Generic buffer facilities for Lua (and libraries)

1 files changed, 81 insertions, 0 deletions

diff --git a/lbuffer.c b/lbuffer.c
new file mode 100644
index 00000000..04820736
--- /dev/null
+++ b/lbuffer.c
@@ -0,0 +1,81 @@
+/*
+** $Id: $
+** Auxiliar functions for building Lua libraries
+** See Copyright Notice in lua.h
+*/
+
+
+#include <stdio.h>
+
+#include "lauxlib.h"
+#include "lmem.h"
+#include "lstate.h"
+
+
+/*-------------------------------------------------------
+**  Auxiliar buffer
+-------------------------------------------------------*/
+
+#define BUFF_STEP       32
+
+#define openspace(size)  if (L->Mbuffnext+(size) > L->Mbuffsize) Openspace(size)
+
+static void Openspace (int size)
+{
+  LState *l = L;  /* to optimize */
+  int base = l->Mbuffbase-l->Mbuffer;
+  l->Mbuffsize *= 2;
+  if (l->Mbuffnext+size > l->Mbuffsize)  /* still not big enough? */
+    l->Mbuffsize = l->Mbuffnext+size;
+  l->Mbuffer = luaM_realloc(l->Mbuffer, l->Mbuffsize);
+  l->Mbuffbase = l->Mbuffer+base;
+}
+
+
+char *luaL_openspace (int size)
+{
+  openspace(size);
+  return L->Mbuffer+L->Mbuffnext;
+}
+
+
+void luaL_addchar (int c)
+{
+  openspace(BUFF_STEP);
+  L->Mbuffer[L->Mbuffnext++] = c;
+}
+
+
+void luaL_resetbuffer (void)
+{
+  L->Mbuffnext = L->Mbuffbase-L->Mbuffer;
+}
+
+
+void luaL_addsize (int n)
+{
+  L->Mbuffnext += n;
+}
+
+
+int luaL_newbuffer (int size)
+{
+  int old = L->Mbuffbase-L->Mbuffer;
+  openspace(size);
+  L->Mbuffbase = L->Mbuffer+L->Mbuffnext;
+  return old;
+}
+
+
+void luaL_oldbuffer (int old)
+{
+  L->Mbuffnext = L->Mbuffbase-L->Mbuffer;
+  L->Mbuffbase = L->Mbuffer+old;
+}
+
+
+char *luaL_buffer (void)
+{
+  return L->Mbuffbase;
+}
+