压缩和解压函数的问题

Question

var
  filename:string;
  bt:TBytes;
begin
filename:='丰碑';
SetLength(bt,12); //'丰碑'压缩后的TBytes
bt[0]:=120;
bt[1]:=1;
bt[2]:=51;
bt[3]:=240;
bt[4]:=155;
bt[5]:=88;
bt[6]:=1;
bt[7]:=0;
bt[8]:=3;
bt[9]:=72;
bt[10]:=1;
bt[11]:=136;
//bt:=ZCompressStr(filename, zcFastest); //压缩
ShowMessage(ZDecompressStr(bt)); //解压
end;这里都是能够正常压缩和解压的
但是我真正需要用的一些TBytes，是已经压缩过的，需要直接解压，一使用ZDecompressStr函数就报错：data error
数据损坏或者数据不完整！
这个要怎么办？？

Answer 1

bt:=ZCompressStr(filename, zcFastest); //压缩
这个返回出来的bt就是12个字节的

Answer 2

unit uZlibHelper;interface
uses
  zlib, Classes;procedure PackStream(const Src:TStream; Dst:TStream; CompressionLevel: TCompressionLevel = clFastest); inline;
function ZlibPackString(const SrcString: AnsiString; CompressionLevel: TCompressionLevel = clFastest): AnsiString; inline;
function ZlibPackBuffer(const SrcData: PAnsiChar; SrcDataLen: LongWord; CompressionLevel: TCompressionLevel = clFastest): AnsiString; inline;
procedure UnpackStream(const Src:TStream; Dst:TStream); inline;
function ZlibUnpackString(const SrcString: AnsiString): AnsiString; inline;
implementation
//将Src使用Zlib压缩后存入Dst当中
procedure PackStream(const Src:TStream; Dst:TStream; CompressionLevel: TCompressionLevel); inline;
var
  CompStream: TCompressionStream;
begin
  //增加“断言”以防止输入参数有误
  Assert(Src <> Nil);
  Assert(Dst <> Nil);  CompStream := TCompressionStream.Create(CompressionLevel,Dst);
  try
    //将源数据的偏移转到首部
    Src.Seek(0,soFromBeginning);
    //使用CopyFrom将源数据输入到压缩流，以实现压缩
    CompStream.CopyFrom(Src,0);
  finally
    CompStream.Free;
  end;
end;function ZlibPackString(const SrcString: AnsiString; CompressionLevel: TCompressionLevel): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcString[1], Length(SrcString));
      PackStream(Src, Dst, CompressionLevel);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;function ZlibPackBuffer(const SrcData: PAnsiChar; SrcDataLen: LongWord; CompressionLevel: TCompressionLevel): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcData^, SrcDataLen);
      PackStream(Src, Dst, CompressionLevel);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;//将以zlib压缩的Src解压缩后存入Dst当中 
procedure UnpackStream(const Src:TStream; Dst:TStream); inline;
var
  DecompStream: TDecompressionStream;
  NewSize: Int64;var
  N: Longint;
  Buffer: array[0..4095] of Byte;
begin
  //增加“断言”以防止输入参数有误
  Assert(Src <> Nil);
  Assert(Dst <> Nil);  DecompStream := TDecompressionStream.Create(Src);
  try
    //NewSize := Src.Size;
    //将源数据的偏移转到首部
    NewSize := 0;
    Dst.Seek(0, soFromBeginning);
    DecompStream.Seek(0,soFromBeginning);
    repeat
      N := DecompStream.Read(Buffer[0],4096);
      Dst.WriteBuffer(Buffer,N);
      NewSize := NewSize + N;
    until N <> 4096;
  finally
    DecompStream.Free;
  end;
end;function ZlibUnpackString(const SrcString: AnsiString): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcString[1], Length(SrcString));
      UnpackStream(Src, Dst);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;
end.

Answer 3

加入Unicode支持
unit uZlibHelper;interface
uses
  zlib125, Classes;procedure PackStream(const Src:TStream; Dst:TStream; CompressionLevel: TCompressionLevel = clFastest); inline;
function ZlibPackString(const SrcString: AnsiString; CompressionLevel: TCompressionLevel = clFastest): AnsiString; overload; inline;
function ZlibPackString(const SrcString: WideString; CompressionLevel: TCompressionLevel = clFastest): WideString; overload; inline;
function ZlibPackBuffer(const SrcData: PAnsiChar; SrcDataLen: LongWord; CompressionLevel: TCompressionLevel = clFastest): AnsiString; inline;
procedure UnpackStream(const Src:TStream; Dst:TStream); inline;
function ZlibUnpackString(const SrcString: AnsiString): AnsiString; overload; inline;
function ZlibUnpackString(const SrcString: WideString): WideString; overload; inline;
implementation
//将Src使用Zlib压缩后存入Dst当中
procedure PackStream(const Src:TStream; Dst:TStream; CompressionLevel: TCompressionLevel); inline;
var
  CompStream: TCompressionStream;
begin
  //增加“断言”以防止输入参数有误
  Assert(Src <> Nil);
  Assert(Dst <> Nil);  CompStream := TCompressionStream.Create(CompressionLevel,Dst);
  try
    //将源数据的偏移转到首部
    Src.Seek(0,soFromBeginning);
    //使用CopyFrom将源数据输入到压缩流，以实现压缩
    CompStream.CopyFrom(Src,0);
  finally
    CompStream.Free;
  end;
end;function ZlibPackString(const SrcString: AnsiString; CompressionLevel: TCompressionLevel): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcString[1], Length(SrcString));
      PackStream(Src, Dst, CompressionLevel);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;function ZlibPackString(const SrcString: WideString; CompressionLevel: TCompressionLevel): WideString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(Pointer(SrcString)^, Length(SrcString)* sizeof(WideChar));
      PackStream(Src, Dst, CompressionLevel);
      SetString(Result, PWideChar(Dst.Memory), (Dst.Size + sizeof(WideChar) - 1) div Sizeof(WideChar));
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;function ZlibPackBuffer(const SrcData: PAnsiChar; SrcDataLen: LongWord; CompressionLevel: TCompressionLevel): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcData^, SrcDataLen);
      PackStream(Src, Dst, CompressionLevel);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;//将以zlib压缩的Src解压缩后存入Dst当中 
procedure UnpackStream(const Src:TStream; Dst:TStream); inline;
var
  DecompStream: TDecompressionStream;
  NewSize: Int64;var
  N: Longint;
  Buffer: array[0..4095] of Byte;
begin
  //增加“断言”以防止输入参数有误
  Assert(Src <> Nil);
  Assert(Dst <> Nil);  DecompStream := TDecompressionStream.Create(Src);
  try
    //NewSize := Src.Size;
    //将源数据的偏移转到首部
    NewSize := 0;
    Dst.Seek(0, soFromBeginning);
    DecompStream.Seek(0,soFromBeginning);
    repeat
      N := DecompStream.Read(Buffer[0],4096);
      Dst.WriteBuffer(Buffer,N);
      NewSize := NewSize + N;
    until N <> 4096;
  finally
    DecompStream.Free;
  end;
end;function ZlibUnpackString(const SrcString: AnsiString): AnsiString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(SrcString[1], Length(SrcString));
      UnpackStream(Src, Dst);
      SetString(Result, PAnsiChar(Dst.Memory), Dst.Size);
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;function ZlibUnpackString(const SrcString: WideString): WideString; inline;
var
  Src:TMemoryStream;
  Dst:TMemoryStream;
begin  Src:=TMemoryStream.Create;
  try
    Dst:=TMemoryStream.Create;
    try
      Src.WriteBuffer(Pointer(SrcString)^, Length(SrcString)*sizeof(WideChar));
      UnpackStream(Src, Dst);
      SetString(Result, PWideChar(Dst.Memory), (Dst.Size + sizeof(WideChar) - 1) div sizeof(WideChar));
    finally
      Dst.Free;
    end;
  finally
    Src.Free;
  end;
end;
end.

Answer 4

对于Unicode支持的时候有可能会因为被解压的源压缩数据比实际的多（实际压缩后得到的是单数字节数），此时就需要对Zlib.pas单元解压过程进行调整
function TDecompressionStream.Read(var Buffer; Count: Longint): Longint;
var
  current,remain: LongInt;
begin
  FZRec.next_out := @Buffer;
  FZRec.avail_out := Count;
  if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
  remain := 0;
  while (FZRec.avail_out > 0) do
  begin
    current := FZRec.avail_in;
    if FZRec.avail_in = remain then
    begin
      FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer));
      if FZRec.avail_in = remain then
      begin
        Result := Count - FZRec.avail_out;
        Exit;
      end;
      FZRec.next_in := FBuffer;
      FStrmPos := FStrm.Position;
      Progress(Self);
    end;
    CCheck(inflate(FZRec, 0));    if current = FZRec.avail_in then remain := current;
  end;
  Result := Count;
end;

Answer 5

unsigned 
(僵哥（自然界因不公平生生不息）) 
太感动了，谢谢分享，我整理学习中

Answer 6

其实里面有一个BUG。
自己找吧