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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 | ||
594a4307 EZ |
29 | static Lisp_Object Qzlib_dll; |
30 | ||
31 | #ifdef WINDOWSNT | |
32 | #include <windows.h> | |
33 | #include "w32.h" | |
34 | ||
35 | /* Macro for defining functions that will be loaded from the zlib DLL. */ | |
36 | #define DEF_ZLIB_FN(rettype,func,args) static rettype (FAR CDECL *fn_##func)args | |
37 | ||
38 | /* Macro for loading zlib functions from the library. */ | |
39 | #define LOAD_ZLIB_FN(lib,func) { \ | |
40 | fn_##func = (void *) GetProcAddress (lib, #func); \ | |
aa942e2b | 41 | if (!fn_##func) return false; \ |
594a4307 EZ |
42 | } |
43 | ||
44 | DEF_ZLIB_FN (int, inflateInit2_, | |
45 | (z_streamp strm, int windowBits, const char *version, int stream_size)); | |
46 | ||
47 | DEF_ZLIB_FN (int, inflate, | |
48 | (z_streamp strm, int flush)); | |
49 | ||
50 | DEF_ZLIB_FN (int, inflateEnd, | |
51 | (z_streamp strm)); | |
52 | ||
aa942e2b EZ |
53 | static bool zlib_initialized; |
54 | ||
594a4307 EZ |
55 | static bool |
56 | init_zlib_functions (void) | |
57 | { | |
58 | HMODULE library = w32_delayed_load (Qzlib_dll); | |
59 | ||
60 | if (!library) | |
61 | { | |
62 | message1 ("zlib library not found"); | |
aa942e2b | 63 | return false; |
594a4307 EZ |
64 | } |
65 | ||
66 | LOAD_ZLIB_FN (library, inflateInit2_); | |
67 | LOAD_ZLIB_FN (library, inflate); | |
68 | LOAD_ZLIB_FN (library, inflateEnd); | |
aa942e2b | 69 | return true; |
594a4307 EZ |
70 | } |
71 | ||
1d238bc7 PE |
72 | #define fn_inflateInit2(strm, windowBits) \ |
73 | fn_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) | |
74 | ||
594a4307 EZ |
75 | #else /* !WINDOWSNT */ |
76 | ||
1d238bc7 | 77 | #define fn_inflateInit2 inflateInit2 |
594a4307 EZ |
78 | #define fn_inflate inflate |
79 | #define fn_inflateEnd inflateEnd | |
80 | ||
81 | #endif /* WINDOWSNT */ | |
82 | ||
313546eb | 83 | \f |
d0e615c3 PE |
84 | struct decompress_unwind_data |
85 | { | |
313546eb LMI |
86 | ptrdiff_t old_point, start; |
87 | z_stream *stream; | |
88 | }; | |
89 | ||
90 | static void | |
d0e615c3 PE |
91 | unwind_decompress (void *ddata) |
92 | { | |
313546eb | 93 | struct decompress_unwind_data *data = ddata; |
594a4307 | 94 | fn_inflateEnd (data->stream); |
d0e615c3 PE |
95 | |
96 | /* Delete any uncompressed data already inserted and restore point. */ | |
97 | if (data->start) | |
98 | { | |
99 | del_range (data->start, PT); | |
100 | SET_PT (data->old_point); | |
101 | } | |
313546eb LMI |
102 | } |
103 | ||
594a4307 EZ |
104 | DEFUN ("zlib-available-p", Fzlib_available_p, Szlib_available_p, 0, 0, 0, |
105 | doc: /* Return t if zlib decompression is available in this instance of Emacs. */) | |
106 | (void) | |
107 | { | |
108 | #ifdef WINDOWSNT | |
109 | Lisp_Object found = Fassq (Qzlib_dll, Vlibrary_cache); | |
110 | if (CONSP (found)) | |
111 | return XCDR (found); | |
112 | else | |
113 | { | |
114 | Lisp_Object status; | |
115 | status = init_zlib_functions () ? Qt : Qnil; | |
116 | Vlibrary_cache = Fcons (Fcons (Qzlib_dll, status), Vlibrary_cache); | |
117 | return status; | |
118 | } | |
119 | #else | |
120 | return Qt; | |
121 | #endif | |
122 | } | |
123 | ||
7699d09e LMI |
124 | DEFUN ("zlib-decompress-region", Fzlib_decompress_region, |
125 | Szlib_decompress_region, | |
313546eb | 126 | 2, 2, 0, |
7699d09e | 127 | doc: /* Decompress a gzip- or zlib-compressed region. |
d0e615c3 PE |
128 | Replace the text in the region by the decompressed data. |
129 | On failure, return nil and leave the data in place. | |
130 | This function can be called only in unibyte buffers. */) | |
313546eb LMI |
131 | (Lisp_Object start, Lisp_Object end) |
132 | { | |
d0e615c3 | 133 | ptrdiff_t istart, iend, pos_byte; |
313546eb | 134 | z_stream stream; |
d0e615c3 | 135 | int inflate_status; |
313546eb LMI |
136 | struct decompress_unwind_data unwind_data; |
137 | ptrdiff_t count = SPECPDL_INDEX (); | |
138 | ||
139 | validate_region (&start, &end); | |
313546eb LMI |
140 | |
141 | if (! NILP (BVAR (current_buffer, enable_multibyte_characters))) | |
d0e615c3 | 142 | error ("This function can be called only in unibyte buffers"); |
313546eb | 143 | |
aa942e2b EZ |
144 | #ifdef WINDOWSNT |
145 | if (!zlib_initialized) | |
146 | zlib_initialized = init_zlib_functions (); | |
147 | #endif | |
148 | ||
313546eb | 149 | /* This is a unibyte buffer, so character positions and bytes are |
d0e615c3 | 150 | the same. */ |
313546eb LMI |
151 | istart = XINT (start); |
152 | iend = XINT (end); | |
99a32242 | 153 | move_gap_both (iend, iend); |
313546eb LMI |
154 | |
155 | stream.zalloc = Z_NULL; | |
156 | stream.zfree = Z_NULL; | |
157 | stream.opaque = Z_NULL; | |
158 | stream.avail_in = 0; | |
159 | stream.next_in = Z_NULL; | |
160 | ||
7699d09e LMI |
161 | /* The magic number 32 apparently means "autodect both the gzip and |
162 | zlib formats" according to zlib.h. */ | |
163 | if (fn_inflateInit2 (&stream, MAX_WBITS + 32) != Z_OK) | |
313546eb LMI |
164 | return Qnil; |
165 | ||
313546eb LMI |
166 | unwind_data.start = iend; |
167 | unwind_data.stream = &stream; | |
d0e615c3 PE |
168 | unwind_data.old_point = PT; |
169 | ||
313546eb LMI |
170 | record_unwind_protect_ptr (unwind_decompress, &unwind_data); |
171 | ||
d0e615c3 PE |
172 | /* Insert the decompressed data at the end of the compressed data. */ |
173 | SET_PT (iend); | |
313546eb | 174 | |
d0e615c3 PE |
175 | pos_byte = istart; |
176 | ||
177 | /* Keep calling 'inflate' until it reports an error or end-of-input. */ | |
178 | do | |
179 | { | |
180 | /* Maximum number of bytes that one 'inflate' call should read and write. | |
181 | zlib requires that these values not exceed UINT_MAX. | |
182 | Do not make avail_out too large, as that might unduly delay C-g. */ | |
183 | ptrdiff_t avail_in = min (iend - pos_byte, UINT_MAX); | |
184 | ptrdiff_t avail_out = min (1 << 14, UINT_MAX); | |
185 | ||
186 | ptrdiff_t decompressed; | |
187 | ||
188 | if (GAP_SIZE < avail_out) | |
189 | make_gap (avail_out - GAP_SIZE); | |
190 | stream.next_in = BYTE_POS_ADDR (pos_byte); | |
191 | stream.avail_in = avail_in; | |
192 | stream.next_out = GPT_ADDR; | |
193 | stream.avail_out = avail_out; | |
594a4307 | 194 | inflate_status = fn_inflate (&stream, Z_NO_FLUSH); |
d0e615c3 PE |
195 | pos_byte += avail_in - stream.avail_in; |
196 | decompressed = avail_out - stream.avail_out; | |
197 | insert_from_gap (decompressed, decompressed, 0); | |
198 | QUIT; | |
199 | } | |
200 | while (inflate_status == Z_OK); | |
313546eb | 201 | |
d0e615c3 PE |
202 | if (inflate_status != Z_STREAM_END) |
203 | return unbind_to (count, Qnil); | |
313546eb LMI |
204 | |
205 | unwind_data.start = 0; | |
313546eb | 206 | |
d0e615c3 | 207 | /* Delete the compressed data. */ |
313546eb LMI |
208 | del_range (istart, iend); |
209 | ||
d0e615c3 | 210 | return unbind_to (count, Qt); |
313546eb LMI |
211 | } |
212 | ||
213 | \f | |
214 | /*********************************************************************** | |
215 | Initialization | |
216 | ***********************************************************************/ | |
217 | void | |
218 | syms_of_decompress (void) | |
219 | { | |
594a4307 | 220 | DEFSYM (Qzlib_dll, "zlib"); |
7699d09e | 221 | defsubr (&Szlib_decompress_region); |
594a4307 | 222 | defsubr (&Szlib_available_p); |
313546eb LMI |
223 | } |
224 | ||
225 | #endif /* HAVE_ZLIB */ |