1------------------------------------------------------------------------------
2--                      ZLib for Ada thick binding.                         --
3--                                                                          --
4--              Copyright (C) 2002-2004 Dmitriy Anisimkov                   --
5--                                                                          --
6--  This library is free software; you can redistribute it and/or modify    --
7--  it under the terms of the GNU General Public License as published by    --
8--  the Free Software Foundation; either version 2 of the License, or (at   --
9--  your option) any later version.                                         --
10--                                                                          --
11--  This library is distributed in the hope that it will be useful, but     --
12--  WITHOUT ANY WARRANTY; without even the implied warranty of              --
13--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       --
14--  General Public License for more details.                                --
15--                                                                          --
16--  You should have received a copy of the GNU General Public License       --
17--  along with this library; if not, write to the Free Software Foundation, --
18--  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.          --
19--                                                                          --
20--  As a special exception, if other files instantiate generics from this   --
21--  unit, or you link this unit with other files to produce an executable,  --
22--  this  unit  does not  by itself cause  the resulting executable to be   --
23--  covered by the GNU General Public License. This exception does not      --
24--  however invalidate any other reasons why the executable file  might be  --
25--  covered by the  GNU Public License.                                     --
26------------------------------------------------------------------------------
27
28--  $Id: zlib.ads,v 1.26 2004/09/06 06:53:19 vagul Exp $
29
30with Ada.Streams;
31
32with Interfaces;
33
34package ZLib is
35
36   ZLib_Error   : exception;
37   Status_Error : exception;
38
39   type Compression_Level is new Integer range -1 .. 9;
40
41   type Flush_Mode is private;
42
43   type Compression_Method is private;
44
45   type Window_Bits_Type is new Integer range 8 .. 15;
46
47   type Memory_Level_Type is new Integer range 1 .. 9;
48
49   type Unsigned_32 is new Interfaces.Unsigned_32;
50
51   type Strategy_Type is private;
52
53   type Header_Type is (None, Auto, Default, GZip);
54   --  Header type usage have a some limitation for inflate.
55   --  See comment for Inflate_Init.
56
57   subtype Count is Ada.Streams.Stream_Element_Count;
58
59   Default_Memory_Level : constant Memory_Level_Type := 8;
60   Default_Window_Bits  : constant Window_Bits_Type  := 15;
61
62   ----------------------------------
63   -- Compression method constants --
64   ----------------------------------
65
66   Deflated : constant Compression_Method;
67   --  Only one method allowed in this ZLib version
68
69   ---------------------------------
70   -- Compression level constants --
71   ---------------------------------
72
73   No_Compression      : constant Compression_Level := 0;
74   Best_Speed          : constant Compression_Level := 1;
75   Best_Compression    : constant Compression_Level := 9;
76   Default_Compression : constant Compression_Level := -1;
77
78   --------------------------
79   -- Flush mode constants --
80   --------------------------
81
82   No_Flush      : constant Flush_Mode;
83   --  Regular way for compression, no flush
84
85   Partial_Flush : constant Flush_Mode;
86   --  Will be removed, use Z_SYNC_FLUSH instead
87
88   Sync_Flush    : constant Flush_Mode;
89   --  All pending output is flushed to the output buffer and the output
90   --  is aligned on a byte boundary, so that the decompressor can get all
91   --  input data available so far. (In particular avail_in is zero after the
92   --  call if enough output space has been provided  before the call.)
93   --  Flushing may degrade compression for some compression algorithms and so
94   --  it should be used only when necessary.
95
96   Block_Flush   : constant Flush_Mode;
97   --  Z_BLOCK requests that inflate() stop
98   --  if and when it get to the next deflate block boundary. When decoding the
99   --  zlib or gzip format, this will cause inflate() to return immediately
100   --  after the header and before the first block. When doing a raw inflate,
101   --  inflate() will go ahead and process the first block, and will return
102   --  when it gets to the end of that block, or when it runs out of data.
103
104   Full_Flush    : constant Flush_Mode;
105   --  All output is flushed as with SYNC_FLUSH, and the compression state
106   --  is reset so that decompression can restart from this point if previous
107   --  compressed data has been damaged or if random access is desired. Using
108   --  Full_Flush too often can seriously degrade the compression.
109
110   Finish        : constant Flush_Mode;
111   --  Just for tell the compressor that input data is complete.
112
113   ------------------------------------
114   -- Compression strategy constants --
115   ------------------------------------
116
117   --  RLE stategy could be used only in version 1.2.0 and later.
118
119   Filtered         : constant Strategy_Type;
120   Huffman_Only     : constant Strategy_Type;
121   RLE              : constant Strategy_Type;
122   Default_Strategy : constant Strategy_Type;
123
124   Default_Buffer_Size : constant := 4096;
125
126   type Filter_Type is tagged limited private;
127   --  The filter is for compression and for decompression.
128   --  The usage of the type is depend of its initialization.
129
130   function Version return String;
131   pragma Inline (Version);
132   --  Return string representation of the ZLib version.
133
134   procedure Deflate_Init
135     (Filter       : in out Filter_Type;
136      Level        : in     Compression_Level  := Default_Compression;
137      Strategy     : in     Strategy_Type      := Default_Strategy;
138      Method       : in     Compression_Method := Deflated;
139      Window_Bits  : in     Window_Bits_Type   := Default_Window_Bits;
140      Memory_Level : in     Memory_Level_Type  := Default_Memory_Level;
141      Header       : in     Header_Type        := Default);
142   --  Compressor initialization.
143   --  When Header parameter is Auto or Default, then default zlib header
144   --  would be provided for compressed data.
145   --  When Header is GZip, then gzip header would be set instead of
146   --  default header.
147   --  When Header is None, no header would be set for compressed data.
148
149   procedure Inflate_Init
150     (Filter      : in out Filter_Type;
151      Window_Bits : in     Window_Bits_Type := Default_Window_Bits;
152      Header      : in     Header_Type      := Default);
153   --  Decompressor initialization.
154   --  Default header type mean that ZLib default header is expecting in the
155   --  input compressed stream.
156   --  Header type None mean that no header is expecting in the input stream.
157   --  GZip header type mean that GZip header is expecting in the
158   --  input compressed stream.
159   --  Auto header type mean that header type (GZip or Native) would be
160   --  detected automatically in the input stream.
161   --  Note that header types parameter values None, GZip and Auto are
162   --  supported for inflate routine only in ZLib versions 1.2.0.2 and later.
163   --  Deflate_Init is supporting all header types.
164
165   function Is_Open (Filter : in Filter_Type) return Boolean;
166   pragma Inline (Is_Open);
167   --  Is the filter opened for compression or decompression.
168
169   procedure Close
170     (Filter       : in out Filter_Type;
171      Ignore_Error : in     Boolean := False);
172   --  Closing the compression or decompressor.
173   --  If stream is closing before the complete and Ignore_Error is False,
174   --  The exception would be raised.
175
176   generic
177      with procedure Data_In
178        (Item : out Ada.Streams.Stream_Element_Array;
179         Last : out Ada.Streams.Stream_Element_Offset);
180      with procedure Data_Out
181        (Item : in Ada.Streams.Stream_Element_Array);
182   procedure Generic_Translate
183     (Filter          : in out Filter_Type;
184      In_Buffer_Size  : in     Integer := Default_Buffer_Size;
185      Out_Buffer_Size : in     Integer := Default_Buffer_Size);
186   --  Compress/decompress data fetch from Data_In routine and pass the result
187   --  to the Data_Out routine. User should provide Data_In and Data_Out
188   --  for compression/decompression data flow.
189   --  Compression or decompression depend on Filter initialization.
190
191   function Total_In (Filter : in Filter_Type) return Count;
192   pragma Inline (Total_In);
193   --  Returns total number of input bytes read so far
194
195   function Total_Out (Filter : in Filter_Type) return Count;
196   pragma Inline (Total_Out);
197   --  Returns total number of bytes output so far
198
199   function CRC32
200     (CRC    : in Unsigned_32;
201      Data   : in Ada.Streams.Stream_Element_Array)
202      return Unsigned_32;
203   pragma Inline (CRC32);
204   --  Compute CRC32, it could be necessary for make gzip format
205
206   procedure CRC32
207     (CRC  : in out Unsigned_32;
208      Data : in     Ada.Streams.Stream_Element_Array);
209   pragma Inline (CRC32);
210   --  Compute CRC32, it could be necessary for make gzip format
211
212   -------------------------------------------------
213   --  Below is more complex low level routines.  --
214   -------------------------------------------------
215
216   procedure Translate
217     (Filter    : in out Filter_Type;
218      In_Data   : in     Ada.Streams.Stream_Element_Array;
219      In_Last   :    out Ada.Streams.Stream_Element_Offset;
220      Out_Data  :    out Ada.Streams.Stream_Element_Array;
221      Out_Last  :    out Ada.Streams.Stream_Element_Offset;
222      Flush     : in     Flush_Mode);
223   --  Compress/decompress the In_Data buffer and place the result into
224   --  Out_Data. In_Last is the index of last element from In_Data accepted by
225   --  the Filter. Out_Last is the last element of the received data from
226   --  Filter. To tell the filter that incoming data are complete put the
227   --  Flush parameter to Finish.
228
229   function Stream_End (Filter : in Filter_Type) return Boolean;
230   pragma Inline (Stream_End);
231   --  Return the true when the stream is complete.
232
233   procedure Flush
234     (Filter    : in out Filter_Type;
235      Out_Data  :    out Ada.Streams.Stream_Element_Array;
236      Out_Last  :    out Ada.Streams.Stream_Element_Offset;
237      Flush     : in     Flush_Mode);
238   pragma Inline (Flush);
239   --  Flushing the data from the compressor.
240
241   generic
242      with procedure Write
243        (Item : in Ada.Streams.Stream_Element_Array);
244      --  User should provide this routine for accept
245      --  compressed/decompressed data.
246
247      Buffer_Size : in Ada.Streams.Stream_Element_Offset
248         := Default_Buffer_Size;
249      --  Buffer size for Write user routine.
250
251   procedure Write
252     (Filter  : in out Filter_Type;
253      Item    : in     Ada.Streams.Stream_Element_Array;
254      Flush   : in     Flush_Mode := No_Flush);
255   --  Compress/Decompress data from Item to the generic parameter procedure
256   --  Write. Output buffer size could be set in Buffer_Size generic parameter.
257
258   generic
259      with procedure Read
260        (Item : out Ada.Streams.Stream_Element_Array;
261         Last : out Ada.Streams.Stream_Element_Offset);
262      --  User should provide data for compression/decompression
263      --  thru this routine.
264
265      Buffer : in out Ada.Streams.Stream_Element_Array;
266      --  Buffer for keep remaining data from the previous
267      --  back read.
268
269      Rest_First, Rest_Last : in out Ada.Streams.Stream_Element_Offset;
270      --  Rest_First have to be initialized to Buffer'Last + 1
271      --  Rest_Last have to be initialized to Buffer'Last
272      --  before usage.
273
274      Allow_Read_Some : in Boolean := False;
275      --  Is it allowed to return Last < Item'Last before end of data.
276
277   procedure Read
278     (Filter : in out Filter_Type;
279      Item   :    out Ada.Streams.Stream_Element_Array;
280      Last   :    out Ada.Streams.Stream_Element_Offset;
281      Flush  : in     Flush_Mode := No_Flush);
282   --  Compress/Decompress data from generic parameter procedure Read to the
283   --  Item. User should provide Buffer and initialized Rest_First, Rest_Last
284   --  indicators. If Allow_Read_Some is True, Read routines could return
285   --  Last < Item'Last only at end of stream.
286
287private
288
289   use Ada.Streams;
290
291   pragma Assert (Ada.Streams.Stream_Element'Size    =    8);
292   pragma Assert (Ada.Streams.Stream_Element'Modulus = 2**8);
293
294   type Flush_Mode is new Integer range 0 .. 5;
295
296   type Compression_Method is new Integer range 8 .. 8;
297
298   type Strategy_Type is new Integer range 0 .. 3;
299
300   No_Flush      : constant Flush_Mode := 0;
301   Partial_Flush : constant Flush_Mode := 1;
302   Sync_Flush    : constant Flush_Mode := 2;
303   Full_Flush    : constant Flush_Mode := 3;
304   Finish        : constant Flush_Mode := 4;
305   Block_Flush   : constant Flush_Mode := 5;
306
307   Filtered         : constant Strategy_Type := 1;
308   Huffman_Only     : constant Strategy_Type := 2;
309   RLE              : constant Strategy_Type := 3;
310   Default_Strategy : constant Strategy_Type := 0;
311
312   Deflated : constant Compression_Method := 8;
313
314   type Z_Stream;
315
316   type Z_Stream_Access is access all Z_Stream;
317
318   type Filter_Type is tagged limited record
319      Strm        : Z_Stream_Access;
320      Compression : Boolean;
321      Stream_End  : Boolean;
322      Header      : Header_Type;
323      CRC         : Unsigned_32;
324      Offset      : Stream_Element_Offset;
325      --  Offset for gzip header/footer output.
326   end record;
327
328end ZLib;
329