pngzlib1.pas

查看html文件的控件

{Version 9.4}
{***************************************************************}
{*                     PNGZLIB1.PAS                            *}
{*                                                             *}
{*                ZLIB Compression Library                     *}
{*            Jean-loup Gailly and Mark Adler                  *}
{*                 http://www.zlib.org/                        *}
{*                                                             *}
{*             Pascal Interface by Gustavo Daud                *}                           
{*                                                             *}
{***************************************************************}

{$i htmlcons.inc}

unit PNGZLIB1;

interface

uses
  Sysutils, Classes;

const
  ZLIB_VERSION = '1.1.3';

type
  TZAlloc = function (opaque: Pointer; items, size: Integer): Pointer;
  TZFree  = procedure (opaque, block: Pointer);

  TZCompressionLevel = (zcNone, zcFastest, zcDefault, zcMax);

  {** TZStreamRec ***********************************************************}

  TZStreamRec = packed record
    next_in  : PChar;     // next input byte
    avail_in : Longint;   // number of bytes available at next_in
    total_in : Longint;   // total nb of input bytes read so far

    next_out : PChar;     // next output byte should be put here
    avail_out: Longint;   // remaining free space at next_out
    total_out: Longint;   // total nb of bytes output so far

    msg      : PChar;     // last error message, NULL if no error
    state    : Pointer;   // not visible by applications

    zalloc   : TZAlloc;   // used to allocate the internal state
    zfree    : TZFree;    // used to free the internal state
    opaque   : Pointer;   // private data object passed to zalloc and zfree

    data_type: Integer;   // best guess about the data type: ascii or binary
    adler    : Longint;   // adler32 value of the uncompressed data
    reserved : Longint;   // reserved for future use
  end;

  {** TCustomZStream ********************************************************}

  TCustomZStream = class(TStream)
  private
    FStream    : TStream;
    FStreamPos : Integer;
    FOnProgress: TNotifyEvent;

    FZStream   : TZStreamRec;
    FBuffer    : Array [Word] of Char;
  protected
    constructor Create(stream: TStream);

    procedure DoProgress; dynamic;

    property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
  end;

  {** TZCompressionStream ***************************************************}

  TZCompressionStream = class(TCustomZStream)
  private
    function GetCompressionRate: Single;
  public
    constructor Create(dest: TStream; compressionLevel: TZCompressionLevel(* = zcDefault*));
    destructor  Destroy; override;

    function  Read(var buffer; count: Longint): Longint; override;
    function  Write(const buffer; count: Longint): Longint; override;
    function  Seek(offset: Longint; origin: Word): Longint; override;

    property CompressionRate: Single read GetCompressionRate;
    property OnProgress;
  end;

  {** TZDecompressionStream *************************************************}

  TZDecompressionStream = class(TCustomZStream)
  public
    constructor Create(source: TStream);
    destructor  Destroy; override;

    function  Read(var buffer; count: Longint): Longint; override;
    function  Write(const buffer; count: Longint): Longint; override;
    function  Seek(offset: Longint; origin: Word): Longint; override;

    property OnProgress;
  end;

{** zlib public routines ****************************************************}

{*****************************************************************************
*  ZCompress                                                                 *
*                                                                            *
*  pre-conditions                                                            *
*    inBuffer  = pointer to uncompressed data                                *
*    inSize    = size of inBuffer (bytes)                                    *
*    outBuffer = pointer (unallocated)                                       *
*    level     = compression level                                           *
*                                                                            *
*  post-conditions                                                           *
*    outBuffer = pointer to compressed data (allocated)                      *
*    outSize   = size of outBuffer (bytes)                                   *
*****************************************************************************}

procedure ZCompress(const inBuffer: Pointer; inSize: Integer;
  out outBuffer: Pointer; out outSize: Integer;
  level: TZCompressionLevel(* = zcDefault*));

{*****************************************************************************
*  ZDecompress                                                               *
*                                                                            *
*  pre-conditions                                                            *
*    inBuffer    = pointer to compressed data                                *
*    inSize      = size of inBuffer (bytes)                                  *
*    outBuffer   = pointer (unallocated)                                     *
*    outEstimate = estimated size of uncompressed data (bytes)               *
*                                                                            *
*  post-conditions                                                           *
*    outBuffer = pointer to decompressed data (allocated)                    *
*    outSize   = size of outBuffer (bytes)                                   *
*****************************************************************************}

procedure ZDecompress(const inBuffer: Pointer; inSize: Integer;
 out outBuffer: Pointer; out outSize: Integer; outEstimate: Integer(* = 0*));

{** string routines *********************************************************}

function ZCompressStr(const s: String; level: TZCompressionLevel(* = zcDefault*)): String;

function ZDecompressStr(const s: String): String;

type
  EZLibError = class(Exception);

  EZCompressionError = class(EZLibError);
  EZDecompressionError = class(EZLibError);

implementation

{** link zlib code **********************************************************}

{$L obj\deflate.obj}
{$L obj\inflate.obj}
{$L obj\infblock.obj}
{$L obj\inftrees.obj}
{$L obj\infcodes.obj}
{$L obj\infutil.obj}
{$L obj\inffast.obj}
{$L obj\trees.obj}
{$L obj\adler32.obj}

{*****************************************************************************
*  note: do not reorder the above -- doing so will result in external        *
*  functions being undefined                                                 *
*****************************************************************************}

const
  {** flush constants *******************************************************}

  Z_NO_FLUSH      = 0;
  Z_PARTIAL_FLUSH = 1;
  Z_SYNC_FLUSH    = 2;
  Z_FULL_FLUSH    = 3;
  Z_FINISH        = 4;

  {** return codes **********************************************************}

  Z_OK            = 0;
  Z_STREAM_END    = 1;
  Z_NEED_DICT     = 2;
  Z_ERRNO         = (-1);
  Z_STREAM_ERROR  = (-2);
  Z_DATA_ERROR    = (-3);
  Z_MEM_ERROR     = (-4);
  Z_BUF_ERROR     = (-5);
  Z_VERSION_ERROR = (-6);

  {** compression levels ****************************************************}

  Z_NO_COMPRESSION       =   0;
  Z_BEST_SPEED           =   1;
  Z_BEST_COMPRESSION     =   9;
  Z_DEFAULT_COMPRESSION  = (-1);

  {** compression strategies ************************************************}

  Z_FILTERED            = 1;
  Z_HUFFMAN_ONLY        = 2;
  Z_DEFAULT_STRATEGY    = 0;

  {** data types ************************************************************}

  Z_BINARY   = 0;
  Z_ASCII    = 1;
  Z_UNKNOWN  = 2;

  {** compression methods ***************************************************}

  Z_DEFLATED = 8;

  {** return code messages **************************************************}

  _z_errmsg: array[0..9] of PChar = (
    'need dictionary',      // Z_NEED_DICT      (2)
    'stream end',           // Z_STREAM_END     (1)
    '',                     // Z_OK             (0)
    'file error',           // Z_ERRNO          (-1)
    'stream error',         // Z_STREAM_ERROR   (-2)
    'data error',           // Z_DATA_ERROR     (-3)
    'insufficient memory',  // Z_MEM_ERROR      (-4)
    'buffer error',         // Z_BUF_ERROR      (-5)
    'incompatible version', // Z_VERSION_ERROR  (-6)
    ''
  );

  ZLevels: array [TZCompressionLevel] of Shortint = (
    Z_NO_COMPRESSION,
    Z_BEST_SPEED,
    Z_DEFAULT_COMPRESSION,
    Z_BEST_COMPRESSION
  );

  SZInvalid = 'Invalid ZStream operation!';

{** deflate routines ********************************************************}

function deflateInit_(var strm: TZStreamRec; level: Integer; version: PChar;
  recsize: Integer): Integer; external;  

function deflate(var strm: TZStreamRec; flush: Integer): Integer;
  external;

function deflateEnd(var strm: TZStreamRec): Integer; external;

{** inflate routines ********************************************************}

function inflateInit_(var strm: TZStreamRec; version: PChar;
  recsize: Integer): Integer; external;

function inflate(var strm: TZStreamRec; flush: Integer): Integer;
  external;

function inflateEnd(var strm: TZStreamRec): Integer; external;

function inflateReset(var strm: TZStreamRec): Integer; external;

{** zlib function implementations *******************************************}

function zcalloc(opaque: Pointer; items, size: Integer): Pointer;
begin
  GetMem(result,items * size);
end;

procedure zcfree(opaque, block: Pointer);
begin
  FreeMem(block);
end;

{** c function implementations **********************************************}

procedure _memset(p: Pointer; b: Byte; count: Integer); cdecl;
begin
  FillChar(p^,count,b);
end;

procedure _memcpy(dest, source: Pointer; count: Integer); cdecl;
begin
  Move(source^,dest^,count);
end;

{** custom zlib routines ****************************************************}

function DeflateInit(var stream: TZStreamRec; level: Integer): Integer;
begin
  result := DeflateInit_(stream,level,ZLIB_VERSION,SizeOf(TZStreamRec));
end;

// function DeflateInit2(var stream: TZStreamRec; level, method, windowBits,
//   memLevel, strategy: Integer): Integer;
// begin
//   result := DeflateInit2_(stream,level,method,windowBits,memLevel,
//     strategy,ZLIB_VERSION,SizeOf(TZStreamRec));
// end;

function InflateInit(var stream: TZStreamRec): Integer;
begin
  result := InflateInit_(stream,ZLIB_VERSION,SizeOf(TZStreamRec));
end;

// function InflateInit2(var stream: TZStreamRec; windowBits: Integer): Integer;
// begin
//   result := InflateInit2_(stream,windowBits,ZLIB_VERSION,SizeOf(TZStreamRec));
// end;

{****************************************************************************}

function ZCompressCheck(code: Integer): Integer;
begin
  result := code;

  if code < 0 then
  begin
    raise EZCompressionError.Create(_z_errmsg[2 - code]);