/*
* Converts a VARCHAR2 type to the specified size.
*
* maxlen is the typmod, ie, declared length plus VARHDRSZ bytes.
* isExplicit is true if this is for an explicit cast to varchar2(N).
*
* Truncation rules: for an explicit cast, silently truncate to the given
* length; for an implicit cast, raise error if length limit is exceeded
*/
PGDLLEXPORT
Datum
varchar2(PG_FUNCTION_ARGS)
{
VarChar *source = PG_GETARG_VARCHAR_PP(0);
int32 typmod = PG_GETARG_INT32(1);
bool isExplicit = PG_GETARG_BOOL(2);
int32 len,
maxlen;
char *s_data;
len = VARSIZE_ANY_EXHDR(source);
s_data = VARDATA_ANY(source);
maxlen = typmod - VARHDRSZ;
/* No work if typmod is invalid or supplied data fits it already */
if (maxlen < 0 || len <= maxlen)
PG_RETURN_VARCHAR_P(source);
/* error out if value too long unless it's an explicit cast */
if (!isExplicit)
{
if (len > maxlen)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input value length is %d; too long for type varchar2(%d)",len ,maxlen)));
}
PG_RETURN_VARCHAR_P((VarChar *) cstring_to_text_with_len(s_data,maxlen));
}
/*
* Converts a NVARCHAR2 type to the specified size.
*
* maxlen is the typmod, ie, declared length plus VARHDRSZ bytes.
* isExplicit is true if this is for an explicit cast to nvarchar2(N).
*
* Truncation rules: for an explicit cast, silently truncate to the given
* length; for an implicit cast, raise error if length limit is exceeded
*/
Datum
nvarchar2(PG_FUNCTION_ARGS)
{
VarChar *source = PG_GETARG_VARCHAR_PP(0);
int32 typmod = PG_GETARG_INT32(1);
bool isExplicit = PG_GETARG_BOOL(2);
int32 len,
maxlen;
size_t maxmblen;
char *s_data;
len = VARSIZE_ANY_EXHDR(source);
s_data = VARDATA_ANY(source);
maxlen = typmod - VARHDRSZ;
/* No work if typmod is invalid or supplied data fits it already */
if (maxlen < 0 || len <= maxlen)
PG_RETURN_VARCHAR_P(source);
/* only reach here if string is too long... */
/* truncate multibyte string preserving multibyte boundary */
maxmblen = pg_mbcharcliplen(s_data, len, maxlen);
/* error out if value too long unless it's an explicit cast */
if (!isExplicit)
{
/* if there is still data beyond maxmblen, error out
*
* Remember - no blankspace truncation on implicit cast
*/
if (len > maxmblen)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input value too long for type nvarchar2(%d)", maxlen)));
}
PG_RETURN_VARCHAR_P((VarChar *) cstring_to_text_with_len(s_data, maxmblen));
}
