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 = 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");