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 #define RLW_RUNNING_BITS (sizeof(eword_t) * 4)
  23 #define RLW_LITERAL_BITS (sizeof(eword_t) * 8 - 1 - RLW_RUNNING_BITS)
  24
  25 #define RLW_LARGEST_RUNNING_COUNT (((eword_t)1 << RLW_RUNNING_BITS) - 1)
  26 #define RLW_LARGEST_LITERAL_COUNT (((eword_t)1 << RLW_LITERAL_BITS) - 1)
  27
  28 #define RLW_LARGEST_RUNNING_COUNT_SHIFT (RLW_LARGEST_RUNNING_COUNT << 1)
  29
  30 #define RLW_RUNNING_LEN_PLUS_BIT (((eword_t)1 << (RLW_RUNNING_BITS + 1)) - 1)
  31
  32 static int rlw_get_run_bit(const eword_t *word)
  33 {
  34         return *word & (eword_t)1;
  35 }
  36
  37 static inline void rlw_set_run_bit(eword_t *word, int b)
  38 {
  39         if (b) {
  40                 *word |= (eword_t)1;
  41         } else {
  42                 *word &= (eword_t)(~1);
  43         }
  44 }
  45
  46 static inline void rlw_xor_run_bit(eword_t *word)
  47 {
  48         if (*word & 1) {
  49                 *word &= (eword_t)(~1);
  50         } else {
  51                 *word |= (eword_t)1;
  52         }
  53 }
  54
  55 static inline void rlw_set_running_len(eword_t *word, eword_t l)
  56 {
  57         *word |= RLW_LARGEST_RUNNING_COUNT_SHIFT;
  58         *word &= (l << 1) | (~RLW_LARGEST_RUNNING_COUNT_SHIFT);
  59 }
  60
  61 static inline eword_t rlw_get_running_len(const eword_t *word)
  62 {
  63         return (*word >> 1) & RLW_LARGEST_RUNNING_COUNT;
  64 }
  65
  66 static inline eword_t rlw_get_literal_words(const eword_t *word)
  67 {
  68         return *word >> (1 + RLW_RUNNING_BITS);
  69 }
  70
  71 static inline void rlw_set_literal_words(eword_t *word, eword_t l)
  72 {
  73         *word |= ~RLW_RUNNING_LEN_PLUS_BIT;
  74         *word &= (l << (RLW_RUNNING_BITS + 1)) | RLW_RUNNING_LEN_PLUS_BIT;
  75 }
  76
  77 static inline eword_t rlw_size(const eword_t *self)
  78 {
  79         return rlw_get_running_len(self) + rlw_get_literal_words(self);
  80 }
  81
  82 struct rlw_iterator {
  83         const eword_t *buffer;
  84         size_t size;
  85         size_t pointer;
  86         size_t literal_word_start;
  87
  88         struct {
  89                 const eword_t *word;
  90                 int literal_words;
  91                 int running_len;
  92                 int literal_word_offset;
  93                 int running_bit;
  94         } rlw;
  95 };
  96
  97 void rlwit_init(struct rlw_iterator *it, struct ewah_bitmap *bitmap);
  98 void rlwit_discard_first_words(struct rlw_iterator *it, size_t x);
  99 size_t rlwit_discharge(
 100         struct rlw_iterator *it, struct ewah_bitmap *out, size_t max, int negate);
 101
 102 static inline size_t rlwit_word_size(struct rlw_iterator *it)
 103 {
 104         return it->rlw.running_len + it->rlw.literal_words;
 105 }
 106
 107 static inline size_t rlwit_literal_words(struct rlw_iterator *it)
 108 {
 109         return it->pointer - it->rlw.literal_words;
 110 }
 111
 112 #endif