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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2011 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
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9 | under the terms of the GNU Lesser General Public License as published by |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
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11 | (at your option) any later version. |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 16 | Lesser General Public License for more details. |
e4e61fdb | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
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19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
20 | ***/ | |
21 | ||
22 | #include <assert.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <lzma.h> | |
26 | ||
27 | #include "compress.h" | |
28 | ||
29 | bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size) { | |
30 | lzma_stream s = LZMA_STREAM_INIT; | |
31 | lzma_ret ret; | |
32 | bool b = false; | |
33 | ||
34 | assert(src); | |
35 | assert(src_size > 0); | |
36 | assert(dst); | |
37 | assert(dst_size); | |
38 | ||
39 | /* Returns false if we couldn't compress the data or the | |
40 | * compressed result is longer than the original */ | |
41 | ||
42 | ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_NONE); | |
43 | if (ret != LZMA_OK) | |
44 | return false; | |
45 | ||
46 | s.next_in = src; | |
47 | s.avail_in = src_size; | |
48 | s.next_out = dst; | |
49 | s.avail_out = src_size; | |
50 | ||
51 | /* Does it fit? */ | |
52 | if (lzma_code(&s, LZMA_FINISH) != LZMA_STREAM_END) | |
53 | goto fail; | |
54 | ||
55 | /* Is it actually shorter? */ | |
56 | if (s.avail_out == 0) | |
57 | goto fail; | |
58 | ||
59 | *dst_size = src_size - s.avail_out; | |
60 | b = true; | |
61 | ||
62 | fail: | |
63 | lzma_end(&s); | |
64 | ||
65 | return b; | |
66 | } | |
67 | ||
68 | bool uncompress_blob(const void *src, uint64_t src_size, | |
69 | void **dst, uint64_t *dst_alloc_size, uint64_t* dst_size) { | |
70 | ||
71 | lzma_stream s = LZMA_STREAM_INIT; | |
72 | lzma_ret ret; | |
73 | bool b = false; | |
74 | ||
75 | assert(src); | |
76 | assert(src_size > 0); | |
77 | assert(dst); | |
78 | assert(dst_alloc_size); | |
79 | assert(dst_size); | |
80 | assert(*dst_alloc_size == 0 || *dst); | |
81 | ||
82 | ret = lzma_stream_decoder(&s, UINT64_MAX, 0); | |
83 | if (ret != LZMA_OK) | |
84 | return false; | |
85 | ||
86 | if (*dst_alloc_size <= src_size) { | |
87 | void *p; | |
88 | ||
89 | p = realloc(*dst, src_size*2); | |
90 | if (!p) | |
91 | return false; | |
92 | ||
93 | *dst = p; | |
94 | *dst_alloc_size = src_size*2; | |
95 | } | |
96 | ||
97 | s.next_in = src; | |
98 | s.avail_in = src_size; | |
99 | ||
100 | s.next_out = *dst; | |
101 | s.avail_out = *dst_alloc_size; | |
102 | ||
103 | for (;;) { | |
104 | void *p; | |
105 | ||
106 | ret = lzma_code(&s, LZMA_FINISH); | |
107 | ||
108 | if (ret == LZMA_STREAM_END) | |
109 | break; | |
110 | ||
111 | if (ret != LZMA_OK) | |
112 | goto fail; | |
113 | ||
114 | p = realloc(*dst, *dst_alloc_size*2); | |
115 | if (!p) | |
116 | goto fail; | |
117 | ||
118 | s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *dst); | |
119 | s.avail_out += *dst_alloc_size; | |
120 | ||
121 | *dst = p; | |
122 | *dst_alloc_size *= 2; | |
123 | } | |
124 | ||
125 | *dst_size = *dst_alloc_size - s.avail_out; | |
126 | b = true; | |
127 | ||
128 | fail: | |
129 | lzma_end(&s); | |
130 | ||
131 | return b; | |
132 | } | |
133 | ||
134 | bool uncompress_startswith(const void *src, uint64_t src_size, | |
135 | void **buffer, uint64_t *buffer_size, | |
136 | const void *prefix, uint64_t prefix_len, | |
137 | uint8_t extra) { | |
138 | ||
139 | lzma_stream s = LZMA_STREAM_INIT; | |
140 | lzma_ret ret; | |
141 | bool b = false; | |
142 | ||
143 | /* Checks whether the uncompressed blob starts with the | |
144 | * mentioned prefix. The byte extra needs to follow the | |
145 | * prefix */ | |
146 | ||
147 | assert(src); | |
148 | assert(src_size > 0); | |
149 | assert(buffer); | |
150 | assert(buffer_size); | |
151 | assert(prefix); | |
152 | assert(*buffer_size == 0 || *buffer); | |
153 | ||
154 | ret = lzma_stream_decoder(&s, UINT64_MAX, 0); | |
155 | if (ret != LZMA_OK) | |
156 | return false; | |
157 | ||
158 | if (*buffer_size <= prefix_len) { | |
159 | void *p; | |
160 | ||
161 | p = realloc(*buffer, prefix_len*2); | |
162 | if (!p) | |
163 | return false; | |
164 | ||
165 | *buffer = p; | |
166 | *buffer_size = prefix_len*2; | |
167 | } | |
168 | ||
169 | s.next_in = src; | |
170 | s.avail_in = src_size; | |
171 | ||
172 | s.next_out = *buffer; | |
173 | s.avail_out = *buffer_size; | |
174 | ||
175 | for (;;) { | |
176 | void *p; | |
177 | ||
178 | ret = lzma_code(&s, LZMA_FINISH); | |
179 | ||
180 | if (ret != LZMA_STREAM_END && ret != LZMA_OK) | |
181 | goto fail; | |
182 | ||
183 | if ((*buffer_size - s.avail_out > prefix_len) && | |
184 | memcmp(*buffer, prefix, prefix_len) == 0 && | |
185 | ((const uint8_t*) *buffer)[prefix_len] == extra) | |
186 | break; | |
187 | ||
188 | if (ret == LZMA_STREAM_END) | |
189 | goto fail; | |
190 | ||
191 | p = realloc(*buffer, *buffer_size*2); | |
192 | if (!p) | |
193 | goto fail; | |
194 | ||
195 | s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *buffer); | |
196 | s.avail_out += *buffer_size; | |
197 | ||
198 | *buffer = p; | |
199 | *buffer_size *= 2; | |
200 | } | |
201 | ||
202 | b = true; | |
203 | ||
204 | fail: | |
205 | lzma_end(&s); | |
206 | ||
207 | return b; | |
208 | } |