2];
+        mem2->used = 0;
+        mem2->next = mem->next;
+        mem2->prev = ptr;
+        /* and insert it between mem and mem->next */
+        mem->next = ptr2;
+        mem->used = 1;
+
+        if (mem2->next != MEM_SIZE_ALIGNED) {
+          ((struct mem *)&ram[mem2->next])->prev = ptr2;
+        }
+#if MEM_STATS
+        lwip_stats.mem.used += (size + SIZEOF_STRUCT_MEM);
+        if (lwip_stats.mem.max < lwip_stats.mem.used) {
+          lwip_stats.mem.max = lwip_stats.mem.used;
+        }
+#endif /* MEM_STATS */
+      } else {
+        /* (a mem2 struct does no fit into the user data space of mem and mem->next will always
+         * be used at this point: if not we have 2 unused structs in a row, plug_holes should have
+         * take care of this).
+         * -> near fit or excact fit: do not split, no mem2 creation
+         * also can't move mem->next directly behind mem, since mem->next
+         * will always be used at this point!
+         */
+        mem->used = 1;
+#if MEM_STATS
+        lwip_stats.mem.used += mem->next - ((u8_t *)mem - ram);
+        if (lwip_stats.mem.max < lwip_stats.mem.used) {
+          lwip_stats.mem.max = lwip_stats.mem.used;
+        }
+#endif /* MEM_STATS */
+      }
+
+      if (mem == lfree) {
+        /* Find next free block after mem and update lowest free pointer */
+        while (lfree->used && lfree != ram_end) {
+          lfree = (struct mem *)&ram[lfree->next];
+        }
+        LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used)));
+      }
+      sys_sem_signal(mem_sem);
+      LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.",
+       (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end);
+      LWIP_ASSERT("mem_malloc: allocated memory properly aligned.",
+       (unsigned long)((u8_t *)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);
+      LWIP_ASSERT("mem_malloc: sanity check alignment",
+        (((mem_ptr_t)mem) & (MEM_ALIGNMENT-1)) == 0);
+
+      return (u8_t *)mem + SIZEOF_STRUCT_MEM;
+    }
+  }
+  LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size));
+#if MEM_STATS
+  ++lwip_stats.mem.err;
+#endif /* MEM_STATS */
+  sys_sem_signal(mem_sem);
+  return NULL;
+}
+
+#endif /* MEM_USE_POOLS */
+/**
+ * Contiguously allocates enough space for count objects that are size bytes
+ * of memory each and returns a pointer to the allocated memory.
+ *
+ * The allocated memory is filled with bytes of value zero.
+ *
+ * @param count number of objects to allocate
+ * @param size size of the objects to allocate
+ * @return pointer to allocated memory / NULL pointer if there is an error
+ */
+void *mem_calloc(mem_size_t count, mem_size_t size)
+{
+  void *p;
+
+  /* allocate 'count' objects of size 'size' */
+  p = mem_malloc(count * size);
+  if (p) {
+    /* zero the memory */
+    memset(p, 0, count * size);
+  }
+  return p;
+}
+
+#endif /* !MEM_LIBC_MALLOC */