lib/lzo/lzo1x_compress.c

   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");