Interface to Memory Manager

lmem.c

@@ -0,0 +1,137 @@
+/*
+** $Id: $
+** Interface to Memory Manager
+** See Copyright Notice in lua.h
+*/
+
+
+#include <stdlib.h>
+
+#include "lmem.h"
+#include "lua.h"
+
+
+
+int luaM_growaux (void **block, unsigned long nelems, int size,
+                       char *errormsg, unsigned long limit)
+{
+  if (nelems >= limit)
+    lua_error(errormsg);
+  nelems = (nelems == 0) ? 32 : nelems*2;
+  if (nelems > limit)
+    nelems = limit;
+  *block = luaM_realloc(*block, nelems*size);
+  return (int)nelems;
+}
+
+
+static unsigned long Mbuffsize = 0;
+static char *Mbuffer = NULL;
+
+
+void *luaM_buffer (unsigned long size)
+{
+  if (size > Mbuffsize) {
+    Mbuffsize = size;
+    Mbuffer = luaM_realloc(Mbuffer, Mbuffsize);
+  }
+  return Mbuffer;
+}
+
+
+void luaM_clearbuffer (void)
+{
+  Mbuffsize /= 2;
+  Mbuffer = luaM_realloc(Mbuffer, Mbuffsize);
+}
+
+
+#ifndef DEBUG
+
+/*
+** generic allocation routine.
+** real ANSI systems do not need some of these tests,
+** since realloc(NULL, s)==malloc(s) and realloc(b, 0)==free(b).
+** But some systems (e.g. Sun OS) are not that ANSI...
+*/
+void *luaM_realloc (void *block, unsigned long size)
+{
+  size_t s = (size_t)size;
+  if (s != size)
+    lua_error("Allocation Error: Block too big");
+  if (size == 0) {
+    if (block) {
+      free(block);
+    }
+    return NULL;
+  }
+  block = block ? realloc(block, s) : malloc(s);
+  if (block == NULL)
+    lua_error(memEM);
+  return block;
+}
+
+
+
+#else
+/* DEBUG */
+
+#include <assert.h>
+#include <string.h>
+
+
+#define MARK    55
+
+static unsigned long numblocks = 0;
+static unsigned long totalmem = 0;
+
+
+
+void luaM_query (void)
+{
+  lua_pushnumber(totalmem);
+  lua_pushnumber(numblocks);
+}
+
+
+static void *checkblock (void *block)
+{
+  unsigned long *b = (unsigned long *)block - 1;
+  unsigned long size = *b;
+  assert(*(((char *)b)+size+sizeof(unsigned long)) == MARK);
+  numblocks--;
+  totalmem -= size;
+  return b;
+}
+
+
+void *luaM_realloc (void *block, unsigned long size)
+{
+  unsigned long realsize = sizeof(unsigned long)+size+sizeof(char);
+  if (realsize != (size_t)realsize)
+    lua_error("Allocation Error: Block too big");
+  if (size == 0) {  /* ANSI doen't need this, but some machines... */
+    if (block) {
+      memset(block, -1, *((unsigned long *)block-1));  /* erase block */
+      block = checkblock(block);
+      free(block);
+    }
+    return NULL;
+  }
+  if (block) {
+    block = checkblock(block);
+    block = (unsigned long *)realloc(block, realsize);
+  }
+  else
+    block = (unsigned long *)malloc(realsize);
+  if (block == NULL)
+    lua_error(memEM);
+  totalmem += size;
+  numblocks++;
+  *(unsigned long *)block = size;
+  *(((char *)block)+size+sizeof(unsigned long)) = MARK;
+  return (unsigned long *)block+1;
+}
+
+
+#endif