source: xtideuniversalbios/tags/Serial_Server_for_v2.0.0_beta1/win32/Win32File.h@ 560

//======================================================================
//
// Project:     XTIDE Universal BIOS, Serial Port Server
//
// File:        Win32File.h - Microsoft Windows file system access.
//
// Routines for accessing the file system under Win32.  It's important
// to use these direct Win32 calls for large files, since FILE * routines,
// in particular ftell() and fseek(), are limites to signed 32-bits (2 GB).
// These are also likely faster since they are more direct.
// 

#include <windows.h>
#include <stdio.h>
#include "../library/library.h"

class FileAccess
{
public:
    int Create( char *p_name )
    {
        fp = CreateFileA( p_name, GENERIC_WRITE, 0, 0, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, 0 );

        if( fp == INVALID_HANDLE_VALUE )
        {
            if( GetLastError() == ERROR_FILE_EXISTS )
            {
                log( 0, "'%s', file already exists", p_name );
                return( 0 );
            }
            else
                log( -1, "'%s', could not create file", p_name );
        }

        name = p_name;

        return( 1 );
    }

    void Open( char *p_name )
    {
        fp = CreateFileA( p_name, GENERIC_READ|GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 );

        if( fp == INVALID_HANDLE_VALUE )
            log( -1, "'%s', could not open file", p_name );

        name = p_name;
    }

    void Close()
    {
        if( fp )
        {
            if( !CloseHandle( fp ) )
                log( 0, "'%s', could not close file handle", name ? name : "unknown" );         
        }
    }

    unsigned long SizeSectors(void)
    {
        LARGE_INTEGER li;
        unsigned long i;

        if( !GetFileSizeEx( fp, &li ) )
            log( -1, "'%s', could not retrieve file size (error %ul)", name, GetLastError() );

        if( li.LowPart & 0x1ff )
            log( -1, "'%s', file size is not a multiple of 512 byte sectors", name );

        if( li.HighPart > 0x1f )
            log( -1, "'%s', file size greater than LBA28 limit of 137,438,952,960 bytes", name );

        i = ((li.HighPart << 23 ) & 0xff800000) | ((li.LowPart >> 9) & 0x7fffff);

        return( (unsigned long) i );
    }

    void SeekSectors( unsigned long lba )
    {
        LARGE_INTEGER dist;

        dist.HighPart = lba >> 23;
        dist.LowPart = lba << 9;

        if( !SetFilePointerEx( fp, dist, NULL, FILE_BEGIN ) )
            log( -1, "'%s', Failed to seek to lba=%lu", name, lba );
    }

    void Read( void *buff, unsigned long len )
    {
        unsigned long out_len;

        if( !ReadFile( fp, buff, len, &out_len, NULL ) || len != out_len )
            log( -1, "'%s', ReadFile failed", name );
    }

    void Write( void *buff, unsigned long len )
    {
        unsigned long out_len;

        if( !WriteFile( fp, buff, len, &out_len, NULL ) || len != out_len )
            log( -1, "'%s', WriteFile failed", name );
    }

    FileAccess()
    {
        fp = NULL;
        name = NULL;
    }

    // LBA 28 limit - 28-bits (could be 1 more, but not worth pushing it)
    const static unsigned long MaxSectors = 0xfffffff; 
#define USAGE_MAXSECTORS "137438 MB (LBA28 limit)"

private:
    HANDLE fp;
    char *name;
};