text: /** @file
   *
   * VBox Host Guest Shared Memory Interface (HGSMI).
   * Host/Guest shared part: types and defines.
   */
  
  /*
   * Copyright (C) 2006-2015 Oracle Corporation
   *
   * This file is part of VirtualBox Open Source Edition (OSE), as
   * available from http://www.virtualbox.org. This file is free software;
   * you can redistribute it and/or modify it under the terms of the GNU
   * General Public License (GPL) as published by the Free Software
   * Foundation, in version 2 as it comes in the "COPYING" file of the
   * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
   * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
   *
   * The contents of this file may alternatively be used under the terms
   * of the Common Development and Distribution License Version 1.0
   * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
   * VirtualBox OSE distribution, in which case the provisions of the
   * CDDL are applicable instead of those of the GPL.
   *
   * You may elect to license modified versions of this file under the
   * terms and conditions of either the GPL or the CDDL or both.
   */
  
  
  #ifndef ___VBox_HGSMI_HGSMIDefs_h
  #define ___VBox_HGSMI_HGSMIDefs_h
  
  #include <iprt/assert.h>
  #include <iprt/types.h>
  
  /* HGSMI uses 32 bit offsets and sizes. */
  typedef uint32_t HGSMISIZE;
  typedef uint32_t HGSMIOFFSET;
  
  #define HGSMIOFFSET_VOID ((HGSMIOFFSET)~0)
  
  /* Describes a shared memory area buffer.
   * Used for calculations with offsets and for buffers verification.
   */
  typedef struct HGSMIAREA
  {
      uint8_t     *pu8Base; /* The starting address of the area. Corresponds to offset 'offBase'. */
      HGSMIOFFSET  offBase; /* The starting offset of the area. */
      HGSMIOFFSET  offLast; /* The last valid offset:
                             * offBase + cbArea - 1 - (sizeof(header) + sizeof(tail)).
                             */
      HGSMISIZE    cbArea;  /* Size of the area. */
  } HGSMIAREA;
  
  
  /* The buffer description flags. */
  #define HGSMI_BUFFER_HEADER_F_SEQ_MASK     0x03 /* Buffer sequence type mask. */
  #define HGSMI_BUFFER_HEADER_F_SEQ_SINGLE   0x00 /* Single buffer, not a part of a sequence. */
  #define HGSMI_BUFFER_HEADER_F_SEQ_START    0x01 /* The first buffer in a sequence. */
  #define HGSMI_BUFFER_HEADER_F_SEQ_CONTINUE 0x02 /* A middle buffer in a sequence. */
  #define HGSMI_BUFFER_HEADER_F_SEQ_END      0x03 /* The last buffer in a sequence. */
  
  
  #pragma pack(1)
  /* 16 bytes buffer header. */
  typedef struct HGSMIBUFFERHEADER
  {
      uint32_t    u32DataSize;            /* Size of data that follows the header. */
  
      uint8_t     u8Flags;                /* The buffer description: HGSMI_BUFFER_HEADER_F_* */
  
      uint8_t     u8Channel;              /* The channel the data must be routed to. */
      uint16_t    u16ChannelInfo;         /* Opaque to the HGSMI, used by the channel. */
  
      union {
          uint8_t au8Union[8];            /* Opaque placeholder to make the union 8 bytes. */
  
          struct
          {                               /* HGSMI_BUFFER_HEADER_F_SEQ_SINGLE */
              uint32_t u32Reserved1;      /* A reserved field, initialize to 0. */
              uint32_t u32Reserved2;      /* A reserved field, initialize to 0. */
          } Buffer;
  
          struct
          {                               /* HGSMI_BUFFER_HEADER_F_SEQ_START */
              uint32_t u32SequenceNumber; /* The sequence number, the same for all buffers in the sequence. */
              uint32_t u32SequenceSize;   /* The total size of the sequence. */
          } SequenceStart;
  
          struct
          {                               /* HGSMI_BUFFER_HEADER_F_SEQ_CONTINUE and HGSMI_BUFFER_HEADER_F_SEQ_END */
              uint32_t u32SequenceNumber; /* The sequence number, the same for all buffers in the sequence. */
              uint32_t u32SequenceOffset; /* Data offset in the entire sequence. */
          } SequenceContinue;
      } u;
  } HGSMIBUFFERHEADER;
  
  /* 8 bytes buffer tail. */
  typedef struct HGSMIBUFFERTAIL
  {
      uint32_t    u32Reserved;        /* Reserved, must be initialized to 0. */
      uint32_t    u32Checksum;        /* Verifyer for the buffer header and offset and for first 4 bytes of the tail. */
  } HGSMIBUFFERTAIL;
  #pragma pack()
  
  AssertCompileSize(HGSMIBUFFERHEADER, 16);
  AssertCompileSize(HGSMIBUFFERTAIL, 8);
  
  /* The size of the array of channels. Array indexes are uint8_t. Note: the value must not be changed. */
  #define HGSMI_NUMBER_OF_CHANNELS 0x100
  
  typedef struct HGSMIENV
  {
      /* Environment context pointer. */
      void *pvEnv;
  
      /* Allocate system memory. */
      DECLCALLBACKMEMBER(void *, pfnAlloc)(void *pvEnv, HGSMISIZE cb);
  
      /* Free system memory. */
      DECLCALLBACKMEMBER(void, pfnFree)(void *pvEnv, void *pv);
  } HGSMIENV;
  
  #endif /* !___VBox_HGSMI_HGSMIDefs_h */
  