1 /* Copyright (C) 1995, 1996, 1997, 1998 Aladdin Enterprises. All rights reserved.
2
3 This software is provided AS-IS with no warranty, either express or
4 implied.
5
6 This software is distributed under license and may not be copied,
7 modified or distributed except as expressly authorized under the terms
8 of the license contained in the file LICENSE in this distribution.
9
10 For more information about licensing, please refer to
11 http://www.ghostscript.com/licensing/. For information on
12 commercial licensing, go to http://www.artifex.com/licensing/ or
13 contact Artifex Software, Inc., 101 Lucas Valley Road #110,
14 San Rafael, CA 94903, U.S.A., +1(415)492-9861.
15 */
16
17 /* $Id: szlibd.c,v 1.7 2004/03/11 14:50:50 igor Exp $ */
18 /* zlib decoding (decompression) filter stream */
19 #include "memory_.h"
20 #include "std.h"
21 #include "gsmemory.h"
22 #include "gsmalloc.h" /* for gs_memory_default */
23 #include "strimpl.h"
24 #include "szlibxx.h"
25
26 /* Initialize the filter. */
27 private int
s_zlibD_init(stream_state * st)28 s_zlibD_init(stream_state * st)
29 {
30 stream_zlib_state *const ss = (stream_zlib_state *)st;
31 int code = s_zlib_alloc_dynamic_state(ss);
32
33 if (code < 0)
34 return ERRC; /****** WRONG ******/
35 if (inflateInit2(&ss->dynamic->zstate,
36 (ss->no_wrapper ? -ss->windowBits : ss->windowBits))
37 != Z_OK
38 ) {
39 s_zlib_free_dynamic_state(ss);
40 return ERRC; /****** WRONG ******/
41 }
42 st->min_left=1;
43 return 0;
44 }
45
46 /* Reinitialize the filter. */
47 private int
s_zlibD_reset(stream_state * st)48 s_zlibD_reset(stream_state * st)
49 {
50 stream_zlib_state *const ss = (stream_zlib_state *)st;
51
52 if (inflateReset(&ss->dynamic->zstate) != Z_OK)
53 return ERRC; /****** WRONG ******/
54 return 0;
55 }
56
57 /* Process a buffer */
58 private int
s_zlibD_process(stream_state * st,stream_cursor_read * pr,stream_cursor_write * pw,bool ignore_last)59 s_zlibD_process(stream_state * st, stream_cursor_read * pr,
60 stream_cursor_write * pw, bool ignore_last)
61 {
62 stream_zlib_state *const ss = (stream_zlib_state *)st;
63 z_stream *zs = &ss->dynamic->zstate;
64 const byte *p = pr->ptr;
65 int status;
66 static const unsigned char jaws_empty[] = {0x58, 0x85, 1, 0, 0, 0, 0, 0, 1, 0x0A};
67
68 /* Detect no input or full output so that we don't get */
69 /* a Z_BUF_ERROR return. */
70 if (pw->ptr == pw->limit)
71 return 1;
72 if (pr->ptr == pr->limit)
73 return 0;
74 zs->next_in = (Bytef *)p + 1;
75 zs->avail_in = pr->limit - p;
76 zs->next_out = pw->ptr + 1;
77 zs->avail_out = pw->limit - pw->ptr;
78 if (zs->total_in == 0 && zs->avail_in >= 10 && !memcmp(zs->next_in, jaws_empty, 10)) {
79 /* JAWS PDF generator encodes empty stream as jaws_empty[].
80 * The stream declares that the data block length is zero
81 * but zlib routines regard a zero length data block to be an error.
82 */
83 pr->ptr += 10;
84 return EOFC;
85 }
86 status = inflate(zs, Z_PARTIAL_FLUSH);
87 pr->ptr = zs->next_in - 1;
88 pw->ptr = zs->next_out - 1;
89 switch (status) {
90 case Z_OK:
91 return (pw->ptr == pw->limit ? 1 : pr->ptr > p ? 0 : 1);
92 case Z_STREAM_END:
93 return EOFC;
94 default:
95 return ERRC;
96 }
97 }
98
99 /* Release the stream */
100 private void
s_zlibD_release(stream_state * st)101 s_zlibD_release(stream_state * st)
102 {
103 stream_zlib_state *const ss = (stream_zlib_state *)st;
104
105 inflateEnd(&ss->dynamic->zstate);
106 s_zlib_free_dynamic_state(ss);
107 }
108
109 /* Stream template */
110 const stream_template s_zlibD_template = {
111 &st_zlib_state, s_zlibD_init, s_zlibD_process, 1, 1, s_zlibD_release,
112 s_zlib_set_defaults, s_zlibD_reset
113 };
114