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{*******************************************************} |
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{ } |
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{ Borland Delphi Supplemental Components } |
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{ ZLIB Data Compression Interface Unit } |
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{ } |
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{ Copyright (c) 1997,99 Borland Corporation } |
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{ } |
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{*******************************************************} |
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|
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{ Updated for zlib 1.2.x by Cosmin Truta <cosmint@cs.ubbcluj.ro> } |
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|
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unit ZLib; |
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|
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interface |
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|
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uses SysUtils, Classes; |
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|
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type |
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TAlloc = function (AppData: Pointer; Items, Size: Integer): Pointer; cdecl; |
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TFree = procedure (AppData, Block: Pointer); cdecl; |
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|
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// Internal structure. Ignore. |
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TZStreamRec = packed record |
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next_in: PChar; // next input byte |
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avail_in: Integer; // number of bytes available at next_in |
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total_in: Longint; // total nb of input bytes read so far |
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|
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next_out: PChar; // next output byte should be put here |
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avail_out: Integer; // remaining free space at next_out |
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total_out: Longint; // total nb of bytes output so far |
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|
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msg: PChar; // last error message, NULL if no error |
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internal: Pointer; // not visible by applications |
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|
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zalloc: TAlloc; // used to allocate the internal state |
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zfree: TFree; // used to free the internal state |
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AppData: Pointer; // private data object passed to zalloc and zfree |
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|
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data_type: Integer; // best guess about the data type: ascii or binary |
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adler: Longint; // adler32 value of the uncompressed data |
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reserved: Longint; // reserved for future use |
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end; |
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|
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// Abstract ancestor class |
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TCustomZlibStream = class(TStream) |
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private |
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FStrm: TStream; |
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FStrmPos: Integer; |
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FOnProgress: TNotifyEvent; |
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FZRec: TZStreamRec; |
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FBuffer: array [Word] of Char; |
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protected |
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procedure Progress(Sender: TObject); dynamic; |
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property OnProgress: TNotifyEvent read FOnProgress write FOnProgress; |
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constructor Create(Strm: TStream); |
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end; |
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|
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{ TCompressionStream compresses data on the fly as data is written to it, and |
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stores the compressed data to another stream. |
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|
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TCompressionStream is write-only and strictly sequential. Reading from the |
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stream will raise an exception. Using Seek to move the stream pointer |
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will raise an exception. |
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|
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Output data is cached internally, written to the output stream only when |
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the internal output buffer is full. All pending output data is flushed |
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when the stream is destroyed. |
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|
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The Position property returns the number of uncompressed bytes of |
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data that have been written to the stream so far. |
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|
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CompressionRate returns the on-the-fly percentage by which the original |
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data has been compressed: (1 - (CompressedBytes / UncompressedBytes)) * 100 |
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If raw data size = 100 and compressed data size = 25, the CompressionRate |
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is 75% |
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|
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The OnProgress event is called each time the output buffer is filled and |
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written to the output stream. This is useful for updating a progress |
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indicator when you are writing a large chunk of data to the compression |
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stream in a single call.} |
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|
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|
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TCompressionLevel = (clNone, clFastest, clDefault, clMax); |
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|
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TCompressionStream = class(TCustomZlibStream) |
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private |
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function GetCompressionRate: Single; |
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public |
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constructor Create(CompressionLevel: TCompressionLevel; Dest: TStream); |
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destructor Destroy; override; |
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function Read(var Buffer; Count: Longint): Longint; override; |
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function Write(const Buffer; Count: Longint): Longint; override; |
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function Seek(Offset: Longint; Origin: Word): Longint; override; |
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property CompressionRate: Single read GetCompressionRate; |
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property OnProgress; |
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end; |
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|
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{ TDecompressionStream decompresses data on the fly as data is read from it. |
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|
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Compressed data comes from a separate source stream. TDecompressionStream |
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is read-only and unidirectional; you can seek forward in the stream, but not |
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backwards. The special case of setting the stream position to zero is |
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allowed. Seeking forward decompresses data until the requested position in |
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the uncompressed data has been reached. Seeking backwards, seeking relative |
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to the end of the stream, requesting the size of the stream, and writing to |
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the stream will raise an exception. |
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|
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The Position property returns the number of bytes of uncompressed data that |
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have been read from the stream so far. |
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|
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The OnProgress event is called each time the internal input buffer of |
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compressed data is exhausted and the next block is read from the input stream. |
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This is useful for updating a progress indicator when you are reading a |
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large chunk of data from the decompression stream in a single call.} |
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|
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TDecompressionStream = class(TCustomZlibStream) |
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public |
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constructor Create(Source: TStream); |
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destructor Destroy; override; |
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function Read(var Buffer; Count: Longint): Longint; override; |
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function Write(const Buffer; Count: Longint): Longint; override; |
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function Seek(Offset: Longint; Origin: Word): Longint; override; |
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property OnProgress; |
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end; |
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|
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|
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|
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{ CompressBuf compresses data, buffer to buffer, in one call. |
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In: InBuf = ptr to compressed data |
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InBytes = number of bytes in InBuf |
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Out: OutBuf = ptr to newly allocated buffer containing decompressed data |
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OutBytes = number of bytes in OutBuf } |
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procedure CompressBuf(const InBuf: Pointer; InBytes: Integer; |
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out OutBuf: Pointer; out OutBytes: Integer); |
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|
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|
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{ DecompressBuf decompresses data, buffer to buffer, in one call. |
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In: InBuf = ptr to compressed data |
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InBytes = number of bytes in InBuf |
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OutEstimate = zero, or est. size of the decompressed data |
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Out: OutBuf = ptr to newly allocated buffer containing decompressed data |
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OutBytes = number of bytes in OutBuf } |
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procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer; |
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OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer); |
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|
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{ DecompressToUserBuf decompresses data, buffer to buffer, in one call. |
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In: InBuf = ptr to compressed data |
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InBytes = number of bytes in InBuf |
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Out: OutBuf = ptr to user-allocated buffer to contain decompressed data |
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BufSize = number of bytes in OutBuf } |
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procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer; |
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const OutBuf: Pointer; BufSize: Integer); |
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|
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const |
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zlib_version = '1.2.8'; |
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|
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type |
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EZlibError = class(Exception); |
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ECompressionError = class(EZlibError); |
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EDecompressionError = class(EZlibError); |
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|
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implementation |
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|
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uses ZLibConst; |
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|
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const |
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Z_NO_FLUSH = 0; |
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Z_PARTIAL_FLUSH = 1; |
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Z_SYNC_FLUSH = 2; |
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Z_FULL_FLUSH = 3; |
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Z_FINISH = 4; |
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|
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Z_OK = 0; |
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Z_STREAM_END = 1; |
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Z_NEED_DICT = 2; |
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Z_ERRNO = (-1); |
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Z_STREAM_ERROR = (-2); |
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Z_DATA_ERROR = (-3); |
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Z_MEM_ERROR = (-4); |
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Z_BUF_ERROR = (-5); |
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Z_VERSION_ERROR = (-6); |
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|
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Z_NO_COMPRESSION = 0; |
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Z_BEST_SPEED = 1; |
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Z_BEST_COMPRESSION = 9; |
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Z_DEFAULT_COMPRESSION = (-1); |
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|
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Z_FILTERED = 1; |
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Z_HUFFMAN_ONLY = 2; |
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Z_RLE = 3; |
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Z_DEFAULT_STRATEGY = 0; |
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|
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Z_BINARY = 0; |
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Z_ASCII = 1; |
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Z_UNKNOWN = 2; |
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|
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Z_DEFLATED = 8; |
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|
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|
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{$L adler32.obj} |
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{$L compress.obj} |
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{$L crc32.obj} |
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{$L deflate.obj} |
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{$L infback.obj} |
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{$L inffast.obj} |
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{$L inflate.obj} |
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{$L inftrees.obj} |
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{$L trees.obj} |
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{$L uncompr.obj} |
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{$L zutil.obj} |
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|
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procedure adler32; external; |
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procedure compressBound; external; |
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procedure crc32; external; |
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procedure deflateInit2_; external; |
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procedure deflateParams; external; |
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|
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function _malloc(Size: Integer): Pointer; cdecl; |
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begin |
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Result := AllocMem(Size); |
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end; |
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|
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procedure _free(Block: Pointer); cdecl; |
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begin |
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FreeMem(Block); |
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end; |
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|
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procedure _memset(P: Pointer; B: Byte; count: Integer); cdecl; |
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begin |
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FillChar(P^, count, B); |
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end; |
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|
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procedure _memcpy(dest, source: Pointer; count: Integer); cdecl; |
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begin |
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Move(source^, dest^, count); |
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end; |
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|
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|
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|
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// deflate compresses data |
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function deflateInit_(var strm: TZStreamRec; level: Integer; version: PChar; |
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recsize: Integer): Integer; external; |
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function deflate(var strm: TZStreamRec; flush: Integer): Integer; external; |
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function deflateEnd(var strm: TZStreamRec): Integer; external; |
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|
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// inflate decompresses data |
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function inflateInit_(var strm: TZStreamRec; version: PChar; |
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recsize: Integer): Integer; external; |
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function inflate(var strm: TZStreamRec; flush: Integer): Integer; external; |
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function inflateEnd(var strm: TZStreamRec): Integer; external; |
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function inflateReset(var strm: TZStreamRec): Integer; external; |
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|
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|
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function zlibAllocMem(AppData: Pointer; Items, Size: Integer): Pointer; cdecl; |
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begin |
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// GetMem(Result, Items*Size); |
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Result := AllocMem(Items * Size); |
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end; |
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|
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procedure zlibFreeMem(AppData, Block: Pointer); cdecl; |
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begin |
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FreeMem(Block); |
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end; |
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|
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{function zlibCheck(code: Integer): Integer; |
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begin |
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Result := code; |
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if code < 0 then |
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raise EZlibError.Create('error'); //!! |
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end;} |
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|
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function CCheck(code: Integer): Integer; |
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begin |
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Result := code; |
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if code < 0 then |
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raise ECompressionError.Create('error'); //!! |
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end; |
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|
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function DCheck(code: Integer): Integer; |
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begin |
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Result := code; |
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if code < 0 then |
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raise EDecompressionError.Create('error'); //!! |
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end; |
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|
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procedure CompressBuf(const InBuf: Pointer; InBytes: Integer; |
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out OutBuf: Pointer; out OutBytes: Integer); |
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var |
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strm: TZStreamRec; |
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P: Pointer; |
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begin |
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FillChar(strm, sizeof(strm), 0); |
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strm.zalloc := zlibAllocMem; |
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strm.zfree := zlibFreeMem; |
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OutBytes := ((InBytes + (InBytes div 10) + 12) + 255) and not 255; |
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GetMem(OutBuf, OutBytes); |
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try |
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strm.next_in := InBuf; |
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strm.avail_in := InBytes; |
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strm.next_out := OutBuf; |
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strm.avail_out := OutBytes; |
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CCheck(deflateInit_(strm, Z_BEST_COMPRESSION, zlib_version, sizeof(strm))); |
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try |
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while CCheck(deflate(strm, Z_FINISH)) <> Z_STREAM_END do |
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begin |
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P := OutBuf; |
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Inc(OutBytes, 256); |
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ReallocMem(OutBuf, OutBytes); |
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strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P))); |
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strm.avail_out := 256; |
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end; |
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finally |
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CCheck(deflateEnd(strm)); |
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end; |
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ReallocMem(OutBuf, strm.total_out); |
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OutBytes := strm.total_out; |
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except |
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FreeMem(OutBuf); |
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raise |
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end; |
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end; |
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|
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|
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procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer; |
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OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer); |
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var |
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strm: TZStreamRec; |
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P: Pointer; |
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BufInc: Integer; |
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begin |
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FillChar(strm, sizeof(strm), 0); |
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strm.zalloc := zlibAllocMem; |
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strm.zfree := zlibFreeMem; |
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BufInc := (InBytes + 255) and not 255; |
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if OutEstimate = 0 then |
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OutBytes := BufInc |
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else |
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OutBytes := OutEstimate; |
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GetMem(OutBuf, OutBytes); |
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try |
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strm.next_in := InBuf; |
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strm.avail_in := InBytes; |
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strm.next_out := OutBuf; |
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strm.avail_out := OutBytes; |
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DCheck(inflateInit_(strm, zlib_version, sizeof(strm))); |
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try |
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while DCheck(inflate(strm, Z_NO_FLUSH)) <> Z_STREAM_END do |
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begin |
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P := OutBuf; |
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Inc(OutBytes, BufInc); |
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ReallocMem(OutBuf, OutBytes); |
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strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P))); |
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strm.avail_out := BufInc; |
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end; |
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finally |
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DCheck(inflateEnd(strm)); |
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end; |
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ReallocMem(OutBuf, strm.total_out); |
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OutBytes := strm.total_out; |
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except |
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FreeMem(OutBuf); |
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raise |
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end; |
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end; |
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|
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procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer; |
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const OutBuf: Pointer; BufSize: Integer); |
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var |
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strm: TZStreamRec; |
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begin |
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FillChar(strm, sizeof(strm), 0); |
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strm.zalloc := zlibAllocMem; |
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strm.zfree := zlibFreeMem; |
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strm.next_in := InBuf; |
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strm.avail_in := InBytes; |
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strm.next_out := OutBuf; |
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strm.avail_out := BufSize; |
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DCheck(inflateInit_(strm, zlib_version, sizeof(strm))); |
| 379 |
try |
| 380 |
if DCheck(inflate(strm, Z_FINISH)) <> Z_STREAM_END then |
| 381 |
raise EZlibError.CreateRes(@sTargetBufferTooSmall); |
| 382 |
finally |
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DCheck(inflateEnd(strm)); |
| 384 |
end; |
| 385 |
end; |
| 386 |
|
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// TCustomZlibStream |
| 388 |
|
| 389 |
constructor TCustomZLibStream.Create(Strm: TStream); |
| 390 |
begin |
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inherited Create; |
| 392 |
FStrm := Strm; |
| 393 |
FStrmPos := Strm.Position; |
| 394 |
FZRec.zalloc := zlibAllocMem; |
| 395 |
FZRec.zfree := zlibFreeMem; |
| 396 |
end; |
| 397 |
|
| 398 |
procedure TCustomZLibStream.Progress(Sender: TObject); |
| 399 |
begin |
| 400 |
if Assigned(FOnProgress) then FOnProgress(Sender); |
| 401 |
end; |
| 402 |
|
| 403 |
|
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// TCompressionStream |
| 405 |
|
| 406 |
constructor TCompressionStream.Create(CompressionLevel: TCompressionLevel; |
| 407 |
Dest: TStream); |
| 408 |
const |
| 409 |
Levels: array [TCompressionLevel] of ShortInt = |
| 410 |
(Z_NO_COMPRESSION, Z_BEST_SPEED, Z_DEFAULT_COMPRESSION, Z_BEST_COMPRESSION); |
| 411 |
begin |
| 412 |
inherited Create(Dest); |
| 413 |
FZRec.next_out := FBuffer; |
| 414 |
FZRec.avail_out := sizeof(FBuffer); |
| 415 |
CCheck(deflateInit_(FZRec, Levels[CompressionLevel], zlib_version, sizeof(FZRec))); |
| 416 |
end; |
| 417 |
|
| 418 |
destructor TCompressionStream.Destroy; |
| 419 |
begin |
| 420 |
FZRec.next_in := nil; |
| 421 |
FZRec.avail_in := 0; |
| 422 |
try |
| 423 |
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos; |
| 424 |
while (CCheck(deflate(FZRec, Z_FINISH)) <> Z_STREAM_END) |
| 425 |
and (FZRec.avail_out = 0) do |
| 426 |
begin |
| 427 |
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer)); |
| 428 |
FZRec.next_out := FBuffer; |
| 429 |
FZRec.avail_out := sizeof(FBuffer); |
| 430 |
end; |
| 431 |
if FZRec.avail_out < sizeof(FBuffer) then |
| 432 |
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer) - FZRec.avail_out); |
| 433 |
finally |
| 434 |
deflateEnd(FZRec); |
| 435 |
end; |
| 436 |
inherited Destroy; |
| 437 |
end; |
| 438 |
|
| 439 |
function TCompressionStream.Read(var Buffer; Count: Longint): Longint; |
| 440 |
begin |
| 441 |
raise ECompressionError.CreateRes(@sInvalidStreamOp); |
| 442 |
end; |
| 443 |
|
| 444 |
function TCompressionStream.Write(const Buffer; Count: Longint): Longint; |
| 445 |
begin |
| 446 |
FZRec.next_in := @Buffer; |
| 447 |
FZRec.avail_in := Count; |
| 448 |
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos; |
| 449 |
while (FZRec.avail_in > 0) do |
| 450 |
begin |
| 451 |
CCheck(deflate(FZRec, 0)); |
| 452 |
if FZRec.avail_out = 0 then |
| 453 |
begin |
| 454 |
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer)); |
| 455 |
FZRec.next_out := FBuffer; |
| 456 |
FZRec.avail_out := sizeof(FBuffer); |
| 457 |
FStrmPos := FStrm.Position; |
| 458 |
Progress(Self); |
| 459 |
end; |
| 460 |
end; |
| 461 |
Result := Count; |
| 462 |
end; |
| 463 |
|
| 464 |
function TCompressionStream.Seek(Offset: Longint; Origin: Word): Longint; |
| 465 |
begin |
| 466 |
if (Offset = 0) and (Origin = soFromCurrent) then |
| 467 |
Result := FZRec.total_in |
| 468 |
else |
| 469 |
raise ECompressionError.CreateRes(@sInvalidStreamOp); |
| 470 |
end; |
| 471 |
|
| 472 |
function TCompressionStream.GetCompressionRate: Single; |
| 473 |
begin |
| 474 |
if FZRec.total_in = 0 then |
| 475 |
Result := 0 |
| 476 |
else |
| 477 |
Result := (1.0 - (FZRec.total_out / FZRec.total_in)) * 100.0; |
| 478 |
end; |
| 479 |
|
| 480 |
|
| 481 |
// TDecompressionStream |
| 482 |
|
| 483 |
constructor TDecompressionStream.Create(Source: TStream); |
| 484 |
begin |
| 485 |
inherited Create(Source); |
| 486 |
FZRec.next_in := FBuffer; |
| 487 |
FZRec.avail_in := 0; |
| 488 |
DCheck(inflateInit_(FZRec, zlib_version, sizeof(FZRec))); |
| 489 |
end; |
| 490 |
|
| 491 |
destructor TDecompressionStream.Destroy; |
| 492 |
begin |
| 493 |
FStrm.Seek(-FZRec.avail_in, 1); |
| 494 |
inflateEnd(FZRec); |
| 495 |
inherited Destroy; |
| 496 |
end; |
| 497 |
|
| 498 |
function TDecompressionStream.Read(var Buffer; Count: Longint): Longint; |
| 499 |
begin |
| 500 |
FZRec.next_out := @Buffer; |
| 501 |
FZRec.avail_out := Count; |
| 502 |
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos; |
| 503 |
while (FZRec.avail_out > 0) do |
| 504 |
begin |
| 505 |
if FZRec.avail_in = 0 then |
| 506 |
begin |
| 507 |
FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer)); |
| 508 |
if FZRec.avail_in = 0 then |
| 509 |
begin |
| 510 |
Result := Count - FZRec.avail_out; |
| 511 |
Exit; |
| 512 |
end; |
| 513 |
FZRec.next_in := FBuffer; |
| 514 |
FStrmPos := FStrm.Position; |
| 515 |
Progress(Self); |
| 516 |
end; |
| 517 |
CCheck(inflate(FZRec, 0)); |
| 518 |
end; |
| 519 |
Result := Count; |
| 520 |
end; |
| 521 |
|
| 522 |
function TDecompressionStream.Write(const Buffer; Count: Longint): Longint; |
| 523 |
begin |
| 524 |
raise EDecompressionError.CreateRes(@sInvalidStreamOp); |
| 525 |
end; |
| 526 |
|
| 527 |
function TDecompressionStream.Seek(Offset: Longint; Origin: Word): Longint; |
| 528 |
var |
| 529 |
I: Integer; |
| 530 |
Buf: array [0..4095] of Char; |
| 531 |
begin |
| 532 |
if (Offset = 0) and (Origin = soFromBeginning) then |
| 533 |
begin |
| 534 |
DCheck(inflateReset(FZRec)); |
| 535 |
FZRec.next_in := FBuffer; |
| 536 |
FZRec.avail_in := 0; |
| 537 |
FStrm.Position := 0; |
| 538 |
FStrmPos := 0; |
| 539 |
end |
| 540 |
else if ( (Offset >= 0) and (Origin = soFromCurrent)) or |
| 541 |
( ((Offset - FZRec.total_out) > 0) and (Origin = soFromBeginning)) then |
| 542 |
begin |
| 543 |
if Origin = soFromBeginning then Dec(Offset, FZRec.total_out); |
| 544 |
if Offset > 0 then |
| 545 |
begin |
| 546 |
for I := 1 to Offset div sizeof(Buf) do |
| 547 |
ReadBuffer(Buf, sizeof(Buf)); |
| 548 |
ReadBuffer(Buf, Offset mod sizeof(Buf)); |
| 549 |
end; |
| 550 |
end |
| 551 |
else |
| 552 |
raise EDecompressionError.CreateRes(@sInvalidStreamOp); |
| 553 |
Result := FZRec.total_out; |
| 554 |
end; |
| 555 |
|
| 556 |
|
| 557 |
end. |