1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * LZO1X Compressor from LZO
4 *
5 * Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>
6 *
7 * The full LZO package can be found at:
8 * http://www.oberhumer.com/opensource/lzo/
9 *
10 * Changed for Linux kernel use by:
11 * Nitin Gupta <nitingupta910@gmail.com>
12 * Richard Purdie <rpurdie@openedhand.com>
13 */
14
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <asm/unaligned.h>
18 #include <linux/lzo.h>
19 #include "lzodefs.h"
20
21 static noinline size_t
22 lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
23 unsigned char *out, size_t *out_len,
24 size_t ti, void *wrkmem, signed char *state_offset,
25 const unsigned char bitstream_version)
26 {
27 const unsigned char *ip;
28 unsigned char *op;
29 const unsigned char * const in_end = in + in_len;
30 const unsigned char * const ip_end = in + in_len - 20;
31 const unsigned char *ii;
32 lzo_dict_t * const dict = (lzo_dict_t *) wrkmem;
33
34 op = out;
35 ip = in;
36 ii = ip;
37 ip += ti < 4 ? 4 - ti : 0;
38
39 for (;;) {
40 const unsigned char *m_pos = NULL;
41 size_t t, m_len, m_off;
42 u32 dv;
43 u32 run_length = 0;
44 literal:
45 ip += 1 + ((ip - ii) >> 5);
46 next:
47 if (unlikely(ip >= ip_end))
48 break;
49 dv = get_unaligned_le32(ip);
50
51 if (dv == 0 && bitstream_version) {
52 const unsigned char *ir = ip + 4;
53 const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
54 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
55 defined(LZO_FAST_64BIT_MEMORY_ACCESS)
56 u64 dv64;
57
58 for (; (ir + 32) <= limit; ir += 32) {
59 dv64 = get_unaligned((u64 *)ir);
60 dv64 |= get_unaligned((u64 *)ir + 1);
61 dv64 |= get_unaligned((u64 *)ir + 2);
62 dv64 |= get_unaligned((u64 *)ir + 3);
63 if (dv64)
64 break;
65 }
66 for (; (ir + 8) <= limit; ir += 8) {
67 dv64 = get_unaligned((u64 *)ir);
68 if (dv64) {
69 # if defined(__LITTLE_ENDIAN)
70 ir += __builtin_ctzll(dv64) >> 3;
71 # elif defined(__BIG_ENDIAN)
72 ir += __builtin_clzll(dv64) >> 3;
73 # else
74 # error "missing endian definition"
75 # endif
76 break;
77 }
78 }
79 #else
80 while ((ir < (const unsigned char *)
81 ALIGN((uintptr_t)ir, 4)) &&
82 (ir < limit) && (*ir == 0))
83 ir++;
84 if (IS_ALIGNED((uintptr_t)ir, 4)) {
85 for (; (ir + 4) <= limit; ir += 4) {
86 dv = *((u32 *)ir);
87 if (dv) {
88 # if defined(__LITTLE_ENDIAN)
89 ir += __builtin_ctz(dv) >> 3;
90 # elif defined(__BIG_ENDIAN)
91 ir += __builtin_clz(dv) >> 3;
92 # else
93 # error "missing endian definition"
94 # endif
95 break;
96 }
97 }
98 }
99 #endif
100 while (likely(ir < limit) && unlikely(*ir == 0))
101 ir++;
102 run_length = ir - ip;
103 if (run_length > MAX_ZERO_RUN_LENGTH)
104 run_length = MAX_ZERO_RUN_LENGTH;
105 } else {
106 t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
107 m_pos = in + dict[t];
108 dict[t] = (lzo_dict_t) (ip - in);
109 if (unlikely(dv != get_unaligned_le32(m_pos)))
110 goto literal;
111 }
112
113 ii -= ti;
114 ti = 0;
115 t = ip - ii;
116 if (t != 0) {
117 if (t <= 3) {
118 op[*state_offset] |= t;
119 COPY4(op, ii);
120 op += t;
121 } else if (t <= 16) {
122 *op++ = (t - 3);
123 COPY8(op, ii);
124 COPY8(op + 8, ii + 8);
125 op += t;
126 } else {
127 if (t <= 18) {
128 *op++ = (t - 3);
129 } else {
130 size_t tt = t - 18;
131 *op++ = 0;
132 while (unlikely(tt > 255)) {
133 tt -= 255;
134 *op++ = 0;
135 }
136 *op++ = tt;
137 }
138 do {
139 COPY8(op, ii);
140 COPY8(op + 8, ii + 8);
141 op += 16;
142 ii += 16;
143 t -= 16;
144 } while (t >= 16);
145 if (t > 0) do {
146 *op++ = *ii++;
147 } while (--t > 0);
148 }
149 }
150
151 if (unlikely(run_length)) {
152 ip += run_length;
153 run_length -= MIN_ZERO_RUN_LENGTH;
154 put_unaligned_le32((run_length << 21) | 0xfffc18
155 | (run_length & 0x7), op);
156 op += 4;
157 run_length = 0;
158 *state_offset = -3;
159 goto finished_writing_instruction;
160 }
161
162 m_len = 4;
163 {
164 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)
165 u64 v;
166 v = get_unaligned((const u64 *) (ip + m_len)) ^
167 get_unaligned((const u64 *) (m_pos + m_len));
168 if (unlikely(v == 0)) {
169 do {
170 m_len += 8;
171 v = get_unaligned((const u64 *) (ip + m_len)) ^
172 get_unaligned((const u64 *) (m_pos + m_len));
173 if (unlikely(ip + m_len >= ip_end))
174 goto m_len_done;
175 } while (v == 0);
176 }
177 # if defined(__LITTLE_ENDIAN)
178 m_len += (unsigned) __builtin_ctzll(v) / 8;
179 # elif defined(__BIG_ENDIAN)
180 m_len += (unsigned) __builtin_clzll(v) / 8;
181 # else
182 # error "missing endian definition"
183 # endif
184 #elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)
185 u32 v;
186 v = get_unaligned((const u32 *) (ip + m_len)) ^
187 get_unaligned((const u32 *) (m_pos + m_len));
188 if (unlikely(v == 0)) {
189 do {
190 m_len += 4;
191 v = get_unaligned((const u32 *) (ip + m_len)) ^
192 get_unaligned((const u32 *) (m_pos + m_len));
193 if (v != 0)
194 break;
195 m_len += 4;
196 v = get_unaligned((const u32 *) (ip + m_len)) ^
197 get_unaligned((const u32 *) (m_pos + m_len));
198 if (unlikely(ip + m_len >= ip_end))
199 goto m_len_done;
200 } while (v == 0);
201 }
202 # if defined(__LITTLE_ENDIAN)
203 m_len += (unsigned) __builtin_ctz(v) / 8;
204 # elif defined(__BIG_ENDIAN)
205 m_len += (unsigned) __builtin_clz(v) / 8;
206 # else
207 # error "missing endian definition"
208 # endif
209 #else
210 if (unlikely(ip[m_len] == m_pos[m_len])) {
211 do {
212 m_len += 1;
213 if (ip[m_len] != m_pos[m_len])
214 break;
215 m_len += 1;
216 if (ip[m_len] != m_pos[m_len])
217 break;
218 m_len += 1;
219 if (ip[m_len] != m_pos[m_len])
220 break;
221 m_len += 1;
222 if (ip[m_len] != m_pos[m_len])
223 break;
224 m_len += 1;
225 if (ip[m_len] != m_pos[m_len])
226 break;
227 m_len += 1;
228 if (ip[m_len] != m_pos[m_len])
229 break;
230 m_len += 1;
231 if (ip[m_len] != m_pos[m_len])
232 break;
233 m_len += 1;
234 if (unlikely(ip + m_len >= ip_end))
235 goto m_len_done;
236 } while (ip[m_len] == m_pos[m_len]);
237 }
238 #endif
239 }
240 m_len_done:
241
242 m_off = ip - m_pos;
243 ip += m_len;
244 if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
245 m_off -= 1;
246 *op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
247 *op++ = (m_off >> 3);
248 } else if (m_off <= M3_MAX_OFFSET) {
249 m_off -= 1;
250 if (m_len <= M3_MAX_LEN)
251 *op++ = (M3_MARKER | (m_len - 2));
252 else {
253 m_len -= M3_MAX_LEN;
254 *op++ = M3_MARKER | 0;
255 while (unlikely(m_len > 255)) {
256 m_len -= 255;
257 *op++ = 0;
258 }
259 *op++ = (m_len);
260 }
261 *op++ = (m_off << 2);
262 *op++ = (m_off >> 6);
263 } else {
264 m_off -= 0x4000;
265 if (m_len <= M4_MAX_LEN)
266 *op++ = (M4_MARKER | ((m_off >> 11) & 8)
267 | (m_len - 2));
268 else {
269 if (unlikely(((m_off & 0x403f) == 0x403f)
270 && (m_len >= 261)
271 && (m_len <= 264))
272 && likely(bitstream_version)) {
273 // Under lzo-rle, block copies
274 // for 261 <= length <= 264 and
275 // (distance & 0x80f3) == 0x80f3
276 // can result in ambiguous
277 // output. Adjust length
278 // to 260 to prevent ambiguity.
279 ip -= m_len - 260;
280 m_len = 260;
281 }
282 m_len -= M4_MAX_LEN;
283 *op++ = (M4_MARKER | ((m_off >> 11) & 8));
284 while (unlikely(m_len > 255)) {
285 m_len -= 255;
286 *op++ = 0;
287 }
288 *op++ = (m_len);
289 }
290 *op++ = (m_off << 2);
291 *op++ = (m_off >> 6);
292 }
293 *state_offset = -2;
294 finished_writing_instruction:
295 ii = ip;
296 goto next;
297 }
298 *out_len = op - out;
299 return in_end - (ii - ti);
300 }
301
302 static int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
303 unsigned char *out, size_t *out_len,
304 void *wrkmem, const unsigned char bitstream_version)
305 {
306 const unsigned char *ip = in;
307 unsigned char *op = out;
308 unsigned char *data_start;
309 size_t l = in_len;
310 size_t t = 0;
311 signed char state_offset = -2;
312 unsigned int m4_max_offset;
313
314 // LZO v0 will never write 17 as first byte (except for zero-length
315 // input), so this is used to version the bitstream
316 if (bitstream_version > 0) {
317 *op++ = 17;
318 *op++ = bitstream_version;
319 m4_max_offset = M4_MAX_OFFSET_V1;
320 } else {
321 m4_max_offset = M4_MAX_OFFSET_V0;
322 }
323
324 data_start = op;
325
326 while (l > 20) {
327 size_t ll = min_t(size_t, l, m4_max_offset + 1);
328 uintptr_t ll_end = (uintptr_t) ip + ll;
329 if ((ll_end + ((t + ll) >> 5)) <= ll_end)
330 break;
331 BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
332 memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
333 t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
334 &state_offset, bitstream_version);
335 ip += ll;
336 op += *out_len;
337 l -= ll;
338 }
339 t += l;
340
341 if (t > 0) {
342 const unsigned char *ii = in + in_len - t;
343
344 if (op == data_start && t <= 238) {
345 *op++ = (17 + t);
346 } else if (t <= 3) {
347 op[state_offset] |= t;
348 } else if (t <= 18) {
349 *op++ = (t - 3);
350 } else {
351 size_t tt = t - 18;
352 *op++ = 0;
353 while (tt > 255) {
354 tt -= 255;
355 *op++ = 0;
356 }
357 *op++ = tt;
358 }
359 if (t >= 16) do {
360 COPY8(op, ii);
361 COPY8(op + 8, ii + 8);
362 op += 16;
363 ii += 16;
364 t -= 16;
365 } while (t >= 16);
366 if (t > 0) do {
367 *op++ = *ii++;
368 } while (--t > 0);
369 }
370
371 *op++ = M4_MARKER | 1;
372 *op++ = 0;
373 *op++ = 0;
374
375 *out_len = op - out;
376 return LZO_E_OK;
377 }
378
379 int lzo1x_1_compress(const unsigned char *in, size_t in_len,
380 unsigned char *out, size_t *out_len,
381 void *wrkmem)
382 {
383 return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
384 }
385
386 int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
387 unsigned char *out, size_t *out_len,
388 void *wrkmem)
389 {
390 return lzogeneric1x_1_compress(in, in_len, out, out_len,
391 wrkmem, LZO_VERSION);
392 }
393
394 EXPORT_SYMBOL_GPL(lzo1x_1_compress);
395 EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
396
397 MODULE_LICENSE("GPL");
398 MODULE_DESCRIPTION("LZO1X-1 Compressor");
399
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