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allow forcing or merge; unchanged support; add subtraction

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This commit is contained in:
Bob Halley
1999-06-16 21:03:07 +00:00
parent a7e185ff3f
commit 926cde044f
2 changed files with 148 additions and 3 deletions
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138
lib/dns/rdataslab.c
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@@ -15,7 +15,7 @@
* SOFTWARE.
*/
/* $Id: rdataslab.c,v 1.3 1999/04/01 04:00:39 halley Exp $ */
/* $Id: rdataslab.c,v 1.4 1999/06/16 21:03:07 halley Exp $ */
#include <config.h>
@@ -128,12 +128,13 @@ dns_result_t
dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
unsigned int reservelen, isc_mem_t *mctx,
dns_rdataclass_t rdclass, dns_rdatatype_t type,
unsigned char **tslabp)
isc_boolean_t force, unsigned char **tslabp)
{
unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent;
unsigned int ocount, ncount, count, olength, tlength, tcount, length;
isc_region_t oregion, nregion;
dns_rdata_t ordata, nrdata;
isc_boolean_t added_something = ISC_FALSE;
/*
* Merge 'oslab' and 'nslab'.
@@ -202,11 +203,15 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
*/
tlength += nregion.length + 2;
tcount++;
added_something = ISC_TRUE;
}
ncurrent += nregion.length;
ncount--;
} while (ncount > 0);
if (!added_something && !force)
return (DNS_R_UNCHANGED);
/*
* Copy the reserved area from the new slab.
*/
@@ -266,3 +271,132 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
return (DNS_R_SUCCESS);
}
dns_result_t
dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
unsigned int reservelen, isc_mem_t *mctx,
dns_rdataclass_t rdclass, dns_rdatatype_t type,
unsigned char **tslabp)
{
unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent;
unsigned int mcount, scount, count, tlength, tcount;
isc_region_t mregion, sregion;
dns_rdata_t srdata, mrdata;
/*
* Subtract 'sslab' from 'mslab'.
*/
REQUIRE(tslabp != NULL && *tslabp == NULL);
REQUIRE(mslab != NULL && sslab != NULL);
mcurrent = mslab + reservelen;
mcount = *mcurrent++ * 256;
mcount += *mcurrent++;
scurrent = sslab + reservelen;
scount = *scurrent++ * 256;
scount += *scurrent++;
sstart = scurrent;
INSIST(mcount > 0 && mcount > 0);
/*
* Yes, this is inefficient!
*/
/*
* Start figuring out the target length and count.
*/
tlength = reservelen + 2;
tcount = 0;
/*
* Add in the length of rdata in the mslab that aren't in
* the sslab.
*/
do {
mregion.length = *mcurrent++ * 256;
mregion.length += *mcurrent++;
mregion.base = mcurrent;
dns_rdata_fromregion(&mrdata, rdclass, type, &mregion);
scurrent = sstart;
for (count = 0; count < scount; count++) {
sregion.length = *scurrent++ * 256;
sregion.length += *scurrent++;
sregion.base = scurrent;
dns_rdata_fromregion(&srdata, rdclass, type, &sregion);
scurrent += sregion.length;
if (dns_rdata_compare(&mrdata, &srdata) == 0)
break;
}
if (count == scount) {
/*
* This rdata isn't in the sslab, and thus isn't
* being subtracted.
*/
tlength += mregion.length + 2;
tcount++;
}
mcurrent += mregion.length;
mcount--;
} while (mcount > 0);
/*
* Don't continue if the new rdataslab would be empty.
*/
if (tcount == 0)
return (DNS_R_NXRDATASET);
/*
* Copy the reserved area from the mslab.
*/
tstart = isc_mem_get(mctx, tlength);
if (tstart == NULL)
return (DNS_R_NOMEMORY);
memcpy(tstart, mslab, reservelen);
tcurrent = tstart + reservelen;
/*
* Write the new count.
*/
*tcurrent++ = (tcount & 0xff00) >> 8;
*tcurrent++ = (tcount & 0x00ff);
/*
* Copy the parts of mslab not in sslab.
*/
mcurrent = sslab + reservelen;
mcount = *mcurrent++ * 256;
mcount += *mcurrent++;
do {
mregion.length = *mcurrent++ * 256;
mregion.length += *mcurrent++;
mregion.base = mcurrent;
dns_rdata_fromregion(&mrdata, rdclass, type, &mregion);
scurrent = sstart;
for (count = 0; count < scount; count++) {
sregion.length = *scurrent++ * 256;
sregion.length += *scurrent++;
sregion.base = scurrent;
dns_rdata_fromregion(&srdata, rdclass, type, &sregion);
scurrent += sregion.length;
if (dns_rdata_compare(&mrdata, &srdata) == 0)
break;
}
if (count == scount) {
/*
* This rdata isn't in the sslab, and thus should be
* copied to the tslab.
*/
*tcurrent++ = (mregion.length & 0xff00) >> 8;
*tcurrent++ = (mregion.length & 0x00ff);
memcpy(tcurrent, mregion.base, mregion.length);
tcurrent += mregion.length;
}
mcurrent += mregion.length;
mcount--;
} while (mcount > 0);
*tslabp = tstart;
return (DNS_R_SUCCESS);
}