MdeModulePkg/Library/BrotliCustomDecompressLib/dec/huffman.c

   1 /* Copyright 2013 Google Inc. All Rights Reserved.
   2
   3    Distributed under MIT license.
   4    See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
   5 */
   6
   7 /* Utilities for building Huffman decoding tables. */
   8
   9 #include "./huffman.h"
  10
  11 //#include <string.h>  /* memcpy, memset */
  12
  13 #include "../common/constants.h"
  14 #include "../common/platform.h"
  15 #include <brotli/types.h>
  16
  17 #if defined(__cplusplus) || defined(c_plusplus)
  18 extern "C" {
  19 #endif
  20
  21 #define BROTLI_REVERSE_BITS_MAX 8
  22
  23 #if defined(BROTLI_RBIT)
  24 #define BROTLI_REVERSE_BITS_BASE \
  25   ((sizeof(brotli_reg_t) << 3) - BROTLI_REVERSE_BITS_MAX)
  26 #else
  27 #define BROTLI_REVERSE_BITS_BASE 0
  28 static uint8_t kReverseBits[1 << BROTLI_REVERSE_BITS_MAX] = {
  29   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
  30   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
  31   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
  32   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
  33   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
  34   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
  35   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
  36   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
  37   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
  38   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
  39   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
  40   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
  41   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
  42   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
  43   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
  44   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
  45   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
  46   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
  47   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
  48   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
  49   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
  50   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
  51   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
  52   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
  53   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
  54   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
  55   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
  56   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
  57   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
  58   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
  59   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
  60   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
  61 };
  62 #endif  /* BROTLI_RBIT */
  63
  64 #define BROTLI_REVERSE_BITS_LOWEST \
  65   ((brotli_reg_t)1 << (BROTLI_REVERSE_BITS_MAX - 1 + BROTLI_REVERSE_BITS_BASE))
  66
  67 /* Returns reverse(num >> BROTLI_REVERSE_BITS_BASE, BROTLI_REVERSE_BITS_MAX),
  68    where reverse(value, len) is the bit-wise reversal of the len least
  69    significant bits of value. */
  70 static BROTLI_INLINE brotli_reg_t BrotliReverseBits(brotli_reg_t num) {
  71 #if defined(BROTLI_RBIT)
  72   return BROTLI_RBIT(num);
  73 #else
  74   return kReverseBits[num];
  75 #endif
  76 }
  77
  78 /* Stores code in table[0], table[step], table[2*step], ..., table[end] */
  79 /* Assumes that end is an integer multiple of step */
  80 static BROTLI_INLINE void ReplicateValue(HuffmanCode* table,
  81                                          int step, int end,
  82                                          HuffmanCode code) {
  83   do {
  84     end -= step;
  85     table[end] = code;
  86   } while (end > 0);
  87 }
  88
  89 /* Returns the table width of the next 2nd level table. |count| is the histogram
  90    of bit lengths for the remaining symbols, |len| is the code length of the
  91    next processed symbol. */
  92 static BROTLI_INLINE int NextTableBitSize(const uint16_t* const count,
  93                                           int len, int root_bits) {
  94   int left = 1 << (len - root_bits);
  95   while (len < BROTLI_HUFFMAN_MAX_CODE_LENGTH) {
  96     left -= count[len];
  97     if (left <= 0) break;
  98     ++len;
  99     left <<= 1;
 100   }
 101   return len - root_bits;
 102 }
 103
 104 void BrotliBuildCodeLengthsHuffmanTable(HuffmanCode* table,
 105                                         const uint8_t* const code_lengths,
 106                                         uint16_t* count) {
 107   HuffmanCode code;       /* current table entry */
 108   int symbol;             /* symbol index in original or sorted table */
 109   brotli_reg_t key;       /* prefix code */
 110   brotli_reg_t key_step;  /* prefix code addend */
 111   int step;               /* step size to replicate values in current table */
 112   int table_size;         /* size of current table */
 113   int sorted[BROTLI_CODE_LENGTH_CODES];  /* symbols sorted by code length */
 114   /* offsets in sorted table for each length */
 115   int offset[BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH + 1];
 116   int bits;
 117   int bits_count;
 118   BROTLI_DCHECK(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH <=
 119                 BROTLI_REVERSE_BITS_MAX);
 120
 121   /* Generate offsets into sorted symbol table by code length. */
 122   symbol = -1;
 123   bits = 1;
 124   BROTLI_REPEAT(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH, {
 125     symbol += count[bits];
 126     offset[bits] = symbol;
 127     bits++;
 128   });
 129   /* Symbols with code length 0 are placed after all other symbols. */
 130   offset[0] = BROTLI_CODE_LENGTH_CODES - 1;
 131
 132   /* Sort symbols by length, by symbol order within each length. */
 133   symbol = BROTLI_CODE_LENGTH_CODES;
 134   do {
 135     BROTLI_REPEAT(6, {
 136       symbol--;
 137       sorted[offset[code_lengths[symbol]]--] = symbol;
 138     });
 139   } while (symbol != 0);
 140
 141   table_size = 1 << BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH;
 142
 143   /* Special case: all symbols but one have 0 code length. */
 144   if (offset[0] == 0) {
 145     code.bits = 0;
 146     code.value = (uint16_t)sorted[0];
 147     for (key = 0; key < (brotli_reg_t)table_size; ++key) {
 148       table[key] = code;
 149     }
 150     return;
 151   }
 152
 153   /* Fill in table. */
 154   key = 0;
 155   key_step = BROTLI_REVERSE_BITS_LOWEST;
 156   symbol = 0;
 157   bits = 1;
 158   step = 2;
 159   do {
 160     code.bits = (uint8_t)bits;
 161     for (bits_count = count[bits]; bits_count != 0; --bits_count) {
 162       code.value = (uint16_t)sorted[symbol++];
 163       ReplicateValue(&table[BrotliReverseBits(key)], step, table_size, code);
 164       key += key_step;
 165     }
 166     step <<= 1;
 167     key_step >>= 1;
 168   } while (++bits <= BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH);
 169 }
 170
 171 uint32_t BrotliBuildHuffmanTable(HuffmanCode* root_table,
 172                                  int root_bits,
 173                                  const uint16_t* const symbol_lists,
 174                                  uint16_t* count) {
 175   HuffmanCode code;       /* current table entry */
 176   HuffmanCode* table;     /* next available space in table */
 177   int len;                /* current code length */
 178   int symbol;             /* symbol index in original or sorted table */
 179   brotli_reg_t key;       /* prefix code */
 180   brotli_reg_t key_step;  /* prefix code addend */
 181   brotli_reg_t sub_key;   /* 2nd level table prefix code */
 182   brotli_reg_t sub_key_step;  /* 2nd level table prefix code addend */
 183   int step;               /* step size to replicate values in current table */
 184   int table_bits;         /* key length of current table */
 185   int table_size;         /* size of current table */
 186   int total_size;         /* sum of root table size and 2nd level table sizes */
 187   int max_length = -1;
 188   int bits;
 189   int bits_count;
 190
 191   BROTLI_DCHECK(root_bits <= BROTLI_REVERSE_BITS_MAX);
 192   BROTLI_DCHECK(BROTLI_HUFFMAN_MAX_CODE_LENGTH - root_bits <=
 193                 BROTLI_REVERSE_BITS_MAX);
 194
 195   while (symbol_lists[max_length] == 0xFFFF) max_length--;
 196   max_length += BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1;
 197
 198   table = root_table;
 199   table_bits = root_bits;
 200   table_size = 1 << table_bits;
 201   total_size = table_size;
 202
 203   /* Fill in the root table. Reduce the table size to if possible,
 204      and create the repetitions by memcpy. */
 205   if (table_bits > max_length) {
 206     table_bits = max_length;
 207     table_size = 1 << table_bits;
 208   }
 209   key = 0;
 210   key_step = BROTLI_REVERSE_BITS_LOWEST;
 211   bits = 1;
 212   step = 2;
 213   do {
 214     code.bits = (uint8_t)bits;
 215     symbol = bits - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1);
 216     for (bits_count = count[bits]; bits_count != 0; --bits_count) {
 217       symbol = symbol_lists[symbol];
 218       code.value = (uint16_t)symbol;
 219       ReplicateValue(&table[BrotliReverseBits(key)], step, table_size, code);
 220       key += key_step;
 221     }
 222     step <<= 1;
 223     key_step >>= 1;
 224   } while (++bits <= table_bits);
 225
 226   /* If root_bits != table_bits then replicate to fill the remaining slots. */
 227   while (total_size != table_size) {
 228     memcpy(&table[table_size], &table[0],
 229            (size_t)table_size * sizeof(table[0]));
 230     table_size <<= 1;
 231   }
 232
 233   /* Fill in 2nd level tables and add pointers to root table. */
 234   key_step = BROTLI_REVERSE_BITS_LOWEST >> (root_bits - 1);
 235   sub_key = (BROTLI_REVERSE_BITS_LOWEST << 1);
 236   sub_key_step = BROTLI_REVERSE_BITS_LOWEST;
 237   for (len = root_bits + 1, step = 2; len <= max_length; ++len) {
 238     symbol = len - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1);
 239     for (; count[len] != 0; --count[len]) {
 240       if (sub_key == (BROTLI_REVERSE_BITS_LOWEST << 1U)) {
 241         table += table_size;
 242         table_bits = NextTableBitSize(count, len, root_bits);
 243         table_size = 1 << table_bits;
 244         total_size += table_size;
 245         sub_key = BrotliReverseBits(key);
 246         key += key_step;
 247         root_table[sub_key].bits = (uint8_t)(table_bits + root_bits);
 248         root_table[sub_key].value =
 249             (uint16_t)(((size_t)(table - root_table)) - sub_key);
 250         sub_key = 0;
 251       }
 252       code.bits = (uint8_t)(len - root_bits);
 253       symbol = symbol_lists[symbol];
 254       code.value = (uint16_t)symbol;
 255       ReplicateValue(
 256           &table[BrotliReverseBits(sub_key)], step, table_size, code);
 257       sub_key += sub_key_step;
 258     }
 259     step <<= 1;
 260     sub_key_step >>= 1;
 261   }
 262   return (uint32_t)total_size;
 263 }
 264
 265 uint32_t BrotliBuildSimpleHuffmanTable(HuffmanCode* table,
 266                                        int root_bits,
 267                                        uint16_t* val,
 268                                        uint32_t num_symbols) {
 269   uint32_t table_size = 1;
 270   const uint32_t goal_size = 1U << root_bits;
 271   switch (num_symbols) {
 272     case 0:
 273       table[0].bits = 0;
 274       table[0].value = val[0];
 275       break;
 276     case 1:
 277       table[0].bits = 1;
 278       table[1].bits = 1;
 279       if (val[1] > val[0]) {
 280         table[0].value = val[0];
 281         table[1].value = val[1];
 282       } else {
 283         table[0].value = val[1];
 284         table[1].value = val[0];
 285       }
 286       table_size = 2;
 287       break;
 288     case 2:
 289       table[0].bits = 1;
 290       table[0].value = val[0];
 291       table[2].bits = 1;
 292       table[2].value = val[0];
 293       if (val[2] > val[1]) {
 294         table[1].value = val[1];
 295         table[3].value = val[2];
 296       } else {
 297         table[1].value = val[2];
 298         table[3].value = val[1];
 299       }
 300       table[1].bits = 2;
 301       table[3].bits = 2;
 302       table_size = 4;
 303       break;
 304     case 3: {
 305       int i, k;
 306       for (i = 0; i < 3; ++i) {
 307         for (k = i + 1; k < 4; ++k) {
 308           if (val[k] < val[i]) {
 309             uint16_t t = val[k];
 310             val[k] = val[i];
 311             val[i] = t;
 312           }
 313         }
 314       }
 315       for (i = 0; i < 4; ++i) {
 316         table[i].bits = 2;
 317       }
 318       table[0].value = val[0];
 319       table[2].value = val[1];
 320       table[1].value = val[2];
 321       table[3].value = val[3];
 322       table_size = 4;
 323       break;
 324     }
 325     case 4: {
 326       int i;
 327       if (val[3] < val[2]) {
 328         uint16_t t = val[3];
 329         val[3] = val[2];
 330         val[2] = t;
 331       }
 332       for (i = 0; i < 7; ++i) {
 333         table[i].value = val[0];
 334         table[i].bits = (uint8_t)(1 + (i & 1));
 335       }
 336       table[1].value = val[1];
 337       table[3].value = val[2];
 338       table[5].value = val[1];
 339       table[7].value = val[3];
 340       table[3].bits = 3;
 341       table[7].bits = 3;
 342       table_size = 8;
 343       break;
 344     }
 345   }
 346   while (table_size != goal_size) {
 347     memcpy(&table[table_size], &table[0],
 348            (size_t)table_size * sizeof(table[0]));
 349     table_size <<= 1;
 350   }
 351   return goal_size;
 352 }
 353
 354 #if defined(__cplusplus) || defined(c_plusplus)
 355 }  /* extern "C" */
 356 #endif