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export libpng and zlib so Windows and OS/2 builds cleanly.

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1----------------------------------------------------------------
2-- ZLib for Ada thick binding. --
3-- --
4-- Copyright (C) 2002-2003 Dmitriy Anisimkov --
5-- --
6-- Open source license information is in the zlib.ads file. --
7----------------------------------------------------------------
8
9-- $Id: zlib.adb,v 1.1 2004/11/15 16:42:25 bird Exp $
10
11with Ada.Exceptions;
12with Ada.Unchecked_Conversion;
13with Ada.Unchecked_Deallocation;
14
15with Interfaces.C.Strings;
16
17with ZLib.Thin;
18
19package body ZLib is
20
21 use type Thin.Int;
22
23 type Z_Stream is new Thin.Z_Stream;
24
25 type Return_Code_Enum is
26 (OK,
27 STREAM_END,
28 NEED_DICT,
29 ERRNO,
30 STREAM_ERROR,
31 DATA_ERROR,
32 MEM_ERROR,
33 BUF_ERROR,
34 VERSION_ERROR);
35
36 type Flate_Step_Function is access
37 function (Strm : Thin.Z_Streamp; flush : Thin.Int) return Thin.Int;
38 pragma Convention (C, Flate_Step_Function);
39
40 type Flate_End_Function is access
41 function (Ctrm : in Thin.Z_Streamp) return Thin.Int;
42 pragma Convention (C, Flate_End_Function);
43
44 type Flate_Type is record
45 Step : Flate_Step_Function;
46 Done : Flate_End_Function;
47 end record;
48
49 subtype Footer_Array is Stream_Element_Array (1 .. 8);
50
51 Simple_GZip_Header : constant Stream_Element_Array (1 .. 10)
52 := (16#1f#, 16#8b#, -- Magic header
53 16#08#, -- Z_DEFLATED
54 16#00#, -- Flags
55 16#00#, 16#00#, 16#00#, 16#00#, -- Time
56 16#00#, -- XFlags
57 16#03# -- OS code
58 );
59 -- The simplest gzip header is not for informational, but just for
60 -- gzip format compatibility.
61 -- Note that some code below is using assumption
62 -- Simple_GZip_Header'Last > Footer_Array'Last, so do not make
63 -- Simple_GZip_Header'Last <= Footer_Array'Last.
64
65 Return_Code : constant array (Thin.Int range <>) of Return_Code_Enum
66 := (0 => OK,
67 1 => STREAM_END,
68 2 => NEED_DICT,
69 -1 => ERRNO,
70 -2 => STREAM_ERROR,
71 -3 => DATA_ERROR,
72 -4 => MEM_ERROR,
73 -5 => BUF_ERROR,
74 -6 => VERSION_ERROR);
75
76 Flate : constant array (Boolean) of Flate_Type
77 := (True => (Step => Thin.Deflate'Access,
78 Done => Thin.DeflateEnd'Access),
79 False => (Step => Thin.Inflate'Access,
80 Done => Thin.InflateEnd'Access));
81
82 Flush_Finish : constant array (Boolean) of Flush_Mode
83 := (True => Finish, False => No_Flush);
84
85 procedure Raise_Error (Stream : Z_Stream);
86 pragma Inline (Raise_Error);
87
88 procedure Raise_Error (Message : String);
89 pragma Inline (Raise_Error);
90
91 procedure Check_Error (Stream : Z_Stream; Code : Thin.Int);
92
93 procedure Free is new Ada.Unchecked_Deallocation
94 (Z_Stream, Z_Stream_Access);
95
96 function To_Thin_Access is new Ada.Unchecked_Conversion
97 (Z_Stream_Access, Thin.Z_Streamp);
98
99 procedure Translate_GZip
100 (Filter : in out Filter_Type;
101 In_Data : in Ada.Streams.Stream_Element_Array;
102 In_Last : out Ada.Streams.Stream_Element_Offset;
103 Out_Data : out Ada.Streams.Stream_Element_Array;
104 Out_Last : out Ada.Streams.Stream_Element_Offset;
105 Flush : in Flush_Mode);
106 -- Separate translate routine for make gzip header.
107
108 procedure Translate_Auto
109 (Filter : in out Filter_Type;
110 In_Data : in Ada.Streams.Stream_Element_Array;
111 In_Last : out Ada.Streams.Stream_Element_Offset;
112 Out_Data : out Ada.Streams.Stream_Element_Array;
113 Out_Last : out Ada.Streams.Stream_Element_Offset;
114 Flush : in Flush_Mode);
115 -- translate routine without additional headers.
116
117 -----------------
118 -- Check_Error --
119 -----------------
120
121 procedure Check_Error (Stream : Z_Stream; Code : Thin.Int) is
122 use type Thin.Int;
123 begin
124 if Code /= Thin.Z_OK then
125 Raise_Error
126 (Return_Code_Enum'Image (Return_Code (Code))
127 & ": " & Last_Error_Message (Stream));
128 end if;
129 end Check_Error;
130
131 -----------
132 -- Close --
133 -----------
134
135 procedure Close
136 (Filter : in out Filter_Type;
137 Ignore_Error : in Boolean := False)
138 is
139 Code : Thin.Int;
140 begin
141 Code := Flate (Filter.Compression).Done
142 (To_Thin_Access (Filter.Strm));
143
144 Filter.Opened := False;
145
146 if Ignore_Error or else Code = Thin.Z_OK then
147 Free (Filter.Strm);
148 else
149 declare
150 Error_Message : constant String
151 := Last_Error_Message (Filter.Strm.all);
152 begin
153 Free (Filter.Strm);
154 Ada.Exceptions.Raise_Exception
155 (ZLib_Error'Identity,
156 Return_Code_Enum'Image (Return_Code (Code))
157 & ": " & Error_Message);
158 end;
159 end if;
160 end Close;
161
162 -----------
163 -- CRC32 --
164 -----------
165
166 function CRC32
167 (CRC : in Unsigned_32;
168 Data : in Ada.Streams.Stream_Element_Array)
169 return Unsigned_32
170 is
171 use Thin;
172 begin
173 return Unsigned_32 (crc32
174 (ULong (CRC),
175 Bytes.To_Pointer (Data'Address),
176 Data'Length));
177 end CRC32;
178
179 procedure CRC32
180 (CRC : in out Unsigned_32;
181 Data : in Ada.Streams.Stream_Element_Array) is
182 begin
183 CRC := CRC32 (CRC, Data);
184 end CRC32;
185
186 ------------------
187 -- Deflate_Init --
188 ------------------
189
190 procedure Deflate_Init
191 (Filter : in out Filter_Type;
192 Level : in Compression_Level := Default_Compression;
193 Strategy : in Strategy_Type := Default_Strategy;
194 Method : in Compression_Method := Deflated;
195 Window_Bits : in Window_Bits_Type := 15;
196 Memory_Level : in Memory_Level_Type := 8;
197 Header : in Header_Type := Default)
198 is
199 use type Thin.Int;
200 Win_Bits : Thin.Int := Thin.Int (Window_Bits);
201 begin
202 -- We allow ZLib to make header only in case of default header type.
203 -- Otherwise we would either do header by ourselfs, or do not do
204 -- header at all.
205
206 if Header = None or else Header = GZip then
207 Win_Bits := -Win_Bits;
208 end if;
209
210 -- For the GZip CRC calculation and make headers.
211
212 if Header = GZip then
213 Filter.CRC := 0;
214 Filter.Offset := Simple_GZip_Header'First;
215 else
216 Filter.Offset := Simple_GZip_Header'Last + 1;
217 end if;
218
219 Filter.Strm := new Z_Stream;
220 Filter.Compression := True;
221 Filter.Stream_End := False;
222 Filter.Opened := True;
223 Filter.Header := Header;
224
225 if Thin.Deflate_Init
226 (To_Thin_Access (Filter.Strm),
227 Level => Thin.Int (Level),
228 method => Thin.Int (Method),
229 windowBits => Win_Bits,
230 memLevel => Thin.Int (Memory_Level),
231 strategy => Thin.Int (Strategy)) /= Thin.Z_OK
232 then
233 Raise_Error (Filter.Strm.all);
234 end if;
235 end Deflate_Init;
236
237 -----------
238 -- Flush --
239 -----------
240
241 procedure Flush
242 (Filter : in out Filter_Type;
243 Out_Data : out Ada.Streams.Stream_Element_Array;
244 Out_Last : out Ada.Streams.Stream_Element_Offset;
245 Flush : in Flush_Mode)
246 is
247 No_Data : Stream_Element_Array := (1 .. 0 => 0);
248 Last : Stream_Element_Offset;
249 begin
250 Translate (Filter, No_Data, Last, Out_Data, Out_Last, Flush);
251 end Flush;
252
253 -----------------------
254 -- Generic_Translate --
255 -----------------------
256
257 procedure Generic_Translate
258 (Filter : in out ZLib.Filter_Type;
259 In_Buffer_Size : Integer := Default_Buffer_Size;
260 Out_Buffer_Size : Integer := Default_Buffer_Size)
261 is
262 In_Buffer : Stream_Element_Array
263 (1 .. Stream_Element_Offset (In_Buffer_Size));
264 Out_Buffer : Stream_Element_Array
265 (1 .. Stream_Element_Offset (Out_Buffer_Size));
266 Last : Stream_Element_Offset;
267 In_Last : Stream_Element_Offset;
268 In_First : Stream_Element_Offset;
269 Out_Last : Stream_Element_Offset;
270 begin
271 Main : loop
272 Data_In (In_Buffer, Last);
273
274 In_First := In_Buffer'First;
275
276 loop
277 Translate
278 (Filter,
279 In_Buffer (In_First .. Last),
280 In_Last,
281 Out_Buffer,
282 Out_Last,
283 Flush_Finish (Last < In_Buffer'First));
284
285 Data_Out (Out_Buffer (Out_Buffer'First .. Out_Last));
286
287 exit Main when Stream_End (Filter);
288
289 -- The end of in buffer.
290 exit when In_Last = Last;
291
292 In_First := In_Last + 1;
293 end loop;
294 end loop Main;
295
296 end Generic_Translate;
297
298 ------------------
299 -- Inflate_Init --
300 ------------------
301
302 procedure Inflate_Init
303 (Filter : in out Filter_Type;
304 Window_Bits : in Window_Bits_Type := 15;
305 Header : in Header_Type := Default)
306 is
307 use type Thin.Int;
308 Win_Bits : Thin.Int := Thin.Int (Window_Bits);
309
310 procedure Check_Version;
311 -- Check the latest header types compatibility.
312
313 procedure Check_Version is
314 begin
315 if Version <= "1.1.4" then
316 Raise_Error
317 ("Inflate header type " & Header_Type'Image (Header)
318 & " incompatible with ZLib version " & Version);
319 end if;
320 end Check_Version;
321
322 begin
323 case Header is
324 when None =>
325 Check_Version;
326
327 -- Inflate data without headers determined
328 -- by negative Win_Bits.
329
330 Win_Bits := -Win_Bits;
331 when GZip =>
332 Check_Version;
333
334 -- Inflate gzip data defined by flag 16.
335
336 Win_Bits := Win_Bits + 16;
337 when Auto =>
338 Check_Version;
339
340 -- Inflate with automatic detection
341 -- of gzip or native header defined by flag 32.
342
343 Win_Bits := Win_Bits + 32;
344 when Default => null;
345 end case;
346
347 Filter.Strm := new Z_Stream;
348 Filter.Compression := False;
349 Filter.Stream_End := False;
350 Filter.Opened := True;
351 Filter.Header := Header;
352
353 if Thin.Inflate_Init
354 (To_Thin_Access (Filter.Strm), Win_Bits) /= Thin.Z_OK
355 then
356 Raise_Error (Filter.Strm.all);
357 end if;
358 end Inflate_Init;
359
360 -----------------
361 -- Raise_Error --
362 -----------------
363
364 procedure Raise_Error (Message : String) is
365 begin
366 Ada.Exceptions.Raise_Exception (ZLib_Error'Identity, Message);
367 end Raise_Error;
368
369 procedure Raise_Error (Stream : Z_Stream) is
370 begin
371 Raise_Error (Last_Error_Message (Stream));
372 end Raise_Error;
373
374 ----------
375 -- Read --
376 ----------
377
378 procedure Read
379 (Filter : in out Filter_Type;
380 Item : out Ada.Streams.Stream_Element_Array;
381 Last : out Ada.Streams.Stream_Element_Offset)
382 is
383 In_Last : Stream_Element_Offset;
384 Item_First : Ada.Streams.Stream_Element_Offset := Item'First;
385
386 begin
387 pragma Assert (Rest_First in Buffer'First .. Buffer'Last + 1);
388
389 loop
390 if Rest_First > Buffer'Last then
391 Read (Buffer, Rest_Last);
392 Rest_First := Buffer'First;
393 end if;
394
395 pragma Assert (Rest_Last in Buffer'First - 1 .. Buffer'Last);
396
397 Translate
398 (Filter => Filter,
399 In_Data => Buffer (Rest_First .. Rest_Last),
400 In_Last => In_Last,
401 Out_Data => Item (Item_First .. Item'Last),
402 Out_Last => Last,
403 Flush => Flush_Finish (Rest_Last < Rest_First));
404
405 Rest_First := In_Last + 1;
406
407 exit when Last = Item'Last or else Stream_End (Filter);
408
409 Item_First := Last + 1;
410 end loop;
411 end Read;
412
413 ----------------
414 -- Stream_End --
415 ----------------
416
417 function Stream_End (Filter : in Filter_Type) return Boolean is
418 begin
419 if Filter.Header = GZip and Filter.Compression then
420 return Filter.Stream_End
421 and then Filter.Offset = Footer_Array'Last + 1;
422 else
423 return Filter.Stream_End;
424 end if;
425 end Stream_End;
426
427 --------------
428 -- Total_In --
429 --------------
430
431 function Total_In (Filter : in Filter_Type) return Count is
432 begin
433 return Count (Thin.Total_In (To_Thin_Access (Filter.Strm).all));
434 end Total_In;
435
436 ---------------
437 -- Total_Out --
438 ---------------
439
440 function Total_Out (Filter : in Filter_Type) return Count is
441 begin
442 return Count (Thin.Total_Out (To_Thin_Access (Filter.Strm).all));
443 end Total_Out;
444
445 ---------------
446 -- Translate --
447 ---------------
448
449 procedure Translate
450 (Filter : in out Filter_Type;
451 In_Data : in Ada.Streams.Stream_Element_Array;
452 In_Last : out Ada.Streams.Stream_Element_Offset;
453 Out_Data : out Ada.Streams.Stream_Element_Array;
454 Out_Last : out Ada.Streams.Stream_Element_Offset;
455 Flush : in Flush_Mode) is
456 begin
457 if Filter.Header = GZip and then Filter.Compression then
458 Translate_GZip
459 (Filter => Filter,
460 In_Data => In_Data,
461 In_Last => In_Last,
462 Out_Data => Out_Data,
463 Out_Last => Out_Last,
464 Flush => Flush);
465 else
466 Translate_Auto
467 (Filter => Filter,
468 In_Data => In_Data,
469 In_Last => In_Last,
470 Out_Data => Out_Data,
471 Out_Last => Out_Last,
472 Flush => Flush);
473 end if;
474 end Translate;
475
476 --------------------
477 -- Translate_Auto --
478 --------------------
479
480 procedure Translate_Auto
481 (Filter : in out Filter_Type;
482 In_Data : in Ada.Streams.Stream_Element_Array;
483 In_Last : out Ada.Streams.Stream_Element_Offset;
484 Out_Data : out Ada.Streams.Stream_Element_Array;
485 Out_Last : out Ada.Streams.Stream_Element_Offset;
486 Flush : in Flush_Mode)
487 is
488 use type Thin.Int;
489 Code : Thin.Int;
490
491 begin
492 if Filter.Opened = False then
493 raise ZLib_Error;
494 end if;
495
496 if Out_Data'Length = 0 then
497 raise Constraint_Error;
498 end if;
499
500 Set_Out (Filter.Strm.all, Out_Data'Address, Out_Data'Length);
501 Set_In (Filter.Strm.all, In_Data'Address, In_Data'Length);
502
503 Code := Flate (Filter.Compression).Step
504 (To_Thin_Access (Filter.Strm),
505 Thin.Int (Flush));
506
507 if Code = Thin.Z_STREAM_END then
508 Filter.Stream_End := True;
509 else
510 Check_Error (Filter.Strm.all, Code);
511 end if;
512
513 In_Last := In_Data'Last
514 - Stream_Element_Offset (Avail_In (Filter.Strm.all));
515 Out_Last := Out_Data'Last
516 - Stream_Element_Offset (Avail_Out (Filter.Strm.all));
517
518 end Translate_Auto;
519
520 --------------------
521 -- Translate_GZip --
522 --------------------
523
524 procedure Translate_GZip
525 (Filter : in out Filter_Type;
526 In_Data : in Ada.Streams.Stream_Element_Array;
527 In_Last : out Ada.Streams.Stream_Element_Offset;
528 Out_Data : out Ada.Streams.Stream_Element_Array;
529 Out_Last : out Ada.Streams.Stream_Element_Offset;
530 Flush : in Flush_Mode)
531 is
532 Out_First : Stream_Element_Offset;
533
534 procedure Add_Data (Data : in Stream_Element_Array);
535 -- Add data to stream from the Filter.Offset till necessary,
536 -- used for add gzip headr/footer.
537
538 procedure Put_32
539 (Item : in out Stream_Element_Array;
540 Data : in Unsigned_32);
541 pragma Inline (Put_32);
542
543 --------------
544 -- Add_Data --
545 --------------
546
547 procedure Add_Data (Data : in Stream_Element_Array) is
548 Data_First : Stream_Element_Offset renames Filter.Offset;
549 Data_Last : Stream_Element_Offset;
550 Data_Len : Stream_Element_Offset; -- -1
551 Out_Len : Stream_Element_Offset; -- -1
552 begin
553 Out_First := Out_Last + 1;
554
555 if Data_First > Data'Last then
556 return;
557 end if;
558
559 Data_Len := Data'Last - Data_First;
560 Out_Len := Out_Data'Last - Out_First;
561
562 if Data_Len <= Out_Len then
563 Out_Last := Out_First + Data_Len;
564 Data_Last := Data'Last;
565 else
566 Out_Last := Out_Data'Last;
567 Data_Last := Data_First + Out_Len;
568 end if;
569
570 Out_Data (Out_First .. Out_Last) := Data (Data_First .. Data_Last);
571
572 Data_First := Data_Last + 1;
573 Out_First := Out_Last + 1;
574 end Add_Data;
575
576 ------------
577 -- Put_32 --
578 ------------
579
580 procedure Put_32
581 (Item : in out Stream_Element_Array;
582 Data : in Unsigned_32)
583 is
584 D : Unsigned_32 := Data;
585 begin
586 for J in Item'First .. Item'First + 3 loop
587 Item (J) := Stream_Element (D and 16#FF#);
588 D := Shift_Right (D, 8);
589 end loop;
590 end Put_32;
591
592 begin
593 Out_Last := Out_Data'First - 1;
594
595 if not Filter.Stream_End then
596 Add_Data (Simple_GZip_Header);
597
598 Translate_Auto
599 (Filter => Filter,
600 In_Data => In_Data,
601 In_Last => In_Last,
602 Out_Data => Out_Data (Out_First .. Out_Data'Last),
603 Out_Last => Out_Last,
604 Flush => Flush);
605
606 CRC32 (Filter.CRC, In_Data (In_Data'First .. In_Last));
607
608 end if;
609
610 if Filter.Stream_End and then Out_Last <= Out_Data'Last then
611 -- This detection method would work only when
612 -- Simple_GZip_Header'Last > Footer_Array'Last
613
614 if Filter.Offset = Simple_GZip_Header'Last + 1 then
615 Filter.Offset := Footer_Array'First;
616 end if;
617
618 declare
619 Footer : Footer_Array;
620 begin
621 Put_32 (Footer, Filter.CRC);
622 Put_32 (Footer (Footer'First + 4 .. Footer'Last),
623 Unsigned_32 (Total_In (Filter)));
624 Add_Data (Footer);
625 end;
626 end if;
627 end Translate_GZip;
628
629 -------------
630 -- Version --
631 -------------
632
633 function Version return String is
634 begin
635 return Interfaces.C.Strings.Value (Thin.zlibVersion);
636 end Version;
637
638 -----------
639 -- Write --
640 -----------
641
642 procedure Write
643 (Filter : in out Filter_Type;
644 Item : in Ada.Streams.Stream_Element_Array;
645 Flush : in Flush_Mode)
646 is
647 Buffer : Stream_Element_Array (1 .. Buffer_Size);
648 In_Last, Out_Last : Stream_Element_Offset;
649 In_First : Stream_Element_Offset := Item'First;
650 begin
651 if Item'Length = 0 and Flush = No_Flush then
652 return;
653 end if;
654
655 loop
656 Translate
657 (Filter => Filter,
658 In_Data => Item (In_First .. Item'Last),
659 In_Last => In_Last,
660 Out_Data => Buffer,
661 Out_Last => Out_Last,
662 Flush => Flush);
663
664 if Out_Last >= Buffer'First then
665 Write (Buffer (1 .. Out_Last));
666 end if;
667
668 exit when In_Last = Item'Last or Stream_End (Filter);
669
670 In_First := In_Last + 1;
671 end loop;
672 end Write;
673
674end ZLib;
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