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313546eb LMI |
1 | /* Interface to zlib. |
2 | Copyright (C) 2013 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU Emacs. | |
5 | ||
6 | GNU Emacs 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 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | GNU Emacs is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <config.h> | |
20 | ||
21 | #ifdef HAVE_ZLIB | |
22 | ||
23 | #include <zlib.h> | |
24 | ||
25 | #include "lisp.h" | |
26 | #include "character.h" | |
27 | #include "buffer.h" | |
28 | ||
53b64418 PE |
29 | #include <verify.h> |
30 | ||
594a4307 EZ |
31 | static Lisp_Object Qzlib_dll; |
32 | ||
33 | #ifdef WINDOWSNT | |
34 | #include <windows.h> | |
35 | #include "w32.h" | |
36 | ||
37 | /* Macro for defining functions that will be loaded from the zlib DLL. */ | |
38 | #define DEF_ZLIB_FN(rettype,func,args) static rettype (FAR CDECL *fn_##func)args | |
39 | ||
40 | /* Macro for loading zlib functions from the library. */ | |
41 | #define LOAD_ZLIB_FN(lib,func) { \ | |
42 | fn_##func = (void *) GetProcAddress (lib, #func); \ | |
aa942e2b | 43 | if (!fn_##func) return false; \ |
594a4307 EZ |
44 | } |
45 | ||
46 | DEF_ZLIB_FN (int, inflateInit2_, | |
47 | (z_streamp strm, int windowBits, const char *version, int stream_size)); | |
48 | ||
49 | DEF_ZLIB_FN (int, inflate, | |
50 | (z_streamp strm, int flush)); | |
51 | ||
52 | DEF_ZLIB_FN (int, inflateEnd, | |
53 | (z_streamp strm)); | |
54 | ||
aa942e2b EZ |
55 | static bool zlib_initialized; |
56 | ||
594a4307 EZ |
57 | static bool |
58 | init_zlib_functions (void) | |
59 | { | |
60 | HMODULE library = w32_delayed_load (Qzlib_dll); | |
61 | ||
62 | if (!library) | |
63 | { | |
64 | message1 ("zlib library not found"); | |
aa942e2b | 65 | return false; |
594a4307 EZ |
66 | } |
67 | ||
68 | LOAD_ZLIB_FN (library, inflateInit2_); | |
69 | LOAD_ZLIB_FN (library, inflate); | |
70 | LOAD_ZLIB_FN (library, inflateEnd); | |
aa942e2b | 71 | return true; |
594a4307 EZ |
72 | } |
73 | ||
1d238bc7 PE |
74 | #define fn_inflateInit2(strm, windowBits) \ |
75 | fn_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) | |
76 | ||
594a4307 EZ |
77 | #else /* !WINDOWSNT */ |
78 | ||
1d238bc7 | 79 | #define fn_inflateInit2 inflateInit2 |
594a4307 EZ |
80 | #define fn_inflate inflate |
81 | #define fn_inflateEnd inflateEnd | |
82 | ||
83 | #endif /* WINDOWSNT */ | |
84 | ||
313546eb | 85 | \f |
d0e615c3 PE |
86 | struct decompress_unwind_data |
87 | { | |
313546eb LMI |
88 | ptrdiff_t old_point, start; |
89 | z_stream *stream; | |
90 | }; | |
91 | ||
92 | static void | |
d0e615c3 PE |
93 | unwind_decompress (void *ddata) |
94 | { | |
313546eb | 95 | struct decompress_unwind_data *data = ddata; |
594a4307 | 96 | fn_inflateEnd (data->stream); |
d0e615c3 PE |
97 | |
98 | /* Delete any uncompressed data already inserted and restore point. */ | |
99 | if (data->start) | |
100 | { | |
101 | del_range (data->start, PT); | |
102 | SET_PT (data->old_point); | |
103 | } | |
313546eb LMI |
104 | } |
105 | ||
594a4307 EZ |
106 | DEFUN ("zlib-available-p", Fzlib_available_p, Szlib_available_p, 0, 0, 0, |
107 | doc: /* Return t if zlib decompression is available in this instance of Emacs. */) | |
108 | (void) | |
109 | { | |
110 | #ifdef WINDOWSNT | |
111 | Lisp_Object found = Fassq (Qzlib_dll, Vlibrary_cache); | |
112 | if (CONSP (found)) | |
113 | return XCDR (found); | |
114 | else | |
115 | { | |
116 | Lisp_Object status; | |
117 | status = init_zlib_functions () ? Qt : Qnil; | |
118 | Vlibrary_cache = Fcons (Fcons (Qzlib_dll, status), Vlibrary_cache); | |
119 | return status; | |
120 | } | |
121 | #else | |
122 | return Qt; | |
123 | #endif | |
124 | } | |
125 | ||
7699d09e LMI |
126 | DEFUN ("zlib-decompress-region", Fzlib_decompress_region, |
127 | Szlib_decompress_region, | |
313546eb | 128 | 2, 2, 0, |
7699d09e | 129 | doc: /* Decompress a gzip- or zlib-compressed region. |
d0e615c3 PE |
130 | Replace the text in the region by the decompressed data. |
131 | On failure, return nil and leave the data in place. | |
132 | This function can be called only in unibyte buffers. */) | |
313546eb LMI |
133 | (Lisp_Object start, Lisp_Object end) |
134 | { | |
d0e615c3 | 135 | ptrdiff_t istart, iend, pos_byte; |
313546eb | 136 | z_stream stream; |
d0e615c3 | 137 | int inflate_status; |
313546eb LMI |
138 | struct decompress_unwind_data unwind_data; |
139 | ptrdiff_t count = SPECPDL_INDEX (); | |
140 | ||
141 | validate_region (&start, &end); | |
313546eb LMI |
142 | |
143 | if (! NILP (BVAR (current_buffer, enable_multibyte_characters))) | |
d0e615c3 | 144 | error ("This function can be called only in unibyte buffers"); |
313546eb | 145 | |
aa942e2b EZ |
146 | #ifdef WINDOWSNT |
147 | if (!zlib_initialized) | |
148 | zlib_initialized = init_zlib_functions (); | |
866c710e EZ |
149 | if (!zlib_initialized) |
150 | return Qnil; | |
aa942e2b EZ |
151 | #endif |
152 | ||
313546eb | 153 | /* This is a unibyte buffer, so character positions and bytes are |
d0e615c3 | 154 | the same. */ |
313546eb LMI |
155 | istart = XINT (start); |
156 | iend = XINT (end); | |
99a32242 | 157 | move_gap_both (iend, iend); |
313546eb LMI |
158 | |
159 | stream.zalloc = Z_NULL; | |
160 | stream.zfree = Z_NULL; | |
161 | stream.opaque = Z_NULL; | |
162 | stream.avail_in = 0; | |
163 | stream.next_in = Z_NULL; | |
164 | ||
7699d09e LMI |
165 | /* The magic number 32 apparently means "autodect both the gzip and |
166 | zlib formats" according to zlib.h. */ | |
167 | if (fn_inflateInit2 (&stream, MAX_WBITS + 32) != Z_OK) | |
313546eb LMI |
168 | return Qnil; |
169 | ||
313546eb LMI |
170 | unwind_data.start = iend; |
171 | unwind_data.stream = &stream; | |
d0e615c3 PE |
172 | unwind_data.old_point = PT; |
173 | ||
313546eb LMI |
174 | record_unwind_protect_ptr (unwind_decompress, &unwind_data); |
175 | ||
d0e615c3 PE |
176 | /* Insert the decompressed data at the end of the compressed data. */ |
177 | SET_PT (iend); | |
313546eb | 178 | |
d0e615c3 PE |
179 | pos_byte = istart; |
180 | ||
181 | /* Keep calling 'inflate' until it reports an error or end-of-input. */ | |
182 | do | |
183 | { | |
184 | /* Maximum number of bytes that one 'inflate' call should read and write. | |
53b64418 | 185 | Do not make avail_out too large, as that might unduly delay C-g. |
2d065031 | 186 | zlib requires that avail_in and avail_out not exceed UINT_MAX. */ |
d0e615c3 | 187 | ptrdiff_t avail_in = min (iend - pos_byte, UINT_MAX); |
2d065031 PE |
188 | int avail_out = 16 * 1024; |
189 | int decompressed; | |
d0e615c3 PE |
190 | |
191 | if (GAP_SIZE < avail_out) | |
192 | make_gap (avail_out - GAP_SIZE); | |
193 | stream.next_in = BYTE_POS_ADDR (pos_byte); | |
194 | stream.avail_in = avail_in; | |
195 | stream.next_out = GPT_ADDR; | |
196 | stream.avail_out = avail_out; | |
594a4307 | 197 | inflate_status = fn_inflate (&stream, Z_NO_FLUSH); |
d0e615c3 PE |
198 | pos_byte += avail_in - stream.avail_in; |
199 | decompressed = avail_out - stream.avail_out; | |
200 | insert_from_gap (decompressed, decompressed, 0); | |
201 | QUIT; | |
202 | } | |
203 | while (inflate_status == Z_OK); | |
313546eb | 204 | |
d0e615c3 PE |
205 | if (inflate_status != Z_STREAM_END) |
206 | return unbind_to (count, Qnil); | |
313546eb LMI |
207 | |
208 | unwind_data.start = 0; | |
313546eb | 209 | |
d0e615c3 | 210 | /* Delete the compressed data. */ |
313546eb LMI |
211 | del_range (istart, iend); |
212 | ||
d0e615c3 | 213 | return unbind_to (count, Qt); |
313546eb LMI |
214 | } |
215 | ||
216 | \f | |
217 | /*********************************************************************** | |
218 | Initialization | |
219 | ***********************************************************************/ | |
220 | void | |
221 | syms_of_decompress (void) | |
222 | { | |
594a4307 | 223 | DEFSYM (Qzlib_dll, "zlib"); |
7699d09e | 224 | defsubr (&Szlib_decompress_region); |
594a4307 | 225 | defsubr (&Szlib_available_p); |
313546eb LMI |
226 | } |
227 | ||
228 | #endif /* HAVE_ZLIB */ |