81 lines
2 KiB
C
81 lines
2 KiB
C
/* cdb_findnext.c: sequential cdb_find routines
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*
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* This file is a part of tinycdb package by Michael Tokarev, mjt+cdb@corpit.ru.
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* Public domain.
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*/
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/* see cdb_find.c for comments */
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#include "cdb_int.h"
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int
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cdb_findinit(struct cdb_find *cdbfp, struct cdb *cdbp,
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const void *key, unsigned klen)
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{
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unsigned n, pos;
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cdbfp->cdb_cdbp = cdbp;
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cdbfp->cdb_key = key;
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cdbfp->cdb_klen = klen;
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cdbfp->cdb_hval = cdb_hash(key, klen);
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cdbfp->cdb_htp = cdbp->cdb_mem + ((cdbfp->cdb_hval << 3) & 2047);
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n = cdb_unpack(cdbfp->cdb_htp + 4);
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cdbfp->cdb_httodo = n << 3;
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if (!n)
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return 0;
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pos = cdb_unpack(cdbfp->cdb_htp);
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if (n > (cdbp->cdb_fsize >> 3)
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|| pos < cdbp->cdb_dend
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|| pos > cdbp->cdb_fsize
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|| cdbfp->cdb_httodo > cdbp->cdb_fsize - pos)
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return errno = EPROTO, -1;
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cdbfp->cdb_htab = cdbp->cdb_mem + pos;
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cdbfp->cdb_htend = cdbfp->cdb_htab + cdbfp->cdb_httodo;
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cdbfp->cdb_htp = cdbfp->cdb_htab + (((cdbfp->cdb_hval >> 8) % n) << 3);
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return 1;
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}
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int
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cdb_findnext(struct cdb_find *cdbfp) {
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struct cdb *cdbp = cdbfp->cdb_cdbp;
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unsigned pos, n;
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unsigned klen = cdbfp->cdb_klen;
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while(cdbfp->cdb_httodo) {
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pos = cdb_unpack(cdbfp->cdb_htp + 4);
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if (!pos)
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return 0;
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n = cdb_unpack(cdbfp->cdb_htp) == cdbfp->cdb_hval;
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if ((cdbfp->cdb_htp += 8) >= cdbfp->cdb_htend)
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cdbfp->cdb_htp = cdbfp->cdb_htab;
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cdbfp->cdb_httodo -= 8;
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if (n) {
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if (pos > cdbp->cdb_fsize - 8)
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return errno = EPROTO, -1;
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if (cdb_unpack(cdbp->cdb_mem + pos) == klen) {
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if (cdbp->cdb_fsize - klen < pos + 8)
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return errno = EPROTO, -1;
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if (memcmp(cdbfp->cdb_key,
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cdbp->cdb_mem + pos + 8, klen) == 0) {
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n = cdb_unpack(cdbp->cdb_mem + pos + 4);
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pos += 8;
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if (cdbp->cdb_fsize < n ||
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cdbp->cdb_fsize - n < pos + klen)
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return errno = EPROTO, -1;
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cdbp->cdb_kpos = pos;
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cdbp->cdb_klen = klen;
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cdbp->cdb_vpos = pos + klen;
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cdbp->cdb_vlen = n;
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return 1;
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}
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}
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}
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}
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return 0;
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}
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