include/common/ZoneHeader.h

   1 /**
   2         Aesalon, a tool to visualize a program's behaviour at run-time.
   3         Copyright (C) 2010, Aesalon Development Team.
   4
   5         Aesalon is distributed under the terms of the GNU GPLv3. For more
   6         licensing information, see the file LICENSE included with the distribution.
   7
   8         @file include/common/ZoneHeader.h
   9
  10 */
  11
  12 #ifndef AesalonCommon_ZoneHeader_H
  13 #define AesalonCommon_ZoneHeader_H
  14
  15 #include <stdint.h>
  16 #include <semaphore.h>
  17 #include <sys/types.h>
  18
  19 #define ZoneDataOffset (sizeof(ZoneHeader_t) + 16)
  20
  21 typedef struct ZoneHeader_t ZoneHeader_t;
  22 struct ZoneHeader_t {
  23         /** Head element of the data region for the circular buffer. */
  24         uint32_t head;
  25
  26         /** Tail element of the data region for the circular buffer. */
  27         uint32_t tail;
  28
  29         /** Packet semaphore: incremented when a packet is available for reading. */
  30         sem_t packetSemaphore;
  31
  32         /** Overflow value: if set to a non-zero value, then the value is how many more bytes are
  33                 required before the next packet can be written. When this value reaches < 0, @a overflowSemaphore
  34                 should be incremented.
  35         */
  36         int32_t overflow;
  37
  38         /** The overflow semaphore, see @a overflow for description. */
  39         sem_t overflowSemaphore;
  40
  41         /** The size of the end-gap. This is used when a size larger than the remaining space on the end of the
  42                 circular buffer is required.
  43
  44                 A zero value indicates either the absence of a gap or the absence of a packet in that region of memory.
  45                 This value should be cleared whenever the gap is read.
  46         */
  47         uint32_t gapSize;
  48
  49         /** The PID that the zone's data comes from. */
  50         uint32_t processID;
  51
  52         /** The thread ID the zone's data comes from. */
  53         uint32_t threadID;
  54 };
  55
  56 #endif