On Fri, 26 Nov 1999, jose soares wrote:
> Try this:
>
> --returns the $2 field delimited by $3
> drop function field(text,int,text);
> create function field(text,int,text) returns text as
> 'declare
> string text;
> pos int2:= 0;
> pos1 int2:= 0;
> times int2:= 0;
> totpos int2:= 0;
> begin
> times:= $2 - 1;
> string:= $1;
> while totpos < times loop
> string:= substr(string,pos+1);
> pos:= strpos(string,$3);
> totpos:= totpos + 1;
> end loop;
> string:= substr(string,pos+1);
> pos1:= strpos(string,$3);
> return substr(string,1,pos1 - 1);
> end;
> ' language 'plpgsql';
>
Oh, it is great! But my implementation in C for this is
a little longer (only) :-)
I send this question to the hacker list because "extract delimited
substring" is not a abnormal uses's request, and (IMHO) will very
good if this will in PgSQL. How much uses known write this in
C or any PL?
'C' implementafion "extract delimited substring":
-----------------------------------------------
text
*strcut( text *string, char *d, int field )
{char *ptr = NULL, *p = NULL, *pe = NULL;text *result = NULL;int siz;ptr =
VARDATA(string);*(ptr+(VARSIZE(string) - VARHDRSZ)) = '\0';for(p = ptr; *p != '\0'; p++) { if (field == 1)
break; if (*p == (int) d) --field;} if (!*p) return textin(""); for(pe = p; *pe != '\0'; pe++) {
if(*pe == (int) d) break;} result = (text *) palloc(sizeof(text) * (siz = pe - p) +
VARHDRSZ);strncpy(VARDATA(result),p, siz);*(VARDATA(result) + siz) = '\0'; VARSIZE(result) = siz + VARHDRSZ;return
result;
}
CREATE FUNCTION strcut(text, char, int) RETURNS text AS '@module_dir@'
LANGUAGE 'c';
template1=> select strcut('aaa.bbb.ccc', '.', 2);
strcut
------
bbb
Karel
