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/* cdb_findnext.c: sequential cdb_find routines
*
* This file is a part of tinycdb package.
* Copyright (C) 2001-2023 Michael Tokarev <mjt+cdb@corpit.ru>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/* see cdb_find.c for comments */
#include "cdb_int.h"
int
cdb_findinit(struct cdb_find *cdbfp, struct cdb *cdbp,
const void *key, unsigned klen)
{
unsigned n, pos;
cdbfp->cdb_cdbp = cdbp;
cdbfp->cdb_key = key;
cdbfp->cdb_klen = klen;
cdbfp->cdb_hval = cdb_hash(key, klen);
cdbfp->cdb_htp = cdbp->cdb_mem + ((cdbfp->cdb_hval << 3) & 2047);
n = cdb_unpack(cdbfp->cdb_htp + 4);
cdbfp->cdb_httodo = n << 3;
if (!n)
return 0;
pos = cdb_unpack(cdbfp->cdb_htp);
if (n > (cdbp->cdb_fsize >> 3)
|| pos < cdbp->cdb_dend
|| pos > cdbp->cdb_fsize
|| cdbfp->cdb_httodo > cdbp->cdb_fsize - pos)
return errno = EPROTO, -1;
cdbfp->cdb_htab = cdbp->cdb_mem + pos;
cdbfp->cdb_htend = cdbfp->cdb_htab + cdbfp->cdb_httodo;
cdbfp->cdb_htp = cdbfp->cdb_htab + (((cdbfp->cdb_hval >> 8) % n) << 3);
return 1;
}
int
cdb_findnext(struct cdb_find *cdbfp) {
struct cdb *cdbp = cdbfp->cdb_cdbp;
unsigned pos, n;
unsigned klen = cdbfp->cdb_klen;
while(cdbfp->cdb_httodo) {
pos = cdb_unpack(cdbfp->cdb_htp + 4);
if (!pos)
return 0;
n = cdb_unpack(cdbfp->cdb_htp) == cdbfp->cdb_hval;
if ((cdbfp->cdb_htp += 8) >= cdbfp->cdb_htend)
cdbfp->cdb_htp = cdbfp->cdb_htab;
cdbfp->cdb_httodo -= 8;
if (n) {
if (pos > cdbp->cdb_fsize - 8)
return errno = EPROTO, -1;
if (cdb_unpack(cdbp->cdb_mem + pos) == klen) {
if (cdbp->cdb_fsize - klen < pos + 8)
return errno = EPROTO, -1;
if (memcmp(cdbfp->cdb_key,
cdbp->cdb_mem + pos + 8, klen) == 0) {
n = cdb_unpack(cdbp->cdb_mem + pos + 4);
pos += 8;
if (cdbp->cdb_fsize < n ||
cdbp->cdb_fsize - n < pos + klen)
return errno = EPROTO, -1;
cdbp->cdb_kpos = pos;
cdbp->cdb_klen = klen;
cdbp->cdb_vpos = pos + klen;
cdbp->cdb_vlen = n;
return 1;
}
}
}
}
return 0;
}
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