怎么获取大文件的MD5？

报错原因是啥？看看MD5.HashStreamAsHex(FS)的方法是怎么实现的~

我用的是网上找的MD5的源码，测试了一个2G的文件，应该是没问题：unit MD5;interface
uses Windows;
type
  MD5Count = array[0..1] of DWORD;
  MD5State = array[0..3] of DWORD;
  MD5Block = array[0..15] of DWORD;
  MD5CBits = array[0..7] of byte;
  MD5Digest = array[0..15] of byte;
  MD5Buffer = array[0..63] of byte;
  MD5Context = record
    State: MD5State;
    Count: MD5Count;
    Buffer: MD5Buffer;
  end;
procedure MD5Init(var Context: MD5Context);
procedure MD5Update(var Context: MD5Context; Input: pChar; Length: longword);
procedure MD5Final(var Context: MD5Context; var Digest: MD5Digest);
function MD5String(M: string): MD5Digest;
function MD5File(N: string): MD5Digest;
function MD5Print(D: MD5Digest): string;
function MD5Match(D1, D2: MD5Digest): boolean;
// -----------------------------------------------------------------------------------------------
implementation
// -----------------------------------------------------------------------------------------------
var
  PADDING: MD5Buffer = (
    $80, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00,
    $00, $00, $00, $00, $00, $00, $00, $00
    );function F(x, y, z: DWORD): DWORD;
begin
  Result := (x and y) or ((not x) and z);
end;function G(x, y, z: DWORD): DWORD;
begin
  Result := (x and z) or (y and (not z));
end;function H(x, y, z: DWORD): DWORD;
begin
  Result := x xor y xor z;
end;function I(x, y, z: DWORD): DWORD;
begin
  Result := y xor (x or (not z));
end;procedure rot(var x: DWORD; n: BYTE);
begin
  x := (x shl n) or (x shr (32 - n));
end;procedure FF(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);
begin
  inc(a, F(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;procedure GG(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);
begin
  inc(a, G(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;procedure HH(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);
begin
  inc(a, H(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;procedure II(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD);
begin
  inc(a, I(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;
// -----------------------------------------------------------------------------------------------
// Encode Count bytes at Source into (Count / 4) DWORDs at Targetprocedure Encode(Source, Target: pointer; Count: longword);
var
  S: PByte;
  T: PDWORD;
  I: longword;
begin
  S := Source;
  T := Target;
  for I := 1 to Count div 4 do begin
    T^ := S^;
    inc(S);
    T^ := T^ or (S^ shl 8);
    inc(S);
    T^ := T^ or (S^ shl 16);
    inc(S);
    T^ := T^ or (S^ shl 24);
    inc(S);
    inc(T);
  end;
end;
// Decode Count DWORDs at Source into (Count * 4) Bytes at Targetprocedure Decode(Source, Target: pointer; Count: longword);
var
  S: PDWORD;
  T: PByte;
  I: longword;
begin
  S := Source;
  T := Target;
  for I := 1 to Count do begin
    T^ := S^ and $FF;
    inc(T);
    T^ := (S^ shr 8) and $FF;
    inc(T);
    T^ := (S^ shr 16) and $FF;
    inc(T);
    T^ := (S^ shr 24) and $FF;
    inc(T);
    inc(S);
  end;
end;

// Transform State according to first 64 bytes at Bufferprocedure Transform(Buffer: pointer; var State: MD5State);
var
  a, b, c, d: DWORD;
  Block: MD5Block;
begin
  Encode(Buffer, @Block, 64);
  a := State[0];
  b := State[1];
  c := State[2];
  d := State[3];
  FF(a, b, c, d, Block[0], 7, $D76AA478);
  FF(d, a, b, c, Block[1], 12, $E8C7B756);
  FF(c, d, a, b, Block[2], 17, $242070DB);
  FF(b, c, d, a, Block[3], 22, $C1BDCEEE);
  FF(a, b, c, d, Block[4], 7, $F57C0FAF);
  FF(d, a, b, c, Block[5], 12, $4787C62A);
  FF(c, d, a, b, Block[6], 17, $A8304613);
  FF(b, c, d, a, Block[7], 22, $FD469501);
  FF(a, b, c, d, Block[8], 7, $698098D8);
  FF(d, a, b, c, Block[9], 12, $8B44F7AF);
  FF(c, d, a, b, Block[10], 17, $FFFF5BB1);
  FF(b, c, d, a, Block[11], 22, $895CD7BE);
  FF(a, b, c, d, Block[12], 7, $6B901122);
  FF(d, a, b, c, Block[13], 12, $FD987193);
  FF(c, d, a, b, Block[14], 17, $A679438E);
  FF(b, c, d, a, Block[15], 22, $49B40821);
  GG(a, b, c, d, Block[1], 5, $F61E2562);
  GG(d, a, b, c, Block[6], 9, $C040B340);
  GG(c, d, a, b, Block[11], 14, $265E5A51);
  GG(b, c, d, a, Block[0], 20, $E9B6C7AA);
  GG(a, b, c, d, Block[5], 5, $D62F105D);
  GG(d, a, b, c, Block[10], 9, $2441453);
  GG(c, d, a, b, Block[15], 14, $D8A1E681);
  GG(b, c, d, a, Block[4], 20, $E7D3FBC8);
  GG(a, b, c, d, Block[9], 5, $21E1CDE6);
  GG(d, a, b, c, Block[14], 9, $C33707D6);
  GG(c, d, a, b, Block[3], 14, $F4D50D87);
  GG(b, c, d, a, Block[8], 20, $455A14ED);
  GG(a, b, c, d, Block[13], 5, $A9E3E905);
  GG(d, a, b, c, Block[2], 9, $FCEFA3F8);
  GG(c, d, a, b, Block[7], 14, $676F02D9);
  GG(b, c, d, a, Block[12], 20, $8D2A4C8A);
  HH(a, b, c, d, Block[5], 4, $FFFA3942);
  HH(d, a, b, c, Block[8], 11, $8771F681);
  HH(c, d, a, b, Block[11], 16, $6D9D6122);
  HH(b, c, d, a, Block[14], 23, $FDE5380C);
  HH(a, b, c, d, Block[1], 4, $A4BEEA44);
  HH(d, a, b, c, Block[4], 11, $4BDECFA9);
  HH(c, d, a, b, Block[7], 16, $F6BB4B60);
  HH(b, c, d, a, Block[10], 23, $BEBFBC70);
  HH(a, b, c, d, Block[13], 4, $289B7EC6);
  HH(d, a, b, c, Block[0], 11, $EAA127FA);
  HH(c, d, a, b, Block[3], 16, $D4EF3085);
  HH(b, c, d, a, Block[6], 23, $4881D05);
  HH(a, b, c, d, Block[9], 4, $D9D4D039);
  HH(d, a, b, c, Block[12], 11, $E6DB99E5);
  HH(c, d, a, b, Block[15], 16, $1FA27CF8);
  HH(b, c, d, a, Block[2], 23, $C4AC5665);
  II(a, b, c, d, Block[0], 6, $F4292244);
  II(d, a, b, c, Block[7], 10, $432AFF97);
  II(c, d, a, b, Block[14], 15, $AB9423A7);
  II(b, c, d, a, Block[5], 21, $FC93A039);
  II(a, b, c, d, Block[12], 6, $655B59C3);
  II(d, a, b, c, Block[3], 10, $8F0CCC92);
  II(c, d, a, b, Block[10], 15, $FFEFF47D);
  II(b, c, d, a, Block[1], 21, $85845DD1);
  II(a, b, c, d, Block[8], 6, $6FA87E4F);
  II(d, a, b, c, Block[15], 10, $FE2CE6E0);
  II(c, d, a, b, Block[6], 15, $A3014314);
  II(b, c, d, a, Block[13], 21, $4E0811A1);
  II(a, b, c, d, Block[4], 6, $F7537E82);
  II(d, a, b, c, Block[11], 10, $BD3AF235);
  II(c, d, a, b, Block[2], 15, $2AD7D2BB);
  II(b, c, d, a, Block[9], 21, $EB86D391);
  inc(State[0], a);
  inc(State[1], b);
  inc(State[2], c);
  inc(State[3], d);
end;
// -----------------------------------------------------------------------------------------------
// Initialize given Contextprocedure MD5Init(var Context: MD5Context);
begin
  with Context do begin
    State[0] := $67452301;
    State[1] := $EFCDAB89;
    State[2] := $98BADCFE;
    State[3] := $10325476;
    Count[0] := 0;
    Count[1] := 0;
    ZeroMemory(@Buffer, SizeOf(MD5Buffer));
  end;
end;
// Update given Context to include Length bytes of Inputprocedure MD5Update(var Context: MD5Context; Input: pChar; Length: longword);
var
  Index: longword;
  PartLen: longword;
  I: longword;
begin
  with Context do begin
    Index := (Count[0] shr 3) and $3F;
    inc(Count[0], Length shl 3);
    if Count[0] < (Length shl 3) then inc(Count[1]);
    inc(Count[1], Length shr 29);
  end;
  PartLen := 64 - Index;
  if Length >= PartLen then begin
    CopyMemory(@Context.Buffer[Index], Input, PartLen);
    Transform(@Context.Buffer, Context.State);
    I := PartLen;
    while I + 63 < Length do begin
      Transform(@Input[I], Context.State);
      inc(I, 64);
    end;
    Index := 0;
  end else I := 0;
  CopyMemory(@Context.Buffer[Index], @Input[I], Length - I);
end;
// Finalize given Context, create Digest and zeroize Contextprocedure MD5Final(var Context: MD5Context; var Digest: MD5Digest);
var
  Bits: MD5CBits;
  Index: longword;
  PadLen: longword;
begin
  Decode(@Context.Count, @Bits, 2);
  Index := (Context.Count[0] shr 3) and $3F;
  if Index < 56 then PadLen := 56 - Index else PadLen := 120 - Index;
  MD5Update(Context, @PADDING, PadLen);
  MD5Update(Context, @Bits, 8);
  Decode(@Context.State, @Digest, 4);
  ZeroMemory(@Context, SizeOf(MD5Context));
end;
// -----------------------------------------------------------------------------------------------
// Create digest of given Messagefunction MD5String(M: string): MD5Digest;
var
  Context: MD5Context;
begin
  MD5Init(Context);
  MD5Update(Context, pChar(M), length(M));
  MD5Final(Context, Result);
end;
// Create digest of file with given Namefunction MD5File(N: string): MD5Digest;
var
  FileHandle: THandle;
  MapHandle: THandle;
  ViewPointer: pointer;
  Context: MD5Context;
begin
  MD5Init(Context);
  FileHandle := CreateFile(pChar(N), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE,
    nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or FILE_FLAG_SEQUENTIAL_SCAN, 0);
  if FileHandle <> INVALID_HANDLE_VALUE then try
    MapHandle := CreateFileMapping(FileHandle, nil, PAGE_READONLY, 0, 0, nil);
    if MapHandle <> 0 then try
      ViewPointer := MapViewOfFile(MapHandle, FILE_MAP_READ, 0, 0, 0);
      if ViewPointer <> nil then try
        MD5Update(Context, ViewPointer, GetFileSize(FileHandle, nil));
      finally
        UnmapViewOfFile(ViewPointer);
      end;
    finally
      CloseHandle(MapHandle);
    end;
  finally
    CloseHandle(FileHandle);
  end;
  MD5Final(Context, Result);
end;
// Create hex representation of given Digestfunction MD5Print(D: MD5Digest): string;
var
  I: byte;
const
  Digits: array[0..15] of char =
  ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f');
begin
  Result := '';
  for I := 0 to 15 do Result := Result + Digits[(D[I] shr 4) and $0F] + Digits[D[I] and $0F];
end;
// -----------------------------------------------------------------------------------------------
// Compare two Digestsfunction MD5Match(D1, D2: MD5Digest): boolean;
var
  I: byte;
begin
  I := 0;
  Result := TRUE;
  while Result and (I < 16) do begin
    Result := D1[I] = D2[I];
    inc(I);
  end;
end;
end.

这个单元我测试了，找了一个2G的文件，MD5瞬间就出来了，不用等的（正常情况下应该有计算时间）
结果也不对哦

确实有问题，刚才调试了下MapViewOfFile返回Nil。应该是文件映射出问题了。

unit unit1;interfaceuses
  Windows, SysUtils;const
  MD5BlockSize  = 2*1024*1024;type
  TMD5Digest  = record
    Digest  : array[0..3]of LongWord;
    function ToString: string;
    function CompareWith(const MD5Dig: TMD5Digest): Integer;
    function EqualsTo(const MD5Dig: TMD5Digest): Boolean; inline;
  end;
  PMD5Digest  = ^TMD5Digest;  TMD5Context = record
    Internals : array[0..21]of LongWord;
    MD5Digest : TMD5Digest;
    procedure Initialize; stdcall;
    procedure Update(const Buffer; Count: LongWord); stdcall;
    procedure FinalDigest; stdcall;
    class function MD5(const Buffer; Size: LongWord): TMD5Digest; static;
    class function MD5HashFile(const FileName: string;
      var MD5Dig: TMD5Digest): Boolean; static;
    constructor Create(const Buffer; Size: LongWord);
  end;implementation{ TMD5Digest }function TMD5Digest.CompareWith(const MD5Dig: TMD5Digest): Integer;
var
  i: Integer;
begin
  for i:=0 to 3 do
  begin
    Result  := Digest[i] - MD5Dig.Digest[i];
    if(Result<>0)then Exit;
  end;
end;function TMD5Digest.EqualsTo(const MD5Dig: TMD5Digest): Boolean;
begin
  Result  := ( PInt64(@Digest[0])^=PInt64(@MD5Dig.Digest[0])^)and
              (PInt64(@Digest[2])^=PInt64(@MD5Dig.Digest[2])^);
end;function TMD5Digest.ToString: string;
const HexChars  : array[0..15]of Char = '0123456789ABCDEF';
type  T16Bytes  = array[0..15]of Byte;
var
  i : Integer;
  pSrc  : ^T16Bytes;
  pDst  : PChar;
begin
  SetLength(Result, 32);
  pDst  := Pointer(Result);
  pSrc  := @Digest;
  for i:=0 to 15 do
  begin
    pDst[i*2+0] := HexChars[pSrc[i] div 16];
    pDst[i*2+1] := HexChars[pSrc[i] and $f];
  end;
end;{ TMD5Context }const
  libName = 'AdvApi32.dll';
  lib_md5Init = 'MD5Init';
  lib_md5Final  = 'MD5Final';
  lib_md5Update = 'MD5Update';  function GetFileSizeEx(hFile: THandle; out lpFileSize): LongBool; stdcall;
     external kernel32 name 'GetFileSizeEx';constructor TMD5Context.Create(const Buffer; Size: LongWord);
begin
  Initialize;
  Update(Buffer, Size);
end;procedure TMD5Context.FinalDigest; external libName name lib_md5Final;procedure TMD5Context.Initialize; external libName name lib_md5Init;class function TMD5Context.MD5(const Buffer; Size: LongWord): TMD5Digest;
var
  ctx : TMD5Context;
begin
  ctx.Initialize;
  ctx.Update(Buffer, Size);
  ctx.FinalDigest;
  Result  := ctx.MD5Digest;
end;class function TMD5Context.MD5HashFile(const FileName: string;
  var MD5Dig: TMD5Digest): Boolean;
var
  hFile, hMap: THandle;
  pAddr : Pointer;
  nSize : Cardinal;
  nLeft : Int64;
  md5ctx  : TMD5Context;
  nFileSize, nOffset: record
  case Byte of
    0 : ( FullInt: Int64 );
    1 : ( dw32Lo, dw32Hi: DWORD );
  end;
begin
  hFile := CreateFile(
      Pointer(FileName),
      GENERIC_READ,
      FILE_SHARE_READ,
      nil,
      OPEN_EXISTING,
      FILE_ATTRIBUTE_NORMAL,
      0);
  if(hFile=INVALID_HANDLE_VALUE)then
    Exit(False);  try
    if not(GetFileSizeEx(hFile, nFileSize)) then
      Exit(False);
    hMap  := CreateFileMapping(hFile, nil, PAGE_READONLY, 0, 0, nil);
    if(hMap=0)then
      Exit(False);
    nOffset.FullInt := 0;
    try
      md5ctx.Initialize;
      repeat
        nLeft := nFileSize.FullInt - nOffset.FullInt;
        if(nLeft<MD5BlockSize)then
        begin
          nSize := nLeft;
          if(nSize=0)then
            Break;
        end else
          nSize := MD5BlockSize;        pAddr := MapViewOfFile(hMap, FILE_MAP_READ, nOffset.dw32Hi, nOffset.dw32Lo, nSize);
        md5ctx.Update(pAddr^, nSize);
        UnmapViewOfFile(pAddr);
        Inc(nOffset.FullInt, nSize);
      until False;
    finally
      CloseHandle(hMap);
    end;
  finally
    CloseHandle(hFile);
  end;
  md5ctx.FinalDigest;
  MD5Dig  := md5ctx.MD5Digest;
  Result  := True;
end;procedure TMD5Context.Update(const Buffer; Count: LongWord);
  external libName name lib_md5Update;end.

调试易

怎么获取大文件的MD5？

解决方案 »