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JetReadFileInstance

関数
指定インスタンスのバックアップ用ファイルからデータを読み取る。
DLLESENT.dll呼出規約winapi

シグネチャ

// ESENT.dll
#include <windows.h>

INT JetReadFileInstance(
    JET_INSTANCE instance,
    JET_HANDLE hfFile,
    void* pv,
    DWORD cb,
    DWORD* pcbActual   // optional
);

パラメーター

名前方向説明
instanceJET_INSTANCEin対象のインスタンスを識別するJET_INSTANCEハンドル。
hfFileJET_HANDLEinJetOpenFileInstanceで開いたファイルを識別するJET_HANDLE。
pvvoid*out読み取ったデータを受け取る出力バッファポインタ。
cbDWORDin読み取りを要求する最大バイト数を指定する値。
pcbActualDWORD*outoptional実際に読み取られたバイト数を受け取る出力ポインタ。0で終端を示す。

戻り値の型: INT

各言語での呼び出し定義

// ESENT.dll
#include <windows.h>

INT JetReadFileInstance(
    JET_INSTANCE instance,
    JET_HANDLE hfFile,
    void* pv,
    DWORD cb,
    DWORD* pcbActual   // optional
);
[DllImport("ESENT.dll", ExactSpelling = true)]
static extern int JetReadFileInstance(
    UIntPtr instance,   // JET_INSTANCE
    UIntPtr hfFile,   // JET_HANDLE
    IntPtr pv,   // void* out
    uint cb,   // DWORD
    IntPtr pcbActual   // DWORD* optional, out
);
<DllImport("ESENT.dll", ExactSpelling:=True)>
Public Shared Function JetReadFileInstance(
    instance As UIntPtr,   ' JET_INSTANCE
    hfFile As UIntPtr,   ' JET_HANDLE
    pv As IntPtr,   ' void* out
    cb As UInteger,   ' DWORD
    pcbActual As IntPtr   ' DWORD* optional, out
) As Integer
End Function
' instance : JET_INSTANCE
' hfFile : JET_HANDLE
' pv : void* out
' cb : DWORD
' pcbActual : DWORD* optional, out
Declare PtrSafe Function JetReadFileInstance Lib "esent" ( _
    ByVal instance As LongPtr, _
    ByVal hfFile As LongPtr, _
    ByVal pv As LongPtr, _
    ByVal cb As Long, _
    ByVal pcbActual As LongPtr) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。
import ctypes
from ctypes import wintypes

JetReadFileInstance = ctypes.windll.esent.JetReadFileInstance
JetReadFileInstance.restype = ctypes.c_int
JetReadFileInstance.argtypes = [
    ctypes.c_size_t,  # instance : JET_INSTANCE
    ctypes.c_size_t,  # hfFile : JET_HANDLE
    ctypes.POINTER(None),  # pv : void* out
    wintypes.DWORD,  # cb : DWORD
    ctypes.POINTER(wintypes.DWORD),  # pcbActual : DWORD* optional, out
]
require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ESENT.dll')
JetReadFileInstance = Fiddle::Function.new(
  lib['JetReadFileInstance'],
  [
    Fiddle::TYPE_UINTPTR_T,  # instance : JET_INSTANCE
    Fiddle::TYPE_UINTPTR_T,  # hfFile : JET_HANDLE
    Fiddle::TYPE_VOIDP,  # pv : void* out
    -Fiddle::TYPE_INT,  # cb : DWORD
    Fiddle::TYPE_VOIDP,  # pcbActual : DWORD* optional, out
  ],
  Fiddle::TYPE_INT)
#[link(name = "esent")]
extern "system" {
    fn JetReadFileInstance(
        instance: usize,  // JET_INSTANCE
        hfFile: usize,  // JET_HANDLE
        pv: *mut (),  // void* out
        cb: u32,  // DWORD
        pcbActual: *mut u32  // DWORD* optional, out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.
$sig = @"
[DllImport("ESENT.dll")]
public static extern int JetReadFileInstance(UIntPtr instance, UIntPtr hfFile, IntPtr pv, uint cb, IntPtr pcbActual);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ESENT_JetReadFileInstance' -Namespace Win32 -PassThru
# $api::JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
#uselib "ESENT.dll"
#func global JetReadFileInstance "JetReadFileInstance" sptr, sptr, sptr, sptr, sptr
; JetReadFileInstance instance, hfFile, pv, cb, varptr(pcbActual)   ; 戻り値は stat
; instance : JET_INSTANCE -> "sptr"
; hfFile : JET_HANDLE -> "sptr"
; pv : void* out -> "sptr"
; cb : DWORD -> "sptr"
; pcbActual : DWORD* optional, out -> "sptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。
出力引数:
#uselib "ESENT.dll"
#cfunc global JetReadFileInstance "JetReadFileInstance" sptr, sptr, sptr, int, var
; res = JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
; instance : JET_INSTANCE -> "sptr"
; hfFile : JET_HANDLE -> "sptr"
; pv : void* out -> "sptr"
; cb : DWORD -> "int"
; pcbActual : DWORD* optional, out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。
出力引数:
; INT JetReadFileInstance(JET_INSTANCE instance, JET_HANDLE hfFile, void* pv, DWORD cb, DWORD* pcbActual)
#uselib "ESENT.dll"
#cfunc global JetReadFileInstance "JetReadFileInstance" intptr, intptr, intptr, int, var
; res = JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
; instance : JET_INSTANCE -> "intptr"
; hfFile : JET_HANDLE -> "intptr"
; pv : void* out -> "intptr"
; cb : DWORD -> "int"
; pcbActual : DWORD* optional, out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。
import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	esent = windows.NewLazySystemDLL("ESENT.dll")
	procJetReadFileInstance = esent.NewProc("JetReadFileInstance")
)

// instance (JET_INSTANCE), hfFile (JET_HANDLE), pv (void* out), cb (DWORD), pcbActual (DWORD* optional, out)
r1, _, err := procJetReadFileInstance.Call(
	uintptr(instance),
	uintptr(hfFile),
	uintptr(pv),
	uintptr(cb),
	uintptr(pcbActual),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT
function JetReadFileInstance(
  instance: NativeUInt;   // JET_INSTANCE
  hfFile: NativeUInt;   // JET_HANDLE
  pv: Pointer;   // void* out
  cb: DWORD;   // DWORD
  pcbActual: Pointer   // DWORD* optional, out
): Integer; stdcall;
  external 'ESENT.dll' name 'JetReadFileInstance';
result := DllCall("ESENT\JetReadFileInstance"
    , "UPtr", instance   ; JET_INSTANCE
    , "UPtr", hfFile   ; JET_HANDLE
    , "Ptr", pv   ; void* out
    , "UInt", cb   ; DWORD
    , "Ptr", pcbActual   ; DWORD* optional, out
    , "Int")   ; return: INT
●JetReadFileInstance(instance, hfFile, pv, cb, pcbActual) = DLL("ESENT.dll", "int JetReadFileInstance(int, int, void*, dword, void*)")
# 呼び出し: JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
# instance : JET_INSTANCE -> "int"
# hfFile : JET_HANDLE -> "int"
# pv : void* out -> "void*"
# cb : DWORD -> "dword"
# pcbActual : DWORD* optional, out -> "void*"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。
const std = @import("std");

extern "esent" fn JetReadFileInstance(
    instance: usize, // JET_INSTANCE
    hfFile: usize, // JET_HANDLE
    pv: ?*anyopaque, // void* out
    cb: u32, // DWORD
    pcbActual: [*c]u32 // DWORD* optional, out
) callconv(std.os.windows.WINAPI) i32;
proc JetReadFileInstance(
    instance: uint,  # JET_INSTANCE
    hfFile: uint,  # JET_HANDLE
    pv: pointer,  # void* out
    cb: uint32,  # DWORD
    pcbActual: ptr uint32  # DWORD* optional, out
): int32 {.importc: "JetReadFileInstance", stdcall, dynlib: "ESENT.dll".}
pragma(lib, "esent");
extern(Windows)
int JetReadFileInstance(
    size_t instance,   // JET_INSTANCE
    size_t hfFile,   // JET_HANDLE
    void* pv,   // void* out
    uint cb,   // DWORD
    uint* pcbActual   // DWORD* optional, out
);
ccall((:JetReadFileInstance, "ESENT.dll"), stdcall, Int32,
      (Csize_t, Csize_t, Ptr{Cvoid}, UInt32, Ptr{UInt32}),
      instance, hfFile, pv, cb, pcbActual)
# instance : JET_INSTANCE -> Csize_t
# hfFile : JET_HANDLE -> Csize_t
# pv : void* out -> Ptr{Cvoid}
# cb : DWORD -> UInt32
# pcbActual : DWORD* optional, out -> Ptr{UInt32}
# stdcall は 32bit のみ意味を持つ(x64 では無視)。
local ffi = require("ffi")
ffi.cdef[[
int32_t JetReadFileInstance(
    uintptr_t instance,
    uintptr_t hfFile,
    void* pv,
    uint32_t cb,
    uint32_t* pcbActual);
]]
local esent = ffi.load("esent")
-- esent.JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
-- instance : JET_INSTANCE
-- hfFile : JET_HANDLE
-- pv : void* out
-- cb : DWORD
-- pcbActual : DWORD* optional, out
-- 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。
const koffi = require('koffi');
const lib = koffi.load('ESENT.dll');
const JetReadFileInstance = lib.func('__stdcall', 'JetReadFileInstance', 'int32_t', ['uintptr_t', 'uintptr_t', 'void *', 'uint32_t', 'uint32_t *']);
// JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
// instance : JET_INSTANCE -> 'uintptr_t'
// hfFile : JET_HANDLE -> 'uintptr_t'
// pv : void* out -> 'void *'
// cb : DWORD -> 'uint32_t'
// pcbActual : DWORD* optional, out -> 'uint32_t *'
// 出力ポインタは koffi.out(...) で包む。構造体は koffi.struct で定義。
const lib = Deno.dlopen("ESENT.dll", {
  JetReadFileInstance: { parameters: ["usize", "usize", "pointer", "u32", "pointer"], result: "i32" },
});
// lib.symbols.JetReadFileInstance(instance, hfFile, pv, cb, pcbActual)
// instance : JET_INSTANCE -> "usize"
// hfFile : JET_HANDLE -> "usize"
// pv : void* out -> "pointer"
// cb : DWORD -> "u32"
// pcbActual : DWORD* optional, out -> "pointer"
// 文字列引数は "buffer"(NUL 終端のバイト列を Uint8Array で渡す)。
// 値渡し構造体は { struct: [ ...field types... ] } を使用。
<?php
$ffi = FFI::cdef(<<<C
int32_t JetReadFileInstance(
    size_t instance,
    size_t hfFile,
    void* pv,
    uint32_t cb,
    uint32_t* pcbActual);
C, "ESENT.dll");
// $ffi->JetReadFileInstance(instance, hfFile, pv, cb, pcbActual);
// instance : JET_INSTANCE
// hfFile : JET_HANDLE
// pv : void* out
// cb : DWORD
// pcbActual : DWORD* optional, out
// 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。
// WINAPI(stdcall): x64 では呼出規約が統一されるため問題なし。x86 では __stdcall 対応のラッパが必要な場合あり。
import com.sun.jna.*;
import com.sun.jna.ptr.*;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;

public interface Esent extends StdCallLibrary {
    Esent INSTANCE = Native.load("esent", Esent.class);
    int JetReadFileInstance(
        long instance,   // JET_INSTANCE
        long hfFile,   // JET_HANDLE
        Pointer pv,   // void* out
        int cb,   // DWORD
        IntByReference pcbActual   // DWORD* optional, out
    );
}
@[Link("esent")]
lib LibESENT
  fun JetReadFileInstance = JetReadFileInstance(
    instance : LibC::SizeT,   # JET_INSTANCE
    hfFile : LibC::SizeT,   # JET_HANDLE
    pv : Void*,   # void* out
    cb : UInt32,   # DWORD
    pcbActual : UInt32*   # DWORD* optional, out
  ) : Int32
end
# 構造体/GUID/enum は lib 内に対応する型定義が必要。
# 呼出規約: x64 は規約統一のため OK。x86(32bit)は WINAPI=stdcall だが Crystal の fun に stdcall 付与構文がなく非対応。
import 'dart:ffi';
import 'package:ffi/ffi.dart';

typedef JetReadFileInstanceNative = Int32 Function(UintPtr, UintPtr, Pointer<Void>, Uint32, Pointer<Uint32>);
typedef JetReadFileInstanceDart = int Function(int, int, Pointer<Void>, int, Pointer<Uint32>);
final JetReadFileInstance = DynamicLibrary.open('ESENT.dll')
    .lookupFunction<JetReadFileInstanceNative, JetReadFileInstanceDart>('JetReadFileInstance');
// instance : JET_INSTANCE -> UintPtr
// hfFile : JET_HANDLE -> UintPtr
// pv : void* out -> Pointer<Void>
// cb : DWORD -> Uint32
// pcbActual : DWORD* optional, out -> Pointer<Uint32>
// 文字列は package:ffi の "...".toNativeUtf16()/toNativeUtf8() で変換。
{$mode objfpc}{$H+}
function JetReadFileInstance(
  instance: NativeUInt;   // JET_INSTANCE
  hfFile: NativeUInt;   // JET_HANDLE
  pv: Pointer;   // void* out
  cb: DWORD;   // DWORD
  pcbActual: Pointer   // DWORD* optional, out
): Integer; stdcall;
  external 'ESENT.dll' name 'JetReadFileInstance';
import Foreign
import Foreign.C.Types
import Foreign.C.String

foreign import stdcall safe "JetReadFileInstance"
  c_JetReadFileInstance :: CUIntPtr -> CUIntPtr -> Ptr () -> Word32 -> Ptr Word32 -> IO Int32
-- instance : JET_INSTANCE -> CUIntPtr
-- hfFile : JET_HANDLE -> CUIntPtr
-- pv : void* out -> Ptr ()
-- cb : DWORD -> Word32
-- pcbActual : DWORD* optional, out -> Ptr Word32
-- 要 GHC(Windows)。stdcall は x64 では ccall として扱われる。ブロックする API は safe 呼び出し推奨。
open Ctypes
open Foreign

let jetreadfileinstance =
  foreign "JetReadFileInstance"
    (size_t @-> size_t @-> (ptr void) @-> uint32_t @-> (ptr uint32_t) @-> returning int32_t)
(* instance : JET_INSTANCE -> size_t *)
(* hfFile : JET_HANDLE -> size_t *)
(* pv : void* out -> (ptr void) *)
(* cb : DWORD -> uint32_t *)
(* pcbActual : DWORD* optional, out -> (ptr uint32_t) *)
(* foreign は cdecl 前提。x64 Windows では WINAPI と一致。構造体は ctypes structure を定義のこと。 *)
(cffi:define-foreign-library esent (t "ESENT.dll"))
(cffi:use-foreign-library esent)

(cffi:defcfun ("JetReadFileInstance" jet-read-file-instance :convention :stdcall) :int32
  (instance :uint64)   ; JET_INSTANCE
  (hf-file :uint64)   ; JET_HANDLE
  (pv :pointer)   ; void* out
  (cb :uint32)   ; DWORD
  (pcb-actual :pointer))   ; DWORD* optional, out
; isize/usize(INT_PTR/SIZE_T)は x64 前提で :int64/:uint64。x86 では :int32/:uint32。
use Win32::API;
my $JetReadFileInstance = Win32::API::More->new('ESENT',
    'int JetReadFileInstance(WPARAM instance, WPARAM hfFile, LPVOID pv, DWORD cb, LPVOID pcbActual)');
# my $ret = $JetReadFileInstance->Call($instance, $hfFile, $pv, $cb, $pcbActual);
# instance : JET_INSTANCE -> WPARAM
# hfFile : JET_HANDLE -> WPARAM
# pv : void* out -> LPVOID
# cb : DWORD -> DWORD
# pcbActual : DWORD* optional, out -> LPVOID
# 値渡し構造体は pack() した文字列、または Win32::API::Struct を使用。