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/*
* Copyright (c) 2016 Maxim Sobolev <sobomax@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <md5.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if defined(MKUZ_DEBUG)
# include <stdio.h>
#endif
#include "mkuz_blockcache.h"
struct mkuz_blkcache {
struct mkuz_blkcache_hit hit;
off_t data_offset;
unsigned char digest[16];
struct mkuz_blkcache *next;
};
static struct mkuz_blkcache blkcache;
struct mkuz_blkcache_hit *
mkuz_blkcache_regblock(int fd, uint32_t blkno, off_t offset, ssize_t len,
void *data)
{
struct mkuz_blkcache *bcep;
MD5_CTX mcontext;
off_t data_offset;
unsigned char mdigest[16];
data_offset = lseek(fd, 0, SEEK_CUR);
if (data_offset < 0) {
return (NULL);
}
MD5Init(&mcontext);
MD5Update(&mcontext, data, len);
MD5Final(mdigest, &mcontext);
if (blkcache.hit.len == 0) {
bcep = &blkcache;
} else {
for (bcep = &blkcache; bcep != NULL; bcep = bcep->next) {
if (bcep->hit.len != len)
continue;
if (memcmp(mdigest, bcep->digest, sizeof(mdigest)) == 0) {
break;
}
}
if (bcep != NULL) {
#if defined(MKUZ_DEBUG)
printf("cache hit %d, %d, %d\n", (int)bcep->hit.offset, (int)data_offset, (int)len);
#endif
return (&bcep->hit);
}
bcep = malloc(sizeof(struct mkuz_blkcache));
if (bcep == NULL)
return (NULL);
memset(bcep, '\0', sizeof(struct mkuz_blkcache));
bcep->next = blkcache.next;
blkcache.next = bcep;
}
memcpy(bcep->digest, mdigest, sizeof(mdigest));
bcep->data_offset = data_offset;
bcep->hit.offset = offset;
bcep->hit.len = len;
bcep->hit.blkno = blkno;
return (NULL);
}
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