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/**
* Copyright 2013, GitHub, Inc
* Copyright 2009-2013, Daniel Lemire, Cliff Moon,
* David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "git-compat-util.h"
#include "ewok.h"
#include "ewok_rlw.h"
static inline int next_word(struct rlw_iterator *it)
{
if (it->pointer >= it->size)
return 0;
it->rlw.word = &it->buffer[it->pointer];
it->pointer += rlw_get_literal_words(it->rlw.word) + 1;
it->rlw.literal_words = rlw_get_literal_words(it->rlw.word);
it->rlw.running_len = rlw_get_running_len(it->rlw.word);
it->rlw.running_bit = rlw_get_run_bit(it->rlw.word);
it->rlw.literal_word_offset = 0;
return 1;
}
void rlwit_init(struct rlw_iterator *it, struct ewah_bitmap *from_ewah)
{
it->buffer = from_ewah->buffer;
it->size = from_ewah->buffer_size;
it->pointer = 0;
next_word(it);
it->literal_word_start = rlwit_literal_words(it) +
it->rlw.literal_word_offset;
}
void rlwit_discard_first_words(struct rlw_iterator *it, size_t x)
{
while (x > 0) {
size_t discard;
if (it->rlw.running_len > x) {
it->rlw.running_len -= x;
return;
}
x -= it->rlw.running_len;
it->rlw.running_len = 0;
discard = (x > it->rlw.literal_words) ? it->rlw.literal_words : x;
it->literal_word_start += discard;
it->rlw.literal_words -= discard;
x -= discard;
if (x > 0 || rlwit_word_size(it) == 0) {
if (!next_word(it))
break;
it->literal_word_start =
rlwit_literal_words(it) + it->rlw.literal_word_offset;
}
}
}
size_t rlwit_discharge(
struct rlw_iterator *it, struct ewah_bitmap *out, size_t max, int negate)
{
size_t index = 0;
while (index < max && rlwit_word_size(it) > 0) {
size_t pd, pl = it->rlw.running_len;
if (index + pl > max)
pl = max - index;
ewah_add_empty_words(out, it->rlw.running_bit ^ negate, pl);
index += pl;
pd = it->rlw.literal_words;
if (pd + index > max)
pd = max - index;
ewah_add_dirty_words(out,
it->buffer + it->literal_word_start, pd, negate);
rlwit_discard_first_words(it, pd + pl);
index += pd;
}
return index;
}
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