src/add-ons/kernel/file_systems/ramfs/Stack.h

   1 /* Stack - a template stack class (plus some handy methods)
   2  *
   3  * Copyright 2001-2005, Axel Dörfler, axeld@pinc-software.de.
   4  * This file may be used under the terms of the MIT License.
   5  */
   6 #ifndef KERNEL_UTIL_STACK_H
   7 #define KERNEL_UTIL_STACK_H
   8
   9
  10 #include <SupportDefs.h>
  11
  12
  13 template<class T> class Stack {
  14         public:
  15                 Stack()
  16                         :
  17                         fArray(NULL),
  18                         fUsed(0),
  19                         fMax(0)
  20                 {
  21                 }
  22
  23                 ~Stack()
  24                 {
  25                         free(fArray);
  26                 }
  27
  28                 bool IsEmpty() const
  29                 {
  30                         return fUsed == 0;
  31                 }
  32
  33                 void MakeEmpty()
  34                 {
  35                         // could also free the memory
  36                         fUsed = 0;
  37                 }
  38
  39                 status_t Push(T value)
  40                 {
  41                         if (fUsed >= fMax) {
  42                                 fMax += 16;
  43                                 T *newArray = (T *)realloc(fArray, fMax * sizeof(T));
  44                                 if (newArray == NULL)
  45                                         return B_NO_MEMORY;
  46
  47                                 fArray = newArray;
  48                         }
  49                         fArray[fUsed++] = value;
  50                         return B_OK;
  51                 }
  52
  53                 bool Pop(T *value)
  54                 {
  55                         if (fUsed == 0)
  56                                 return false;
  57
  58                         *value = fArray[--fUsed];
  59                         return true;
  60                 }
  61
  62                 T *Array()
  63                 {
  64                         return fArray;
  65                 }
  66
  67                 int32 CountItems() const
  68                 {
  69                         return fUsed;
  70                 }
  71
  72         private:
  73                 T               *fArray;
  74                 int32   fUsed;
  75                 int32   fMax;
  76 };
  77
  78 #endif  /* KERNEL_UTIL_STACK_H */