lib/lzo/lzo1x_compress.c

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