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/*-
* Copyright (c) 2008-2012 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __block_buffer_to_addr --
* Convert a filesystem address cookie into its components, UPDATING the
* caller's buffer reference so it can be called repeatedly to load a buffer.
*/
static int
__block_buffer_to_addr(WT_BLOCK *block,
const uint8_t **pp, off_t *offsetp, uint32_t *sizep, uint32_t *cksump)
{
uint64_t o, s, c;
WT_RET(__wt_vunpack_uint(pp, 0, &o));
WT_RET(__wt_vunpack_uint(pp, 0, &s));
WT_RET(__wt_vunpack_uint(pp, 0, &c));
/*
* To avoid storing large offsets, we minimize the value by subtracting
* 512B (the size of the description sector), and then storing a count
* of block allocation units. That implies there is no such thing as
* an "invalid" offset though, they could all be valid (other than very
* large numbers), which is what we didn't want to store in the first
* place. Use the size: writing a block of size 0 makes no sense, so
* that's the out-of-band value. Once we're out of this function and
* are working with a real file offset, size and checksum triplet, there
* are invalid offsets, that's simpler than testing sizes of 0 all over
* the place.
*/
if (s == 0) {
*offsetp = 0;
*sizep = *cksump = 0;
} else {
*offsetp = (off_t)o * block->allocsize + WT_BLOCK_DESC_SECTOR;
*sizep = (uint32_t)s * block->allocsize;
*cksump = (uint32_t)c;
}
return (0);
}
/*
* __wt_block_addr_to_buffer --
* Convert the filesystem components into its address cookie.
*/
int
__wt_block_addr_to_buffer(WT_BLOCK *block,
uint8_t **pp, off_t offset, uint32_t size, uint32_t cksum)
{
uint64_t o, s, c;
/* See the comment above: this is the reverse operation. */
if (size == 0) {
o = WT_BLOCK_INVALID_OFFSET;
s = c = 0;
} else {
o = (uint64_t)
(offset - WT_BLOCK_DESC_SECTOR) / block->allocsize;
s = size / block->allocsize;
c = cksum;
}
WT_RET(__wt_vpack_uint(pp, 0, o));
WT_RET(__wt_vpack_uint(pp, 0, s));
WT_RET(__wt_vpack_uint(pp, 0, c));
return (0);
}
/*
* __wt_block_buffer_to_addr --
* Convert a filesystem address cookie into its components NOT UPDATING
* the caller's buffer reference.
*/
int
__wt_block_buffer_to_addr(WT_BLOCK *block,
const uint8_t *p, off_t *offsetp, uint32_t *sizep, uint32_t *cksump)
{
return (__block_buffer_to_addr(block, &p, offsetp, sizep, cksump));
}
/*
* __wt_block_addr_valid --
* Return if an address cookie is valid.
*/
int
__wt_block_addr_valid(WT_SESSION_IMPL *session,
WT_BLOCK *block, const uint8_t *addr, uint32_t addr_size)
{
off_t offset;
uint32_t cksum, size;
WT_UNUSED(session);
WT_UNUSED(addr_size);
/* Crack the cookie. */
WT_RET(__wt_block_buffer_to_addr(block, addr, &offset, &size, &cksum));
/* All we care about is if it's past the end of the file. */
return (offset + size > block->fh->file_size ? 0 : 1);
}
/*
* __wt_block_addr_string --
* Return a printable string representation of an address cookie.
*/
int
__wt_block_addr_string(WT_SESSION_IMPL *session,
WT_BLOCK *block, WT_ITEM *buf, const uint8_t *addr, uint32_t addr_size)
{
off_t offset;
uint32_t cksum, size;
WT_UNUSED(addr_size);
/* Crack the cookie. */
WT_RET(__wt_block_buffer_to_addr(block, addr, &offset, &size, &cksum));
/* Printable representation. */
WT_RET(__wt_buf_fmt(session, buf,
"[%" PRIuMAX "-%" PRIuMAX ", %" PRIu32 ", %" PRIu32 "]",
(uintmax_t)offset, (uintmax_t)offset + size, size, cksum));
return (0);
}
/*
* __wt_block_buffer_to_snapshot --
* Convert a filesystem snapshot cookie into its components.
*/
int
__wt_block_buffer_to_snapshot(WT_SESSION_IMPL *session,
WT_BLOCK *block, const uint8_t *p, WT_BLOCK_SNAPSHOT *si)
{
uint64_t a;
const uint8_t **pp;
si->version = *p++;
if (si->version != WT_BM_SNAPSHOT_VERSION)
WT_RET_MSG(session, WT_ERROR, "illegal snapshot address");
pp = &p;
WT_RET(__block_buffer_to_addr(block, pp,
&si->root_offset, &si->root_size, &si->root_cksum));
WT_RET(__block_buffer_to_addr(block, pp,
&si->alloc.offset, &si->alloc.size, &si->alloc.cksum));
WT_RET(__block_buffer_to_addr(block, pp,
&si->avail.offset, &si->avail.size, &si->avail.cksum));
WT_RET(__block_buffer_to_addr(block, pp,
&si->discard.offset, &si->discard.size, &si->discard.cksum));
WT_RET(__wt_vunpack_uint(pp, 0, &a));
si->file_size = (off_t)a;
WT_RET(__wt_vunpack_uint(pp, 0, &a));
si->snapshot_size = a;
WT_RET(__wt_vunpack_uint(pp, 0, &a));
si->write_gen = a;
return (0);
}
/*
* __wt_block_snapshot_to_buffer --
* Convert the filesystem components into its snapshot cookie.
*/
int
__wt_block_snapshot_to_buffer(WT_SESSION_IMPL *session,
WT_BLOCK *block, uint8_t **pp, WT_BLOCK_SNAPSHOT *si)
{
uint64_t a;
if (si->version != WT_BM_SNAPSHOT_VERSION)
WT_RET_MSG(session, WT_ERROR, "illegal snapshot address");
(*pp)[0] = si->version;
(*pp)++;
WT_RET(__wt_block_addr_to_buffer(block, pp,
si->root_offset, si->root_size, si->root_cksum));
WT_RET(__wt_block_addr_to_buffer(block, pp,
si->alloc.offset, si->alloc.size, si->alloc.cksum));
WT_RET(__wt_block_addr_to_buffer(block, pp,
si->avail.offset, si->avail.size, si->avail.cksum));
WT_RET(__wt_block_addr_to_buffer(block, pp,
si->discard.offset, si->discard.size, si->discard.cksum));
a = (uint64_t)si->file_size;
WT_RET(__wt_vpack_uint(pp, 0, a));
a = (uint64_t)si->snapshot_size;
WT_RET(__wt_vpack_uint(pp, 0, a));
a = si->write_gen;
WT_RET(__wt_vpack_uint(pp, 0, a));
return (0);
}
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