d/keyque.c

   1 ///////////////////////////////////////////////////////////////////////////////\r
   2 // keyque.c\r
   3 \r
   4 \r
   5 ///////////////////////////////////////////////////////////////////////////////\r
   6 // Definitions\r
   7 \r
   8 \r
   9 typedef struct KeyQue {\r
  10         ULONG count;                    // Number of keys in the que\r
  11         ULONG lengthof_que;             // Length of que\r
  12         KEYBOARD_INPUT_DATA *insert;    // Insertion pointer for que\r
  13         KEYBOARD_INPUT_DATA *remove;    // Removal pointer for que\r
  14         KEYBOARD_INPUT_DATA *que;\r
  15 } KeyQue;\r
  16 \r
  17 \r
  18 #define KeyQueSize 100\r
  19 \r
  20 \r
  21 ///////////////////////////////////////////////////////////////////////////////\r
  22 // Prototypes\r
  23 \r
  24 \r
  25 NTSTATUS KqInitialize(KeyQue *kq);\r
  26 void KqClear(KeyQue *kq);\r
  27 NTSTATUS KqFinalize(KeyQue *kq);\r
  28 BOOLEAN KqIsEmpty(KeyQue *kq);\r
  29 ULONG KqEnque(KeyQue *kq, IN  KEYBOARD_INPUT_DATA *buf, IN ULONG lengthof_buf);\r
  30 ULONG KqDeque(KeyQue *kq, OUT KEYBOARD_INPUT_DATA *buf, IN ULONG lengthof_buf);\r
  31 \r
  32 \r
  33 #ifdef ALLOC_PRAGMA\r
  34 #pragma alloc_text( init, KqInitialize )\r
  35 #pragma alloc_text( page, KqFinalize )\r
  36 #endif // ALLOC_PRAGMA\r
  37 \r
  38 \r
  39 ///////////////////////////////////////////////////////////////////////////////\r
  40 // Functions\r
  41 \r
  42 \r
  43 NTSTATUS KqInitialize(KeyQue *kq)\r
  44 {\r
  45         kq->count = 0;\r
  46         kq->lengthof_que = KeyQueSize;\r
  47         kq->que = ExAllocatePool(NonPagedPool,\r
  48                                                          kq->lengthof_que * sizeof(KEYBOARD_INPUT_DATA));\r
  49         kq->insert = kq->que;\r
  50         kq->remove = kq->que;\r
  51         if (kq->que == NULL)\r
  52                 return STATUS_INSUFFICIENT_RESOURCES;\r
  53         else\r
  54                 return STATUS_SUCCESS;\r
  55 }\r
  56 \r
  57 \r
  58 void KqClear(KeyQue *kq)\r
  59 {\r
  60         kq->count = 0;\r
  61         kq->insert = kq->que;\r
  62         kq->remove = kq->que;\r
  63 }\r
  64 \r
  65 \r
  66 NTSTATUS KqFinalize(KeyQue *kq)\r
  67 {\r
  68         if (kq->que)\r
  69                 ExFreePool(kq->que);\r
  70         return STATUS_SUCCESS;\r
  71 }\r
  72 \r
  73 \r
  74 BOOLEAN KqIsEmpty(KeyQue *kq)\r
  75 {\r
  76         return 0 == kq->count;\r
  77 }\r
  78 \r
  79 \r
  80 // return: lengthof copied data\r
  81 ULONG KqEnque(KeyQue *kq, IN KEYBOARD_INPUT_DATA *buf, IN ULONG lengthof_buf)\r
  82 {\r
  83         ULONG rest;\r
  84 \r
  85         if (kq->lengthof_que - kq->count < lengthof_buf) // overflow\r
  86                 lengthof_buf = kq->lengthof_que - kq->count; // chop overflowed datum\r
  87         if (lengthof_buf <= 0)\r
  88                 return 0;\r
  89 \r
  90         rest = kq->lengthof_que - (kq->insert - kq->que);\r
  91         if (rest < lengthof_buf) {\r
  92                 ULONG copy = rest;\r
  93                 if (0 < copy) {\r
  94                         RtlMoveMemory((PCHAR)kq->insert, (PCHAR)buf,\r
  95                                                   sizeof(KEYBOARD_INPUT_DATA) * copy);\r
  96                         buf += copy;\r
  97                 }\r
  98                 copy = lengthof_buf - copy;\r
  99                 if (0 < copy)\r
 100                         RtlMoveMemory((PCHAR)kq->que, (PCHAR)buf,\r
 101                                                   sizeof(KEYBOARD_INPUT_DATA) * copy);\r
 102                 kq->insert = kq->que + copy;\r
 103         } else {\r
 104                 RtlMoveMemory((PCHAR)kq->insert, (PCHAR)buf,\r
 105                                           sizeof(KEYBOARD_INPUT_DATA) * lengthof_buf);\r
 106                 kq->insert += lengthof_buf;\r
 107         }\r
 108         kq->count += lengthof_buf;\r
 109         return lengthof_buf;\r
 110 }\r
 111 \r
 112 \r
 113 // return: lengthof copied data\r
 114 ULONG KqDeque(KeyQue *kq, OUT KEYBOARD_INPUT_DATA *buf, IN ULONG lengthof_buf)\r
 115 {\r
 116         ULONG rest;\r
 117 \r
 118         if (kq->count < lengthof_buf)\r
 119                 lengthof_buf = kq->count;\r
 120         if (lengthof_buf <= 0)\r
 121                 return 0;\r
 122 \r
 123         rest = kq->lengthof_que - (kq->remove - kq->que);\r
 124         if (rest < lengthof_buf) {\r
 125                 ULONG copy = rest;\r
 126                 if (0 < copy) {\r
 127                         RtlMoveMemory((PCHAR)buf, (PCHAR)kq->remove,\r
 128                                                   sizeof(KEYBOARD_INPUT_DATA) * copy);\r
 129                         buf += copy;\r
 130                 }\r
 131                 copy = lengthof_buf - copy;\r
 132                 if (0 < copy)\r
 133                         RtlMoveMemory((PCHAR)buf, (PCHAR)kq->que,\r
 134                                                   sizeof(KEYBOARD_INPUT_DATA) * copy);\r
 135                 kq->remove = kq->que + copy;\r
 136         } else {\r
 137                 RtlMoveMemory((PCHAR)buf, (PCHAR)kq->remove,\r
 138                                           sizeof(KEYBOARD_INPUT_DATA) * lengthof_buf);\r
 139                 kq->remove += lengthof_buf;\r
 140         }\r
 141         kq->count -= lengthof_buf;\r
 142         return lengthof_buf;\r
 143 }\r