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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* deduplicate.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "fstree.h"
#include <string.h>
file_info_t *fragment_by_chksum(file_info_t *fi, uint32_t chksum,
size_t frag_size, file_info_t *list,
size_t block_size)
{
file_info_t *it;
for (it = list; it != NULL; it = it->next) {
if (it == fi)
continue;
if (!(it->flags & FILE_FLAG_HAS_FRAGMENT))
continue;
if (it->flags & FILE_FLAG_FRAGMENT_IS_DUPLICATE)
continue;
if ((it->size % block_size) != frag_size)
continue;
if (it->fragment_chksum == chksum)
break;
}
return it;
}
static size_t get_block_count(file_info_t *fi, size_t block_size)
{
size_t count = fi->size / block_size;
if ((fi->size % block_size) && !(fi->flags & FILE_FLAG_HAS_FRAGMENT))
++count;
while (count > 0 && fi->blocks[count - 1].size == 0)
--count;
return count;
}
static size_t find_first_match(file_info_t *file, file_info_t *cmp,
size_t idx, size_t cmp_blk_count)
{
size_t i;
for (i = 0; i < cmp_blk_count; ++i) {
if (memcmp(file->blocks + idx, cmp->blocks + i,
sizeof(file->blocks[idx])) == 0) {
break;
}
}
return i;
}
uint64_t find_equal_blocks(file_info_t *file, file_info_t *list,
size_t block_size)
{
size_t start, first_match, i, j, block_count, cmp_blk_count;
uint64_t location;
file_info_t *it;
block_count = get_block_count(file, block_size);
if (block_count == 0)
return 0;
for (start = 0; start < block_count; ++start) {
if (file->blocks[start].size != 0)
break;
}
for (it = list; it != NULL; it = it->next) {
if (it == file)
continue;
if (it->flags & FILE_FLAG_BLOCKS_ARE_DUPLICATE)
continue;
cmp_blk_count = get_block_count(it, block_size);
if (cmp_blk_count == 0)
continue;
first_match = find_first_match(file, it, start, cmp_blk_count);
if (first_match == cmp_blk_count)
continue;
i = start;
j = first_match;
while (i < block_count && j < cmp_blk_count) {
if (file->blocks[i].size == 0) {
++i;
continue;
}
if (it->blocks[j].size == 0) {
++j;
continue;
}
if (memcmp(it->blocks + j, file->blocks + i,
sizeof(file->blocks[i])) != 0) {
break;
}
++i;
++j;
}
if (i == block_count)
break;
}
if (it == NULL)
return 0;
location = it->startblock;
for (i = 0; i < first_match; ++i)
location += it->blocks[i].size & ((1 << 24) - 1);
return location;
}
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