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/*-
* Copyright (c) 2014-2016 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __wt_struct_check --
* Check that the specified packing format is valid, and whether it fits
* into a fixed-sized bitfield.
*/
int
__wt_struct_check(WT_SESSION_IMPL *session,
const char *fmt, size_t len, bool *fixedp, uint32_t *fixed_lenp)
{
WT_DECL_PACK_VALUE(pv);
WT_DECL_RET;
WT_PACK pack;
int fields;
WT_RET(__pack_initn(session, &pack, fmt, len));
for (fields = 0; (ret = __pack_next(&pack, &pv)) == 0; fields++)
;
if (ret != WT_NOTFOUND)
return (ret);
if (fixedp != NULL && fixed_lenp != NULL) {
if (fields == 0) {
*fixedp = 1;
*fixed_lenp = 0;
} else if (fields == 1 && pv.type == 't') {
*fixedp = 1;
*fixed_lenp = pv.size;
} else
*fixedp = 0;
}
return (0);
}
/*
* __wt_struct_confchk --
* Check that the specified packing format is valid, configuration version.
*/
int
__wt_struct_confchk(WT_SESSION_IMPL *session, WT_CONFIG_ITEM *v)
{
return (__wt_struct_check(session, v->str, v->len, NULL, NULL));
}
/*
* __wt_struct_size --
* Calculate the size of a packed byte string.
*/
int
__wt_struct_size(WT_SESSION_IMPL *session, size_t *sizep, const char *fmt, ...)
{
WT_DECL_RET;
va_list ap;
va_start(ap, fmt);
ret = __wt_struct_sizev(session, sizep, fmt, ap);
va_end(ap);
return (ret);
}
/*
* __wt_struct_pack --
* Pack a byte string.
*/
int
__wt_struct_pack(WT_SESSION_IMPL *session,
void *buffer, size_t size, const char *fmt, ...)
{
WT_DECL_RET;
va_list ap;
va_start(ap, fmt);
ret = __wt_struct_packv(session, buffer, size, fmt, ap);
va_end(ap);
return (ret);
}
/*
* __wt_struct_unpack --
* Unpack a byte string.
*/
int
__wt_struct_unpack(WT_SESSION_IMPL *session,
const void *buffer, size_t size, const char *fmt, ...)
{
WT_DECL_RET;
va_list ap;
va_start(ap, fmt);
ret = __wt_struct_unpackv(session, buffer, size, fmt, ap);
va_end(ap);
return (ret);
}
/*
* __wt_struct_unpack_size --
* Determine the packed size of a buffer matching the format.
*/
int
__wt_struct_unpack_size(WT_SESSION_IMPL *session,
const void *buffer, size_t size, const char *fmt, size_t *resultp)
{
WT_DECL_PACK_VALUE(pv);
WT_DECL_RET;
WT_PACK pack;
const uint8_t *p, *end;
p = buffer;
end = p + size;
WT_RET(__pack_init(session, &pack, fmt));
while ((ret = __pack_next(&pack, &pv)) == 0)
WT_RET(__unpack_read(session, &pv, &p, (size_t)(end - p)));
/* Be paranoid - __pack_write should never overflow. */
WT_ASSERT(session, p <= end);
if (ret != WT_NOTFOUND)
return (ret);
*resultp = WT_PTRDIFF(p, buffer);
return (0);
}
/*
* __wt_struct_repack --
* Return the subset of the packed buffer that represents part of
* the format. If the result is not contiguous in the existing
* buffer, a buffer is reallocated and filled.
*/
int
__wt_struct_repack(WT_SESSION_IMPL *session, const char *infmt,
const char *outfmt, const WT_ITEM *inbuf, WT_ITEM *outbuf, void **reallocp)
{
WT_DECL_PACK_VALUE(pvin);
WT_DECL_PACK_VALUE(pvout);
WT_DECL_RET;
WT_PACK packin, packout;
const uint8_t *before, *end, *p;
uint8_t *pout;
size_t len;
const void *start;
start = NULL;
p = inbuf->data;
end = p + inbuf->size;
/*
* Handle this non-contiguous case: 'U' -> 'u' at the end of the buf.
* The former case has the size embedded before the item, the latter
* does not.
*/
if ((len = strlen(outfmt)) > 1 && outfmt[len - 1] == 'u' &&
strlen(infmt) > len && infmt[len - 1] == 'U') {
WT_ERR(__wt_realloc(session, NULL, inbuf->size, reallocp));
pout = *reallocp;
} else
pout = NULL;
WT_ERR(__pack_init(session, &packout, outfmt));
WT_ERR(__pack_init(session, &packin, infmt));
/* Outfmt should complete before infmt */
while ((ret = __pack_next(&packout, &pvout)) == 0) {
if (p >= end)
WT_ERR(EINVAL);
WT_ERR(__pack_next(&packin, &pvin));
before = p;
WT_ERR(__unpack_read(session, &pvin, &p, (size_t)(end - p)));
if (pvout.type != pvin.type) {
if (pvout.type == 'u' && pvin.type == 'U') {
/* Skip the prefixed size, we don't need it */
WT_ERR(__wt_struct_unpack_size(session, before,
(size_t)(end - before), "I", &len));
before += len;
} else
WT_ERR(ENOTSUP);
}
if (pout != NULL) {
memcpy(pout, before, WT_PTRDIFF(p, before));
pout += p - before;
} else if (start == NULL)
start = before;
}
WT_ERR_NOTFOUND_OK(ret);
/* Be paranoid - __pack_write should never overflow. */
WT_ASSERT(session, p <= end);
if (pout != NULL) {
outbuf->data = *reallocp;
outbuf->size = WT_PTRDIFF(pout, *reallocp);
} else {
outbuf->data = start;
outbuf->size = WT_PTRDIFF(p, start);
}
err: return (ret);
}
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