ewah/ewok_rlw.h

   1 /**
   2  * Copyright 2013, GitHub, Inc
   3  * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
   4  *      David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #ifndef __EWOK_RLW_H__
  20 #define __EWOK_RLW_H__
  21
  22 #include "ewok.h"
  23
  24 #define RLW_RUNNING_BITS (sizeof(eword_t) * 4)
  25 #define RLW_LITERAL_BITS (sizeof(eword_t) * 8 - 1 - RLW_RUNNING_BITS)
  26
  27 #define RLW_LARGEST_RUNNING_COUNT (((eword_t)1 << RLW_RUNNING_BITS) - 1)
  28 #define RLW_LARGEST_LITERAL_COUNT (((eword_t)1 << RLW_LITERAL_BITS) - 1)
  29
  30 #define RLW_LARGEST_RUNNING_COUNT_SHIFT (RLW_LARGEST_RUNNING_COUNT << 1)
  31
  32 #define RLW_RUNNING_LEN_PLUS_BIT (((eword_t)1 << (RLW_RUNNING_BITS + 1)) - 1)
  33
  34 static int rlw_get_run_bit(const eword_t *word)
  35 {
  36         return *word & (eword_t)1;
  37 }
  38
  39 static inline void rlw_set_run_bit(eword_t *word, int b)
  40 {
  41         if (b) {
  42                 *word |= (eword_t)1;
  43         } else {
  44                 *word &= (eword_t)(~1);
  45         }
  46 }
  47
  48 static inline void rlw_xor_run_bit(eword_t *word)
  49 {
  50         if (*word & 1) {
  51                 *word &= (eword_t)(~1);
  52         } else {
  53                 *word |= (eword_t)1;
  54         }
  55 }
  56
  57 static inline void rlw_set_running_len(eword_t *word, eword_t l)
  58 {
  59         *word |= RLW_LARGEST_RUNNING_COUNT_SHIFT;
  60         *word &= (l << 1) | (~RLW_LARGEST_RUNNING_COUNT_SHIFT);
  61 }
  62
  63 static inline eword_t rlw_get_running_len(const eword_t *word)
  64 {
  65         return (*word >> 1) & RLW_LARGEST_RUNNING_COUNT;
  66 }
  67
  68 static inline eword_t rlw_get_literal_words(const eword_t *word)
  69 {
  70         return *word >> (1 + RLW_RUNNING_BITS);
  71 }
  72
  73 static inline void rlw_set_literal_words(eword_t *word, eword_t l)
  74 {
  75         *word |= ~RLW_RUNNING_LEN_PLUS_BIT;
  76         *word &= (l << (RLW_RUNNING_BITS + 1)) | RLW_RUNNING_LEN_PLUS_BIT;
  77 }
  78
  79 static inline eword_t rlw_size(const eword_t *self)
  80 {
  81         return rlw_get_running_len(self) + rlw_get_literal_words(self);
  82 }
  83
  84 struct rlw_iterator {
  85         const eword_t *buffer;
  86         size_t size;
  87         size_t pointer;
  88         size_t literal_word_start;
  89
  90         struct {
  91                 const eword_t *word;
  92                 int literal_words;
  93                 int running_len;
  94                 int literal_word_offset;
  95                 int running_bit;
  96         } rlw;
  97 };
  98
  99 void rlwit_init(struct rlw_iterator *it, struct ewah_bitmap *bitmap);
 100 void rlwit_discard_first_words(struct rlw_iterator *it, size_t x);
 101 size_t rlwit_discharge(
 102         struct rlw_iterator *it, struct ewah_bitmap *out, size_t max, int negate);
 103
 104 static inline size_t rlwit_word_size(struct rlw_iterator *it)
 105 {
 106         return it->rlw.running_len + it->rlw.literal_words;
 107 }
 108
 109 static inline size_t rlwit_literal_words(struct rlw_iterator *it)
 110 {
 111         return it->pointer - it->rlw.literal_words;
 112 }
 113
 114 #endif