Re: inet increment w/ int8 - Mailing list pgsql-hackers

Would you modify this so it can go in /contrib or pgfoundry?  Is there
general interest for this?

---------------------------------------------------------------------------

Ilya A. Kovalenko wrote:
>    Greetings,
> 
>   I suggest function for "inet" increment w/ int8 (signed).
> 
> FUNCTION inet_inc(int, int8) RETURNS inet
> 
> Function, useful for making address pools (using also
> existing "inet" compare functions to trap boundaries).
> 
> Notes:
>   This version lets address wrap around 0-*ff boundary.
>   Uses couple of non-POSIX functions - betoh64() and htobe64()
>   Tested on i386 with OpenBSD 3.7
>   PostgreSQL 8.0.2
> 
> -----------------------------------------------------
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <arpa/inet.h>
> 
> #include "postgres.h"                   /* general Postgres declarations */
> 
> #include "fmgr.h"                       /* for argument/result macros */
> #include "utils/inet.h"
> 
> Datum           inet_inc(PG_FUNCTION_ARGS);
> 
> //------ stolen from backend/utils/adt/network.c --------
> 
> #define ip_family(inetptr) \
>         (((inet_struct *)VARDATA(inetptr))->family)
> #define ip_bits(inetptr) \
>         (((inet_struct *)VARDATA(inetptr))->bits)
> #define ip_type(inetptr) \
>         (((inet_struct *)VARDATA(inetptr))->type)
> #define ip_addr(inetptr) \
>         (((inet_struct *)VARDATA(inetptr))->ipaddr)
> #define ip_maxbits(inetptr) \
>         (ip_family(inetptr) == PGSQL_AF_INET ? 32 : 128)
> 
> static int
> ip_addrsize(inet *inetptr)
> {
>         switch (ip_family(inetptr))
>         {
>                 case PGSQL_AF_INET:
>                         return 4;
>                 case PGSQL_AF_INET6:
>                         return 16;
>                 default:
>                         return 0;
>         }
> }
> //-------------------------------------------------------
> 
> PG_FUNCTION_INFO_V1(inet_inc);
> 
> Datum
> inet_inc(PG_FUNCTION_ARGS)
> {
>    inet    *src = PG_GETARG_INET_P(0);
>    int64    arg = PG_GETARG_INT64(1);
>    inet    *dst;
>    uint64   wsp;
> 
> // allocate destination structure
>    dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
> 
> // copy to destination
>    *((inet_struct *)VARDATA(dst)) = *((inet_struct *)VARDATA(src));
> 
>    if (ip_family(dst) == PGSQL_AF_INET)
>    {
> // Increment v4 address w/ item truncated to 32 bits
>       *((uint32*)(ip_addr(dst))) =
>           htonl(ntohl(*((int32*)(ip_addr(dst)))) + (int32)arg);
>    }
>    else
>    {
> // Increment v6 address low qword (store to workspace)
>       wsp = htobe64(betoh64(*((int64*)(ip_addr(dst) + 8))) + arg);
>       *((uint64*)(ip_addr(dst) + 8)) = wsp;
> 
> // Carry/borrow high qword
>       if ( arg > 0 && wsp < *((uint64*)(ip_addr(src) + 8)) )
>       {  *((int64*)(ip_addr(dst))) =
>              htobe64(betoh64(*((int64*)(ip_addr(dst)))) + 1);
>       }
>       else
>          if ( arg < 0 && wsp > *((uint64*)(ip_addr(src) + 8)) )
>          {  *((int64*)(ip_addr(dst))) =
>                 htobe64(betoh64(*((int64*)(ip_addr(dst)))) - 1);
>          }
>    }
> 
> // Return result
>    VARATT_SIZEP(dst) = VARHDRSZ
>           + ((char *) ip_addr(dst) - (char *) VARDATA(dst))
>           + ip_addrsize(dst);
> 
>    PG_RETURN_INET_P(dst);
> 
> }
> -----------------------------------------------------
> 
> Thank you
> 
> Ilya A. Kovalenko         (mailto:shadow@oganer.net)
> SpecialEQ SW section
> JSC Oganer-Service
> 
> P.S. Treat as Public Domain
> 
> 
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> 

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