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