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utils/tfstats/regexp/include/jm/jstack.h

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//
+//=============================================================================//
+/*
+ *
+ * Copyright (c) 1998-9
+ * Dr John Maddock
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Dr John Maddock makes no representations
+ * about the suitability of this software for any purpose.  
+ * It is provided "as is" without express or implied warranty.
+ *
+ */
+
+  /*
+  *   FILE     jstack.h
+  *   VERSION  2.12
+  */
+
+#ifndef __JSTACH_H
+#define __JSTACK_H
+
+#ifndef JM_CFG_H
+#include <jm/jm_cfg.h>
+#endif
+
+JM_NAMESPACE(__JM)
+
+//
+// class jstack
+// simplified stack optimised for push/peek/pop
+// operations, we could use std::stack<std::vector<T>> instead...
+//
+template <class T, class Allocator JM_DEF_ALLOC_PARAM(T) >
+class jstack
+{
+private:
+   typedef JM_MAYBE_TYPENAME REBIND_TYPE(unsigned char, Allocator) alloc_type;
+   typedef typename REBIND_TYPE(T, Allocator)::size_type size_type;
+   struct node
+   {
+      node* next;
+      T* start;  // first item
+      T* end;    // last item
+      T* last;   // end of storage
+   };
+   
+   //
+   // empty base member optimisation:
+   struct data : public alloc_type
+   {
+      unsigned char buf[sizeof(T)*16];
+      data(const Allocator& a) : alloc_type(a){}
+   };
+
+   data alloc_inst;
+   mutable node* stack;
+   mutable node* unused;
+   node base;
+   size_type block_size;
+
+   void RE_CALL pop_aux()const;
+   void RE_CALL push_aux();
+
+public:
+   jstack(size_type n = 64, const Allocator& a = Allocator());
+
+   ~jstack();
+
+   node* RE_CALL get_node()
+   {
+      node* new_stack = (node*)alloc_inst.allocate(sizeof(node) + sizeof(T) * block_size);
+      new_stack->last = (T*)(new_stack+1);
+      new_stack->start = new_stack->end = new_stack->last + block_size;
+      new_stack->next = 0;
+      return new_stack;
+   }
+
+   bool RE_CALL empty()
+   {
+      return (stack->start == stack->end) && (stack->next == 0);
+   }
+
+   bool RE_CALL good()
+   {
+      return (stack->start != stack->end) || (stack->next != 0);
+   }
+
+   T& RE_CALL peek()
+   {
+      if(stack->start == stack->end)
+         pop_aux();
+      return *stack->end;
+   }
+
+   const T& RE_CALL peek()const
+   {
+      if(stack->start == stack->end)
+         pop_aux();
+      return *stack->end;
+   }
+
+   void RE_CALL pop()
+   {
+      if(stack->start == stack->end)
+         pop_aux();
+      jm_destroy(stack->end);
+      ++(stack->end);
+   }
+
+   void RE_CALL pop(T& t)
+   {
+      if(stack->start == stack->end)
+         pop_aux();
+      t = *stack->end;
+      jm_destroy(stack->end);
+      ++(stack->end);
+   }
+
+   void RE_CALL push(const T& t)
+   {
+      if(stack->end == stack->last)
+         push_aux();
+      --(stack->end);
+      jm_construct(stack->end, t);
+   }
+
+};
+
+template <class T, class Allocator>
+jstack<T, Allocator>::jstack(size_type n, const Allocator& a)
+    : alloc_inst(a)
+{
+  unused = 0;
+  block_size = n;
+  stack = &base;
+  base.last = (T*)alloc_inst.buf;
+  base.end = base.start = base.last + 16;
+  base.next = 0;
+}
+
+template <class T, class Allocator>
+void RE_CALL jstack<T, Allocator>::push_aux()
+{
+   // make sure we have spare space on TOS:
+   register node* new_node;
+   if(unused)
+   {
+      new_node = unused;
+      unused = new_node->next;
+      new_node->next = stack;
+      stack = new_node;
+   }
+   else
+   {
+      new_node = get_node();
+      new_node->next = stack;
+      stack = new_node;
+   }
+}
+
+template <class T, class Allocator>
+void RE_CALL jstack<T, Allocator>::pop_aux()const
+{
+   // make sure that we have a valid item
+   // on TOS:
+   jm_assert(stack->next);
+   register node* p = stack;
+   stack = p->next;
+   p->next = unused;
+   unused = p;
+}
+
+template <class T, class Allocator>
+jstack<T, Allocator>::~jstack()
+{
+   node* condemned;
+   while(good())
+      pop();
+   while(unused)
+   {
+      condemned = unused;
+      unused = unused->next;
+      alloc_inst.deallocate((unsigned char*)condemned, sizeof(node) + sizeof(T) * block_size);
+   }
+   while(stack != &base)
+   {
+      condemned = stack;
+      stack = stack->next;
+      alloc_inst.deallocate((unsigned char*)condemned, sizeof(node) + sizeof(T) * block_size);
+   }
+}
+
+JM_END_NAMESPACE
+
+#endif
+
+
+
+
+