1
2
3
4
5
6
7
8#ifndef _LINUX_NTFS3_LIB_DECOMPRESS_COMMON_H
9#define _LINUX_NTFS3_LIB_DECOMPRESS_COMMON_H
10
11#include <linux/string.h>
12#include <linux/compiler.h>
13#include <linux/types.h>
14#include <linux/slab.h>
15#include <asm/unaligned.h>
16
17
18
19#define forceinline __always_inline
20
21
22#if defined(__i386__) || defined(__x86_64__) || defined(__ARM_FEATURE_UNALIGNED)
23# define FAST_UNALIGNED_ACCESS
24#endif
25
26
27#define WORDBYTES (sizeof(size_t))
28
29static forceinline void
30copy_unaligned_word(const void *src, void *dst)
31{
32 put_unaligned(get_unaligned((const size_t *)src), (size_t *)dst);
33}
34
35
36
37
38
39static forceinline size_t repeat_byte(u8 b)
40{
41 size_t v;
42
43 v = b;
44 v |= v << 8;
45 v |= v << 16;
46 v |= v << ((WORDBYTES == 8) ? 32 : 0);
47 return v;
48}
49
50
51
52
53
54
55struct input_bitstream {
56
57
58
59
60 u32 bitbuf;
61
62
63 u32 bitsleft;
64
65
66 const u8 *next;
67
68
69 const u8 *end;
70};
71
72
73static forceinline void init_input_bitstream(struct input_bitstream *is,
74 const void *buffer, u32 size)
75{
76 is->bitbuf = 0;
77 is->bitsleft = 0;
78 is->next = buffer;
79 is->end = is->next + size;
80}
81
82
83
84
85
86
87static forceinline void bitstream_ensure_bits(struct input_bitstream *is,
88 u32 num_bits)
89{
90 if (is->bitsleft < num_bits) {
91 if (is->end - is->next >= 2) {
92 is->bitbuf |= (u32)get_unaligned_le16(is->next)
93 << (16 - is->bitsleft);
94 is->next += 2;
95 }
96 is->bitsleft += 16;
97 }
98}
99
100
101
102
103
104static forceinline u32
105bitstream_peek_bits(const struct input_bitstream *is, const u32 num_bits)
106{
107 return (is->bitbuf >> 1) >> (sizeof(is->bitbuf) * 8 - num_bits - 1);
108}
109
110
111
112
113
114static forceinline void
115bitstream_remove_bits(struct input_bitstream *is, u32 num_bits)
116{
117 is->bitbuf <<= num_bits;
118 is->bitsleft -= num_bits;
119}
120
121
122
123
124
125static forceinline u32
126bitstream_pop_bits(struct input_bitstream *is, u32 num_bits)
127{
128 u32 bits = bitstream_peek_bits(is, num_bits);
129
130 bitstream_remove_bits(is, num_bits);
131 return bits;
132}
133
134
135static forceinline u32
136bitstream_read_bits(struct input_bitstream *is, u32 num_bits)
137{
138 bitstream_ensure_bits(is, num_bits);
139 return bitstream_pop_bits(is, num_bits);
140}
141
142
143static forceinline u8
144bitstream_read_byte(struct input_bitstream *is)
145{
146 if (unlikely(is->end == is->next))
147 return 0;
148 return *is->next++;
149}
150
151
152static forceinline u16
153bitstream_read_u16(struct input_bitstream *is)
154{
155 u16 v;
156
157 if (unlikely(is->end - is->next < 2))
158 return 0;
159 v = get_unaligned_le16(is->next);
160 is->next += 2;
161 return v;
162}
163
164
165static forceinline u32
166bitstream_read_u32(struct input_bitstream *is)
167{
168 u32 v;
169
170 if (unlikely(is->end - is->next < 4))
171 return 0;
172 v = get_unaligned_le32(is->next);
173 is->next += 4;
174 return v;
175}
176
177
178
179
180
181static forceinline void *bitstream_read_bytes(struct input_bitstream *is,
182 void *dst_buffer, size_t count)
183{
184 if ((size_t)(is->end - is->next) < count)
185 return NULL;
186 memcpy(dst_buffer, is->next, count);
187 is->next += count;
188 return (u8 *)dst_buffer + count;
189}
190
191
192static forceinline void bitstream_align(struct input_bitstream *is)
193{
194 is->bitsleft = 0;
195 is->bitbuf = 0;
196}
197
198extern int make_huffman_decode_table(u16 decode_table[], const u32 num_syms,
199 const u32 num_bits, const u8 lens[],
200 const u32 max_codeword_len,
201 u16 working_space[]);
202
203
204
205
206
207
208static forceinline u32 read_huffsym(struct input_bitstream *istream,
209 const u16 decode_table[],
210 u32 table_bits,
211 u32 max_codeword_len)
212{
213 u32 entry;
214 u32 key_bits;
215
216 bitstream_ensure_bits(istream, max_codeword_len);
217
218
219 key_bits = bitstream_peek_bits(istream, table_bits);
220 entry = decode_table[key_bits];
221 if (entry < 0xC000) {
222
223
224
225
226 bitstream_remove_bits(istream, entry >> 11);
227 return entry & 0x7FF;
228 }
229
230
231
232
233
234
235 bitstream_remove_bits(istream, table_bits);
236 do {
237 key_bits = (entry & 0x3FFF) + bitstream_pop_bits(istream, 1);
238 } while ((entry = decode_table[key_bits]) >= 0xC000);
239 return entry;
240}
241
242
243
244
245
246
247
248
249
250
251
252
253
254static forceinline u8 *lz_copy(u8 *dst, u32 length, u32 offset, const u8 *bufend,
255 u32 min_length)
256{
257 const u8 *src = dst - offset;
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272#ifdef FAST_UNALIGNED_ACCESS
273 u8 * const end = dst + length;
274
275 if (bufend - end >= (ptrdiff_t)(WORDBYTES - 1)) {
276
277 if (offset >= WORDBYTES) {
278
279
280
281
282
283
284
285
286
287 copy_unaligned_word(src, dst);
288 src += WORDBYTES;
289 dst += WORDBYTES;
290
291 if (dst < end) {
292 do {
293 copy_unaligned_word(src, dst);
294 src += WORDBYTES;
295 dst += WORDBYTES;
296 } while (dst < end);
297 }
298 return end;
299 } else if (offset == 1) {
300
301
302
303
304
305 size_t v = repeat_byte(*(dst - 1));
306
307 do {
308 put_unaligned(v, (size_t *)dst);
309 src += WORDBYTES;
310 dst += WORDBYTES;
311 } while (dst < end);
312 return end;
313 }
314
315
316
317
318
319
320
321
322
323 }
324#endif
325
326
327
328 if (min_length >= 2) {
329 *dst++ = *src++;
330 length--;
331 }
332 if (min_length >= 3) {
333 *dst++ = *src++;
334 length--;
335 }
336 do {
337 *dst++ = *src++;
338 } while (--length);
339
340 return dst;
341}
342
343#endif
344