Andrew's git - gitweb.git/blob

   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, write to the Free Software
  18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19 */
  20#include "git-compat-util.h"
  21#include "ewok.h"
  22#include "ewok_rlw.h"
  23
  24static inline int next_word(struct rlw_iterator *it)
  25{
  26        if (it->pointer >= it->size)
  27                return 0;
  28
  29        it->rlw.word = &it->buffer[it->pointer];
  30        it->pointer += rlw_get_literal_words(it->rlw.word) + 1;
  31
  32        it->rlw.literal_words = rlw_get_literal_words(it->rlw.word);
  33        it->rlw.running_len = rlw_get_running_len(it->rlw.word);
  34        it->rlw.running_bit = rlw_get_run_bit(it->rlw.word);
  35        it->rlw.literal_word_offset = 0;
  36
  37        return 1;
  38}
  39
  40void rlwit_init(struct rlw_iterator *it, struct ewah_bitmap *from_ewah)
  41{
  42        it->buffer = from_ewah->buffer;
  43        it->size = from_ewah->buffer_size;
  44        it->pointer = 0;
  45
  46        next_word(it);
  47
  48        it->literal_word_start = rlwit_literal_words(it) +
  49                it->rlw.literal_word_offset;
  50}
  51
  52void rlwit_discard_first_words(struct rlw_iterator *it, size_t x)
  53{
  54        while (x > 0) {
  55                size_t discard;
  56
  57                if (it->rlw.running_len > x) {
  58                        it->rlw.running_len -= x;
  59                        return;
  60                }
  61
  62                x -= it->rlw.running_len;
  63                it->rlw.running_len = 0;
  64
  65                discard = (x > it->rlw.literal_words) ? it->rlw.literal_words : x;
  66
  67                it->literal_word_start += discard;
  68                it->rlw.literal_words -= discard;
  69                x -= discard;
  70
  71                if (x > 0 || rlwit_word_size(it) == 0) {
  72                        if (!next_word(it))
  73                                break;
  74
  75                        it->literal_word_start =
  76                                rlwit_literal_words(it) + it->rlw.literal_word_offset;
  77                }
  78        }
  79}
  80
  81size_t rlwit_discharge(
  82        struct rlw_iterator *it, struct ewah_bitmap *out, size_t max, int negate)
  83{
  84        size_t index = 0;
  85
  86        while (index < max && rlwit_word_size(it) > 0) {
  87                size_t pd, pl = it->rlw.running_len;
  88
  89                if (index + pl > max)
  90                        pl = max - index;
  91
  92                ewah_add_empty_words(out, it->rlw.running_bit ^ negate, pl);
  93                index += pl;
  94
  95                pd = it->rlw.literal_words;
  96                if (pd + index > max)
  97                        pd = max - index;
  98
  99                ewah_add_dirty_words(out,
 100                        it->buffer + it->literal_word_start, pd, negate);
 101
 102                rlwit_discard_first_words(it, pd + pl);
 103                index += pd;
 104        }
 105
 106        return index;
 107}
 108
 109void rlwit_discharge_empty(struct rlw_iterator *it, struct ewah_bitmap *out)
 110{
 111        while (rlwit_word_size(it) > 0) {
 112                ewah_add_empty_words(out, 0, rlwit_word_size(it));
 113                rlwit_discard_first_words(it, rlwit_word_size(it));
 114        }
 115}