/***********************************************************************
* Microsoft (R) 32-Bit Incremental Linker
*
* Copyright (C) Microsoft Corp 1992-95. All rights reserved.
*
* File: bufio.h
*
* File Comments:
*
*  This file contains the private data structures for file i/o.
*
***********************************************************************/

#ifndef BUFIO__H
#define BUFIO__H

// i/o buffer flags
#define BUF_Active           0x01   // buffer is active
#define BUF_Dirty            0x02   // buffer has been written to
#define BUF_PreviousWrite    0x04   // buffer range was previously written to
#define BUF_Random           0x08   // buffer has random contents
#define BUF_Current          0x10   // current buffer for a file, !reallocatable

// i/o buffer parameters
#define cbIOBuf              4096L  // size of buffer in bytes
#define cshiftBuf            12     // log base two of cbIOBuf

#define cbufTot              30     // number of buffers for system

// logical file descriptor parameters
#define cfiInSystemNT            16 // # logical file descriptors
#define cfiCacheableInSystemNT   14 // # cacheable logical file descriptors
#define cfiInSystemTNT           8  // # logical file descriptors
#define cfiCacheableInSystemTNT  6  // # cacheable logical file descriptors

typedef struct BUF                  // i/o buffer structure
{
    INT ifi;                        // logical file descriptor
    LONG ibStart;                   // starting offset of buffer span in file
    LONG ibEnd;                     // ending offset of buffer span in file
    LONG ibCur;                     // current offset of buffer in file
    LONG ibLast;                    // highest memory address written to
    DWORD flags;                    // status flags
    BYTE rgbBuf[cbIOBuf];           // physical memory for buffer
    BYTE *pbCur;                    // pointer to current position in buffer
    struct BUF *pbufNext;           // next contiguous memory, free chain
    struct BUF *pbufLRURight;       // LRU next memory buffer to right
    struct BUF *pbufLRULeft;        // LRU next memory buffer to left
} BUF, *PBUF, **PPBUF;

// logical file descriptor flags
#define FI_Read              0x01   // file is open for read
#define FI_Write             0x02   // file is open for write
#define FI_Closed            0x04   // file is closed
#define FI_Mapped            0x08   // file is opened for NT mapped i/o
#define FI_Create            0x10   // file is being created

// mapped I/O tuning constants
#define cbMapViewDefault     (512 * 1024)       // map 0.5mb by default
#define cbInitialILKMapSize  (256 * 1024)       // initial size of ILK map file

typedef struct FI                  // linker file descriptor
{
    char *szFileName;              // name of file
    DWORD flags;                   // file flags, see above
    INT ifi;                       // index in rgpfi table
    LONG cbSoFar;                  // last seeked or written off !FI_Read
    union {
        struct {                   // buffering on top of low i/o
            INT fd;                // physical file handle
            PPBUF rgpbuf;          // buffer table for file
            DWORD cb;              // size of file in bytes
            LONG cbMap;            // amount of file spanned by buffers
            PBUF pbufCur;          // current buffer for file
        };
        struct {                   // file mapped i/o
            HANDLE hFile;          // file handle
            PVOID pvMapView;       // view of file
            LONG cbMapView;        // size of file mapping
            LONG ibCur;            // current offset
            DWORD MapAddr;         // start address of mapped view
        };
    };
    struct FI *pfiNext;            // next logical file descriptor
} FI, *PFI, **PPFI;

#endif  // BUFIO__H