#include "postgres.h"
#include "executor/spi.h"

#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
typedef unsigned long ulong;
typedef unsigned char uchar;

void hash_password(ulong *result, const char *password)
{
        register ulong nr=1345345333L, add= 7 , nr2=0x12345671L;
        ulong tmp;
        for (; *password ; password++)
        {
                if (*password == ' ' || *password == '\t')
                        continue;     /* skipp space in password */
                tmp= (ulong) (uchar) *password;
                nr^= (((nr &  63 )+add)*tmp)+ (nr <<  8 ); 
                nr2+=(nr2 <<  8 ) ^ nr; 
                add+=tmp;
        }
        result[ 0 ]=nr & (((ulong) 1L <<  31 ) -1L); /* Don't use sign bit (str2int) */;
        result[ 1 ]=nr2 & (((ulong) 1L <<  31 ) -1L);
        return;
}

void make_scrambled_password(char *to,const char *password)
{
        ulong hash_res[ 2 ];
        hash_password(hash_res,password);
        sprintf(to,"%08lx%08lx",hash_res[ 0 ],hash_res[ 1 ]);
}

PG_FUNCTION_INFO_V1(password);
Datum password (PG_FUNCTION_ARGS)
{
        int len =  16 ;
        char *pwd = GET_STR (PG_GETARG_TEXT_P( 0 ));
        char buffer[ 17 ]="";
        text *res;
        make_scrambled_password (buffer, pwd);
        res = palloc(len + VARHDRSZ);
        memcpy(VARDATA(res), buffer, len);
        VARATT_SIZEP(res) = len + VARHDRSZ;
        PG_RETURN_TEXT_P(res);
}